Black-lighting (moth edition)

A gorgeous moth that came to the black-light at Yanayacu.

One of the great things about entomology is the variety of ways in which you can hunt down, collect or attract insects. Butterfly nets, aquatic nets, malaise traps, pitfall traps, rotting fruit, heck if you defecate in the forest you'll attract something. One way to get the night fliers is to hang a black-light or a mercury vapor light next to a sheet.

Why are insects, particularly moths, attracted to lights at night? This is still somewhat of a mystery to entomologists. The oft-touted response is that they use moonlight to navigate, and that other nearby light sources disrupt their flight paths and cause them to spiral in. This makes for a nice story, but it needs further testing. Many insects are sensitive to blue and ultraviolet wavelengths, and may have a tough time adjusting their eyes to the darkness once they have landed near a bright light. Once they land on the sheet, they are often docile and easy to collect. Perhaps they think it is daylight, and time to sleep? We set up the black-light almost every night we were at Yanayacu - just for fun.

One of the most interesting behaviors I noticed was the defense response of some saturniid moths. When disturbed they would curl up into a ball! Seems rather counter-intuitive for a moth, when flight appears to be a better escape option. But pay attention to the coloration on the abdomen - black and yellow, classic aposematism (warning colors). Luckily I did not handle them much, because I was later told the warning was for the urticating hairs on their abdomen - could be a pretty bad irritant for humans if touched to a sensitive area like the face. Sneaky moths!

Another fun behavior is when moths try to pretend they're something they're not, or simply want to break up the pattern of their body. This pyralid on the left doesn't exactly scream "I'm a moth!", now, does it? With its upturned abdomen and thin, splayed out wings it looks more like a little broken twig. Certainly, it does not fit the typical search image a predator would have for a moth. It even lays out its antennae along the wings so they do not stand out.

A lot of wonderful moth diversity came to our sheet. Mostly arctiids, saturniids, geometrids and pyralids, with some sphingids, micros, and other families thrown in. Stay tuned for more moth-y goodness.