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.

Sierran Treefrog

On the same trip that I found the Scaphinotus ground beetle (see previous post) I came upon a stream less than a mile further up the hill. I was a bit surprised that there was as much water as there was. For even though this is the foothills of the Sierra Nevada, this particular drainage is fairly low - just the back side of Table Mountain, a low elevation plateau.

I was even more surprised to hear many frog calls and went in for a closer look. I spent several minutes (it seemed a lot longer) looking for the creatures but couldn't find a single one and as I approached the water their calling stopped. How hard could it be to find a frog when I knew there had to be several of them there?


Finally I spotted a little movement in the water and there they were - perfectly quiet and holding on to small rocks in the slight current. I'm not a frog expert by any means so I had to dig out the field guide for an identification. I think it fits pretty well with the description of the Sierran treefrog Pseudacris sierra. It's quite an attractive animal and a bit unusual in that for a treefrog it was obviously adapted here for life on the ground. Of course, the Sierra foothills are quite dry most of the year so this makes sense. I'm not really certain though that the stream even runs all year. I may go back in September and take a look.

Scaphinotus subtilis

Snail eating ground beetles are some of the most fascinating insects around. They have a rounded body with a narrow head and prothorax that gives them a fairly sleek appearance. I'll be honest though, I've never learned just how this particular morphology benefits them. I invite anybody reading this post to inform me if they happen to know. Part of the uncertainty is why the wide abdomen is mostly filled with air.

This beetle (Scaphinotus subtilis) is the most common snail eating carabid around Fresno. It has fairly smooth wing covers and is a bit smaller than some of the other Scaphinotus but it is still an impressive creature.

I found this one on the back side of Table Mountain (northeast of Fresno) in February. It was under the logs seen here along with several isopods and various other edaphic creatures.

Limonius crotchii

This is the first individual of Limonius crotchii that I have ever seen alive. It is not a very commonly seen insect. Jon and I came across it a couple of weeks ago just north of Lake Isabella along the North Fork of the Kern River (just into Tulare County, California). The orange elytra are quite striking and are a lot brighter than in preserved specimens.

It isn't all that big - just about a half inch long (over a centimeter) and it does look similar to other black and orange elaterids. Species of Ampedus can often look similar and even have the double sutures on the prosternum (on the underside of the pronotum). Even the front of the head in L. crotchii looks more like Ampedus than some other Limonius.

A good way to distinguish this beetle, though, is to look at the base of the front legs which are nearly completely closed (meaning they are surrounded by the hypomera). If this sounds all too complex, you can simply take my word for it (fortunately I'm only wrong less than half the time :).

It has been a wet year in many parts of California and the North Fork was very high. We saw several brave river rats floating rapidly along in bright red rafts. The habitat shot is just off the road from the river near an unmarked camping area where we stayed.

Paracotalpa ursina

Unofficially this attractive beetle has been called the little bear beetle. Officially it is Paracotalpa ursina - which literally means the little bear Paracotalpa. And the bear is easy enough to imagine with the long setae (hair) and the plump body. The beetle belongs to the family Scarabaeidae - notice the fan-like antennae. It is a bit over half an inch long but seems bigger, especially as it climbs up grass stems and topples them over with its weight.

Jon and Michael found a population of the beetles last week in a city park here in Fresno and I went out yesterday to see them myself. There is something about a scarab in flight - with its elevated wing covers, low buzzing and erratic flight - that gets my beetle juices flowing. Museum specimens of this insect tend to be dull reddish brown. Live specimens have a much deeper red color. They're a sight to behold. Sadly, there were several along the park trail that had been smashed.

The place where the beetles were flying is not all that remarkable. It's maybe a quarter of a mile from the San Joaquin River and is just a fenced-off area with tall grass and a few other plant species. But that's often how you find interesting insects. They don't always live in the places we would consider ideal. And a grassy path in a park seems to be just fine for these brightly colored bruins.

Eleodes gigantea

Eleodes gigantea is a big black darkling beetle common throughout California in dry areas. It gets to be about an inch long and is really the epitome of the so-called "stink beetle". There are several species of Eleodes throughout the Western US and Mexico but E. gigantea is certainly one of the biggest. It is also one of the most - how should I describe it - expressive. Once it gets bothered, it sticks its rear end into the air, threatening to give off a foul odor, if anybody gets too close.



Last November, Michael decided he wanted to do a science fair project on these insects. He wanted to see if they had evolved their defense response as a protection more from aerial predators than from terrestrial ones. He made silhouettes of a predatory bird and another one the same size of a fox. Then Michael, Jon and I took a trip out past Coalinga (southwest of Fresno) to find the creatures. We spent 2 days driving around mountain roads and ended up finding several individuals that Michael exposed to the two silhouettes.

Michael thought that the beetles would go into defensive mode quicker when exposed to the fox. After all there are a lot of terestrial predators around - including a lot of non-native cats and dogs. But the beetles were much quicker to respond to the bird. It was a fun project and leaves open a lot of questions that somebody doing more than a high school science fair project might want to tackle.

In any event, the canyon was nice. Not too many insects were out (it was November) but the cool weather didn't seem to bother the beetles.

Hypera brunneipennis

This time of year alfalfa can really be hit hard by weevils. Here in the Central Valley we have to deal with the Egyptian alfalfa weevil (Hypera brunneipennis). These pictures are from about a week ago on a plot that has had a heavy infestation the last few years. As you can see the feeding damage can be significant.This first picture is of a mature larva - the stage that does most of the damage. Smaller larvae don't eat nearly as much as the larger ones. This particular individual is about a quarter of an inch long.

It surprises me how much of a problem these weevils have become. They are really not that hard to control if you disrupt their life cycle with an early cutting. This only needs to be done once (on the year's first growth) because the insect only goes through a single generation a year. Here in the Central Valley, a cutting around the middle of March would kill most of the population. A good pyrethroid will do a good job too if you decide to wait and make the first cutting with a more mature crop.

The Second picture is of the cocoon. When the larva gets as big as it is going to get, it will find a secluded place on the plant (sometimes on the ground) and encircle itself with a silky protective covering. You can see that it isn't as tightly constructed as the cocoons of other insects but it does the job at keeping most predators and parasitoids away.

This last picture is the mature adult - no doubt out looking for a mate