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1. Fledgling sex-ratio is biased towards the helping sex in a Neotropical cooperative breeder, the brown-and-yellow marshbird (Pseudoleistes virescens)

Author:
Mermoz, Myriam E.; Villarruel, Cecilia; de la Colina, Alicia; Mahler, Bettina
ISSN:
0005-7959
Subject:
sex ratio,   etc   ; Neotropics; fledglings;     Show all 3 Subjects
Abstract:
... In many cooperatively breeding species, helpers increase the breeding success of their parents. The repayment hypothesis predicts a skewed sex-ratio towards the helping sex at population level; at individual level bias would increase in broods attended by a smaller number of helpers. We studied a brown-and-yellow marshbird (Pseudoleistes virescens) population during 11 breeding seasons. We found t ...
DOI:
10.1163/1568539X-bja10061

2. Breeding Status and Sex Ratio of Ancient Murrelets Captured in the Nocturnal At-Sea Congregation Off Teuri Island, Japan

Author:
Matsui, Shin; Whitworth, Darrell; Sugita, Norimasa; Nishiumi, Isao
Source:
Ornithological science 2020 v.19 no.2 pp. 203-209
ISSN:
1347-0558
Subject:
sex ratio,   etc   ; Japan; skull;     Show all 3 Subjects
Abstract:
... We examined brood patch development, sex ratios, and morphological traits of 30 Ancient Murrelets Synthliboramphus antiquus captured from the nocturnal at-sea congregation off Teuri Island, Hokkaido, Japan during late May to early June 2016. Molecular sexing determined that 12 of the murrelets were males and 18 were females. The proportions of murrelets with brood patches (an indicator of breeding ...
DOI:
10.2326/osj.19.203

3. Museum records indicate male bias in pollinators of sexually deceptive orchids

Author:
Brunton Martin, A. L.; Gaskett, A. C.; O’Hanlon, J. C.
Source:
Die Naturwissenschaften 2021 v.108 no.4 pp. 25
ISSN:
0028-1042
Subject:
sex ratio,   etc   ; Ichneumonidae; Orchidaceae; males; museums; pollinators; prediction; spermatozoa; surveys;     Show all 9 Subjects
Abstract:
... Deception has evolved in a range of taxa. When deception imposes costs, yet persists over generations, exploited species typically have traits to help them bear or minimise costs. The sexually deceptive orchids, Cryptostylis spp., are pollinated by tricking male haplodiploid wasps (Lissopimpla excelsa) into mating with flowers, which offer no reward and often elicit sperm wastage. We hypothesise t ...
DOI:
10.1007/s00114-021-01737-x

4. Males can adjust offspring sex ratio in an adaptive fashion through different mechanisms

Author:
Douhard, Mathieu; Geffroy, Benjamin
Source:
BioEssays 2021 v.43 no.5 pp. e2000264
ISSN:
0265-9247
Subject:
sex ratio,   etc   ; epigenetics; fish; progeny; sex allocation; sex determination;     Show all 6 Subjects
Abstract:
... Sex allocation research has primarily focused on offspring sex‐ratio adjustment by mothers. Yet, fathers also benefit from producing more of the sex with greater fitness returns. Here, we review the state‐of‐the art in the study of male‐driven sex allocation and, counter to the current paradigm, we propose that males can adaptively influence offspring sex ratio through a wide variety of mechanisms ...
DOI:
10.1002/bies.202000264

5. Field assessment of the efficiency of two sampling techniques for adult caddisflies (Insecta: Trichoptera)

Author:
Pereira, Rafael; Rodrigues, Gilberto Gonçalves; Calor, Adolfo Ricardo; Vasconcelos, Simão Dias
Source:
International journal of tropical insect science 2021 v.41 no.1 pp. 903-908
ISSN:
1742-7592
Subject:
sex ratio,   etc   ; ; Trichoptera; conservation areas; insects; rain forests;     Show all 6 Subjects
Abstract:
... Sampling small-sized, nocturnal amphibiotic insects poses practical questions onto which technique should be used. This is the case of Trichoptera adults, which have been sampled mostly by using pan, light sheets associated with UV lamps. The urgency of selective and efficient sampling, however, requires quantitative comparison of different methods. We evaluated in situ efficiency of two technique ...
DOI:
10.1007/s42690-020-00255-z

6. Symbiont dynamics during the blood meal of Ixodes ricinus nymphs differ according to their sex

Author:
Daveu, Romain; Laurence, Cindy; Bouju-Albert, Agnès; Sassera, Davide; Plantard, Olivier
Source:
Ticks and tick-borne diseases 2021 v.12 no.4 pp. 101707
ISSN:
1877-959X
Subject:
sex ratio,   etc   ; Candidatus Midichloria mitochondrii; Ixodes ricinus; blood meal; body weight; endosymbionts; engorgement; experimental design; ticks;     Show all 9 Subjects
Abstract:
... Ticks harbour rich and diverse microbiota and, among the microorganisms associated with them, endosymbionts are the subject of a growing interest due to their crucial role in the biology of their arthropod host. Midichloria mitochondrii is the main endosymbiont of the European tick Ixodes ricinus and is found in abundance in all I. ricinus females, while at a much lower density in males, where it ...
DOI:
10.1016/j.ttbdis.2021.101707

7. Identification of sex-specific sequences through 2b-RAD sequencing in Pseudobagrus ussuriensis

Author:
Zhu, Chuankun; Liu, Haiyang; Cheng, Lei; Pan, Zhengjun; Chang, Guoliang; Wu, Nan; Wang, Hui; Ding, Huaiyu; Fang, Ying; Wang, Long
Source:
Aquaculture 2021 v.539 pp. 736639
ISSN:
0044-8486
Subject:
sex ratio,   etc   ; DNA; Pseudobagrus; aquaculture; females; fish; males; sex chromosomes; sex determination;     Show all 9 Subjects
Abstract:
... Sex-specific markers and sequences are essential tools for sex-determination mechanism analyses and sex-control breeding of fishes. Pseudobagrus ussuriensis is a high-value aquaculture fish with great potential for all-male breeding, as males grow much faster than females. In the present study, reduced restriction site-associated DNA sequencing was performed in five female and five male P. ussurie ...
DOI:
10.1016/j.aquaculture.2021.736639

8. Spatial distribution, sampling efficiency and Taylor's power law. 2. Interpreting density‐dependent sampling efficiency

Author:
Taylor, R. A. J.
Source:
Agricultural and forest entomology 2021 v.23 no.2 pp. 173-188
ISSN:
1461-9555
Subject:
sex ratio,   etc   ; Lymantria dispar; egg masses; entomology; females; forests; males; moths; variance;     Show all 9 Subjects
Abstract:
... The intimate relationship between sampling efficiency and Taylor's power law (TPL) was investigated with gypsy moth sample data. The data were used to compute sampling efficiency directly and indirectly by TPL. Comparison of TPLs and efficiency plots of male and female pupae confirmed the identities linking TPL with sampling efficiency. Divergence of sex‐specific TPL plots indicated local scale de ...
DOI:
10.1111/afe.12416

9. Sex Ratio, Fecundity and Morphometry of the Eggs of Freshwater Prawn Macrobrachium Americanum (Bate, 1868) in the Petatlán River, Sinaloa, Mexico

Author:
Diarte-Plata, Genaro; Escamilla-Montes, Ruth; Granados-Alcantar, Salvador; Luna-González, Antonio
Source:
Croatian journal of fisheries 2021 v.79 no.1 pp. 1-14
ISSN:
1848-0586
Subject:
sex ratio,   etc   ; Macrobrachium; cephalothorax; eggs; embryogenesis; fecundity; fisheries; linear models; morphometry; rivers; Mexico;     Show all 11 Subjects
Abstract:
... Macrobrachium americanum has a high commercial value with good fishing and cultivation possibilities in Mexico. Currently there is little information on reproductive aspects so the present work analyzed the sex ratio, fecundity and morphometry of the eggs of M. americanum in the Petatlán River, Sinaloa, Mexico. A total of 31 ovigerous females were captured. The sex ratio was 0.39 F: 1 M. The parti ...
DOI:
10.2478/cjf-2021-0001

10. Sex Investment Ratio and Split Sex Ratio in the Fission-Performing Ant Cataglyphis tartessica

Author:
Amor, Fernando; Cerdá, Xim; Boulay, Raphaël
Source:
Journal of insect behavior 2021 v.34 no.1-2 pp. 8-15
ISSN:
0892-7553
Subject:
sex ratio,   etc   ; Cataglyphis; asymmetry; females; insect behavior; males; monogyny; national parks; Spain;     Show all 9 Subjects
Abstract:
... Inclusive fitness theory predicts that the sex investment ratio should be female biased in social insects with haplodiploidy-generated relatedness asymmetry (between females and males and also among females). However, this ratio should become male biased if related females are competing with each other for resources, as it is predicted by local resource competition hypothesis. This specific situat ...
DOI:
10.1007/s10905-020-09764-8

11. Field and Laboratory Observations on the Life History of Gordius terrestris (Phylum Nematomorpha), a Terrestrial Nematomorph

Author:
Anaya, Christina; Hanelt, Ben; Bolek, Matthew G.
Source:
TheJournal of parasitology 2021 v.107 no.1 pp. 48-58
ISSN:
0022-3395
Subject:
sex ratio,   etc   ; Nematomorpha; adults; eggs; females; life history; parasitology; soil; winter; Oklahoma;     Show all 10 Subjects
Abstract:
... To date, all free-living adult hairworms have been reported from aquatic habitats. However, in Oklahoma, a recently described gordiid, Gordius terrestris, is consistently encountered in terrestrial habitats. We found this gordiid species has a unique egg morphology, unlike that of any other hairworm species, with an outer shell separated by distinct space from a thick inner membrane surrounding th ...
DOI:
10.1645/20-53

12. Egg size‐mediated sex allocation and mating‐regulated reproductive investment in a haplodiploid thrips species

Author:
Katlav, Alihan; Cook, James M.; Riegler, Markus
Source:
Functional ecology 2021 v.35 no.2 pp. 485-498
ISSN:
0269-8463
Subject:
sex ratio,   etc   ; ecology; eggs; fecundity; females; males; natural selection; progeny; resource allocation; sex allocation; spermatozoa;     Show all 11 Subjects
Abstract:
... The partitioning of resources between male and female offspring is a fundamental aspect of the reproductive biology of animals. Sex allocation can be adjusted by controlling offspring sex ratio or by sex‐specific resource allocation towards individual eggs. The latter is well‐known in birds and reptiles, but less studied in other organisms, especially haplodiploids with females that can adjust off ...
DOI:
10.1111/1365-2435.13724

13. Population parameters of the orange mud crab Scylla olivacea (Herbst, 1796) from the Sundarban mangrove forest in Bangladesh

Author:
Rouf, Muhammad Abdur; Shahriar, Sheik Istiak Md; Antu, Al-Hasan; Siddiqui, Md Noman
Source:
Heliyon 2021 v.7 no.2 pp. e06223
ISSN:
2405-8440
Subject:
sex ratio,   etc   ; Scylla olivacea; allometry; crabs; females; males; mangrove forests; mortality; Bangladesh;     Show all 9 Subjects
Abstract:
... Population parameters of orange mud crab (Scylla olivacea) were estimated, aiming to determine sex ratios, carapace width-body weight (CW-BW) relationships, asymptotic width (CW∝), growth coefficient (K), mortality (Z, M, and F), recruitment and level of exploitation (E) in the Sundarban mangrove forest, located in the south-western part of Bangladesh. Year-round samples were collected using hook- ...
DOI:
10.1016/j.heliyon.2021.e06223

14. Effect of high temperature during larval and juvenile stages on masculinization of common carp (Cyprinus carpio, L)

Author:
Biswas, Chandroshakar; Chakraborty, Srijit; Munilkumar, S.; Gireesh-Babu, P.; Sawant, Paramita Banerjee; Chadha, Narinder Kumar; Krishna, Gopal; Dasgupta, Subrata
Source:
Aquaculture 2021 v.530 pp. 735803
ISSN:
0044-8486
Subject:
sex ratio,   etc   ; Cyprinus carpio; carp; hatching; juveniles; larvae; males; masculinization; phenotype; sex determination; temperature; thermosensitivity;     Show all 12 Subjects
Abstract:
... Temperature can influence sex differentiation in gonochoristic fish with a genetic sex-determination system (GSD). The precise effect of high temperature on sex remains unknown in a eurythermal carp (Cyprinus carpio). The present study aimed to identify the critical thermosensitive period and the effect of temperature on sex differentiation in common carp, C. carpio. Our results demonstrated the l ...
DOI:
10.1016/j.aquaculture.2020.735803

15. Variables Biológicas Relacionadas con la Cría Masiva de Trichopria drosophilae¹, Principal Parasitoide de Drosophila suzukii

Author:
Pérez-Pérez, Williams J.; Sánchez-González, Jorge A.; Cruz-Rodríguez, Juan A.; Gómez-Tovar, Laura; Pérez-Godínez, Edmundo A.; González-Cabrera, J.; Arredondo-Bernal, Hugo C.
Source:
TheSouthwestern entomologist 2021 v.45 no.4 pp. 985-996
ISSN:
0147-1724
Subject:
sex ratio,   etc   ; Trichopria drosophilae; agar; bananas; entomologists; mass rearing; parasitism; parasitoids; Mexico;     Show all 9 Subjects
Abstract:
... Rearing of the parasitoid Trichopria drosophilae (Perkins) (Hymenoptera: Diapriidae) was implemented in 2015 in Mexico. Since then, the parasitoid and its host D. suzukii have been reared using a mass-rearing approach. The equipment and facilities utilize household instruments, and the parasitoid and its host are reared on fresh banana fruit, and neither agar nor preservatives are used. Five biolo ...
DOI:
10.3958/059.045.0417

16. Seasonal changes in maturational status, body condition, and population structure in the Moroccan Atlantic Sardine Sardina pilchardus (Teleostei: Clupeidae) from Safi fishing area

Author:
Znari, Mohammed; Mounir, Abdelaziz
Source:
Regional studies in marine science 2021 v.41 pp. 101571
ISSN:
2352-4855
Subject:
sex ratio,   etc   ; Sardina pilchardus; body condition; body weight; gonadosomatic index; immatures; marine science; morphometry; population structure;     Show all 9 Subjects
Abstract:
... Aspects of reproduction and population structure were investigated between June 2017 to May 2018 in sardines, Sardina pilchardus (Walbaum, 1792) from the Safi fishing area. The sex ratio was generally in favor of males (χ2=19.50). Out of 3252 total specimens sampled, 1404 were females (46.00%), 1648 males 50.68%) and 200 immatures (6.15%). The immatures were best represented in the small size clas ...
DOI:
10.1016/j.rsma.2020.101571

17. Split sex ratios and genetic relatedness in a primitively eusocial sweat bee

Author:
Pennell, Tanya M; Field, Jeremy
Source:
Behavioral ecology and sociobiology 2021 v.75 no.1 pp. 5
ISSN:
0340-5443
Subject:
sex ratio,   etc   ; Lasioglossum malachurum; asymmetry; ecology; evolutionary biology; females; males; paternity; progeny; reproduction; sociobiology;     Show all 11 Subjects
Abstract:
... In eusocial Hymenoptera, queens and their helper offspring should favour different sex investment ratios. Queens should prefer a 1:1 investment ratio, as they are equally related to offspring of both sexes (r = 0.5). In contrast, helpers should favour an investment ratio of 3:1 towards the production of female brood. This conflict arises because helpers are more closely related to full sisters (r  ...
DOI:
10.1007/s00265-020-02944-8

18. Trade-off between mate choice speed and decision accuracy under mating competition in female sand gobies

Author:
Diaz Pauli, Beatriz; Lindström, Kai
Source:
Journal of ethology 2021 v.39 no.1 pp. 55-64
ISSN:
0289-0771
Subject:
sex ratio,   etc   ; adults; animal behavior; eggs; females; males; sexual selection; social environment;     Show all 8 Subjects
Abstract:
... Variation in female mating performance can affect the direction and rate of evolution through sexual selection. The social environment determines the availability of mates and the competitive situation, and hence can influence mating strategies. However, these effects have to be considered within time constraints. Here we show that female sand gobies exposed to same-sex competitors (female-biased ...
DOI:
10.1007/s10164-020-00673-z

19. 50 Sex ratio at birth in dairy cattle is affected by the invitro embryo production process

Author:
Vivanco-Mackie, H. W.; Díaz, R.; Ponce-Salazar, M. D.; Alayo, E.; Bustamante, G.; Mesía, I.
Source:
Reproduction, fertility, and development 2021 v.33 no.2 pp. 132
ISSN:
1031-3613
Subject:
sex ratio,   etc   ; blastocyst; coculture; embryo transfer; farms; glucose; herds; males; semen;     Show all 9 Subjects
Abstract:
... Data from a herd of 3,000 high-producing milking dairy cows under an intensive feeding system was analysed. The IVF laboratory at the farm uses a co-culture system (Vivanco-Mackie; page 30-48 in Proc. 2000 Australian Embryo Transfer Society) and transfers ∼1000 embryos per year. The semen used for IVF and for inseminations (AI) in the herd was female-sexed (F-sexed) and non-sexed (conventional). D ...
DOI:
10.1071/RDv33n2Ab50

20. High temperature induced masculinization of zebrafish by down-regulation of sox9b and esr1 via DNA methylation

Author:
Han, Jiangyuan; Hu, Yan; Qi, Yongmei; Yuan, Cong; Naeem, Sajid; Huang, Dejun
Source:
Journal of environmental sciences (China) 2021 v.107 pp. 160-170
ISSN:
1001-0742
Subject:
sex ratio,   etc   ; DNA methylation; DNA methyltransferase; Danio rerio; epigenetics; fish; gene expression; masculinization; temperature; transcription factors; China;     Show all 11 Subjects
Abstract:
... Elevated temperature could influence the sex differentiation by altering the expression of sex-related genes in fish. However, the underlying mechanisms by which the gene expression is altered remain poorly understood. Here, we aimed to explore the role of DNA methylation in sex differentiation of zebrafish (Danio rerio) in response to elevated temperature. The results showed that high temperature ...
DOI:
10.1016/j.jes.2021.01.032