Overview

• The nocturnal sheet web spider Psechrus clavis was observed leaving trapped winter fireflies (Diaphanes lampyroides) glowing in its web to lure additional insects.
• In field trials at National Taiwan University’s Xitou Nature Educational Area, LED devices mimicking firefly glow increased overall prey capture threefold and firefly capture tenfold versus control webs.
• Video showed spiders immediately consuming moths yet keeping fireflies alive and intermittently checking them for roughly an hour before feeding.
• Most fireflies caught were males, consistent with males mistaking stationary light for a mate during courtship.
• Authors interpret the tactic as predators exploiting prey signals rather than evolving bioluminescence themselves, while noting LED mimics are imperfect proxies for live insects.