Earth Notes: Angel Lichen Moths

Jan 11, 2017

Angel lichen moths take their beautiful name from Bright Angel Creek in Grand Canyon where early specimens were found, and from lichens that the larvae eat. 

Boaters light- trap for moths
Credit Freshwaters Illustrated

Members of the tiger moth family, these insects are only about the size of a quarter. Their bright orange and pink wings are thought to warn predators of their bad taste. Hungry bats don’t seem to be deterred, but the moths have defenses against them too—they respond to bats’ echolocation clicks with their own bursts of clicks, warning the bats to avoid a foul meal.

U.S. Geological Survey ecologist Anya Metcalfe has teamed up with Grand Canyon river runners to study these moths. She and other ecologists trained boaters to use light traps to catch night-flying insects. Between 2012 and 2014, they captured more than 73,000 angel lichen moths in the canyon.

The trap contents revealed that these moths fly only during the spring and fall. Spring moths were much bigger than the ones in autumn. Also, males show up earlier in spring than females, allowing them first chance at finding mates. The larger spring females lay more eggs than the smaller fall females, so mating with them gives males a bigger genetic payoff.

River runners will continue trapping, to see how the moths use the Grand Canyon and whether they’re affected by climate change.