Algodones Dunes Beetles

Algodones Dunes a few miles west of Glamis, CA.

We went over to the Algodones Dunes in California, northwest of Yuma, AZ last weekend to see what beetle species were out this spring. Early April is when several species endemic to the dunes fly – right at dusk. Two years ago I was able to collect a few specimens of Pseudocotalpa andrewsi in an area south of Glamis along I-8. Last year (when the above picture was taken) we were rained out. This year, I hoped to collect Pseudocotalpa sonorica which fly closer to the tops of the dunes.

We dropped off our equipment and drove to the parking area, then proceeded to set up generator, mercury vapor light, and 2 ultra-violet lights. We also hauled in jackets and food for a picnic supper! Going downhill through the deep sand wasn’t nearly as bad as hauling everything back uphill in the dark! But I am getting ahead of myself…

I received a tip that sometimes the beetles can be dug out of the sand by watching for divots which appear a little before dusk. We watched for divots but didn’t find any for a while. During our supper, I watched a bee digging a tunnel in the sand near our picnic spot. It would back up, scooting sand with it’s legs as it came out of it’s hole and continued for several inches before scurrying back into it’s hole. It would have made a great video!

My Canon 100mm macro lens and one flash are on a (possibly) year long field trip to Colombia, South America, so I wasn’t able to get any pictures of the beetles… Oh, the stories that lens is going to be able to tell!

We found a few Tenebrionids but I refrained from collecting any (for the most part). I have picked up a few here and there and already had some from Algodones at home.

As dusk approached we hiked the area looking for divots, and sure enough, we found one – one scoop and out popped Pseudocotalpa sonorica! After that, we dug tons more divots and didn’t find anything (I was warned this would happen…). We found a few more specimens by inspecting the bottom of steep dune faces, where beetles had probably emerged and rolled downhill.

Interestingly, we found a plant that drops seed pods that are almost an exact match in size, shape and color to Pseudocotalpa sonorica! The match is so uncanny that I believe there must be some kind of mimicry involved.

I left all but one small collecting vial in my truck and the parking area was a long (uphill) way away. I decided to drop the beetles in a sandwich bag in which we had packed the wrappers from our supper. I figured the trash would keep them apart and from tearing each other up. The children got into the action and found a few beetles in divots! Closer to dusk, we started finding a species of camel cricket in some of the divots – they had large feet like snowshoes for jumping on the sand. This year, we didn’t encounter any of the sand roaches that were some common last year after the rain.

Right at dusk, the beetles in the sandwich bag began trying to fly. We heard the buzzing and rustling in the bag, and suddenly as if on cue, there were beetles flying all over the dunes! We chased them (fairly unsuccessfully) for a while before realizing that most of them were flying to the lights! I started scooping them up and putting them in the bag.

There were some smaller beetles coming to the light. Scarabs in the genus Diplotaxis (as yet unidentified to species), Leptohoplia testaceipennis and Anomala hardyorum, all species restricted to these sand dunes!

(UPDATE! I examined my series of Leptohoplia testaceipennis and found that all but one were actually another endemic dune beetle – Anomala carlsoni! The two beetle species look almost identical, with only minute differences in mouth, antenna, and leg parts which must be examined under a microscope. The Diplotaxis are likely D. corbula, another dune endemic, but that will be confirmed by an expert at a later date.)

I had enough for my collection and for a few friends in 10 minutes. After that we threw all the extra beetles off the sheets and got the lights turned off  so no more would come. We packed everything up and started carrying loads up to the truck, uphill, in the dark, through deep sand… An hour later we were in Yuma at our hotel getting rid of all the sand!

I really like the dunes and wish they were closer than the 3 hour drive we have to make to get there. We were fortunate to get a night that was calm enough for the beetles to fly. This is the 4th year I have tried to collect at this location, and the only time I have encountered conditions that allowed success!