Friday, July 1, 2016

75 Common Arkansas Insects (continued)


False Crocus Geometer, Xanthotype urticaria

I don't know what these attractive moths have done to deserve their notorious name. And, to tell the truth, I don't know anyone who has seen a genuine Crocus Geometer. But whatever the false one's personal morality, it is an often seen, pretty, day-flying, almost always mating moth. Once you spot a pair lying in the grass at your feet, you will not forget it, nor, once you hear it, will you forget its unfair name, associated as it is with the basest treachery.






Rock-loving Grasshopper, Trimerotropis saxatilis

Grasshoppers, with a few exceptions, are the grazing animals of the insect world, the things that everything else eats. Therefore evolution has pushed them, not towards better weapons, but towards better evasion tactics. Camouflage is one of them, and this grasshopper is one of the supreme examples. It flourishes on lichen-covered limestone glades, its pattern imitating the shapes and colors of the lichen to perfection. People who have noticed this grasshopper spontaneously call it "the lichen grasshopper."







Fruit Fly, Rhagoletis sp.

 
Another (and very common) defense for a weaponless creature is to pretend to be something dangerous. Here is a particularly clever example: The wing markings make this look astonishingly like a jumping spider, a very fierce big-game hunter, walking in the other direction. In fact when being stalked by a jumping spider this fly has been seen to walk backwards towards the spider, actually making the spider back off and seek some other target. Here is a typical jumping spider for comparison.







Striped Hairstreak, Satyrium liparops


There are half a dozen or so species of hairstreaks in Arkansas, small, pretty, fast flying butterflies that almost always land with their wings closed up above their head, so that you see the wings' underside. There are various patterns on the wings, but they usually feature large red or blue spots, and "tails" at the end of the hind wings. As a sort of nervous habit, they constantly slide their hind wings back and forth against each other with the effect that the tails seem to be waving up and down. The blue and red spots resemble eyes, the tails are very like waving antennae, and that's their trick. A spider or a bird that wants to catch a butterfly goes for the head, that being the quickest way to disable it. But mistaking the big eyes and the waving tails for the front end, they make their grab, and the butterfly escapes in the other direction. This has been photographed in the case of jumping spiders, and the back ends of healthy active butterflies often have a beak-shaped rip.





 Glowworm, Phengodidae, Phengodes sp.


Glowworms always sound like mythical beasts, something in soppy songs, but here one is, in the middle of a huge outbreak of flat-backed millipedes. This is the larval form of a beetle, and it could be an actual larva, but it could also be an adult female, which sexually matures, mates, and lays eggs retaining its larval form, only the male metamorphosing into a beetle form.

Another oddity: Millipedes are so poisonous nothing eats them, that is, except glowworms, and glowworms feed entirely on millipedes. Here is the glowworm attacking a millipede it is about to devour.


Of course, you have to see a glowworm at night to see its third oddity, from which it takes its name.




Sunday, June 19, 2016

75 Common Arkansas Insects

Most people don't seem to notice insects. If they do see one, there is first a look of revulsion, followed by a search for something to swat it with. I'm probably being optimistic, but I think if they had any idea how intricate and fascinating the life stories of insects can be, they might alter their attitude. I think anyway there are a lot of people who spend time out in nature, hikers, fishermen, gardeners, who notice things, and are at least a little bit curious about what they see. I'm contemplating writing a little booklet just for these people. If I can point out something to them that is commonly around, and is easy to recognize, and if I can tell them some little something of interest about it, maybe they will look at it a bit more favorably the next time they see it. This booklet (to be called 75 or whatever number I finally arrive at Common Arkansas Insects) will have a photograph of an insect at the top of each page, with a small paragraph about the insect beneath it. Here are some sample pages.

75 Common Arkansas Insects





American Carrion Beetle (Necrophila americana)

Don't confuse the name of this common species with that of the rare and endangered American Burying Beetle. But it is in the same lugubrious business: helping to clean up dead bodies. Its name Necrophila means 'lover of dead bodies.' When they get a whiff of a road-kill opossum or some other delectable, they head for it. They fly fast and directly, at about our eye-height, and something odd occurs. They are suitably black for their job, but note the yellow thorax with a dark patch in the center of it. This is the pattern of a bumble bee, with its fat black body and hairy yellow thorax with a dark bald spot in the center of it. When you see one of these beetles flying, you can't believe it isn't a bumble bee. I'm an experienced field biologist, and even I have to strain my eyes to see that it is actually a beetle pretending to be a bumble bee. It might make a bird hesitate to grab something out of the air if that something might have a formidable stinger.

Once it arrives at the kill it feeds on the abundant fly maggots, and lays its own eggs, and when they hatch, they begin feeding on the skin and dried bits of sinew the other scavengers can't handle.



13-Year Periodical Cicadas


Cicadas in general, found all over the world, are the large oval-shaped insects that sing and clank and zing all through the long hot days of summer. You see the empty skins of their nymphs clinging to the base of trees when you get up in the morning, but after that you only hear them, because the adults sing hidden in the tops of trees.

However one special group, the Periodical Cicadas, are easy to see just because there re so many of them. These harmless, but rather sinister looking creatures have jet black bodies, blood-red eyes, bright yellow veins on their transparent wings. Here's their bizarre story: The nymphs hatch from eggs laid in trees and burrow underground where they feed by sucking the juice from tree roots. All species of cicadas do this, and most emerge and change into adults in a year of so. But the Periodicals found in Arkansas stay underground for thirteen years, and then emerge in scattered places (each place well known to biologists) around the state. The populations are staggered so every few years some will come out somewhere. There are four species, and in May and June of 2015 all four emerged at once. If you looked up in the trees you could see them constantly flying out from among the leaves, as numerous as bees. Their high-pitched whining hissing sound could be heard, in places, for over a square mile. They had no fear or avoidance instinct. Birds and other animals could eat them all day till they were sick; there were still millions left, to mate and lay eggs for the next thirteen years. Within days the dead and dying began littering the ground. After a month they were all gone, not to appear again for several years.

An identical set of four species comes out every seventeen years, but none of these happen to occur in Arkansas. The two groups, 13- and 17-year, are found in scattered localities in the eastern United States, and nowhere else in the world.




Hanging Thief, Diogmites sp., Asilidae, Robber Flies


Unless someone points them out to you, you are likely to overlook robber flies. There are over a hundred species in Arkansas in all sizes (from 3 mm to 50 mm) and shapes (they often mimic wasps or bees, especially bumble bees). They are powerful charismatic predators, in fact each is the alpha predator in its particular ecological community. Once you get your eye in for them, you will see them sitting at the tip of a twig, or on a bare patch of ground, with an unobstructed view of the sky, and suddenly they will fly up so rapidly they seem to vanish, only to reappear at the same spot an instant later, this time carrying some insect they have just snatched out of the sky. They fly up like falcons, wrap their long spiky legs around their prey (often wasps or other dangerous creatures, even other robber flies), stab it with their beak loaded with neuro-toxins and digestive enzymes, and return to earth to suck its juices. Those like this one, in the genus Diogmites (sometimes called "hanging thieves") have the habit of getting under the foliage and hanging by their forelegs to eat their prey. You can recognize them by this behavior.

Robber flies have these features in common: widely separated eyes for good depth perception, a sharp beak, a sort of beard or mustache above the beak, which is thought to protect the eyes during encounters with dangerous prey, and long muscular spiky legs with hawk-like talons at the ends.




Hanging Fly

Here is another kind of predatory hanging fly. This one is a member of the Scorpionfly family (Panorpidae), and is much less formidable than a robber fly. It's a spindly creature looking rather like a crane fly, but has its own novel way to capture its prey. The male, pictured here, like the Hanging Thief, gets down low in the foliage and hangs by its front legs. But look at its hind legs danging below it, with their complicated spiny feet. They are like loaded mousetraps, and if a moth or other soft creature in its flight brushes against these feet they snap around it in a flash.

The Hanging Fly is not hunting on his own account. The female will not allow him to mate with her unless he presents her with a meaty gift to eat while he is doing so.

Mantises catch prey with their predatory front legs, robber flies catch prey by wrapping all six legs around it. The hanging fly is one of the very few I can think of that catch prey with their hind legs.






Braconid Wasp sp., Genus Cotesia

Sometimes something white down in the shrubbery will catch your eye. When you bend down and look, you will see a stationary caterpillar with up to a hundred tiny white cocoons clustered on its back, or sometimes in a tidy stack underneath it. It has been parasitized by a tiny (5 mm) Braconid wasp which has used its ovipositor to inject dozens of eggs inside the caterpillar's body. The wasp larvae have devoured the caterpillar from inside, eating non-vital tissues at first, so that the caterpillar could continue eating and growing, but now to feed them, not the moth or butterfly it might have become. When they were ready, they punched their way out and spun their cocoons. The caterpillar may still be alive for a while, but hasn't the energy left to make it own cocoon.

It's a common fate for caterpillars, but actually the wasps are the heroes here, the great controllers of population. Without them, and the migrating warblers and other carnivores, caterpillars would overrun the world, eat everything green, and bring down their own environment.



What do you think? Should I go on with it?





Thursday, May 12, 2016

Sweating the SMALL small stuff

Everyone, I expect, knows about the guy (his name now forgotten) who said the key to a stress-free life is, Rule 1: Don't sweat the small stuff, and Rule 2: It's ALL small stuff.

He was a genius, and I try to live by those rules. But when I came to write a blog that would concern itself mainly with insects and other small creatures, I called it "Sweating the small stuff," and thought that was rather clever, until I looked into it and discovered about forty people had already used that name for their blog.

Anyway, lately we seem to have been looking at smaller and smaller stuff. It started when I got a new camera and macro lens set-up, a step up from my last one, and to try it out went around the garden taking pictures of every small thing I could find. It started with this honey bee, coming to a spiderwort.



 I downloaded this picture, then put it to the test: I blew it up until just the bee filled the whole frame.



I was very pleased that the image could keep so much sharpness after being enlarged so many times.

Then (I was out with Cheryl) we saw a tiny thing that looked like an ant trundling along. If the bee was, let us say, 10 mm long, this new thing was closer to 5 mm long. When we looked really closely, we saw it was actually a jumping spider mimicking an ant. Here it is blown way up so you can see it more clearly.



An ant has six legs and a pair of antennae; a spider has eight legs and no antennae. But this spider is walking on its back six legs, and is waving its front legs in front of it to simulate antennae. Very clever, but why would a tiny spider imitate an ant? Well, ants are full of formic acid, which means they don't taste very good, so most things leave them alone.

Anyway, to get on with small things, Cheryl has an old pot in the front yard full of radish seedlings, and with her sharp eyes spotted some things in them that she had to point out several times before I could see them. Here's the pot. If you look carefully, you might see some little whitish dots sticking to the stems.



Here, from closer up, is what Cheryl saw.




We knew what these were right away. The pot had been overrun with aphids, but now the aphids were virtually wiped out. Tiny parasitic wasps (we're talking really tiny now, 1.5 mm) had visited them, and with their sharp ovipositors had injected an egg into each aphid. The egg hatched into a wasp grub, and the grub fed on the aphid. To show you how small the grub was, that aphid provided enough food for that grub to grow to full size and form a pupa (all this inside the shelter of the aphid's outer skin). While the grub was feeding, the aphid turned brown, which made it easy to see which ones had been parasitized.



Here is the scene several sizes larger. On the top left are two healthy juicy green aphids, on the right brownish ones that are harboring feeding or already pupated grubs. One has a round hole in the top, marking where a wasp had metamorphosed and chewed its way out.

Once we got our eye in, we noticed that the wasps were flitting all about. Making pictures and blowing them up helped us to see more of the action, though we are far from having everything figured out.



Here, for example, is one of the wasps.  It's possible that it just emerged from the hole in the aphid beside it.  Its fairly slender abdomen, its lack of an ovipositor, and its very long antennae make us believe it is a male. This is guess-work, but perhaps the long antennae are very sensitive to the alluring odors of females. Perhaps he can smell a female about ready to burst out of the aphid shell he is sitting on, and he is waiting around to make sure he gets first dibs. For the moment all the many wasps we see seem to be males, and perhaps it is timed this way to make sure each emerging female has a mate waiting for her. Otherwise it might be impossible for such tiny things in such an enormous world (millions of times bigger for them than for us) to ever find each other.

The wasps can't waste too much time sitting around, because they are themselves part of the stream of life, and are just right for slightly larger creatures to feed on. We see a half-grown jumping spider is already feeding on one.


Cheryl looks under a leaf that has spider webbing in it (her thumb and the nearby wasp will give you a sense of scale) and finds another spider that has a wasp wrapped up.


Perhaps you still can't see it; it's just down from the wrapped wasp, and a little to the left). It's not only minuscule, but has protective coloring. Here it is still larger.



Okay, one more try.



The next day a more serious threat appears. You know the big black and yellow garden spider that makes enormous webs in the corner of your yard. They are formidable hunters. Those that live over our pond feed mainly on tree frogs. Well, here's what they look like when they hatch from the egg, and they already have something magic in their web, ultra-violet coloring or something, because look how many wasps this one has caught in a single day.



And now we believe we have seen the most sinister predator of all.



We thought at first this was finally a female. Note the fat abdomen, the short ovipositor, the short antennae. But now we have seen it poking its ovipositor into the aphid shells. There is nothing inside those shells but the newly forming parasitic wasps. Besides, this wasp is marked differently from the male wasps. Is this a different species? Is this, in fact, a hyper parasite, a parasite upon parasites?

Who would have imagined a few shots with a camera and macro lens could open up a lifetime of studies.










Sunday, April 24, 2016

Trying to get summer underway.

One sign of winter shifting slowly into spring and summer is when we stop putting food in all our bird feeders. The feeder birds themselves are mostly leaving now, heading back up north. The big winter flock of American Goldfinches that inhaled our bags of niger seeds changed from their olive drab winter plumage to their lemon yellow breeding plumage, and have left us; of the even bigger flock of White-throated Sparrows, those that were already in adult plumage when they came down last fall, after entertaining us with their high-pitched whistling, have all left us for their breeding grounds. The hang-up is that the immature first-year birds have lingered behind, now themselves in adult plumage, but still living off my charity. "Get up there and get jobs and settle down, you malingerers!"

I stopped putting out sunflower seeds and they glared at me like they had been betrayed (and a few days later deserted me without a word of thanks).



Also living in our house on our generosity are the three or four species of ants that hang-out on our kitchen counters. Here, we are following E.O.Wilson's instructions: A woman after attending one of his lectures on the desirability and necessity of ants asked him afterwards, "Yes, but what should I do with the ants that come into my kitchen?" He said, "About once a week give them a teaspoon of tuna. They love tuna."

Well, they don't cause us any problem at all, and we were glad to see them dress up their marriageable girls in wings and send them flying off to meet suitable husbands and start new homes. They had a bit of a problem that they were inside a house, so every time there was a surge of new females, we had to keep slipping the window open to let them out into the greater world.


There are some moochers out in my study I don't feel charitable towards, and those are the dermestid beetles. When I find interesting dead insects or other small creatures I often bring them home and set them on a shelf in the study while I decide what to do with them. What generally happens is, they mysteriously turn into dust. For instance I found a dead mummified snapping turtle that must have died right out of the shell, because its body was only an inch long. It was a perfect little specimen.

It was too young to have many hard parts, and the next time I looked all its leathery parts were powder. If you look closely, you will see the many empty beetle pupal cases lying around it.



It turns out that not all the creatures I generously share my quarters with are ungrateful. I allow the cellar spiders to live in my study, filling the room with their billowing cobwebs. Today this one was eating a dermestid beetle.



One morning we found this elaborately complicated thing like a decorated cake on the side of our garbage can.



We knew what it was at once. It was the caterpillar of the butterfly, the Red-spotted Purple. The small cherry tree next to the garbage can had cranked them out all last summer, and they had hung their chrysalises from the cherry tree twigs, and we would often come by in time to see them eclosing, and holding to the empty chrysalis cases drying their wings. We hadn't realized before that they also came out in early spring when it seems like there would be little for them to feed on. This one had already attached its tail-end to the garbage can in preparation for shrugging off its larval skin to expose the chrysalis beneath. The garbage truck was coming the next day, and it would probably smash it up, so we separated it from the can and brought it in and let it attach itself to a stick, which we then put on the window sill in front of the kitchen sink. It immediately made its chrysalis.

We learned something: The chrysalis was one of those active jobs. If you saw it at night, it hung straight down.



If you saw it in the morning, it angled itself towards the east, to minimize its hanging shadow, which would give it away to a passing bird. In the afternoon it angled itself to the west.






After three weeks it emerged, and we put it out on the porch, and when the cool damp morning finally dried and warmed sufficiently, it was gone.



It is one of the prettiest of butterflies, and a day later we saw one of the prettiest of moths, a Luna Moth. Every time we see a fresh one, just out of its cocoon, we photograph it. How could you resist? But this one was the most beautiful we have ever seen.


In the really hot weather of midsummer, snakes tend to become nocturnal, so you don't see very much of them. The best time to see lots of snakes is in spring (when it is first warming up and they spend a lot of time on the move, and a lot of time basking), and in the fall. So far this spring we have already seen two rather neat snakes. The first one we saw (and it was the first time we had ever seen this species) was the Pygmy Rattlesnake, a beautiful little pit viper only about eighteen inches long.



Not long afterwards we got lucky again, and saw another seldom-seen species, Graham's Crayfish Snake, a watersnake that, as the name makes clear, feeds almost entirely on crayfish.



I think the natural year is off to a good start. To be ready, I have just bought upgrades on all my photographic gear. If I can ever figure out how everything works, I hope you will see an improvements in my illustrations.

Let me end this blog with a nice photo Cheryl took of a Gemmed Satyr, a drab little brown butterfly which has as its only claim to our notice, half a dozen little three-dimensional blue "gems" on its hind wing. This unusual individual had what resembled a setting of tiny diamonds around the gems.


Saturday, March 12, 2016

Sweating some big stuff for a change

Winter is sort of a down time for invertebrates, a dreary boring endless period I endure grumpily.

This winter was quite different.

In December we went out to the west coast for a big family get together. My sister, who lives in San Jose, and my niece, who lives in Berkeley, got together and rented a house right on the water in Pacific Grove which was quite lovely. We could see whales spouting right outside the bedroom window of our room, we could walk the beachfront path which went, if we had wanted, all the way around Monterey Bay. The wonderful Monterey Aquarium was a short walk up the road. Sea otters were abundant, almost every one a female with a young one.


We came back to Arkansas January first, and I was looking up some spiders in BugGuide when I realized for the first time that when I had a species up I could click on "data" and a map of the US came up and each state that had reported that particular species was filled in and the other states remained empty. The map gave a general and very useful idea of the distribution.


But as I checked through the different species, I noticed that, as in this map here, the Arkansas map was virtually never filled in, even though, as here, it is obvious from the filled in maps around it that the spider must occur in Arkansas. Of course what it meant was there was no one in the state specializing in Arkansas spiders, or at least no one (including me) who was reporting records to BugGuide. I was embarrassed for my poor state, which looked as barren of spiders as the South Pole. I checked, and I had photographs of about a hundred species that were blanks on the data map. I decided to literally put Arkansas on the map!

I spent the entire month of January sending them in one by one, and it was a real education for me (especially the ones disapproved as being either mistaken, or else as being part of a cluster of species that could not be told apart without dissection). So there was another month or more of winter gone by. Then we got ready and went down to Florida to visit old friends in St. Petersburg, and of course we visited the nice wetland reserves around the city. I had just upgraded my camera and lenses, and I thought I could get some practice using the new equipment by taking pictures of the long-legged wading birds that Florida has in such profusion.

Here, for anyone who might be interested, is an album of pictures I took down there.

 https://picasaweb.google.com/105943400667867775182/FloridaBirdsSpring2016

Anyway, what I am leading up to saying is, we got back home, rested up a couple of days, and suddenly it is almost the middle of March, flowers are out, leaves are sprouting, birds are pairing up, I saw a couple of fresh orb webs showing up in this morning's dew. What in the world happened to winter?

Sunday, October 25, 2015

Fall trip to Tucson.

We left the house on the last day of September and drove out to Arizona to visit my son Gawain and his girlfriend Heather in Tucson. The monsoon was lingering late this year and there was tall grass growing along the roadsides as we entered the state, and the mountainsides were unexpectedly green. The sky was often cloudy for our stay, and we had occasional very heavy rains. The temperatures were comfortable, 80s by day (instead of 100), 60s at night. Afternoons and evenings and weekends we spent together, but during the day when they were busy with their work Cheryl and I were left on our own.

This was no hardship in Tucson and we spent beautiful days at our favorite places. For instance, the water conditioning plant with its acres of rich wetlands ringed with trails. This is a place mostly for birding (best, the day we went, was a handsome prairie falcon chasing killdeer around the waste ponds). Another day we went to Saguaro West with its many trails (we like walking up the dry washes), and we visited local botanical gardens, but over and over again we visited our favorite, Saguaro East, a thorn-forest wilderness that looks like a planted garden of desert plants and trees, each trail or dry wash passing through a different habitat.

It was a different time of year from our past visits so we were interested in what creatures we might see. Herps were interesting. Desert Spiny lizards we had seen before (they're fairly common) but this time they were more in the open and we saw them better. The particularly handsome local race is called Purple-backed Spiny Lizard. I like the way the yellow scales and blue scales meld into green scales down on the tail.



Because it had rained and there were some new surface puddles, the Red-spotted Spadefoot Toads were out. This was the first time we had timed it right to see them. In our walks we had caught glimpses of them disappearing down holes, but it wasn't until we visited our friends the Braddys on the edge of Tucson that we rescued one from their pool and so got to see it up close.





These little guys show one of the extreme measures amphibians can take to survive in the desert. A hard sharpened area on the inner edge of the inner toe on each leg (you can see the yellowish bump clearly at the base of the inside toes in the above picture) allows them to dig into the soil, where they remain for most of the year. When it rains, they are ready. They come hopping out and look for anything moving to put in their stomachs (this being their only chance to feed), meanwhile singing nonstop all night (this being their only chance to breed), then as quick as they can, they lay their eggs in every temporary pond, hoping their offspring can get through the tadpole-to-adult stage before the pond evaporates (in warm weather the whole process from egg hatch to metamorphosis takes as little as two weeks). Then everybody digs down into the soil to wait months for the next rain.

We also saw a couple of very nice small mammals. If you have walked through  the desert, you have seen packrat nests, a meter-diameter pile of old dried cactus fronds, other detritus, sticks and stones, anything else around that a small rodent could drag into the mix. The nests are obvious everywhere, but seeing the packrat that lives underneath (more correctly, the White-throated Wood Rat), is trickier. You aren't supposed to feed the wildlife, but we were eating our lunch, and before we knew it we had dropped a few large juicy grapes on the ground near a nest, which was enough to lure out the occupant. He was quite endearing, despite being, well, pretty ratty.



But the next animal we saw was the star of the trip. We walked around a corner of the trail, and a big animal went bounding off. Through the brush I saw a flashing white rump and huge ears.

"A deer!" I shouted at Cheryl, but I was already changing my mind. "Or was it a huge jackrabbit?"

Cheryl was a few paces ahead of me, and she saw it where it had come to a stop around the other side of a big bush.

"A jackrabbit," she said.

But it was quite unbelievable, an enormous woolly animal with a highly intelligent face, more like something from Alice in Wonderland or some other child's fiction. It was watching us with great interest. "I'm late," it might have said.



We had to wait for it to wander off before it would stick up its marvelous ears, and we could get a picture of them.



We looked him up: this was the Antelope Jackrabbit, the largest and heaviest of his kind. His name comes from the huge white antelope-like rump that he could flash when he was running away, probably to alert other rabbits in the vicinity that there was a predator approaching.

However this is meant to be a blog about invertebrates.

Just beyond where we saw the jackrabbit we walked up a rocky dry streambed and Filigree Skimmers were flying up ahead of us and landing on the next big boulder. These are fancy tropical dragonflies that don't come very far north of the Mexican border. A field guide I read said that identification was "unmistakable because of the wing pattern alone."


Another much commoner but equally unmistakable species of dragonfly was the Flame Skimmer.


It was near the end of the season, so many moth and butterfly caterpillars had reached their full size before pupating. Here are two butterfly species poisonous because of eating poisonous plants, first the Queen from eating milkweed, and then the Pipevine Swallowtail, from eating pipevine.




In keeping with the harsh desert scene, in addition to the poisonous species there were a number of venomous species (a neat distinction to keep).

This first caterpillar, though the photograph doesn't show it so much, looked so much like a lichen growing on this branch that Cheryl and I both passed it by, until Gawain called us back and pointed it out to us. It's a subtropical species related to our Io Moths, and like the Io Moth has spines that can sting you and raise a nettle-like rash on you if you carelessly brush against it.


  The next is quite interesting and one we have long wanted to find. It's a Puss Moth caterpillar, the name obviously coming from its hairy coat and what looks like a tail. If you brush against this one, the effects can be quite serious. "Sensitive individuals," says Wagner, the writer of our caterpillar  field guide, "who begin to develop systemic symptoms should seek immediate medical attention." We have heard of deaths occurring.



 In the last couple of years we have been mainly interested in learning something about spiders as a group, so we were particularly paying attention to the spiders. Mostly we were seeing here desert versions of species we have at home in Arkansas.

This jumping spider for example we are certain is Phidippus clarus, a familiar species at home, but here seemingly twice as big with its wide pancake abdomen.



And everywhere we found Green Lynx spiders (handsomer with a paler pattern than ours at home) clinging protectively to their egg nests, which they will continue to do all winter until they freeze or starve. Spiders are often quite good parents.



Most abundant was the Labyrinth Orbweaver, a species also fairly common in Arkansas. It is best known for weaving two separate kinds of webs side by side. First it has a tidy and typical orb web, round in shape with spokes radiating around it like a bicycle tire. And then, a little bit over to the side, it has a chaotic tangle of lines with no order to it (the "labyrinth"); perhaps these two webs each catch specific kinds of insects. A few lines connect the two webs to each other, and in between the webs the spider weaves a few leaves together to make a little retreat it can hide in if it's disturbed. That's how it does it at home, anyway.  Here is a typical Arkansas set-up with the orb web in the background, the tangled web in the foreground, and the spider itself in between in its refuge.



But in Arizona they do something different (this is our first season studying them, so perhaps those in Arkansas will do this same thing only a little bit later than the Arizona ones). In Arizona I did not see them in a little leaf bower, but rather, they began laying egg nests. Here is the first egg nest.


Here is a second. They are laid in a line, with the spider at one end. Notice how the spider resembles the egg nests.




The spiders keep on doing it.




And I think I get what their dodge is. At this time of year the mesquite trees their webs are located in or under all have their seed pods drying and ready to fall to the ground. The least breath of wind and there is a rain of these tiny strings of seeds. Frequently instead of reaching the ground, they are caught in a spider web. I think a hungry bird coming along and seeing this juicy spider with its nourishing eggs might pass it by thinking it is only a dry and tasteless mesquite pod.




Postcript added 26 October: After a comment made about the egg nests of the Labyrinth Orbweaver, I made the mistake of doing a little research, and what I find is, that the eastern Labyrinth Orbweaver, such as I see in Arkansas, Metepeira labyrinthea, is not the same species as I have just written about in Arizona. In fact there are at least five different Metepeira species in Arizona (numerous other species throughout the west), and only the eastern one should be called a Labyrinth Orbweaver, though the others are nearly identical in appearance and nest building and egg laying. This is why, I suppose, the one I photographed in Arizona might mimic mesquite seed pods when there are no mesquites in Arkansas. Everything is so much simpler in the east.