|Barnard, Donald - Don|
Submitted to: Journal of Vector Ecology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/25/2004
Publication Date: 12/1/2004
Citation: Xue, R., Ali, A., Barnard, D.R. 2004. Effects of forced egg retention in aedes albopictus on adult survival and reproduction following application of deet as an oviposition deterrent. Journal of Vector Ecology. 30(1):45-48. Interpretive Summary: Insect repellents intended for application on skin are normally not evaluated for other types of biological activity. However, when scientists at the ARS Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida, the University of Florida and the Anastasia Mosquito Control District tested the effect of mosquito repellents added to the water in which females normally lay their eggs, they found that the females exposed to repellent-treated water retained their eggs and lived longer than females not exposed to repellent treated water. In addition, emales exposed to repellent-treated water ultimately deposited fewer eggs (and these eggs had a lower average hatch rate) than did females not exposed to repellent-treated water. Thus, while egg-retention in repellent-exposed female mosquitoes slightly lengthened the life span, it resulted in lower overall fecundity and average egg hatch rates. The results of this study indicate that oviposition repellents may be useful for mosquito control. For example, in urban/suburban environments where container inhabiting mosquitoes are frequently found, repellents could be used to deprive female mosquitoes of a place to lay their eggs. A second control strategy would comprise locating repellents in the environment to force gravid females away from their normal oviposition sites towards lethal ovitraps.
Technical Abstract: The insect repellent deet (0.1% concentration), used as mosquito oviposition deterrent in the laboratory, influenced caged gravid female Aedes albopictus Skuse to retain (and maintain) mature eggs. This egg-retention mechanism could benefit survival because the gravid females were ultimately able to lay maintained eggs upon availability of water or other liquid media; however, the length of forced egg-retention time reduced the number of eggs laid per female. Gravid females with retained eggs also laid a higher percentage of eggs that failed to tan, and this percentage increased with time duration of egg-retention. Percent egg hatch was not significantly affected by deet, when used as an oviposition deterrent; however, percent hatch was affected by time duration of egg-retention in both treated (exposed to deet) and untreated (control) gravid females. The rate of egg hatch was considerably reduced after 3 weeks of retention; this reduction declined to zero for treated and control females at 6 and 4 weeks posttreatment, respectively. The fecundity and fertility of gravid female Ae. albopictus were affected by the time duration of forced egg-retention.