Taste sensitivity of detritivorous mosquito larvae to decomposed leaf litter.

Dietary leaf litter chemistry is known to play an important ecotoxicological role in the plant-mosquito interaction in subalpine flooded areas surrounded by vegetation because of differential larvicidal effects of insoluble polyphenols formed during the leaf decaying process. This dietary interaction was investigated through comparative evaluation of the role of toxic/nontoxic leaf litter in both larval foraging and feeding behavior, by using different samples of decomposed alder leaf litter and larval Aedes aegypri as experimental references. Track analysis showed significant differences in larval foraging behavior in the absence or presence of leaf litter. Comparative alimentary preference investigations and further track analysis suggested that larvae are unable to detect leaf litter toxicity. These characteristics of the larval behavioral feeding pattern suggested that: (1) decomposed leaf litter may be involved as an important attractive food source in the habitat selection and evolutionary history of culicids, and (2) preingestive behavioral mechanisms appear to be minimally involved in the differential larval dietary adaptation to toxic leaf litter. These results may have interesting consequences for culicid biological control.