One of the most unusual blister beetle genera in the United States is Cysteodemus. It occurs in the desserts of the Southwest. There are only two species, C. armatus and C. wislizeni and both look like inflated and highly sculptured versions of what your more typical blister beetle looks like. Werner, Ens and Parker (in the Meloidae of Arizona (Technical Bulletin 175 (1966) of the University of Arizona Agricultural Experiment Station)) write that they sometimes look "more like a Christmas ornament than an insect when ... seen on its food plant". Their inflated appearance certainly makes them look bigger than they really are (even though they're only half an inch long). Underneath the inflated wing-covers there is mostly air and the flight wings are missing.
The two species are fairly easy to tell apart. Cysteodemus armatus is black and has a more sculptured back. Cysteodemus wislizeni is metallic purple or bluish and has a finer and a more pitted sculpturing on the back. The best place to find these fascinating beetles is in the deserts of Arizona, California and New Mexico at night with a flashlight, where they crawl along the sand. One beetle enthusiast claims that they have a glow about them if spotted with a UV flashlight.
Saturday, July 18, 2009
About an hour northeast of Fresno, Caifornia, up past Shaver Lake and then above Dinkey Creek Campground is a stream that has no name on any map that I have seen. The thin blue line that marks its position is apparent enough, but even the Dinkey Creek Quadrangle map doesn't condescend to give it a name. This is a bit odd because it is known by a lot more people than many of the bigger streams in the area. I don't mean to imply that it is a well known stream. It isn't. But any summer weekend there will be a handful of hikers doffing t-shirts and jumping into one of the many refreshing pools. It's a great place for a swim. This picture is of one of my favorite pools. Occasionally I get up the nerve to jump in from the 10-15 feet edge off to the right. There are lot of other pools with swimming, sliding and diving opportunities depending on your level of interest.
We learned about the place from some friends while camping near Dinkey Creek last year and decided to check it out. The road (10S36) heads north from Camp Fresno less than a mile east of the Dinkey Creek bridge (on the road to Courtright Reservoir). It's a dirt road that climbs over a thousand feet to a dead-end a few miles up the mountain. About a mile after you pass Reese Creek (and maybe two miles after you pass a gated road to the east) you come to a bank of earth across the road that prevents you from driving any further. Park here and then walk less than half a mile along this road to where it ends. This is the point of the pink line on the map.
The road/trail ends below an incline. If you climb to the top, you can see the stream a few hundred feet down a steep canyon. It's tempting to descend from this point - and in fact, this is what we did last year with a handful of young teenagers. It took us a while to get to the stream because of the steep rock face. This descent is not for faint hearts. I should also mention that there are no trails down to the stream. You have the option to go down here or take the longer rout.
This year we followed the longer rout (the pink line on the map) and went around the rocky area. It is still a tiring hike through pines and over boulders but it is doable for anyone who doesn't mind fairly steep climbs or descents. Anyway, the hike only makes you eager to jump into the pools when you get there. You won't want to leave. (But don't go without sunscreen if you have light skin. The sun shines bright at 7,000 feet.). This last picture is of the rocky descent from across the canyon to the north (looking south). You can see a couple of the minor pools at the bottom of the canyon.
Wednesday, July 15, 2009
The onion thrips (Thrips tabaci) has had a very productive season so far here in the Central Valley. Thousands - make that hundreds of thousands - of onions have little pieces of chlorophyl missing were the minute insects have chewed, sawed, and slurped the energy producing tissues from their stems. What makes the damage so disturbing is that the culprits (no bigger than a small comma) are hardly ever seen. In fact a farmer might get most of the way through a crop without even a hint that they have been guests in his field. When he does notice, it's often too late and the damage is done. The onions are smaller than they should be and often don't make the grade.
So here's a bit of advice for next year: start watching out for the litte critters when your onions are at the four or five leaf stage. That's the point when middle leaves are pushing up adjacent to one another. This is the hiding place that thrips prefer. It's also the place you can look to see if you have a developing problem. Just peel the leaves apart gently, look down into the fleshy tissue close to the developing bulb and look for tiny yellow bits of movement. If you don't see anything, try another plant. If you do find them, ask a local extension entomologist what product to use to control them. Make sure you add an adjuvant to spread the spray solution. Onions have a healthy wax layer and if you apply just a watery mix, it often fails to get down into the tight places where the thrips hide. You may need a couple of applications. They can be tough to control. If you see little black bugs around, leave them alone. They're pirate bugs eating the thrips.
Saturday, July 4, 2009
The eyed click beetle (Alaus oculatus) is probably the most well known click beetle in North America. It is a fairly large insect (usually longer than an inch) and quite attractive - even arresting. The large eye spots on the pronotum are enough to stop most anybody who might happen upon one of these insects. Of course the eye spots are not true eyes. Eyes, after all, don't occur on the pronota (or any of the thoracic segments) of insects. But it's hard not to think that the impressive insect is looking at you when you happen upon them in the woods.
What is less well known is that the eyed click beetle per se is just one of six related species of click beetles with similar eye spots that occur in the United States. Three of them (A. oculatus, A. myops, and A. melanops also occur in Canada). One of them occurs only at the tip of Florida (A. patricius). In fact it is very likely that if you come upon one of these attractive insects, you will be looking at one of the other five species. Following are a few pictures that I hope will help you figure out which species are which. For a full treatment of the species see Sonia Casari's excellent treatment of the genus Alaus (Systematics and Phylogenetic Analysis of Alaus Eschscholtz, 1829 (Coleoptera: Elateridae) in Revta. Bras. Ent. (1996) 40(2): 249-298).
By far the most common species in the Rocky mountains and west is A. melanops. The only exceptions
to this are in Arizona and New Mexico where two other species also occur. Alaus zunianus (occuring only in Arizona) and A. lusciosus (which occurs from Arizona east to Texas and north to Kansas). The best way to tell the difference between A. zunianus and A. melanops is the amount of white on the pronotum. In A. melanops, there is much less white. The eye spots are surrounded by black. In A. zunianus, the eye spots are adjacent to a lot of white. To separate A. zunianus from A. lusciosus it is best to look at the position of the eye spot relative to the middle of the pronotum. In A. zunianus, each eye spot is as close to the center as it is to the side. In a A. lusciosus each eye spot is closer to the side. Alaus melanops can also be separated from A. lusciosus by the width of the white lateral band on the pronotum. This band is wide and connects to the outer edge of the eye spots in A. lusciosus much like it is in A. zunianus.
If you find an eyed click beetle east of the Rocky mountains there are primarily three species you need to be able to tell apart. The easiest to recognize is A. myops which has much smaller eye spots than than the other species. In fact the eye spots of this species are often much more elongate than in either A. oculatus or A. lusciosus.
The ranges of both A. myops and A. oculatus overlap extensively (both occur in all states east of the Great Plaines and north into Canada). The range of A. lusciosus, on the other hand, only overlaps with these two species in Kansas, Oklahoma and Texas. Nonetheless, where there is overlap, A. lusciosus is commonly misidentified with its better known congener, A. oculatus. The best way to tell these two species apart is to look closely at the base of the elytra (that is the wing covers behind the pronotum where the eye spots are located). If the space between the elytral lines (called striae) are convex than the species is A. oculatus. If the space is nearly flat it is A. lusciosus. Hopefully you can see this is the picture details of both species.
The only other species in the United States is A. patricius which occurs in the south of Florida. It has even smaller eye spots than A. myops but the more important character is that the eye spots in A. patricius are not surrounded by a white band as they are in A. myops (and the other four species).
Of course, there are always individual beetles that don't always fit neatly into the expected patterns. If you have a specimen that you aren't sure of and you need an acurate identification, your best bet is to contact a click beetle taxonomist or maybe take a visit to your state's land grant university and talk with the insect curator on staff. Good luck.