Predator feeding vibrations encourage mosquito larvae to shorten their development and so become smaller adults

1. Water-borne predator kairomones are known to allow mosquito larvae to detect and identify the presence of a specific predator, so that they can deploy defences tailored to that predator. Kairomones, however, have limitations, and detection of specific water-borne vibrations produced by a predator would allow fine-tuning of their anti-predator defences. 2. Larvae of the mosquito Culiseta longiareolata have previously been shown to recognise the specific vibration pattern of a feeding dragonfly nymph and respond by altering their feeding behaviour from active bottom-scraping to a more passive surface filter-feeding, while other water vibrations did not produce this response. Culex perexiguus larvae also responded, but to a much lesser extent. 3. In this study, C. perexiguus larvae responded strongly to dragonfly vibrations by reducing their larval duration from 9.8 to 8.7 days, but this resulted in significantly smaller (and thus probably less successful) adults. However, Culiseta longiareolata larvae did not alter their larval duration in response to dragonfly vibrations.