Wednesday, June 29, 2011

Xylocrius agassizi

Over Father's Day weekend (last week) we decided to celebrate and go camping at Dinkey Creek (at about 5,000 feet and just east of Shaver Lake in Fresno County, California). The campground had just been open the week before. This is quite late in the year but the heavy rains and snow had required the delay. Not long after setting up the tent we took a short walk down to Dinkey Creek by the famous bridge. It was there on a large granite boulder that I saw this impressive longhorn beetle, Xylocrius agassizi.

With antennae poised, it is a bit over an inch long and the black body is heavily punctate and covered with black hair. If you look close you can see that the 3rd and 4th segments of the antennae are roughly equal in length and are more rounded at the end than the later segments. These are diagnostic characters of the species.

It is sometimes referred to (unofficially) as the gooseberry borer because it feeds on Ribes, although I've never seen it recognized as a pest. It probably takes a couple of years to complete its life cycle and is not all that frequently encountered. This particular individual is hardly tarnished at all and seems to have just recently emerged. It's quite an attractive insect in its bold black simplicity. The habitat shot is from Dinkey Creek where I found the beetle but from two years ago when the water was much lower.

Saturday, June 18, 2011

Prionus californicus

Over 30 years ago I hung out my first blackight trap to attract night flying insects. It was in the early summer along the Wasatch Front of the Rocky Mountains and I really didn't know what to expect. I hung it out behind our barn and after I had watched it for some time with nothing more than midges and water boatmen coming in I left for the house. Then several minutes later my brother came in quite excited and said that there was a big beetle on the sheet. I ran out to see for myself and found the largest beetle I could imagine. It was Prionus californicus and it was almost 2 inches long.

Since then, I've discovered that this insect isn't uncommon at all. In fact in some places it can be a pest of fruit trees. It is a Western species occuring from Colorado to the West Coast. In the North it occurs in southern Canada and ranges south into northern Mexico.

These pictures are of an individual that landed just outside my office west of Fresno this week. I'm not sure where it came from - maybe somebody's apple orchard. Finding it was like finding an old friend.

Tuesday, June 7, 2011

Omus californicus

The California night-stalking tiger beetle Omus californicus intermedius occurs sporadically through the Sierra Nevada of California. It can be fairly common if you find the right place. Fortunately for us, we found such a place this last weekend a few miles south of Shaver Lake (in Fresno County). Because of the many rains this year and cool temperatures, the area (at an elevation of about 5,000 feet) was still moist (almost wet) and the California dogwoods were still in "bloom". The beetles themselves were under pieces of wood or logs or just under fallen leaves. Jon found the first one. The habitat shot is of Michael in a prime spot.

Finding Omus is always a thrill for me. Having lived in a number of states where I've seen and collected a number of impressive "tigers" I've often rued the fact that Omus was so restricted to the West Coast. Now that I'm living in California I find that they're not all that hard to find after all, at least if you're persistent. Even so, they're an impressive insect. Their mandibles are certainly capable of drawing blood if you gave them the chance.

I've collected them at elevations ranging from 5,000 feet to 8,000 in the Sierra Nevada above Fresno. I know Dennis Haines has found them at lower elevations further south. He tells me that there may be subspecific (or even specific) differences between some of these populations, but further work is needed (which Dennis is currently doing). In the mean time keep your eyes open for them (or any Omus) and let us know if you find some.