Thursday, December 31, 2009

South Fork of the Merced River

We had an extra day during the week of Thanksgiving and decided to take a hike along the South Fork of the Merced River. The river itself is designated a Wild & Scenic River and there is a trail some three to four miles from Highway 140 to the old mining site of Hite Cove. The trailhead starts some 20-plus miles northeast of Mariposa (and a few miles west of the Yosemite National Park entrance) in Mariposa County, California.

November is a good time of the year to make the hike if you want to have the trail to yourself. The wildflowers that draw most visitors won’t be out for another few months. The scenery is nice nonetheless. Long terraces of moss-covered stones line the river and are reflected from the limpid slow-moving river.

Because the sun is low in the sky this time of year, Gimasol Ridge (to the north) kept the canyon shaded and cool in many paces while the bright sun also warmed us up in other places. The few autumn colors were clothed in a diffuse November light that made for a beautiful day.

There weren’t many insects out so late in the year but we did find a few things. Most notable were the several lady bird beetles (Hippodamia convergens) that had congregated en masse on the pines and other plants near the metal ruins just down-stream from Hite Cove.

Apparently Hite Cove was a mining settlement. It was named after John Hite who discovered gold here. There was once a small settlement - including a post office – during the late Nineteenth Century. There are still a few large processing tanks with fittings still attached, along the trail. In a few places you can still see old stone walls and even an old house.

Wednesday, November 11, 2009

Tarantula Crossing

Two years ago when I first moved to California, I took a detour through the San Rafael Mountains east of Santa Ynez. Much to my surprise, I came upon this warning sign with a spider on it. Where I come from there are no such things as Tarantula Crossing warning signs and I was intrigued. I have known of other animal notable enough to be sign worthy. Cows and sheep come readily to mind. And occasionally you see a sign of a pedestrian walking a dog. On Maui I once saw a Nene Crossing sign and had to check a dictionary to be sure of what I was seeing (the nene is the Hawaiian duck). In Germany, in the Palatinate, I recently saw a sign with the large black longhorn beetle (Cerambyx cerdo) featured. I guess there must be a lot of these signs around the world. Maybe somebody should make a field guide of them.

I haven’t yet made it back to the San Rafael Mountains to see the massive tarantula migration but I did discover another one just a couple of weeks ago. I was just north of Auberry (California) a couple of days after a good rain storm and almost ran over one of the impressive arachnids (Aphonopelma sp.) as I came around a bend in the road. I asked around a bit and discovered that I had jut missed the big annual event – or rather I was seeing the very end of it. After the first good rain of the year (and in California that means the first good rain after the hot and dry summer) the spiders move out of the lower drainage areas to higher ground. Locals often gather them up by the buckets-full, as they cross the road, and sell them to pet stores. I think the area needs a few more Tarantula Crossing signs.

Sunday, October 4, 2009

Puncture Vine Weevil

Here are a couple of pictures of the puncture vine weevils (Microlarinus lareynii) I found on a healthy puncture vine (Tribulus terrestris) in the Central Valley near Fresno, California this last week. They were most easily seen by turning the plant over and looking closely on the ground just beneath the sprawling plant. I've been watching them fairly closely for several days. Two weeks ago when I first noticed them, the goatheads (or the thorn-covered seeds) looked healthy and were beginning to harden to the point of becoming very annoying. A few days ago I looked again and noticed that many of them were being hollowed-out by the growing puncture vine weevils. The
picture of the mature larva is a bit staged. I had
to remove it from the hole (seen below it) in order
to take the picture.

The weevils were introduced to the United States
over 40 years ago to control this weed. But, since
the weed is still a problem, the weevils have been
pretty much ignored. This is too bad. The weevils
are effective in at least reducing the puncture vine
problem; and, importantly, they haven't jumped
onto other useful plants. Many of our intoroduced biological control organisms have done just that.

Saturday, August 15, 2009

Spider Mites

We are in the middle of mite season right now in the Central Valley. These small animals - smaller than a pinhead - are causing all kinds of damage to vegetables and fruit / nut trees alike. Like spiders - to which they are related - they make webs. In fact the webbing is one of the ways that you can spot them. Here's a couple of pictures of what the mites and the webs look like. But be warned, if you wait until the mites are this far along, you may not be able to control them. Even the best products will fail if there are too many mites around. The webbing, when it becomes too extensive intercepts whatever spray is directed their way and the mites wait beneath until the danger of being poisoned is past.

The first picture is of mite damage to almonds. I found in the same orchard a couple of trees that had lost all of their leaves because of the mites. The second picture is of grapes. The poor vineyard looked like it had been torched. If you live in an area with mites, it really pays to watch closely for the first signs of the mites. Around Fresno, we're watching through most of July. This year things got really bad about the third week of the month, but in varies depending on place and no two years are exactly alike.

Sunday, August 9, 2009


Species of the click beetle genus Danosoma can be easily misplaced in the genus Lacon. Both genera contain species with colorful scales and look similar in their general appearance. The reason why they are placed in a different group is because Danosoma lack a defining seta at the base of the tarsal claws. This can be confusing to locate (since there are other setae on the tarsae) and becuase the claws are small (at least they are if there is not adequate magnification) so be careful wih your id's.

Here are pictures of the two American species D. obtectus and D. brevicornis. They both have a diagnostic groove down the middle of the pronotum but D. brevicornis also has a couple of round impressions(on each side of the groove). Danosoma obtectus is a bit narrower and lacks the impressions.

Geographically, D. brevicornis occurs in the northern parts of the US and into Canada (essentially coast to coast), whereas, D. obtectus occurs in the Northeast US and adjacent areas in Canada.

Saturday, July 25, 2009


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

Swimming Pools on No-Name Creek

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

Onion Thrips

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 Beetles of the United States and Canada (Coleoptera: Elateridae)

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.

Saturday, June 27, 2009

Golofa pizarro

On the same trip that we found the Megasoma (q.v.) we decided to check out Cusuco National Park (Parque Nacional Cusuco). It is just west of San Pedro Sula on the north coast of Honduras near the Guatemala border. The road to the park goes north from the town of Cofradia. National Parks in Honduras are not always well marked and the road through Cofradia is often rutted and not always intuitive. Once you get through town, you will gain elevation and eventually make it into pine forest. The occasional clearings reveal an extensive montane forest - often shrouded in mist.

We eventually came to the town of Buenos Aires (which doesn't show up on the map) and drove right through it - missing the road to the park. After backtracking, we asked for directions and were directed to an inconspicuous dirt side road that wound through a few rural houses and wound up again to the forest. It was getting dark by this time so we pulled off to the side of the road and set up our light. Since there were only a few things flying at the time, we pitched our tents and went to bed.

A couple of hours later, I stumbled out of the tent to check the light and was startled by the low buzzing sound of insects flying over the light and around the overhanging pine boughs. Then a large beetle hit my head and I instinctively reached out to grab it. It turned out to be one of the remarkable scarabs of Middle America Golofa pizarro. There were several at the light and around the car - among other things. I took this picture of a giant silkmoth (genus Rothschildia) that was resting on the forest floor near the light. You can get an idea of the size by the pine needles it is resting on. They are over six inches long.

The next day we made it to the park and found several students, including a visiting scientist from Great Britain, working on faunal studies. There is a lot of interest in birds, mammals and other vertebrates there and an increasing interest in insects. One student was looking at dung beetles. The director of the park took us to a forested area where they had seen a quetzal the day before. We weren't so lucky. Cusuco is certainly one of the gems of Honduras.

Sunday, June 21, 2009

Megasoma elaphas

Here's a picture of a large male elephant beetle, Megasoma elaphas, that I collected a couple of years ago in Honduras. It was quite the memorable experience. We were below Pico Bonito just a few miles north of La Ceiba (in August) collecting at night with a small blacklight hooked up to our rental car. We had parked in an area where the forest comes up to the road and had been seeing a few scarabs and moths attracted to the light. Maybe an hour after it was dark, we heard a droning buzz not far away and made a few light remarks about how we wished it might be Megasoma. Then the sound went away and a giant tropical cockroach (Blaberus giganteus) flew onto the sheet. We were impressed by the size of the creature and attempted several times to throw it back ino the forest. Each time we did, it just flew back to the light. The picture is of the impressive roach on our rental vehicle's tire.

Then some minutes later my friend happened to shine his flashlight on the ground between the feet of my son. Amid his excitement he managed to persuade us not to move an inch. There in the dirt was a magnificant male elephant beetle. The picture is of the beetle in my friends hand minutes later. One doesn't always get so lucky. It's a thrill when it happens. It is one magnificant creature.

Friday, June 12, 2009

Mealy Plum Aphid

The mealy plum aphid (Hyalopterus pruni) is out in numbers in Central Valley right now. I don't mean that it is necessarily a problem all across the valley, but where it tends to hang out, it's that time of the year when it is covering various trees of the genus Prunus (such as apricots, plums, etc.) by the tens of thousands - and that is just for a single (albeit heavily infested) tree. We can thank Europe for the insect.
The picture on the right is a cluster of the aphids on French prunes. The picture below is of the whitened leaf margins that are the diagnostic sign of the pests. The aphids tend to hang out on the bottom side of leaves and are less visible. The whitened leaves and the vast amounts of honeydew on the bottom leaves are easier to see.
If you have a problem with these aphids you shouldn't panic. They're pretty easy to kill with any aphicide that's labelled for fruit trees. Or you can just let them alone for a bit (they hardly ever carry diseases) and let their natural enemies clean them up.

Monday, June 8, 2009

The Blue Dasher

Last Saturday I was lucky to get this picture of a blue dasher (Pachydiplax longipennis) feeding on a planthopper. We had a couple of thunderstorms during the previous week - which is quite unusual in the Central Valley this late in the year. The dragonflies, however (along with the rest of us) were quite happy for the rain.

I had been beating a few willows in a backwater area near Lost Lake (just below Millerton Reservoir in Fresno County) looking for beetles and had scared up several planthoppers from their resting place (you can see one of them in the second picture). They're apparently quite tasty to the blue dashers, which are known to feed on small insects. You can see a few uneaten parts of one in the mouth of the pictured dasher. It was so intent on finishing its meal that it let me get close enough for the candid shot.

Saturday, June 6, 2009

A New Blog About Bugs

Welcome to The Sam Wells Entomology Page. This picture is of me collecting insects just below Long's Peak in the Colorado Rockies. In the posts to come I hope to provide useful, perhaps entertaining, and, if possible, meaningful posts about insects. I am not a professional photographer or essayist but hopefully some of the insects you'll see and learn about here will be worth your visit. I also hope that they'll motivate you to get out and discover them for yourself. I have been enjoying these small creatures all of my life. They have taken me to many places around the world. They have a remarkable ability to enrich any life that takes the time to look at them in any detail. Enjoy.