Petrophila confusalis Crambidae
Missoula, MT
July 21, 2015
Robert Niese
These adorable moths are absolutely fascinating! They often rest with their hindwings partially visible, displaying these prominent black spots. It’s likely that these patterns look like jumping spiders to potential predators or parasites (i.e. wasps). Check out this awesome video of the moth moving its wings to make its eyespots look extra scary, and this cool video of a different species chasing a male jumping spider like it’s a potential mate. In addition to this cool ability to mimic its predators, these moths also lay their eggs underwater! Females actually dive down to the bottom of fast-flowing streams to lay their eggs on algae-ridden rocks in riffles and rapids. During these dives, their abdomens get encased in a bubble of air, providing them with oxygen just like a scuba diver! The larvae then hatch and consume the diatoms and algae growing on the stream-bottom.
We must have had six of these moths at our lights last night! Happy National Moth Week!
Northwest Naturalist 