June Beetles and Night Lights

July 1, 2013

This last weekend I stayed at Table Mountain campground in the Los Angeles National Forest and was visited by a group of beetles. No, not the British pop group out on a time-travelling-night-time-forest jaunt – though that would be blog worthy indeed. My camp buddies and I were visited by a gang of 40 adult male scarab beetles!

Three of the gang, hanging out on our picnic table. No they're not eating our hot dogs, they prefer pine needles But what are they, you may ask? They are Ten-lined June Beetles, Polyphylla decemlineata, one of California's largest and most conspicuous scarab beetle species. And how did I know they were all males? This species exhibits sexual dimorphism (a fancy way for saying males and females look differently), which is most noticeable in the antennae (sure you could look at the genitals too, but I didn't take a microscope camping with me this time – geez)! The antennae of these male beetles are large and fan-like in appearance. If you're into awesome scientific terminology, you can call them lamellate antennae. Whereas, the females have much smaller antennae of the same variety. The reason males have enlarged antennae is the exact same reason male moths do, to sense female sex pheromones, and hopefully find a willing mate! Unfortunately, for the males that showed up at our camp ground, there were no female beetles pumping out sexy pheromones. Instead they were attracted to our lights. The phenomenon of nocturnal insects being drawn into bright lights is not an uncommon one. You just have to venture outside on warm nights and take a gander at your porch light. Chances are, you'll find a few insects circling it. If you are in a more wild part of the world, you might find A LOT. Entomologists take advantage of this behavior when trying to understand the vast diversity of insect life on this planet. It is not uncommon to see us putting up bright lights in the middle of nowhere to see what wonders arrive. But don't worry, entomologists in exotic locales aren't getting all the fun, we're going to do it here in L.A. too as part of our BioSCAN NightWatch project.

One of my geeky entomologist friends, Dale Halbritter, checking out a lot of insects attracted to our night light in the Arizonan Sonoran desert. BioSCAN staff have partnered with L.A. Makerspace to create DIY night lights. Once the final design of these traps is set, the Museum will be enlisting 100 citizen scientists to set them up in their backyards all over L.A.! That's right, it'll be one massive night of insect collecting, which will help our scientists get a snap shot of nocturnal insect biodiversity in urban Los Angeles. How cool is that? Sign up here to join the fun.    

(Posted by: Lila Higgins)

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