Estimation of Aedes aegypti (Diptera: Culicidae) population size and adult male survival in an urban area in Panama

Traditional mosquito control strategies rely heavily on the use of chemical insecticides. However, concerns about the efficiency of traditional control methods, environmental impact and emerging pesticide resistance have highlighted the necessity for developing innovative tools for mosquito control. Some novel strategies, including release of insects carrying a dominant lethal gene (RIDL®), rely on the sustained release of modified male mosquitoes and therefore benefit from a thorough understanding of the biology of the male of the species. In this report we present the results of a mark-release-recapture study aimed at: (i) establishing the survival in the field of laboratory-reared, wild-type male Aedes aegypti and (b) estimating the size of the local adult Ae. aegypti population. The study took place in Panama, a country where recent increases in the incidence and severity of dengue cases have prompted health authorities to evaluate alternative strategies for vector control. Results suggest a life expectancy of 2.3 days for released male mosquitoes (confidence interval: 1.78-2.86). Overall, the male mosquito population was estimated at 58 males/ha (range 12-81 males/ha), which can be extrapolated to an average of 0.64 pupae/person for the study area. The practical implications of these results are discussed.

Physiological age and longevity of Anopheles (Kerteszia) cruzii Dyar Knab (Diptera: Culicidae) in the Atlantic Forest of Southern Brazil

We analyzed the reproductive status, ovarian development, daily survival rate, and length of the gonotrophic cycle in females of Anopheles ( Kerteszia ) cruzii Dyar & Knab, to determine how these factors influence the risk of malaria transmission in the coastal region of the state of Paraná, southern Brazil. In the Palmito State Forest, Paranaguá, females were captured at dawn and dusk by aspiration, bimonthly from December 2006 through March 2007. A total of 2,268 females were captured, of which 454 were dissected. Of these, 48 percent were parous, 50 percent not reproductive, 73 percent in Christopher and Mer stages I and II, 23 percent in stages III to V, 55 percent nulliparous, 14 percent uniparous, and 11 percent had blood in their midgut. Daily survival was 0.24 ± 0.03 overall, 0.51 ± 0.04 for females captured at dusk, and 0.25 ± 0.03 for those captured at dawn. The Davidson equation for calculation of the gonotrophic cycle was inadequate for An. cruzii populations. Females captured at dusk had a higher survival rate than those from dawn, which means that more females of the dusk population enter the parasite extrinsic cycle. The continuous activity and abundance of A. cruzii in the Palmito State Forest suggests that the conditions are very favorable for its development, with a potential for participation in the protozoan's transmission cycle.