Do Glow-Worm Larvae (Coleoptera: Lampyridae) Use Warning Coloration?

Authors


Raphaël De Cock, University of Antwerp (UIA), Department of Biology, Group of Animal Ecology, Universiteitsplein 1, B–2610 Wilrijk, Belgium. E-mail: rdecock@uia.ua.ac.be

Abstract

It is generally believed that the glowing behaviour of lampyrid larvae may be an aposematic display. Moreover, larvae of the common glow-worm (Lampyris noctiluca) show at least two other features, which can be used in aposematic strategies. The first is their suggestive colour pattern of yellow-pinkish lateral dots on a jet-black background and the second a possible warning odour. We performed experiments with starlings (Sturnus vulgaris) to test, in particular, for the significance of the colour pattern as a warning signal. Learning experiments showed that glow-worm larvae were distasteful and that starlings showed increasing avoidance of the distasteful prey through a learning process. Experiments with mimics and glow-worm larvae with obscured colours showed that starlings recognized glow-worm larvae by their colour pattern. However, there was an important effect of experience as one group of starlings that had previous contact with edible glow-worm mimics, showed delayed avoidance learning and was able to discriminate mimics from glow-worms thereafter.

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