Egg survivorship of A. albopictus and A. aegypti in flower vases was compared in six South Florida cemeteries. At three of these locations, populations of the two species coexist, but at the other three cemeteries A. aegypti has gone extinct subsequent to the A. albopictus invasion of the early 1990s. For our dry-season experiment, egg samples were collected at two- and four-week intervals, and survivorship assessed by responses to hatching stimuli in the laboratory. Concurrently, we monitored temperature and humidity within similar vases at each site using HOBOŽ data loggers.
Egg survivorship was significantly higher for A. aegypti and differed significantly among cemeteries for both species. Climatic variables recorded from vases at each cemetery throughout the periods of egg exposure were subjected to a principal components analysis. MANOVA of PCs showed that aegypti-persistent cemeteries were significantly warmer and with lower average relative humidity than aegypti-extinct cemeteries. However, the means of climatic variables for the six cemeteries were weak predictors of egg survivorship in logistic regressions, in part because of one anomalous cemetery. A complementary field study demonstrated that there are significant differences in the microclimate within a vase due to the presence of water in vases and the incidence of shade. Thus, we expect considerable inter-vase variation in environmental effects on egg survival, and that mean microclimate variables for a cemetery may provide only limited information about the influence of microclimate on egg survival.
Species 1: Diptera Culicidae Aedes aegypti (yellow fever mosquito)
Species 2: Diptera Culicidae Aedes albopictus (Asian tiger mosquito)
Keywords: survivorship, extinction
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