|Geden, Christopher - Chris|
|Pires Do Prado, Angelo|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2002
Publication Date: 8/1/2002
Citation: FERREIRA, M.A., GEDEN, C.J., PIRES DO PRADO, A. INFLUENCE OF FEEDING TREATMENT, HOST DENSITY, TEMPERATURE AND COOL STORAGE ON ATTACK RATES OF TACHINAEPHAGUS ZEALANDICUS AHSMEAD (HYMENOPTERA: ENCYRTIDAE). ENVIRONMENTAL ENTOMOLOGY. 2002. v.31. p.732-738. Interpretive Summary: Parasitic wasps are important tools for managing house flies and stable flies on livestock and poultry farms. Native species of wasps attack the flies when they are pupae, and numerous studies have shown that releases of these wasps on farms can help control flies while reducing the use of chemical insecticides. Because some of the stages of the flies are not attacked by native species of wasps, there is a need to evaluate exotic species that may compliment the ability of our native species to control pest species. In the present study, scientists at USDA's Center for Medical, Agricultural and Veterinary Entomology (Gainesville, FL) and the University of Campinas (Brazil) evaluated a species of wasp (Tachinaephagus zealandicus) that attacks flies when they are still in the larval stage. Allowing the parasitoids to feed on honey after emergence resulted in a three-fold increase in their attack rates on target flies. Maximum attack rates (ca. 21 flies killed per parasitoid per day) occurred at host densities of 32 larvae per parasitoid. The parasitoids were most effective at cooler temperatures, and had good survival under low-temperature storage conditions.
Technical Abstract: Tachinaephagus zealandicus Ashmead is a gregarious endoparasitoid that attacks third instars of muscoid flies, including house flies (Musca domestica L.). A colony of this parasitoid was established from samples collected from a poultry farm in Santa Cruz da Conceicao, Sao Paulo, Brazil. The objectives of this study were to evaluate the influence of feeding treatment, host density and temperature on attack rates of T. zealandicus. Parasitoids that were given honey as adults attacked 2-3 times as many house fly larvae (25 host attacks/female/day) as parasitoids given only water or nothing. Host attacks and progeny production by T. zealandicus on house fly and Chrysomyia putoria increased over the range of host:parasitoid ratios tested, reaching a maximum of 21-22 hosts killed and 13 progeny produced/female/day at the highest host density of 32 larvae/female. Host attacks were higher at 22oC than at the other temperatures studied (20-29oC), but differences in attack rates were small over the range of 20-27oC (10-13 host attacks/female). Comparatively few hosts (6.3) were attacked at 29oC. Higher rates of progeny production also were observed among parasitoids tested at lower temperatures (9-11 progeny produced/female at 20-22oC) than at 29oC.