Effects of different temperature regimens on the development of Aedes aegypti (L.) (Diptera: Culicidae) mosquitoes

This study was conducted to determine the effects of increased water temperatures on the development of Aedes aegypti immatures under laboratory conditions in Trinidad, West Indies using temperature regulated water baths to cover a range of temperatures from 24-25 degrees C to 34-35 degrees C at a relative humidity of 80%. Two experiments were designed: (1) at constant temperature regimens and (2) under diurnal temperature regimens ranging from 24-25 degrees C to 34-35 degrees C. At 24-25 degrees C egg hatching success was 98% at 48h, however at 34-35 degrees C egg hatching rates declined to 1.6% after 48h. Ae. aegypti larvae reared under constant temperature regimens showed pupation on day 4 with highest pupation occurring at 30 degrees C (78.4%) However, under diurnal temperature regimens, pupation began on day 4 but only at the higher temperatures of 30-35 degrees C. Under diurnal temperature regimens ranging from 24 degrees C to 35 degrees C significantly more females emerged at higher temperatures, than males. In contrast, at constant temperatures of 24-35 degrees C no significant difference in M/F ratios were observed. The body size of Ae. aegypti reared at constant temperature regimens was significantly larger than males and females larvae reared under diurnal temperature regimens of 25-30 degrees C. The results of this study are discussed in the context of changing or increasing water temperatures, seasonal changes in vector populations and vector competence. Using these key factors control strategies are recommended to manage vector populations as expected increases in temperatures impact the Caribbean region. (C) 2011 Elsevier B.V. All rights reserved.