Glowworms are more diverse than we thought: cave and forest-adapted species in Australia David J Merritt School of Biological Sciences, The University of Queensland, Qld 4072, Australia. Email:
[email protected] Abstract glowworms of Australia and New Zealand. The main finding is that cave-adapted species such as Glowworms emit light to attract prey into their webs. Arachnocampa tasmaniensis synchronise their They are found in suitable wet caves as well as in bioluminescence in caves, a form of cooperation that forests. In wild caves of Tasmania and New Zealand, appears to give the participants an advantage in being glowworm populations ( Arachnocampa tasmaniensis and able to attract prey more efficiently. In essence, it is Arachnocampa luminosa , respectively) maintain an approach known as group foraging. synchronised rhythmic light output, waxing and waning together in a 24 hour cycle. Here I show how First, I’ll present some background on glowworms. the Tasmanian species (and also probably the New They are members of the genus Arachnocampa . They Zealand species) is capable of synchronizing the produce light to attract prey into their sticky snares. bioluminescence cycle. In laboratory experiments we Light (bioluminescence) is produced in cells located at exposed a single larva to three others that were on a the tips of internal tubular structures branching from different cycle. The single larva shifted its time of the gut, known as Malpighian tubules. In most insects glowing to match the others over about eight days. they function solely as excretory structures, but in This synchronisation capability probably allows the glowworms they have taken on a dual function; glowworm colonies in caves to glow most brightly all excretion and light production.