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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North Campus Unveiled with a Bang and a Bug!

April 20, 2012

Yesterday, we unveiled the North Campus at a press preview! We wowed the press with our amazing scientists, Poppy the pond turtle from our Live Animal Program, and a gaggle of school children planting in the Home Garden.

Dr. Greg Pauly, Museum Herpetology Curator withPoppy the Pond Turtle

Student from the Ambassador School of Global Education inspecting the Home GardenAlthough there was a lot going on, there were a few distractions. Firstly, in the middle of Poppy's debut performance, there was a loud bangyes people, that was a collision between a motorist and the new Exposition light rail. Thankfully, no one was seriously injured! Secondly, I found a Green Fruit Beetle grub! In my mind, both of these distractions are equally diverting.

Big bangs aren't always theoretical!Green Fruit Beetles, Cotinis mutabilis (or GFBs as I fondly refer to them), are a well-known scarab beetle here in the L.A. basin. Many people regale me with stories of their dealings with these insects. It's either, "Oh yeah, I used to tie dental floss to their legs and let them fly around my head." Or, "that's what has been eating the fruit in my garden, they are Japanese beetles right?" These beetles do indeed feed on a wide variety of fruits including tomatoes, peaches, plums, figs, apricots, nectarines, grapes, and even cactus fruit! However, they are not Japanese Beetles, Popilla japonica, which is an East coast species. To make matters more confusing, these insects are commonly referred to by many names including "junebugs", "fig eating beetles", and even "crawlybacks" when speaking of the grubs!

Finding a picture of the adult in my copy of Insects of the Los Angeles Basin

Green Fruit Beetle grubI usually find GFB grubs in compost piles. These c-shaped larvae are, like caterpillars, tube-shaped eating machines. They hang out in decomposing plant material and move around on their backs. According to Insects of the Los Angeles Basin, "they obtain purchase on the substratum with transverse rows of stiff short stout bristles on the back of the thorax." Next time you find one of these grubs, pick it up and rub the top of the thoraxthe area right behind the grub's headand you can actually feel the bristles (I just tried it, they are really there). 

(Posted by: Lila Higgins)

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L.A.'s Super Bloom

April 4, 2017