Impact of rearing temperature and water pH on longevity and pesticide resistance in Aedes aegypti (Diptera: Culicidae)
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
PUCE - Quito
Abstract
Background: Aedes aegypti (Diptera: Culicidae) is considered as one of the
main arboviral disease vectors around the planet. Because A. aegypti is an
ectotherm and breeds in fresh water pools, climatic conditions influence its
biology, distribution, population dynamics and vectorial capacity. To investigate
the potential impact of future climate change on A. aegypti´s biology, we studied
the effect of variations in environmental temperature and the pH of breeding
water on this species longevity and pesticide resistance.
Methods: Mosquitoes of both geographic (experimental) and control strains
were reared under different environmental conditions (environmental
temperatures of 25°, 28°, 31°C, maintained throughout the insects´ life span;
water pH values of 4, 5 and 6 set at the beginning of larval development). Upon
adult emergence, we monitored the longevity and pesticide 25 resistance for each
treatment.
Results: Both environmental temperature and water pH seem to influence adult
longevity and pesticide resistance in A. aegypti. Longevity is significantly
diminished in temperatures above or below 28°C, as well as with the
acidification of the initial breeding water. Similarly, pesticide resistance seems
to decrease significantly in specimens reared above or below 28oC, and in
specimens reared in acidic environments.
Conclusions: We found that within our temperature gradient there is an optimal
rearing temperature (28°C) which maximizes the longevity of our specimens.
Additionally, the acidification of the aquatic habitats of larval stages diminished
the lifespan of the vector. In reference to deltamethrin resistance, acidification
of the breeding water as well as non-optimal rearing temperatures (25 & 31°C)
produced lower levels of resistance than those observed in the control
treatments, for both temperature and water pH.
Although the definitive effects of climate change on A. aegypti biology and
physiology in the field are hard to predict, our study contributes novel
information about the biology and physiology of this vector species under
controlled conditions. This information could help us understand the potential
effects of putative future climate scenarios on the transmission of arboviral diseases.
Description
Keywords
Flies, Ecuador - Insects, Yellow fever, Global environmental change