Temperature effects on the dynamics of Aedes albopictus (Diptera: Culicidae) populations in the laboratory

Abstract

We investigated how constant temperatures of 22, 24, and 26 degrees C experienced across the full life cycle affected the dynamics of caged populations of Aedes albopictus (Skuse). All cages were equipped with plastic beakers that served as sites for oviposition and larval development. We measured the per capita daily mortality and emergence rates of the adults and size of adult females, and estimated the intrinsic rate of increase (r) and asymptotic density (K) for each caged population. Populations at 26 degrees C had greater intrinsic rates of increase and lower asymptotic densities than populations at 22 and 24 degrees C. Populations at high temperatures initially had greater daily per capita emergence rates, and steeper declines in per capita emergence rate as density increased over the course of the experiment. There was no temperature effect on the size of adult females nor on the per capita daily mortality rate of adults. Results indicated that populations of Ae. albopictus occurring in regions with relatively high summer temperatures are likely to have high rates of population growth with populations of adults peaking early in the season. These populations may attain relatively low peak densities of adults. Populations occurring in regions with low summer temperatures are likely to experience slow, steady production of adults throughout the season with population size peaking later in the season, and may attain higher peak densities of adults. High temperature conditions, associated with climate change, may increase the rate of spread of Ae. albopictus by increasing rates of increase and by enhancing colonization due to rapid population growth.

Fig. 1

Estimated number of adults based on daily emergences and daily adult mortality in each population at (a) 22°C, (b) 24°C, and (c) 26°C. Intrinsic rate of increase (r) and asymptotic density (K) for the adult population were determined for each cage using the logistic growth equation.

Fig. 2

Means ± SE for intrinsic rate of increase (r), asymptotic densities (K), and time to emergence for females and males of the first cohort for the adult populations at 22, 24, and 26°C. Means of temperature treatments followed by the same letter are not significantly different. Points lacking error bars indicate standard errors that were too small to appear on the graph.