L. PHILIP LOUNIBOS A1
A1 Florida Medical Entomology Laboratory, University of Florida
Hypotheses concerning the developmental plasticity of species that occupy temporary versus permanent aquatic habitats were tested on Psorophora howardii, a mosquito whose predatory larvae occur in ditches flooded for brief periods to irrigate citrus trees in Florida. Responses of P. howardii to experimental variations in temperature and prey availability were compared to those of Toxorhynchites rutilus, a mosquito species whose predatory larvae occupy the relatively permanent waters of treeholes. As predicted, the permanent-water species was more variable in developmental time, and some results suggested that the temporary-habitat predator was more plastic in weight at pupation. Survival of P. howardii was reduced when prey were scarce, and in the complete absence of prey this species died 7–12 times faster than T. rutilus, probably as a result of the higher energy costs of active versus ambush predation. Adults of P. howardii mated precociously after emergence in cages and lived, on average, only 6–11 days compared to an average life span of 84–93 days for T. rutilus. Information on other temporarywater mosquito species indicates that boom-or-bust development of larvae may be associated frequently with early mating and reduced longevity of adults.
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