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Survival and predation of Delphastus catalinae (Coleoptera: Coccinellidae), a predator of whitefiles (Homoptera: Aleyrodidae), after exposure to a range of constant temperatures
- Simmons, A.M., Legaspi, J.C.
- Environmental entomology 2004 v.33 no.4 pp. 839
- predatory insects, Aleyrodidae, Bemisia tabaci, Bemisia argentifolii, predator-prey relationships, predation, mortality, temperature, developmental stages, overwintering, biological control agents
- Delphastus catalinae (Horn) is a predator of whiteflies that has shown promise as a tool in pest management strategies. Exposure to short-term temperature extremes can affect the survival of predators in a greenhouse or field environment. The B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius), survives the winters of mild climates (where temperatures are commonly above 0°C), but it is not known if D. catalinae can survive such winters. The influence of constant temperature on the survival of D. catalinae was determined in the laboratory using eggs and nymphs of the B-biotype B. tabaci. Over 90% of the adult beetles exposed to temperature regimens of 5, 10, 15, 20, 25, 30, and 35°C for 24 h survived when confined with hosts. The lower and upper thresholds for survival over that duration were around 0 and 40°C, respectively; 1% of the insects survived temperatures beyond these extremes. Survival of D. catalinae pupae was similar to that of adults. Adult D. catalinae survived up to 5.8 mo when confined on a plant infested with whitefly eggs and nymphs and held at 25°C; 50% of the cohort survived for 3.4 mo. Those held in a similar test at 35°C lived up to 0.6 mo. The number of immature whiteflies consumed during 24 h by adult D. catalinae generally increased with temperatures of 14-30°C. This study provides information on temperatures that may affect the survival of D. catalinae during commercial shipment and after release for biological control in the field or greenhouse, and it may help in the understanding of their ability to survive mild winters.