Abstract

Mosquito control pesticides are applied in the Florida Keys as mosquitoes pose a health threat and a nuisance to humans. However, there is a need to investigate the effects that these pesticides have on non-targeted marine organisms. As such, we tested the two mosquito control pesticides used in the Keys (i.e. naled and permethrin) on a critical early life history stage of queen conch (Strombus gigas). We conducted 12-hour exposure experiments on competent queen conch larvae using environmentally relevant pesticide concentrations. We found that there was little to no mortality, probably due to the low exposure time. However, a significantly higher proportion of larvae underwent metamorphosis in the pesticide treatments. Molluscan larvae undergo metamorphosis when exposed to neuroactive compounds (e.g. KCl, DOPA) and the mode of action in both pesticides targets the nervous system. Aerial drift can carry these pesticides over nearshore waters, where they may act as a false metamorphic cue and induce queen conch larvae to settle in potentially inappropriate habitats. This has implications for coastal development in the Keys as mosquito control pesticides may be negatively affecting the recovery of nearshore queen conch populations

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