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You searched for: Subject females Remove constraint Subject: females Subject term dimorphism Remove constraint Subject term: dimorphism
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1. Dimorphic Foraging Strategies of a Salticid Spider (Phidippus Audax)

Author:
Robert P. Givens
Source:
Ecology 1978 v.59 no.2 pp. 309-321
ISSN:
0012-9658
Subject:
Dermestes; Diptera; Oncopeltus fasciatus; Phidippus audax; Photuris; adults; biomass; cephalothorax; dimorphism; eggs; feeding methods; females; foraging; lightning; males; satiety; sclerotization
Abstract:
... Adult ♂ and ♀ Phidippus audax (Salticidae) have different feeding strategies reflecting major differences in their time budgets and food requirements. Males are 89% as large as ♀ ♀ (measured by cephalothorax width), but size dimorphism is insufficient to account for differences between their rate and pattern of feeding on flies provided experimentally. The ♂ ♂ feed at a uniformly low rate througho ...
DOI:
10.2307/1936376

2. Sex and Gender Dynamics in Jack‐in‐the‐Pulpit, Arisaema Triphyllum (Araceae)

Author:
Jon Lovett Doust; Paul B. Cavers
Source:
Ecology 1982 v.63 no.3 pp. 797-808
ISSN:
0012-9658
Subject:
Arisaema triphyllum; biomass; body size; dimorphism; environmental factors; females; flowering; fruiting; males; models; nutrient content; phenology; sex reversal; soil nutrients; soil pH; survival rate
Abstract:
... Eleven populations of Arisaema triphyllum (L.) Schott (jack—in—the—pulpit) were studied in 1978—1979. There was a range of population gender ratios, from strongly female biased to strongly male biased; gender dimorphism with respect to body size and phenology was found. The proportion of a plant's biomass found in reproductive and ancillary reproductive organs was determined for plants of each gen ...
DOI:
10.2307/1936800

3. The mating systems of pinnipeds and marine iguanas: convergent evolution of polygyny

Author:
TRILLMICH, FRITZ; TRILLMICH, KRISZTINA G.K.
Source:
Biological journal of the Linnean Society 1984 v.21 no.1/2 pp. 209-216
ISSN:
0024-4066
Subject:
Otariidae; convergent evolution; dimorphism; fasting; females; foods; habitats; islands; males; mating systems; polygyny; predation; predators; risk; seals; territoriality; thermoregulation
Abstract:
... The convergent polygynous mating systems of marine iguanas and otariid pinnipeds depend on the existence of large female aggregations. These can build up where abundant marine food resources occur around oceanic islands which harbour fewer predators than continental areas. For marine iguanas distribution of food resources appears to determine the location of colonies, while for pinnipeds habitat c ...
DOI:
10.1111/j.1095-8312.1984.tb02062.x

4. The Evolution of Flightlessness in Insects

Author:
Derek A. Roff
Source:
Ecological monographs 1990 v.60 no.4 pp. 389-421
ISSN:
0012-9615
Subject:
Hymenoptera; Lepidoptera; Orthoptera; adults; altitude; aquatic habitat; arthropods; autumn; deserts; dimorphism; dunes; eclosion; ectoparasites; egg production; endothermy; evolution; females; forests; insect flight; insects; islands; larvae; latitude; males; metamorphosis; mutation; parthenogenesis; phoresy; ponds; probability; rivers; spring; streams; temperature; termite mounds; winter; woodlands
Abstract:
... Many pterygote (winged) insects have secondarily become flightless; why has this occurred? In this paper I test for an association between the frequency of flightlessness and (1) environmental heterogeneity, (2) geographic variables, (3) gender, (4) alternate modes of migration, and (5) taxonomic variation. Various authors have predicted that decreased environmental heterogeneity will favor the ev ...
DOI:
10.2307/1943013

5. Function and evolution of the frill of the frillneck lizard, Chlamydosaurus kingii (Sauria: Agamidae)

Author:
SHINE, RICHARD
Source:
Biological journal of the Linnean Society 1990 v.40 no.1 pp. 11-20
ISSN:
0024-4066
Subject:
Agamidae; body size; dimorphism; females; forelimbs; lizards; males; predators; sexual selection; thermoregulation
Abstract:
... Relative to body size, the frill of the Australian agamid lizard Chlamydosaurus kingii is one of the largest and most spectacular display structures seen in any animal species. More than 300 hours observation of free-ranging lizards, combined with data on museum specimens, revealed that the frill is used primarily for intraspecific communication and predator deterrence. Earlier hypotheses on alter ...
DOI:
10.1111/j.1095-8312.1990.tb00531.x

6. The occurrence of sexual reproduction among ant workers

Author:
Peeters, C.
Source:
Biological journal of the Linnean Society 1991 v.44 no.2 pp. 141-152
ISSN:
0024-4066
Subject:
dimorphism; nests; fecundity; males; social behavior; sexual reproduction; Formicidae; females
Abstract:
... In less than 100 species of ponerine ants, queens no longer exist and have been replaced by mated egg-laying workers. Workers in other subfamilies can lay haploid eggs when queens are removed, but they never reproduce sexually. Ponerine workers are able to mate because they have a spermatheca in most species, foreign males are sexually active near their nests, and their pygidial gland secretions c ...
DOI:
10.1111/j.1095-8312.1991.tb00612.x

7. Adaptive significance of wing dimorphism in males of Nilaparvata lugens

Author:
Novotný, V.
Source:
Entomologia experimentalis et applicata 1995 v.76 no.3 pp. 233-239
ISSN:
0013-8703
Subject:
Nilaparvata lugens; body weight; dimorphism; females; habitats; juvenile hormones; males; morphs; population density
Abstract:
... The trade-offs associated with macroptery in males were investigated in a wing-dimorphic planthopper, Nilaparvata lugens (Stål) (Delphacidae, Hemiptera). Developmental time of brachypters was significantly shorter than that of macropters across a wide range of population densities, while no within-population differences between wing morphs in body weight were found. In mating experiments, brachypt ...
DOI:
10.1111/j.1570-7458.1995.tb01967.x

8. Evolution of reversed sex roles, sexual size dimorphism, and mating system in coucals (Centropodidae, Aves)

Author:
ANDERSSON, MALTE
Source:
Biological journal of the Linnean Society 1995 v.54 no.2 pp. 173-181
ISSN:
0024-4066
Subject:
foods; dimorphism; nests; males; eggs; habitats; sexual selection; Cuculiformes; polyandry; mating systems; chicks; clutch size; females
Abstract:
... The evolution of greater male than female parental care remains poorly understood. In birds it is thought to be related to precocial chicks and small clutch size. This review shows, however, that such role reversal has also evolved in a family with altricial young and relatively large clutch size: coucals (Centropodidae, Cuculiformes). Males perform most nest building, incubation, and feeding of y ...
DOI:
10.1111/j.1095-8312.1995.tb01030.x

9. Gender Specialization Across a Climatic Gradient: Experimental Comparison of Monoecious and Dioecious Ecballium

Author:
Denise E. Costich
Source:
Ecology 1995 v.76 no.4 pp. 1036-1050
ISSN:
0012-9658
Subject:
Ecballium elaterium; arid zones; canopy; dimorphism; dioecy; evolution; female flowers; females; fruits; gardens; habitats; heterozygosity; life history; male flowers; males; outcrossing; seeds; Iberian Peninsula; Spain
Abstract:
... The ecological basis for breeding—system evolution was explored in Ecballium elaterium (L.) A. Rich. (Cucurbitaceae). Two subspecies are parapatric on the Iberian Peninsula: dioicum (dioecious) is found in southern, more arid regions and elaterium (monoecious) is found in northern, wetter regions. Six experimental gardens were set up in three sites that span the climatic gradient of the species' n ...
DOI:
10.2307/1940914

10. Ornaments or offspring: costs to reproductive success restrict sexual selection processes

Author:
Susan Fitzpatrick; Anders Berglund; Gunilla Rosenqvist
Source:
Biological journal of the Linnean Society 1995 v.55 no.3 pp. 251-260
ISSN:
0024-4066
Subject:
dimorphism; fecundity; females; males; progeny; reproductive success; sexual selection
Abstract:
... If, in their partner choice, males seek direct benefits (fecund females), the result will be selection for traits indicating female quality rather than for arbitrary (Fisherian) traits. However, the costs of developing and maintaining the sexually selected traits (ornaments) may reduce the resources available to the female for allocation to reproduction and hence result in lower reproductive succe ...
DOI:
10.1111/j.1095-8312.1995.tb01063.x

11. Timing of ornament growth, phenotypic variation, and size dimorphism in two promiscuous African whydahs (Ploceidae: Vidua)

Author:
BARNARD, PHOEBE
Source:
Biological journal of the Linnean Society 1995 v.55 no.2 pp. 129-141
ISSN:
0024-4066
Subject:
Fringillidae; Ploceidae; body size; dimorphism; females; males; molting; phenotypic variation; sexual selection; tail; temporal variation
Abstract:
... Variation within populations is a prerequisite for the action of selection on morphological traits. Darwin assumed that there was much greater variation in sexual ornament size than in body size, but this may not be generally true of natural populations. I analyse field data on variation in body size and the length, area and mass of tail ornaments in paradise (Vidua paradisaea) and shaft-tailed wh ...
DOI:
10.1111/j.1095-8312.1995.tb01055.x

12. Sexual size dimorphism and phylogeny in North American minnows

Author:
Mark Pyron
Source:
Biological journal of the Linnean Society 1996 v.57 no.4 pp. 327-341
ISSN:
0024-4066
Subject:
branches; dimorphism; females; males; mating systems; minnows; models; phylogeny; probability; sperm competition
Abstract:
... Sexual size dimorphism (SSD) is predicted to vary across mating systems. A previous study examined a model of SSD in fishes as it relates to three mating system variables: probability of sperm competition, male territorial guarding, and male‐male contest. I tested the ability of these variables to predict SSD in North American freshwater minnows, after controlling for phylogenetic effects by an ...
DOI:
10.1111/j.1095-8312.1996.tb01854.x

13. Covariation of sexual size dimorphism and adult sex ratio in parasitic nematodes

Author:
Poulin, Robert
Source:
Biological journal of the Linnean Society 1997 v.62 no.4 pp. 567-580
ISSN:
0024-4066
Subject:
Nematoda; body size; dimorphism; fecundity; females; invertebrates; males; sex ratio; sexual selection; vertebrates
Abstract:
... Females are larger than males in most invertebrate taxa, a phenomenon believed to result from the pressures exerted on female body size by size-dependent fecundity. Male-male competition, which can act on male body size, is not thought to play as important a role in the evolution of sexual size dimorphism in invertebrates as it apparently does in some vertebrate groups. Here, using a comparative a ...
DOI:
10.1111/j.1095-8312.1997.tb00322.x

14. Feeding behaviour, digestive physiology and lipid content in macropterous females of Pyrrhocoris apterus (L.) (Heteroptera: Pyrrhocoridae)

Author:
Socha, R.; Sula, J.; Zemek, R.
Source:
Physiological entomology 1998 v.23 no.1 pp. 91-96
ISSN:
0307-6962
Subject:
temporal variation; females; drinking; dimorphism; reproduction; glycogen; fat body; lipids; diapause; hemolymph; digestive tract; feeding behavior; digestive enzymes; Pyrrhocoris apterus; wings; enzyme activity
Abstract:
... Macropterous females of Pyrrhocoris apterus (L.) reared under short-day conditions (LD 12:12 h) were analysed for temporal patterns of feeding and drinking behaviour, activities of digestive enzymes in the gut, and lipid and glycogen content in the haemolymph and fat body. Peaks of drinking activity were recorded at days 3, 7 and 10 during the first 14 days after imaginal ecdysis. Feeding activity ...
DOI:
10.1046/j.1365-3032.1998.2310091.x

15. Differences in adipokinetic response of Pyrrhocoris apterus (Heteroptera) in relation to wing dimorphism and diapause

Author:
Socha, R.; Kodrik, D.
Source:
Physiological entomology 1999 v.24 no.3 pp. 278-284
ISSN:
0307-6962
Subject:
Pyrrhocoris apterus; Locusta migratoria; Manduca sexta; injection; wings; dimorphism; diapause; hormonal regulation; hemolymph; lipids; females
Abstract:
... Three experimental groups of adult females (reproductive and diapausing brachypters, and macropters with reproductive arrest) of Pyrrhocoris apterus (Linnaeus) (Heteroptera: Pyrrhocoridae) from a temperate population were analysed for their adipokinetic responses. The adipokinetic response, expressed as an increase of haemolymph lipids after injection of adipokinetic hormone from Locusta migratori ...
DOI:
10.1046/j.1365-3032.1999.00143.x

16. Reproductive conflict and division of labor in Eutetramorium mocquerysi, a myrmicine ant without morphologically distinct female reproductives

Author:
Heinze, J.; Holldobler, B.; Alpert, G.
Source:
Ethology 1999 v.105 no.8 pp. 701-717
ISSN:
0179-1613
Subject:
caste determination; dimorphism; oviposition; aggression; ovarioles; social dominance; Formicidae; females; Madagascar
DOI:
10.1046/j.1439-0310.1999.00450.x

17. Age and growth of the ajime-loach,niwaella delicata, in the yura river, kyoto, japan

Author:
Yuichi Kano
Source:
Ichthyological research 2000 v.47 no.2 pp. 183-186
ISSN:
1341-8998
Subject:
Cobitidae; dimorphism; females; indigenous species; males; rivers; sexual maturity; Japan
Abstract:
... The age of the Ajime-loach,Niwaella delicata (a species endemic to Japan), was determined from the number of concentric rings appearing on the cross-sectional surface of the erectile spine (peculiar to Cobitidae). The ages of loaches caught in the Yura River, Kyoto, were determined and growth rates for each sex estimated. It was found that size dimorphism in this species was due to different growt ...
DOI:
10.1007/BF02684239

18. Factors driving extreme sexual size dimorphism of a sit-and-wait predator under low density

Author:
LEGRAND, REBECCA S.; MORSE, DOUGLASS H.
Source:
Biological journal of the Linnean Society 2000 v.71 no.4 pp. 643-664
ISSN:
0024-4066
Subject:
Thomisidae; dimorphism; fecundity; females; flowers; males; mating behavior; predators; protandry; reproductive traits; sex ratio; sexual selection
Abstract:
... Sexual size dimorphism is often a likely outcome of the interplay between natural selection and sexual selection, with female size dictated primarily by natural selection that maximizes fecundity and male size by sexual selection that maximizes reproductive opportunities. Attention to male fitness has focused heavily on direct male-male conflict selecting for superior male size and/or fighting abi ...
DOI:
10.1111/j.1095-8312.2000.tb01283.x

19. Genetic variability in sexually dimorphic and monomorphic populations of Populus euphratica (Salicaceae)

Author:
Rottenberg, A.; Nevo, E.; Zohary, D.
Source:
Canadian journal of forest research = 2000 v.30 no.3 pp. 482-486
ISSN:
0045-5067
Subject:
founder effect; dimorphism; loci; alleles; enzyme polymorphism; males; asexual reproduction; sex ratio; genetic variation; population; isozymes; genetic polymorphism; females; Israel
Abstract:
... The genetic polymorphism of three populations of the dioecious riparian tree Populus euphratica Oliv. In Israel was examined with isozyme tests. Twelve enzyme systems revealed 20 putative loci, of which 13 were polymorphic. A centrally located population (comprising both females and males) was sampled, as well as two small peripheral and isolated stands: one comprised of only females and one conta ...
DOI:
10.1139/x99-230

20. Sex-related Differences in Migration Chronology and Winter Habitat Use of Common Snipe

Author:
McCloskey Jon T.; Thompson Jonathan E.
Source:
Wilson bulletin 2000 v.112 no.1 pp. 143-148
ISSN:
0043-5643
Subject:
Gallinago; autumn; breeding sites; coasts; dimorphism; females; gender differences; habitat preferences; habitats; males; marshes; paddies; sex ratio; spring; winter; wintering grounds; Texas
Abstract:
... There is little information concerning differences in migration chronology between male and female Common Snipe (Gallinago gallinago) and virtually no accounts of sex-related differences in winter habitat use. We collected 372 Common Snipe in five different habitat types during the non-breeding period along the central Gulf Coast of Texas. Proportions of male and female snipe collected on winterin ...
DOI:
10.1676/0043-5643(2000)112[0143:SRDIMC]2.0.CO;2

21. Sexual size dimorphism of the musk duck

Author:
McCracken Kevin G.; Paton David C.; Afton Alan D.
Source:
Wilson bulletin 2000 v.112 no.4 pp. 457-466
ISSN:
0043-5643
Subject:
dimorphism; ducks; females; foraging; males; multivariate analysis; Australia
Abstract:
... We examined sexual size dimorphism of a lek-displaying diving duck from Australia, the Musk Duck (Biziura lobata). Like other lek-displaying species, Musk Ducks exhibit extreme sexual size dimorphism in addition to structural dimorphism. Body mass ratios (male:female) for Musk Ducks are among the highest reported for birds (more than 3:1). Multivariate analyses of 16 anatomical measurements indica ...
DOI:
10.1676/0043-5643(2000)112[0457:SSDOTM]2.0.CO;2

22. Ecological differentiation of combined and separate sexes of wurmbea dioica (colchicaceae) in sympatry

Author:
Andrea L. Case; Spencer C. H. Barrett
Source:
Ecology 2001 v.82 no.9 pp. 2601-2616
ISSN:
0012-9658
Subject:
Colchicaceae; carbon; roots; carbon dioxide; genetic factors; nitrogen content; isotopes; males; transpiration; photosynthesis; females; stomatal movement; sympatry; dimorphism; sexual systems; soil water; biomass; dry matter partitioning; nitrogen; corms; stomata; Australia
Abstract:
... The evolution and maintenance of combined vs. separate sexes in flowering plants is influenced by both ecological and genetic factors; variation in resources, particularly moisture availability, is thought to play a role in selection for gender dimorphism in some groups. We investigated the density, distribution, biomass allocation, and physiology of sympatric monomorphic (cosexual) and dimorphic ...
DOI:
10.1890/0012-9658(2001)082[2601:EDOCAS]2.0.CO;2

23. Mandibular allometry and male dimorphism in a group of obligately mycophagous beetles (Insecta: Coleoptera: Staphylinidae: Oxyporinae)

Author:
HANLEY, RODNEY S.
Source:
Biological journal of the Linnean Society 2001 v.72 no.3 pp. 451-459
ISSN:
0024-4066
Subject:
Staphylinidae; allometry; dimorphism; females; males; maneuverability
Abstract:
... Analyses of seven species of the obligately mycophagous staphylinid beetle genus Oxyporus indicate that five species display male mandibular allometry. Among species with dimorphic separations, two general allometric patterns were observed: (1) change in mandibular length at a hypothesized switch point is discontinuous rather than continuous, and (2) the linear slope of mandibular length versus el ...
DOI:
10.1111/j.1095-8312.2001.tb01330.x

24. A darkling beetle population in West Texas during the 1997–1998 El Niño

Author:
Deslippe, Richard J.; Salazar, Jesus R.; Guo, Yu-Jie
Source:
Journal of arid environments 2001 v.49 no.4 pp. 711-721
ISSN:
0140-1963
Subject:
Eleodes; autumn; climatic factors; dimorphism; drought; dry environmental conditions; females; grasslands; males; population structure; sand; semiarid zones; sex ratio; spring; Texas
Abstract:
... TWe examined the abundance and distribution of Eleodes extricata (Tenebrionidae) in a semi-arid region of West Texas. During the 2-year study, climatic conditions were extreme but opposite, with 1997 being unusually wet and mild, and 1998 being unusually dry and hot. These conditions were associated with striking differences in the population structure of the beetles. Under identical pitfall-sampl ...
DOI:
10.1006/jare.2001.0821

25. Mating success in the spittlebug Cercopis sanguinolenta (Scopoli, 1763) (Homoptera, Cercopidae): the role of body size and mobility

Author:
Robert Biedermann
Source:
Journal of ethology 2002 v.20 no.1 pp. 13-18
ISSN:
0289-0771
Subject:
Cercopidae; body size; covariance; dimorphism; females; insects; males; mating behavior; polygyny; sexual selection
Abstract:
... In insects, a sexual size dimorphism commonly occurs, with larger females. However, as a deviation from this general rule, larger males are found in some species. In these species often sexual selection for large males has been presumed. The spittlebug Cercopis sanguinolenta exhibits a distinct sexual size dimorphism with larger males. Mating behaviour was studied in a field population in respect ...
DOI:
10.1007/s10164-002-0048-9

26. Sexual dichromatism and differential conspicuousness in two populations of the common collared lizard (Crotaphytus collaris) from Utah and New Mexico, USA

Author:
Joseph M. Macedonia; Yoni Brandt; David L. Clark
Source:
Biological journal of the Linnean Society 2002 v.77 no.1 pp. 67-85
ISSN:
0024-4066
Subject:
color; dimorphism; females; habitats; lizards; males; predators; prey species; reflectance spectroscopy; rocks; social behavior; New Mexico; Utah
Abstract:
... The common collared lizard (Crotaphytus collaris) exhibits considerable geographical colour variation, particularly among males. Populations of this diurnal saxicolous iguanian inhabit patches of rocky habitat throughout the species' broad distribution in North America and are anticipated to experience local differences in selective pressures that influence colouration. Specifically, while social ...
DOI:
10.1046/j.1095-8312.2002.00092.x

27. Sexual differences in body size of Common Tern (Sterna hirundo) fledglings

Author:
Peter H. Becker; Michael Winke
Source:
Journal für Ornithologie 2002 v.143 no.1 pp. 51-56
ISSN:
0021-8375
Subject:
adults; body weight; coasts; dimorphism; females; fledglings; starvation; North Sea
Abstract:
... We studied wing-length, head-bill-length, sternum-length and body mass of Common Tern fledgling cadavers from a colony in Wilhelmshaven on the German North Sea coast, relative to sex, which was determined by PCR. The masses after death indicated that the birds had died of starvation. The body measurements indicated post-fledging growth. The dimorphism in head-bill length, which was longer in adult ...
DOI:
10.1007/BF02465458

28. Egg size and laying order in relation to offspring sex in the extreme sexually size dimorphic brown songlark, Cinclorhamphus cruralis

Author:
Michael J. L. Magrath; Lyanne Brouwer; Jan Komdeur
Source:
Behavioral ecology and sociobiology 2003 v.54 no.3 pp. 240-248
ISSN:
0340-5443
Subject:
daughters; prediction; dimorphism; mothers; polygyny; starvation; brothers; eggs; sex ratio; food availability; hatching; nutrient reserves; chicks; females; nestlings
Abstract:
... In some bird species, mothers can advantage the offspring of one sex either by elevating them in the laying order to promote earlier hatching or by allocating greater resources to eggs of the preferred sex. In size dimorphic species, the predictions as to which sex should benefit most from such pre-laying adjustments are ambiguous. The smaller sex would benefit from an initial size advantage to he ...
DOI:
10.1007/s00265-003-0627-y

29. Fitness consequences of sexual cannibalism in female Argiope bruennichi

Author:
Lutz Fromhage; Gabriele Uhl; Jutta M. Schneider
Source:
Behavioral ecology and sociobiology 2003 v.55 no.1 pp. 60-64
ISSN:
0340-5443
Subject:
Argiope bruennichi; aggression; cannibalism; clutch size; copulation; dimorphism; evolution; fecundity; females; foraging; hatching; males; models; nutritive value
Abstract:
... The evolution of sexual cannibalism as the most extreme form of nuptial feeding is still poorly understood. Although increasing evidence suggests that female aggressiveness is related to other aspects of foraging behaviour, it is not clear whether the nutritional value of a male is sufficient to provide an adaptive significance for sexual cannibalism. A widely cited though rarely tested explanatio ...
DOI:
10.1007/s00265-003-0656-6

30. Reproductive conflict in animal societies: hierarchy length increases with colony size in queenless ponerine ants

Author:
Thibaud Monnin; Francis L. W. Ratnieks; Carlos R. F. Brandão
Source:
Behavioral ecology and sociobiology 2003 v.54 no.1 pp. 71-79
ISSN:
0340-5443
Subject:
Dinoponera; alloparental behavior; dimorphism; females; models; prediction; probability; reproduction; reproductives; vertebrates
Abstract:
... Dominance interactions determine reproductive status in many animal societies, including many cooperatively breeding vertebrates and eusocial Hymenoptera without queen-worker dimorphism. Typically, the dominant individual monopolises reproduction, and subordinates behave like helpers. In Dinoponera queenless ants, workers are totipotent females and can potentially reproduce, yet only the top-ranki ...
DOI:
10.1007/s00265-003-0600-9

31. Self-compatibility and floral biology in subdioecious Wurmbea dioica (Colchicaceae)

Author:
Vaughton, Glenda; Ramsey, Mike
Source:
Australian journal of botany 2003 v.51 no.1 pp. 39-45
ISSN:
0067-1924
Subject:
Colchicaceae; flowering; dimorphism; longevity; selfing; stigma; dehiscence; seed abortion; inbreeding depression; dioecy; pollen; seed set; females; self-pollination
Abstract:
... Dioecy has long been interpreted as a mechanism to avoid self-fertilisation and the negative effects of inbreeding depression. We determined relative self-compatibility and temporal overlap of male and female functions for hermaphrodites in subdioecious Wurmbea dioica to assess the role of selfing in the maintenance of gender dimorphism. Plants were self-compatible but did not self-pollinate auton ...
DOI:
10.1071/BT02054

32. Aggressive responses of nesting prairie falcons to territorial intruders

Author:
HOLTHUIJZEN ANTHONIE M. A.; OOSTERHUIS LENORA
Source:
Wilson bulletin 2004 v.116 no.3 pp. 257-261
ISSN:
0043-5643
Subject:
Aquila chrysaetos; Buteo jamaicensis; Cathartes aura; Circus; Corvus; Falco sparverius; Lynx rufus; dimorphism; eagles; falcons; females; food availability; hawks; males; nesting; nesting sites; Idaho; Turkey (country)
Abstract:
... From 1984 through 1987, we studied aggressive responses of Prairie Falcons (Falco mexicanus) to species intruding into their nesting territories in southwestern Idaho (52 nesting attempts, 613 days, 9,085 hr). Prairie Falcons responded aggressively most frequently to Common Ravens (Corvus corax; 49%% of encounters), followed by Red-tailed Hawks (Buteo jamaicensis; 24%%), Golden Eagles (Aquila chry ...
DOI:
10.1676/03-086

33. Sex‐differential resistance and tolerance to herbivory in a gynodioecious wild strawberry

Author:
Tia-Lynn Ashman; Denise H. Cole; Megan Bradburn
Source:
Ecology 2004 v.85 no.9 pp. 2550-2559
ISSN:
0012-9658
Subject:
buds; dimorphism; evolution; females; flowering; flowers; fruit growing; herbivores; morphs; pollen; pollinators; sex allocation; strawberries
Abstract:
... We explore the effects of gender dimorphism on resistance (damage avoidance) and tolerance (growth and fitness compensation) to a flower bud clipping weevil in a gynodioecious wild strawberry. Using both natural populations and a common garden, we document pervasive hermaphrodite‐biased damage and identify several floral traits associated with resistance. Lower flower number, lower pollen producti ...
DOI:
10.1890/03-0495

34. Ecological context and the importance of body and gnathopod size for pairing success in two amphipod ecomorphs

Author:
Gary A. Wellborn; Suzanne E. Bartholf
Source:
Oecologia 2005 v.143 no.2 pp. 308-316
ISSN:
0029-8549
Subject:
Hyalella azteca; appendages; body size; dimorphism; females; freshwater; habitats; interspecific variation; males; mating behavior; predation; sexual selection
Abstract:
... Ecological context generates interspecific variation in mating behavior by imposing differential constraints on the action of sexual selection, but operation of these constraints in nature is not well understood. We used field and laboratory studies to examine the importance of body size and size of sexually dimorphic appendages, the gnathopods, for pairing success in two freshwater amphipod speci ...
DOI:
10.1007/s00442-004-1786-x

35. Sexual size dimorphism and sex ratios in dragonflies (Odonata)

Author:
JOHANSSON, FRANK; CROWLEY, PHILIP H.; BRODIN, TOMAS
Source:
Biological journal of the Linnean Society 2005 v.86 no.4 pp. 507-513
ISSN:
0024-4066
Subject:
Anisoptera (Odonata); animals; body size; dimorphism; females; foraging; males; mortality; sex ratio; sexual selection
Abstract:
... Sexual size dimorphism and biased sex ratios are common in animals. Rensch's rule states that sexual size dimorphism (SSD) would increase with body size in taxa where males are larger than females and decrease with body size in taxa where females are larger. We tested this trend in dragonflies (Odonata) by analysing body size of 21 species and found support for Rensch's rule. The increase in SSD w ...
DOI:
10.1111/j.1095-8312.2005.00549.x

36. Territory size and stability in a sedentary neotropical passerine: is resource partitioning a necessary condition?

Author:
Gorrell Janet V.; Ritchison Gary; Morton Eugene S.
Source:
Journal of field ornithology 2005 v.76 no.4 pp. 395-401
ISSN:
0273-8570
Subject:
Passeriformes; dimorphism; females; foraging; leaves; males; territoriality; tropics; Panama
Abstract:
... Long-term pair bonds and defense of territories year-round are common among tropical passerines. The boundaries of these territories tend to be stable, perhaps reflecting the need to defend an area that, regardless of conditions, provides sufficient food resources. If, however, these stable territories are not, even temporarily, sufficiently large, then intra-pair competition for available food ma ...
DOI:
10.1648/0273-8570(2005)076[0395:TSASIA]2.0.CO;2

37. Bite-force performance and head shape in a sexually dimorphic crevice-dwelling lizard, the common chuckwalla [Sauromalus ater (= obesus)]

Author:
LAPPIN, A. KRISTOPHER; HAMILTON, PAUL S.; SULLIVAN, BRIAN K.
Source:
Biological journal of the Linnean Society 2006 v.88 no.2 pp. 215-222
ISSN:
0024-4066
Subject:
copulation; dimorphism; females; head; lizards; males; predators; sexual selection
Abstract:
... The Common Chuckwalla [Sauromalus ater (= obesus)] is a large, sexually dimorphic lizard with a flattened head that takes refuge from predators in rock crevices. Males use their relatively large heads to bite competing males during territorial fights and to restrain females during copulation. Flattened heads with an antipredator function (i.e. seeking refuge in crevices) and enlarged heads with in ...
DOI:
10.1111/j.1095-8312.2006.00615.x

38. Floral phenology and sex expression in functionally monoecious Rhoiptelea chiliantha (Rhoipteleaceae)

Author:
SUN, SHI-GUO; LU, YANG; HUANG, SHUANG-QUAN
Source:
Botanical journal of the Linnean Society 2006 v.152 no.2 pp. 145-151
ISSN:
0024-4074
Subject:
dimorphism; female flowers; females; flowering; games; indigenous species; insects; males; phenology; pollination; reproductive traits; sexual systems; stigma; China; Vietnam
Abstract:
... The reproductive ecology of wind-pollinated gynomonoecious species, in which the individual plant produces both female (pistillate) and perfect flowers, has rarely been studied. We examined the floral phenology and reproductive traits in Rhoiptelea chiliantha, described as gynomonoecy, to understand the adaptive significance of this sexual system. This species is a rare tree native to south-wester ...
DOI:
10.1111/j.1095-8339.2006.00563.x

39. A New Independently Derived Social Spider with Explosive Colony Proliferation and a Female Size Dimorphism

Author:
Avilés, Leticia; Maddison, Wayne P.; Agnarsson, Ingi
Source:
Biotropica 2006 v.38 no.6 pp. 743-753
ISSN:
1744-7429
Subject:
Theridion; arthropod communities; social behavior; webs; sex ratio; females; body size; dimorphism; animal morphology; redescriptions; social parasitism; phylogeny; Ecuador
Abstract:
... Permanent cooperative sociality is rare in spiders. Here we describe sociality in a cobweb (Theridiidae) genus with no other known social species. In five areas of eastern Ecuador, we found nests of Theridion nigroannulatum containing from a single to several thousand adults living together in a communal web. Spiders cooperated in prey capture and shared their food. Subadult to young adult sex rat ...
DOI:
10.1111/j.1744-7429.2006.00202.x

40. Pollinator response to female and male floral display in a monoecious species and its implications for the evolution of floral dimorphism

Author:
Shuang‐Quan Huang; Lu‐Lu Tang; Ji‐Fan Sun; Yang Lu
Source:
new phytologist 2006 v.171 no.2 pp. 417-424
ISSN:
0028-646X
Subject:
Sagittaria sagittifolia subsp. leucopetala; dimorphism; evolution; females; flower size; males; monoecy; pollen; pollinators
Abstract:
... • Pollinator‐mediated selection has been hypothesized as one cause of size dimorphism between female and male flowers. Flower number, ignored in studies of floral dimorphism, may interact with flower size to affect pollinator selectivity. • In the present study, we explored pollinator response, and estimated pollen receipt and removal, in experimental populations of monoecious Sagittaria trifolia, ...
DOI:
10.1111/j.1469-8137.2006.01766.x

41. Sexual size dimorphism and assortative mating for morphological traits in Passer domesticus

Author:
Gregorio Moreno-Rueda
Source:
Journal of ethology 2006 v.24 no.3 pp. 227-230
ISSN:
0289-0771
Subject:
Passer domesticus; assortative mating; body size; dimorphism; females; males; sexual selection; tail
Abstract:
... In this study, assortative mating for different morphological traits was studied in a captive population of house sparrows (Passer domesticus). Males were larger than females. Assortative mating was found for tail length, wing length and general body size. Males with larger badge size mated with females with longer tails. The strongest assortative mating occurred for tail length (r=0.77), and this ...
DOI:
10.1007/s10164-005-0183-1

42. Castes and asynchronous colony cycle in Polybia bistriata (Fabricius) (Hymenoptera: Vespidae)

Author:
Oliveira, O.A.L. de; Noll, F.B.; Mateus, S.; Gomes, B.
Source:
Neotropical entomology 2007 v.36 no.6 pp. 817-827
ISSN:
1519-566X
Subject:
worker insects; insect morphology; insemination; dimorphism; social insects; queen insects; insect reproduction; insect development; females; Polybia
Abstract:
... Neotropical swarm-founding wasps, the Epiponini, are an outstanding group of social insects whose societies are polygynic and complex nest builders. Caste dimorphism in these wasps ranges from incipient to highly distinct. Morphometric analyses of nine body parts, ovarian status, relative age and development of the 5th gastral sternite gland (Richards[acute accent] gland) of Polybia bistriata Fabr ...
DOI:
10.1590/S1519-566X2007000600001
PubMed:
18246254

43. Daring females, devoted males, and reversed sexual size dimorphism in the sand-dwelling spider Allocosa brasiliensis (Araneae, Lycosidae)

Author:
Aisenberg, Anita; Viera, Carmen; Costa, Fernando G.
Source:
Behavioral ecology and sociobiology 2007 v.62 no.1 pp. 29-35
ISSN:
0340-5443
Subject:
Lycosidae; burrows; copulation; courtship; dimorphism; dunes; females; habitats; males; predation; progeny; sexual selection
Abstract:
... Sexual selection theory predicts that a higher investment in offspring will turn females into the selective sex, while males will compete for accessing and courting them. However, there are exceptions to the rule. When males present a high reproductive investment, sex roles can reverse from typical patterns, turning males into the choosy sex, while females locate males and initiate courtship. In m ...
DOI:
10.1007/s00265-007-0435-x

44. Environmental stress increases skeletal fluctuating asymmetry in the moor frog Rana arvalis

Author:
Fredrik Söderman; Stefan van Dongen; Susanna Pakkasmaa; Juha Merilä
Source:
Oecologia 2007 v.151 no.4 pp. 593-604
ISSN:
0029-8549
Subject:
Rana; acidity; dimorphism; females; frogs; males; pH; sexual selection
Abstract:
... Whether fluctuating asymmetry (FA) provides a useful metric indicator of the degree of environmental stress experienced by populations is still a contentious issue. We investigated whether the degree of FA in skeletal elements is useful in elucidating the degree of environmental stress experienced by frog populations, and further, tested the proposition that a trait’s sensitivity to stress—as refl ...
DOI:
10.1007/s00442-006-0611-0
PubMed:
17136394

45. Functional basis for sexual differences in bite force in the lizard Anolis carolinensis

Author:
ANTHONY HERREL; LANCE D. MCBRAYER; PETER M. LARSON
Source:
Biological journal of the Linnean Society 2007 v.91 no.1 pp. 111-119
ISSN:
0024-4066
Subject:
Anolis carolinensis; body size; dimorphism; females; gender differences; head; jaws; lizards; males; mastication; morphometry; muscles; skeletal muscle; skull
Abstract:
... In many species of lizards, males attain greater body size and have larger heads than female lizards of the same size. Often, the dimorphism in head size is paralleled by a dimorphism in bite force. However, the underlying functional morphological basis for the dimorphism in bite force remains unclear. Here, we test whether males are larger, and have larger heads and bite forces than females for a ...
DOI:
10.1111/j.1095-8312.2007.00772.x

46. Hang on or run? Copepod mating versus predation risk in contrasting environments

Author:
Jersabek, Christian D.; Luger, Martin S.; Schabetsberger, Robert; Grill, Susanne; Strickler, J. Rudi
Source:
Oecologia 2007 v.153 no.3 pp. 761-773
ISSN:
0029-8549
Subject:
Copepoda; copulation; dimorphism; females; fish; lakes; males; natural selection; paternity; pigmentation; predation; risk; risk reduction; spermatophores; spermatozoa
Abstract:
... Mating durations of copepods were found to differ significantly between fishless high-altitude waters and lowland lakes containing fish. In lowland species the whole mating process was completed within a few minutes, but it averaged over an hour in high-altitude species. Alpine copepods showed a prolonged post-copulatory association between mates, during which the male clasped the female for an ex ...
DOI:
10.1007/s00442-007-0768-1
PubMed:
17541790

47. Hormones and the development of sex differences in behavior

Author:
Elizabeth Adkins-Regan
Source:
Journal für Ornithologie 2007 v.148 no.Supplement 1 pp. 17-26
ISSN:
0021-8375
Subject:
Coturnix japonica; Taeniopygia guttata; adulthood; adults; birds; breeding; dimorphism; early development; evolution; females; gender differences; hatching; hormonal regulation; juveniles; males; monogamy; sex hormones; sexual maturity; species diversity; steroid hormones
Abstract:
... Birds exhibit striking diversity in behavioral sex differences. A necessary complement to the study of the ecology and evolution of these sex differences is discovering the proximate physiological mechanisms for their development (sexual differentiation) and adult expression. Experiments with Japanese quail (Coturnix japonica) have shown that sex differences in crowing, strutting, and sexual recep ...
DOI:
10.1007/s10336-007-0188-3

48. Latitudinal clines in food distribution correlate with differential migration in the western sandpiper

Author:
Kimberley J. Mathot; Barry D. Smith; Robert W. Elner
Source:
Ecology 2007 v.88 no.3 pp. 781-791
ISSN:
0012-9658
Subject:
Calidris; biofilm; birds; dimorphism; fauna; females; food availability; invertebrates; latitude; littoral zone; males; prediction; sediments; spatial distribution; winter
Abstract:
... We report that a latitudinal cline in intertidal food distribution is associated with the nonbreeding distribution of the Western Sandpiper (Calidris mauri). This novel result is the first to demonstrate a clear relationship between patterns of differential nonbreeding distribution and food availability for any shorebird species. Within each age class and sex, longer‐billed Western Sandpipers wint ...
DOI:
10.1890/06-1225

49. Prey size and ingestion rate in raptors: importance for sex roles and reversed sexual size dimorphism

Author:
Slagsvold, Tore; Sonerud, Geir A.
Source:
Journal of avian biology 2007 v.38 no.6 pp. 650-661
ISSN:
0908-8857
Subject:
birds of prey; breeding; breeding season; captive animals; diet; dimorphism; females; foraging; ingestion; insects; males; mammals; nests
Abstract:
... Compared to other birds, most raptors take large prey for their size, and feeding bouts are extended. However, ingestion rate has largely been overlooked as a constraint in raptors' foraging and breeding ecology. We measured ingestion rate by offering avian and mammalian prey to eighteen wild raptors temporarily kept in captivity, representing seven species and three orders. Ingestion rate was hig ...
DOI:
10.1111/j.2007.0908-8857.04022.x

50. Sex differences in grey seal diet reflect seasonal variation in foraging behaviour and reproductive expenditure: evidence from quantitative fatty acid signature analysis

Author:
BECK, CARRIE A.; IVERSON, SARA J.; BOWEN, W. DON; BLANCHARD, WADE
Source:
journal of animal ecology 2007 v.76 no.3 pp. 490-502
ISSN:
0021-8790
Subject:
Ammodytes; Halichoerus grypus; Sebastes; adults; carnivores; diet; dimorphism; energy; energy density; fatty acids; females; foraging; gender differences; juveniles; males; niches; predators; pregnancy; reproductive behavior; seals; seasonal variation; spring
Abstract:
... 1. Intraspecific variation in diet can be an important component of a species niche breadth. We tested the hypothesis that sex differences in seasonal foraging behaviour and energy storage of sexually size dimorphic grey seals Halichoerus grypus (Fabrisius 1971) are reflected in differences in the diet and niche breadth. Diet composition was estimated for 496 adult (226 males, 270 females) and 91 ...
DOI:
10.1111/j.1365-2656.2007.01215.x
PubMed:
17439466

51. Sex-specific differences in compensation for poor neonatal nutrition in the zebra finch Taeniopygia guttata

Author:
Arnold, Kathryn E.; Blount, Jonathan D.; Metcalfe, Neil B.; Orr, Kate J.; Adam, Aileen; Houston, David; Monaghan, Pat
Source:
Journal of avian biology 2007 v.38 no.3 pp. 356-366
ISSN:
0908-8857
Subject:
beak; diet; life history; dimorphism; malnutrition; males; early development; adulthood; body size; color; wings; Taeniopygia guttata; feathers; chicks; females
Abstract:
... Individuals can compensate for poor early nutrition by accelerating their growth rates once diet improves, but if malnutrition occurs at a key stage of development only certain body structures may compensate fully. This degrees of compensation is predicted to differ between the sexes and also between species with different life history strategies. In this paper we determine how males and females i ...
DOI:
10.1111/j.0908-8857.2007.03818.x

52. Sex-specific maternal effect on egg mass, laying order, and sibling competition in the Bengalese finch (Lonchura striata var. domestica)

Author:
Masayo Soma; Daichi S. Saito; Toshikazu Hasegawa; Kazuo Okanoya
Source:
Behavioral ecology and sociobiology 2007 v.61 no.11 pp. 1695-1705
ISSN:
0340-5443
Subject:
adults; body size; breeding; chicks; daughters; dimorphism; early development; eggs; females; gender differences; hatching; males; maternal effect; mothers; sons
Abstract:
... Maternal effects, such as investment in eggs, have profound effects on offspring fitness. Mothers are expected to skew their investment depending on the laying order and sex when unequal sibling competition occurs within a brood because of sex-specific vulnerability and age hierarchy caused by asynchronous hatching. The Bengalese finch hatches asynchronously and shows a moderate reversed sexual si ...
DOI:
10.1007/s00265-007-0400-8

53. Sex‐specific plasticity of growth and maturation size in a spider: implications for sexual size dimorphism

Author:
C. FERNÁNDEZ‐MONTRAVETA; J. MOYA‐LARAÑO
Source:
Journal of evolutionary biology 2007 v.20 no.5 pp. 1689-1699
ISSN:
1010-061X
Subject:
Theraphosidae; body size; dimorphism; females; males; resource allocation
Abstract:
... Sex‐specific plasticity in body size has been recently proposed to cause intraspecific patterns of variation in sexual size dimorphism (SSD). We reared juvenile male and female Mediterranean tarantulas (Lycosa tarantula) under two feeding regimes and monitored their growth until maturation. Selection gradients calculated across studies show how maturation size is under net stabilizing selection in ...
DOI:
10.1111/j.1420-9101.2007.01399.x
PubMed:
17714286

54. Skewed paternity distribution in the extremely size dimorphic Musk Duck (Biziura lobata)

Author:
P.-J. Guay; R. A. Mulder
Source:
Emu 2007 v.107 no.3 pp. 190-195
ISSN:
1448-5540
Subject:
Anseriformes; blood sampling; breeding; breeding season; dimorphism; ducklings; females; genetic markers; lakes; lekking; males; mating systems; paternity; polygyny; sexual selection; Australia
Abstract:
... Although most species of Anseriformes form long-term or seasonal pair-bonds and breed monogamously, some are thought to be polygynous. The Musk Duck (Biziura lobata) is unique among Anseriformes in that it has been suggested to have a lek mating system. Musk Ducks also display extreme size dimorphism and many secondary sexual traits whose functions are not clearly understood. We studied paternity ...
DOI:
10.1071/MU07012

55. Stage-dependent patterns of drought tolerance and gas exchange vary between sexes in the alpine willow, Salix glauca

Author:
Dudley, Leah S.; Galen, Candace
Source:
Oecologia 2007 v.153 no.1 pp. 1-9
ISSN:
0029-8549
Subject:
Salix glauca; carbon; dimorphism; drought; drought tolerance; environmental factors; females; flowers; gas exchange; genetic variation; leaf conductance; leaves; males; natural selection; physiological response; reproduction; sexual maturity; shrubs; water stress; water use efficiency
Abstract:
... Females and males of sexually dimorphic species have distinct resource demands due to differential allocation to reproduction. Sexual allocation theory predicts that functional traits will diverge between sexes to support these demands. However, such dimorphism may be masked by the impact of current reproduction on source-sink interactions between vegetative and reproductive organs. We ask whether ...
DOI:
10.1007/s00442-007-0712-4
PubMed:
17406906

56. Temporal pattern of feeding activity in the firebug Pyrrhocoris apterus and its relation to sex, wing dimorphism and physiological state of adults

Author:
SOCHA, RADOMÍR; ZEMEK, ROSTISLAV
Source:
Physiological entomology 2007 v.32 no.1 pp. 16-25
ISSN:
0307-6962
Subject:
Pyrrhocoris apterus; adults; circadian rhythm; diapause; dimorphism; diurnal variation; eggs; feeding frequency; females; males; oviposition; photoperiod; physiological state; rearing
Abstract:
... The present study tested whether the pattern of feeding activity in the firebug Pyrrhocoris apterus (L.) is sex- and wing morph-related, diurnal or nocturnal, as well as whether the feeding rhythm persists in constant darkness. Temporal patterns of feeding activity are analysed in macropterous and brachypterous adults reared under long-day (LD 18 : 6 h) and short-day (LD 12 : 12 h) photoperiods, a ...
DOI:
10.1111/j.1365-3032.2006.00535.x

57. Ultrastructural evidence of sperm dimorphism in Deladenus sp. (Tylenchomorpha: Sphaerularioidea: Allantonematidae)

Author:
Hajime Kosaka; Manabu Kusunoki; Vladimir Yushin
Source:
Nematology v.9 no.3 pp. 397-404
ISSN:
1388-5545
Subject:
Allantonematidae; Deladenus; dimorphism; entomopathogenic nematodes; females; males; mitochondria; nuclear membrane; spermatozoa; testes; transmission electron microscopes; transmission electron microscopy
Abstract:
... The dimorphic spermatozoa of the insect-parasitic nematode Deladenus sp. (Tylenchomorpha: Sphaerularioidea: Allantonematidae) were studied for the first time with a transmission electron microscope (TEM). The immature spermatozoa from the testis of mycetophagous males are 10-12 μm diam. and 4-5 μm long unpolarised cells with a centrally located nucleus without a nuclear envelope. The cytoplasm con ...
DOI:
10.1163/156854107781352043

58. Comparison of spermatheca morphology between reproductive and non-reproductive females in social wasps

Author:
Gotoh, A.; Billen, J.; Hashim, R.; Ito, F.
Source:
Arthropod structure & development 2008 v.37 no.3 pp. 199-209
ISSN:
1467-8039
Subject:
Vespidae; spermatheca; insect anatomy; insect morphology; females; reproductives; dimorphism; caste determination; social insects
Abstract:
... Social wasps show an obvious evolution of the differentiation in behavior and external size between reproductive and non-reproductive females, with no clear differences in the Stenogastrinae, via overlap in the Polistinae, to clear differences in the Vespinae. In this study, we examined the morphological appearance of the spermatheca in representative species of these three subfamilies. The genera ...
DOI:
10.1016/j.asd.2007.11.001
PubMed:
18342263

59. Evolution of prey holding behaviour and large male body size in Ninox owls (Strigidae)

Author:
PAVEY, CHRIS R.
Source:
Biological journal of the Linnean Society 2008 v.95 no.2 pp. 284-292
ISSN:
0024-4066
Subject:
Strigidae; body size; dimorphism; evolution; females; hawks; males; mammals; nesting
Abstract:
... The hawk owl genus Ninox is unique among raptorial birds in that it includes three species in which males are substantially larger than females. This is a reversal of the normal pattern observed in both diurnal and nocturnal raptorial birds in which females are larger. Interestingly, these three Ninox species also are both the largest of the 22 species in the genus and the only species that exhibi ...
DOI:
10.1111/j.1095-8312.2008.01043.x

60. Fighting, dispersing, and sneaking: body-size dependent mating tactics by male Librodor japonicus beetles

Author:
OKADA, KENSUKE; MIYATAKE, TAKAHISA; NOMURA, YUTA; KURODA, KAZUMA
Source:
Ecological entomology 2008 v.33 no.2 pp. 269-275
ISSN:
0307-6946
Subject:
body size; dimorphism; females; foraging; males; spermatozoa; testes; wings
Abstract:
... 1. Scaling relations between weapons and body size depart from linearity in many male beetles. In many previous studies, these males have been divided into major and minor males with a switch point, that is male dimorphism. Major and minor males adopt strikingly different reproductive tactics. 2. We found three size-dependent behaviours, i.e. fighting, dispersing, and sneaking, however, among Libr ...
DOI:
10.1111/j.1365-2311.2007.00965.x

61. Parental care and sexual size dimorphism in wasps and bees

Author:
Gavin Shreeves; Jeremy Field
Source:
Behavioral ecology and sociobiology 2008 v.62 no.5 pp. 843-852
ISSN:
0340-5443
Subject:
Apoidea; birds; body size; dimorphism; eggs; exoskeleton; fecundity; females; invertebrates; males; mammals; nests; parental role; phylogeny; pollen
Abstract:
... Sexual size dimorphism, in which one sex is larger than the other, occurs when body size has differential effects on the fitness of males and females. Mammals and birds usually have male-biased size dimorphism, probably because of strong sexual competition among males. Invertebrates usually have female-biased size dimorphism, perhaps because their inflexible exoskeletons limit ovary size, leading ...
DOI:
10.1007/s00265-007-0510-3

62. Sex allocation in a monomorphic seabird with a single-egg clutch: test of the environment, mate quality, and female condition hypotheses

Author:
Addison, BriAnne; Kitaysky, Alexander S.; Hipfner, J. Mark
Source:
Behavioral ecology and sociobiology 2008 v.63 no.1 pp. 135-141
ISSN:
0340-5443
Subject:
Cerorhinca monocerata; body condition; breeding; corticosterone; daughters; dimorphism; environmental factors; females; hatching; males; mothers; rearing; seabirds; sex allocation; sons
Abstract:
... Sex allocation theory posits that mothers should preferentially invest in sons when environmental conditions are favorable for breeding, their mates are of high quality, or they are in good body condition. We tested these three hypotheses in rhinoceros auklets (Cerorhinca monocerata), monomorphic seabirds that lay a single-egg clutch, in 2 years that differed in environmental conditions for breedi ...
DOI:
10.1007/s00265-008-0643-z

63. Solo and duet calling in the pheasant coucal: sex and individual call differences in a nesting cuckoo with reversed size dimorphism

Author:
Maurer, Golo; Smith, Claire; Süsser, Marc; Magrath, Robert D.
Source:
Australian journal of zoology 2008 v.56 no.3 pp. 143-149
ISSN:
0004-959X
Subject:
Cuculidae; breeding season; dimorphism; females; males; nesting; pheasants; surveys; territoriality
Abstract:
... Duetting and female vocalisations have rarely been studied in tropical non-passerines. In coucals, a subfamily of nesting cuckoos, these behaviours have evolved under unusual conditions of male-biased parental care and reversed sexual size dimorphism. Here we provide the first detailed description of the structure and occurrence of sex-specific calls and duets in a monogamous coucal species, the p ...
DOI:
10.1071/ZO08049

64. Sublethal effects of selected insecticides on fecundity and wing dimorphism of green peach aphid (Hom., Aphididae)

Author:
Wang, X.-Y.; Yang, Z.-Q.; Shen, Z.-R.; Lu, J.; Xu, W.-B.
Source:
Journal of applied entomology 2008 v.132 no.2 pp. 135-142
ISSN:
0931-2048
Subject:
Myzus persicae; abamectin; adults; azadirachtin; dimorphism; fecundity; females; fenvalerate; greenhouses; imidacloprid; mortality; pirimicarb; progeny; rotenone; sublethal effects
Abstract:
... Effects of sublethal concentrations (LC₂₅) of six insecticides (imidacloprid, rotenone, fenvalerate, abamectin, pirimicarb and azadirachtin) on fecundity and wing dimorphism of the green peach aphid, Myzus persicae (Sulzer), were studied both under laboratory and greenhouse conditions. In the laboratory, aphid reproduction reduced by 44.29% and 54.01% when rotenone and abamectin treatments were ap ...
DOI:
10.1111/j.1439-0418.2007.01225.x

65. Who Cares? Males Provide Most Parental Care in a Monogamous Nesting Cuckoo

Author:
Maurer, Golo
Source:
Ethology 2008 v.114 no.6 pp. 540-547
ISSN:
0179-1613
Subject:
Cuculidae; dimorphism; evolution; females; frogs; males; nesting; nests; parasitism; pheasants; progeny; reptiles
Abstract:
... Cuckoos hold a prominent position in the study of parental care, because they show the greatest variation of any bird family in the way they care for their offspring. Despite this, few data are available on cuckoos with biparental care even though it is the most common form of parental care in cuckoos and birds in general. Here I describe the breeding behaviour of the pheasant coucal, Centropus ph ...
DOI:
10.1111/j.1439-0310.2008.01498.x

66. Why get big in the cold? Towards a solution to a life-history puzzle

Author:
Karl, Isabell; Fischer, Klaus
Source:
Oecologia 2008 v.155 no.2 pp. 215-225
ISSN:
0029-8549
Subject:
Lycaena; body protein; body size; butterflies; cold; dimorphism; females; food consumption; food intake; foods; games; life history; lipid content; males; temperature
Abstract:
... The temperature-size rule (TSR), which states that body size increases at lower developmental temperatures, appears to be a near-universal law for ectotherms. Although recent studies seem to suggest that the TSR might be adaptive, the underlying developmental mechanisms are thus far largely unknown. Here, we investigate temperature effects on life-history traits, behaviour and physiology in the co ...
DOI:
10.1007/s00442-007-0902-0
PubMed:
18000685

67. Comparisons of age, growth, and maturity between male and female, and diploid and triploid individuals in Carassius auratus from Okinawa-jima Island, Japan

Author:
Takada, Mikumi; Tachihara, Katsunori
Source:
Aquatic conservation 2009 v.19 no.7 pp. 806-814
ISSN:
1052-7613
Subject:
sexual maturity; life history; rivers; dimorphism; diploidy; otoliths; males; triploidy; spawning; freshwater fish; hatching; population size; Carassius auratus; females; Ryukyu Archipelago
Abstract:
... 1.Carassius auratus, a primary freshwater fish with bisexual diploid and unisexual gynogenetic triploid lineages, is distributed widely in and around the Eurasian continent and is especially common in East Asia. East Asian C. auratus diverged genetically to form local endemic populations in different regions, and those distributed in the Ryukyu Archipelago form a local endemic population that can ...
DOI:
10.1002/aqc.1032

68. Differential Migration by Sex in the Great Bustard: Possible Consequences of an Extreme Sexual Size Dimorphism

Author:
Palacín, Carlos; Alonso, Juan C.; Alonso, Javier A.; Martín, Carlos A.; Magaña, Marina; Martin, Beatriz
Source:
Ethology 2009 v.115 no.7 pp. 617-626
ISSN:
0179-1613
Subject:
Otididae; birds; breeding sites; brood rearing; dimorphism; females; heat; males; migratory behavior; sexual selection; summer; weather; Spain
Abstract:
... We explored migration patterns in Great bustards (Otis tarda), a species that shows strong sexual selection and the most extreme sexual size dimorphism among birds. The aim was to explain differential migration, examining whether Great bustards fulfil the main predictions of bird migration theory hypotheses and sexual segregation theory hypotheses. We radio-tracked the seasonal movements of 65 mal ...
DOI:
10.1111/j.1439-0310.2009.01647.x

69. Diurnal changes and frequency dependence in male mating preference for female morphs in the damselfly Ischnura senegalensis (Rambur) (Odonata: Coenagrionidae)

Author:
TAKAHASHI, Yuma; WATANABE, Mamoru
Source:
Entomological science 2009 v.12 no.3 pp. 219-226
ISSN:
1343-8786
Subject:
Ischnura; color; copulation; correlation; dimorphism; diurnal variation; females; foraging; males; morphs; surveys
Abstract:
... Ischnura senegalensis females exhibit color dimorphism, consisting of an andromorph and a gynomorph, which might be maintained under a frequency-dependent process of mating harassment by mate-searching males. Males change their mating preference for female morph depending on prior copulation experience. Binary choice experiments between two female morphs were carried out in four local populations ...
DOI:
10.1111/j.1479-8298.2009.00326.x

70. Hydrocarbons in the antennal gland secretion of female European beewolves, Philanthus triangulum (Hymenoptera, Crabronidae)

Author:
Kaltenpoth, Martin; Schmitt, Thomas; Strohm, Erhard
Source:
Chemoecology 2009 v.19 no.4 pp. 219-225
ISSN:
0937-7409
Subject:
Philanthus triangulum; Streptomyces; alkanes; antennae; bacteria; brood cells; chemical composition; dimorphism; females; hemolymph; ketones; larvae; mass spectrometry; morphs; secretion
Abstract:
... The antennae of female European beewolves (Philanthus triangulum, Hymenoptera: Crabronidae) contain unique gland reservoirs that are inhabited by the symbiotic bacterium ‘Candidatus Streptomyces philanthi'. The reservoir content is secreted into the subterranean brood cells where it serves a dual function: (1) It provides the larvae with spatial information about the orientation of cocoon spinning ...
DOI:
10.1007/s00049-009-0022-x

71. Male dimorphism, territoriality and mating success in the tropical damselfly, Paraphlebia zoe Selys (Odonata: Megapodagrionidae)

Author:
Romo-Beltrán, Allari; Macías-Ordóñez, Rogelio; Córdoba-Aguilar, Alex
Source:
Evolutionary ecology 2009 v.23 no.5 pp. 699-709
ISSN:
0269-7653
Subject:
Odonata; dimorphism; females; males; oviposition sites; territoriality
Abstract:
... The tropical damselfly Paraphlebia zoe has two male morphs: a black-winged (BW) male which is associated with territorial defense of oviposition sites; and a hyaline-winged (HW) male similar in appearance to females, and, compared to the black morph, less frequently found defending territories. In a wild population of this species, we first assessed the relationship between phenotypic traits [male ...
DOI:
10.1007/s10682-008-9265-1

72. Relationships between bird morphology and prey selection in two sympatric Great Cormorant Phalacrocorax carbo subspecies during winter

Author:
FONTENEAU, FREDERIC; PAILLISSON, JEAN-MARC; MARION, LOÏC
Source:
Ibis 2009 v.151 no.2 pp. 286-298
ISSN:
0019-1019
Subject:
Phalacrocorax carbo; birds; coasts; diet; dimorphism; females; freshwater; habitats; males; predation; winter
Abstract:
... Variation in bird morphology (notably sex size dimorphism) has been suggested to contribute to differences in food use between individuals. We explore the hypothesis of food partitioning (diet overlap and prey size selection) in two sympatric subspecies of the Great Cormorant Phalacrocorax carbo with respect to bird morphology (subspecies and sex) in inland French waters. These areas represent a r ...
DOI:
10.1111/j.1474-919X.2009.00909.x

73. Sex-specific growth patterns and effects of hatching condition on growth in the reversed sexually size-dimorphic great skua Stercorarius skua

Author:
Kalmbach, Ellen; Griffiths, Richard; Furness, Robert W.
Source:
Journal of avian biology 2009 v.40 no.4 pp. 358-368
ISSN:
0908-8857
Subject:
adults; body condition; chicks; daughters; dimorphism; eggs; energy requirements; females; gender differences; hatching; males; mammals; mothers; nests; ontogeny; seabirds; sons; testosterone
Abstract:
... In many sexually size-dimorphic species of birds and mammals, the larger sex, often the males, show increased environmental sensitivity during ontogeny. This is generally assumed to be due to higher energy requirements, reflected in higher absolute growth rates of the larger sex. Poor early conditions often increase the sex differences in vulnerability. However, it is not clear whether these patte ...
DOI:
10.1111/j.1600-048X.2008.04339.x

74. Z and W sex chromosomes in the cane toad (Bufo marinus)

Author:
Abramyan, John; Ezaz, Tariq; Graves, Jennifer A. Marshall; Koopman, Peter
Source:
Chromosome research 2009 v.17 no.8 pp. 1015-1024
ISSN:
0967-3849
Subject:
dimorphism; morphometry; monitoring; Rhinella marina; fluorescence; males; sex determination; pests; nucleotide sequences; nucleolus organizer region; sex chromosomes; comparative genomic hybridization; females; toads; Australia
Abstract:
... The cane toad (Bufo marinus) is one of the most notorious animal pests encountered in Australia. Members of the genus Bufo historically have been regarded as having genotypic sex determination with male homogamety/female heterogamety. Nevertheless, as with many toads, karyotypic analyses of the cane toad have so far failed to identify heteromorphics sex chromosomes. In this study, we used comparat ...
DOI:
10.1007/s10577-009-9095-1
PubMed:
19936947

75. A test of Rensch's rule in dwarf chameleons (Bradypodion spp.), a group with female-biased sexual size dimorphism

Author:
Stuart-Fox, Devi
Source:
Evolutionary ecology 2009 v.23 no.3 pp. 425-433
ISSN:
0269-7653
Subject:
Chamaeleonidae; allometry; body size; dimorphism; fecundity; females; males; natural selection
Abstract:
... Rensch's rule describes a pattern of allometry in sexual size dimorphism (SSD): when males are the larger sex (male-biased SSD), SSD increases with increasing body size, and when females are the larger sex (female-biased SSD), SSD decreases with increasing body size. While this expectation generally holds for taxa with male-biased or mixed SSD, examples of allometry for SSD consistent with Rensch' ...
DOI:
10.1007/s10682-008-9242-8

76. Body Size and Age Structure of a Breeding Population of the Japanese Common Toad, Bufo Japonicus Formosus (Amphibia: Bufonidae)

Author:
Kusano Tamotsu; Maruyama Kazuko; Kaneko Shigenori
Source:
Current herpetology 2010 v.29 no.1 pp. 23-31
ISSN:
1881-1019
Subject:
Bufo; adults; age; age structure; body size; breeding; breeding season; dimorphism; females; males; phalanges; toads
Abstract:
... The body size and age structure of a breeding population of the Japanese common toad, Bufo japonicus formosus, was studied at Yamakitamachi in Kanagawa Prefecture for three breeding seasons from 1992 to 1994. Yearly variation in snout-vent length (SVL) was not significant, but the difference in SVL between the sexes was highly significant; the mean SVL of males and females was 125.8 and 134.2 mm, ...
DOI:
10.3105/018.029.0103

77. Competition between relatives and the evolution of dispersal in a parasitoid wasp

Author:
INNOCENT, T.M.; ABE, J.; WEST, S.A.; REECE, S.E.
Source:
Journal of evolutionary biology 2010 v.23 no.7 pp. 1374-1385
ISSN:
1010-061X
Subject:
Melittobia; dimorphism; dispersal behavior; egg production; evolution; females; morphs; parasitic wasps; prediction; sex ratio
Abstract:
... Evolutionary theory predicts that levels of dispersal vary in response to the extent of local competition for resources and the relatedness between potential competitors. Here, we test these predictions by making use of a female dispersal dimorphism in the parasitoid wasp Melittobia australica. We show that there are two distinct female morphs, which differ in morphology, pattern of egg production ...
DOI:
10.1111/j.1420-9101.2010.02015.x
PubMed:
20492084
PubMed Central:
PMC3939352

78. Domestic chickens defy Rensch's rule: sexual size dimorphism in chicken breeds

Author:
REMEŠ, V.; SZÉKELY, T.
Source:
Journal of evolutionary biology 2010 v.23 no.12 pp. 2754-2759
ISSN:
1010-061X
Subject:
chickens; partridges; dimorphism; meat production; humans; wild relatives; chicken breeds; allometry; fighting behavior; Gallus gallus; ecology; males; pheasants; grouse; eggs; females
Abstract:
... Sexual size dimorphism (SSD), i.e. the difference in sizes of males and females, is a key evolutionary feature that is related to ecology, behaviour and life histories of organisms. Although the basic patterns of SSD are well documented for several major taxa, the processes generating SSD are poorly understood. Domesticated animals offer excellent opportunities for testing predictions of functiona ...
DOI:
10.1111/j.1420-9101.2010.02126.x
PubMed:
21121089

79. Epigenetic modifications on X chromosomes in marsupial and monotreme mammals and implications for evolution of dosage compensation

Author:
Rens, Willem; Wallduck, Margaret S.; Lovell, Frances L.; Ferguson-Smith, Malcolm A.; Ferguson-Smith, Anne C.
Source:
Proceedings of the National Academy of Sciences of the United States of America 2010 v.107 no.41 pp. 17657-17662
ISSN:
0027-8424
Subject:
DNA; DNA methylation; Ornithorhynchus; RNA; Trichosurus vulpecula; X chromosome; antibodies; dimorphism; epigenetics; evolution; females; fluorescent antibody technique; genes; histones; mice; possums; somatic cells
Abstract:
... X chromosome dosage compensation in female eutherian mammals is regulated by the noncoding Xist RNA and is associated with the differential acquisition of active and repressive histone modifications, resulting in repression of most genes on one of the two X chromosome homologs. Marsupial mammals exhibit dosage compensation; however, they lack Xist, and the mechanisms conferring epigenetic control ...
DOI:
10.1073/pnas.0910322107
PubMed:
20861449
PubMed Central:
PMC2955130

80. Gender dimorphism and mycorrhizal symbiosis affect floral visitors and reproductive output in Geranium sylvaticum

Author:
Varga, Sandra; Kytöviita, Minna-Maarit
Source:
Functional ecology 2010 v.24 no.4 pp. 750-758
ISSN:
0269-8463
Subject:
Bombus; Claroideoglomus claroideum; Geranium; Glomus hoi; dimorphism; females; flowers; fungi; insect behavior; insects; nectar; pollen; pollination; pollinators; reproductive performance; seeds; tritrophic interactions; vesicular arbuscular mycorrhizae
Abstract:
... 1. Arbuscular mycorrhizal (AM) symbiosis has been shown to enhance some plant traits to which pollinators are known to respond. Moreover, in gynodioecious species pollinators prefer hermaphrodite flowers over female ones, but the role of fungal symbiosis in sex-specific pollinator attraction is unknown. 2. We examined how plant gender dimorphism and AM symbiosis affect floral visitors and reproduc ...
DOI:
10.1111/j.1365-2435.2010.01708.x

81. Molecular cloning, transcriptional regulation, and differential expression profiling of vitellogenin in two wing‐morphs of the brown planthopper, Nilaparvata lugens Stål (Hemiptera: Delphacidae)

Author:
Tufail, M.; Naeemullah, M.; Elmogy, M.; Sharma, P.N.; Takeda, M.; Nakamura, C.
Source:
Insect molecular biology 2010 v.19 no.6 pp. 787-798
ISSN:
0962-1075
Subject:
rice; Nilaparvata lugens; hemolymph; genes; insects; Southern blotting; lipoproteins; fat body; gene expression; signal peptide; vitellogenin; juvenile hormones; gene expression regulation; females; cysteine; wings; messenger RNA; morphs; dimorphism; transcription (genetics); blood coagulation factors; pests; molecular cloning; Northern blotting; topical application; immunoblotting; crops; Asia
Abstract:
... The brown planthopper, Nilaparvata lugens, is a serious pest of rice crops throughout Asia and exhibits wing dimorphism, with brachypterous adults having reduced wings and macropterous adults possessing fully developed wings. To understand the reproductive strategies in two wing‐morphs of this insect, the transcript encoding the major yolk protein precursor, vitellogenin (Vg), was cloned. The comp ...
DOI:
10.1111/j.1365-2583.2010.01035.x
PubMed:
20698901

82. Physiological performance and xylem water isotopic composition underlie gender-specific responses in the dioecious shrub Corema album

Author:
Álvarez-Cansino, Leonor; Zunzunegui, María; Díaz Barradas, Mari Cruz; Esquivias, Mari Paz
Source:
Physiologia plantarum 2010 v.140 no.1 pp. 32-45
ISSN:
0031-9317
Subject:
Mediterranean climate; chlorophyll; dimorphism; drought; females; fluorescence; fruiting; gas exchange; leaf water potential; leaves; male flowers; net assimilation rate; oxygen; parks; physiological response; population structure; reproduction; seasonal variation; shrubs; soil; temperature; water table; watersheds; winter; woody plants; xylem; xylem water potential; Spain
Abstract:
... Gender-specific requirements of reproduction in dioecious species can lead to different physiological responses in male and female plants, made in relation to environmental constraints, and influencing growth, survival and population structure. Gender-related physiological differences and seasonal responses, indicating the existence of compensatory mechanisms of reproduction, were examined during ...
DOI:
10.1111/j.1399-3054.2010.01382.x
PubMed:
20487375

83. Proximate sources of sexual size dimorphism in insects: locating constraints on larval growth schedules

Author:
Tammaru, Toomas; Esperk, Toomas; Ivanov, Vitali; Teder, Tiit
Source:
Evolutionary ecology 2010 v.24 no.1 pp. 161-175
ISSN:
0269-7653
Subject:
Lepidoptera; body size; dimorphism; eggs; evolution; females; hatching; insects; instars; larvae; larval development; parturition
Abstract:
... Different levels of sexual size dimorphism (SSD) have usually been explained by selective forces operating in the adult stage. Developmental mechanisms leading to SSD during the juvenile development have received less attention. In particular, it is often not clear if the individuals of the ultimately larger sex are larger already at hatching/birth, do they grow faster, or do they grow for a longe ...
DOI:
10.1007/s10682-009-9297-1

84. Reproductive investment of giants and dwarfs: specialized tactics in a cichlid fish with alternative male morphs

Author:
Schütz, Dolores; Pachler, Gudrun; Ripmeester, Erwin; Goffinet, Olivier; Taborsky, Michael
Source:
Functional ecology 2010 v.24 no.1 pp. 131-140
ISSN:
0269-8463
Subject:
Lamprologus; aggression; allometry; animal breeding; capital; courtship; dimorphism; eggs; ejaculation; energy; females; field experimentation; life history; males; morphs; nests; opportunity costs; parasitism; restricted feeding; spawning; spermatozoa; testes; Lake Tanganyika
Abstract:
... 1. Adopting alternative reproductive tactics may require divergent solutions to reproductive competition among individuals of a population. Often investment in reproduction differs substantially between individuals pursuing bourgeois and parasitic tactics, which may result in different trade-offs and limitations. 2. Here we identify divergent behavioural, morphological and physiological traits of ...
DOI:
10.1111/j.1365-2435.2009.01605.x

85. Sex-specific fitness returns are too weak to select for non-random patterns of sex allocation in a viviparous snake

Author:
Baron, Jean-Pierre; Tully, Thomas; Le Galliard, Jean-François
Source:
Oecologia 2010 v.164 no.2 pp. 369-378
ISSN:
0029-8549
Subject:
Vipera ursinii; body size; daughters; dimorphism; environmental factors; females; habitats; inbreeding; litter size; mortality; mothers; sex allocation; sex determination; sex ratio; snakes; sons; surveys; France
Abstract:
... When environmental conditions exert sex-specific selection on offspring, mothers should benefit from biasing their sex allocation towards the sex with the highest fitness in a given environment. Yet, studies show mixed support for such adaptive strategies in vertebrates, which may be due to mechanistic constraints and/or weak selection on facultative sex allocation. In an attempt to disentangle th ...
DOI:
10.1007/s00442-010-1660-y
PubMed:
20503058

86. Age and sex determination of gaur Bos gaurus (Bovidae)

Author:
Farshid S. Ahrestani; Herbert H.T. Prins
Source:
Mammalia 2011 v.75 no.2 pp. 151-155
ISSN:
1864-1547
Subject:
Bos gaurus; adults; age structure; animal age; animal morphology; captive animals; females; horns; males; mithuns; sex determination; zoo animals; zoos; India; United States
Abstract:
... One reason why the gaur Bos gaurus is a poorly understood species is because there are no reliable data to age and sex individuals. We studied captive gaur for two years in Mysore Zoo, India and Omaha Zoo, USA, and determined age-specific differences in morphological features and physical growth, by measuring shoulder height, of male and female gaur. We fitted von Bertalanffy growth functions to t ...
DOI:
10.1515/mamm.2010.078

87. Alternative mating tactics in dimorphic males of the harvestman Longiperna concolor (Arachnida: Opiliones)

Author:
Camila Zatz; Rachel M. Werneck; Rogelio Macías-Ordóñez; Glauco Machado
Source:
Behavioral ecology and sociobiology 2011 v.65 no.5 pp. 995-1005
ISSN:
0340-5443
Subject:
Opiliones; dimorphism; eggs; evolution; females; legs; males; tropics
Abstract:
... Intense male–male competition for females may drive the evolution of male morphological dimorphism, which is frequently associated with alternative mating tactics. Using modern techniques for the detection of discontinuous allometries, we describe male dimorphism in the Neotropical harvestman Longiperna concolor, the males of which use their elongated, sexually dimorphic legs IV in fights for the ...
DOI:
10.1007/s00265-010-1103-0

88. Bateman's principle and immunity in a sex-role reversed pipefish

Author:
ROTH, O.; SCHARSACK, J.P.; KELLER, I.; REUSCH, T.B.H.
Source:
Journal of evolutionary biology 2011 v.24 no.7 pp. 1410-1420
ISSN:
1010-061X
Subject:
Syngnathus typhle; Vibrio; dimorphism; eggs; females; immune response; immune system; immunocompetence; life history; longevity; males; mammals; mating frequency; pathogens; progeny; reproduction; secondary contact
Abstract:
... In diverse animal species, from insects to mammals, females display a more efficient immune defence than males. Bateman's principle posits that males maximize their fitness by increasing mating frequency whereas females gain fitness benefits by maximizing their lifespan. As a longer lifespan requires a more efficient immune system, these implications of Bateman's principle may explain widespread i ...
DOI:
10.1111/j.1420-9101.2011.02273.x
PubMed:
21545418

89. Behavioural and morphological dimorphism of the sexes: an account of two primitively eusocial wasps

Author:
Ruchira Sen; Raghavendra Gadagkar
Source:
Journal of natural history 2011 v.45 no.21-22 pp. 1295-1309
ISSN:
1464-5262
Subject:
dimorphism; nests; males; social insects; methodology; reproductives; Ropalidia marginata; foraging; brood rearing; females; researchers
Abstract:
... In social Hymenoptera, foraging, nest building, brood care and all other colony maintenance functions are carried out by the females while males function solely as reproductives. This asymmetry in social roles of the two sexes has led social insect researchers to focus almost exclusively on the females whereas males have remained relatively neglected. We studied two sympatric, primitively eusocial ...
DOI:
10.1080/00222933.2011.552808

90. Body size and sexual selection in the koala

Author:
William A. H. Ellis; Fred B. Bercovitch
Source:
Behavioral ecology and sociobiology 2011 v.65 no.6 pp. 1229-1235
ISSN:
0340-5443
Subject:
body size; dimorphism; females; males; microsatellite repeats; reproductive performance; sexual selection; sires
Abstract:
... Sexual selection is often characterized by polygynous breeding systems, size dimorphism, and skewed operational sex ratios. Koalas are sexually dimorphic in multiple domains, yet are absent from the literature on sexual selection and the structure of their mating system is unclear. We provide the first documentation of the strength of sexual selection in koalas by using microsatellite markers to i ...
DOI:
10.1007/s00265-010-1136-4

91. Conditional male dimorphism and alternative reproductive tactics in a Neotropical arachnid (Opiliones)

Author:
Buzatto, Bruno A.; Requena, Gustavo S.; Lourenço, Rafael S.; Munguía-Steyer, Roberto; Machado, Glauco
Source:
Evolutionary ecology 2011 v.25 no.2 pp. 331-349
ISSN:
0269-7653
Subject:
Opiliones; allometry; arthropods; body size; dimorphism; evolutionarily stable strategy; females; genetic correlation; genetic variation; legs; males; mark-recapture studies; mating behavior; models; morphs; phenotype; tropics
Abstract:
... In arthropods, most cases of morphological dimorphism within males are the result of a conditional evolutionarily stable strategy (ESS) with status-dependent tactics. In conditionally male-dimorphic species, the status' distributions of male morphs often overlap, and the environmentally cued threshold model (ET) states that the degree of overlap depends on the genetic variation in the distribution ...
DOI:
10.1007/s10682-010-9431-0

92. Distinct colour morphs in nestling European Bee-eaters Merops apiaster: is there an adaptive value?

Author:
Martin Kapun; Alžbeta Darolová; Ján Krištofik; Katharina Mahr; Herbert Hoi
Source:
Journal of ornithology 2011 v.152 no.4 pp. 1001-1005
ISSN:
2193-7192
Subject:
Merops; birds; color; dimorphism; feathers; females; morphs; nestlings; nests; sex ratio
Abstract:
... In a few bird species, dimorphism already exists in nestling and juvenile plumage coloration and these colour morphs are often attributable to different sexes. In this study we detected variation in nestling coloration among European Bee-eaters Merops apiaster. We identified two distinct colour morphs, namely nestlings with yellowish-brown and nestlings with green back feathers. By means of geneti ...
DOI:
10.1007/s10336-011-0688-z

93. Floral dimorphism in plant populations with combined versus separate sexes

Author:
Sarah B. Yakimowski; Mélanie Glaettli; Spencer C. H. Barrett
Source:
Annals of botany 2011 v.108 no.4 pp. 765-776
ISSN:
0305-7364
Subject:
Sagittaria latifolia; dimorphism; dioecy; female flowers; females; flowering; male flowers; monoecy; pollen; pollinators; prediction; selection intensity; sexual selection; North America
Abstract:
... BACKGROUND AND AIMS: Dimorphism among floral traits can evolve through variation in selection intensity between female and male performance, especially when sex functions are separated between flowers on a plant (monoecy), or between individuals (dioecy). In animal-pollinated species, male floral traits are predicted to be larger because competition for pollinators should favour larger displays. F ...
DOI:
10.1093/aob/mcr025
PubMed:
21385777
PubMed Central:
PMC3170149

94. Generational shape shifting: changes in egg shape and size between sexual and asexual generations of a cyclically parthenogenic gall former

Author:
Glen R. Hood; James R. Ott
Source:
Entomologia experimentalis et applicata 2011 v.141 no.1 pp. 88-96
ISSN:
0013-8703
Subject:
Belonocnema treatae; adaptive radiation; body size; dimorphism; eggs; females; models; multivoltine habit; reproductive traits
Abstract:
... Successive generations of multivoltine species experience selection specific to the spatiotemporal environments encountered that may lead to adaptive divergence in reproductive traits among generations. To compare reproductive effort within and between generations, appropriate volumetric models, selected on the basis of the analysis of egg shape, are required to estimate the sizes (volumes) of ind ...
DOI:
10.1111/j.1570-7458.2011.01169.x

95. Growth and survivorship as proximate causes of sexual size dimorphism in peninsula dragon lizards Ctenophorus fionni

Author:
JOHNSTON, GREG
Source:
Austral ecology 2011 v.36 no.2 pp. 117-125
ISSN:
1442-9985
Subject:
Agamidae; body size; captive animals; dimorphism; females; lizards; males; sexual selection; survival rate
Abstract:
... Males and females differ in body size in many animals, but the direction and extent of this sexual size dimorphism (SSD) varies widely. Males are larger than females in most lizards of the iguanian clade, which includes dragon lizards (Agamidae). I tested whether the male larger pattern of SSD in the peninsula dragon lizard, Ctenophorus fionni, is a result of sexual selection for large male size o ...
DOI:
10.1111/j.1442-9993.2010.02113.x

96. Growth differences and dimorphic expression of growth hormone (GH) in female and male Cynoglossus semilaevis after male sexual maturation

Author:
Xiang-Shan Ji; Han-Wen Liu; Song-Lin Chen; Yun-Liang Jiang; Yong-Sheng Tian
Source:
Marine genomics 2011 v.4 no.1 pp. 9-16
ISSN:
1874-7787
Subject:
sexual maturity; messenger RNA; dimorphism; complementary DNA; somatotropin; body weight; Cynoglossus semilaevis; males; models; introns; reverse transcriptase polymerase chain reaction; gene expression; fish; exons; females
Abstract:
... Half-smooth tongue sole, Cynoglossus semilaevis, is an ideal model to investigate the regulatory mechanisms of sexual growth dimorphism in fish species. The aim of the study was to investigate the effect of differential age of sexual maturity for females and males on growth and GH mRNA expression in C. semilaevis. The body weight differences between the sexes were not significant in C. semilaevis ...
DOI:
10.1016/j.margen.2010.11.002
PubMed:
21429460

97. High levels of organochlorines may affect hatching sex ratio and hatchling body mass in arctic glaucous gulls

Author:
Erikstad, Kjell Einar; Moum, Truls; Bustnes, Jan O.; Reiertsen, Tone K.
Source:
Functional ecology 2011 v.25 no.1 pp. 289-296
ISSN:
0269-8463
Subject:
Larus; air; bioaccumulation; blood; body condition; chicks; dimorphism; eggs; embryonic mortality; females; food webs; hatching; islands; males; mothers; oceans; pollutants; predators; progeny; sex hormones; sex ratio; steroids; transportation; Arctic region; Norway
Abstract:
... 1. Long range transportation via ocean currents and air of various organochlorines (OCs) has resulted in their intrusion in the high Arctic marine food web. At the Spitsbergen archipelago, including Bear Island (Norway), bioaccumulation in top predators like glaucous gulls (Larus hyperboreus) is high, severely affecting their breeding performance and survival. 2. In the present study, we examined ...
DOI:
10.1111/j.1365-2435.2010.01771.x

98. Interspecific and sexual shape variation in the filariasis vectors Mansonia dives and Ma. bonneae

Author:
Jiraporn Ruangsittichai; Chamnarn Apiwathnasorn; Jean-Pierre Dujardin
Source:
Infection, genetics, and evolution 2011 v.11 no.8 pp. 2089-2094
ISSN:
1567-1348
Subject:
DNA barcoding; breeding; breeding sites; complement; diagnostic techniques; dimorphism; females; filariasis; forests; geographical variation; males; medical entomology; morphometry; risk; swamps; Thailand
Abstract:
... In the South of Thailand, six Mansonia species are recorded as filariasis vectors, among which Ma. bonneae and Ma. dives. These two species are distributed in the same breeding place, mainly the swamp forest, but appear to be of problematic identification using traditional morphological characters. Because of the risk of wrong identification during epidemiological or biological studies, complement ...
DOI:
10.1016/j.meegid.2011.10.002
PubMed:
22020254

99. Male mate choice based on ontogenetic colour changes of females in the damselfly Ischnura senegalensis

Author:
Takahashi, Yuma; Watanabe, Mamoru
Source:
Journal of ethology 2011 v.29 no.2 pp. 293-299
ISSN:
0289-0771
Subject:
Ischnura; color; copulation; dimorphism; females; males; morphs; rearing; sexual maturity
Abstract:
... While male mate choice behaviour has been reported in many taxa, little is known about its plasticity and evolutionary consequences. In the damselfly Ischnura senegalensis, females exhibit colour dimorphism (gynomorph and andromorph). The body colour of gynomorphs changed ontogenetically in accordance with sexual maturation, while little change occurred in andromorphs. To test the male mate choice ...
DOI:
10.1007/s10164-010-0257-6

100. Modeling the effects of estradiol and progesterone on the acute phase proinflammatory axis: Variability in tumor necrosis factor-α, nitric oxide, and xanthine oxidase responses to endotoxin challenge in steers

Author:
S. Kahl; T.H. Elsasser; C.-J. Li
Source:
Domestic animal endocrinology 2011 v.40 no.4 pp. 213-221
ISSN:
0739-7240
Subject:
Escherichia coli; appetite; biomarkers; blood; crossbreds; diet; dimorphism; disease resistance; estradiol; estrous cycle; females; immune response; innate immunity; intravenous injection; lipopolysaccharides; models; necrosis; nitric oxide; progesterone; steers; steroid hormones; tumor necrosis factor-alpha; xanthine oxidase
Abstract:
... The severity of host response in some diseases differs between sexes, and this dimorphism has been attributed to the immunomodulating effects of reproductive steroid hormones. In females, susceptibility to disease stress has been associated with reproductive status and attributed to prevailing progesterone (P4) or estrogen concentrations during different estrous cycle phases. Our objective was to ...
DOI:
10.1016/j.domaniend.2011.01.003
PubMed:
21356584