The silk webs of glowworms (Arachnocampa tasmaniensis) look like diamond chandeliers, their glowing threads dangling from dark cave ceilings to attract and snare flying insects. A new study reveals that unlike rainforest glowworms, these cave-dwelling larvae of fungus gnats synchronize their glowing patterns so the colony shines brightest during the day. After collecting two species of Arachnocampa larva from Australia, one from a cave in southern Tasmania and one from a rainforest in Queensland, scientists recreated their environments in the lab and allowed the creatures to build their webs. Then they filmed the bioluminescence patterns of each species throughout the day. The cave-dwelling glowworms observe their neighbors and synchronize their cycles of luminescence to match one another , while the rainforest species do not, the team reports this month in Integrative and Comparative Biology. And though the rainforest species shine brightest at night, the cave dwellers peak during the day—a strategy the researchers think may help the species ensnare the most prey.
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