Parasites, predators and defence of fireflies and glow-worms

It has been argued that bioluminescence in fireflies and glow-worms (Lampyridae) presents a conspicuous signal to attract potential predators. If correct, luminescence should be naturally selected against; however this appears not to be the case. To counter this constant threat insects have developed a range of defensive mechanisms, either active or passive, that protect them from the threat of predation. Fireflies and glow-worms are no exception and it has been argued that defence mechanisms may in fact be enhanced by luminescence. This review examines a range of defence mechanisms identified in lampyrids including thanatosis or death feigning; camouflage or crypsis; chemical defence and aposematism. The predators, parasites and pathogens that seem to overcome these defences are highlighted: including large numbers of endosymbionts associated with lampyrids; beetle parasitoids; phorid flies and the Photuris ‘femme fatale’ fireflies.