Associative Learning Capabilities of Adult Culex quinquefasciatus Say and Other Mosquitoes

摘要

The association of olfactory information with a resource is broadly known asolfactory-based associative learning. From an ecological perspective, associativelearning can reduce search time for resources and fine tune responses to changing bioticand abiotic factors in a variable environment, which in mosquitoes has implications forpathogen transmission and vector control strategies. The purpose of this dissertation wasto examine the ability for olfactory-based associative learning across the major lifehistory domains of mosquitoes.Six different experiments comprise this dissertation. The first was to evaluate theresponse of mosquitoes following conditioning to 5, 10 or 50% sucrose concentrationswith individual level mosquito conditioning and testing and introduction of statisticalanalysis with binary logistic regression. Mosquitoes did not respond in a dose dependentmanner with respect to positive response to target odors following conditioning. Thiseffect appears to be related to the mosquitoes' prior exposure to sugar as those exposedto 10% sucrose before conditioning did not prefer 50% sucrose but significantly fewer chose 5% sucrose. In an evaluation of host associated odors and second blood mealchoice by females using a dual-choice olfactometer no significant effects were observed.The lack of significance may have been due to insufficient sample sizes, problems withodor collection or physiological state of mosquitoes. Effects of predatory mosquitofishon larval development and female oviposition choice were evaluated by rearing inseparated habitats under three different treatments followed by an oviposition choiceassay. Females did not prefer their natal habitat or avoid predators but chose substratethat had contained mosquitofish fed conspecific larvae. Mosquitofish affected larvaldevelopment with acceleration in treatments with mosquitofish fed Tetramin? anddelayed pupation in treatments with mosquitofish fed conspecific larvae. Mosquitomemory length was evaluated by conditioning and testing at six time intervals fromcolony and field populations at two ages. Younger mosquitoes showed higher levels ofpositive response after conditioning at all time intervals except the longest (24h). Finallythe olfactory-based associative learning ability of Anopheles cracens was evaluated.Significant evidence for learning was observed in males but not females at a memorylength interval of 24h.