Friday, May 27, 2016

Eight Illinois Wasp and Bee Mimics in Twenty Minutes

One of the few entomologically-rewarding stops on our recent road trip was at the National Trail Rest Area on Interstate 70 near Altamont, Illinois, on May 16. A brief bit of sunshine warmed the woodland edges enough to bring out a wealth of fly diversity, many of which were mimics of various wasps and bees. There were even a few real wasps.

Somula decora syrphid fly

Large patches of touch-me-nots (aka "jewelweed") carpeted the edges of the lawn where it gave way to forest, and the leaves of this plant offered places to bask for many insects. The first fly I spotted was one of my favorites in the family Syrphidae (flower flies). Somula decora is roughly the size of a honey bee, black in color but heavily marked with golden yellow. I suspected that this species is a mimic of scoliid wasps, but at this time of year a more likely candidate for a model would be a queen yellowjacket.

Helophilus sp. syrphid fly

Helophilus spp. are also probably yellowjacket mimics. The vertical yellow stripes on the thorax help to identify them fairly easily. Apparently the larvae develop in decaying plant matter that is submerged in water, as do other Syrphidae species like the "rat-tailed maggots." The adults certainly are sun-loving as their genus name suggests.

Temnostoma sp. syrphid fly

Syrphid flies in the genus Temnostoma are likely mimics of the solitary mason wasps that are in the same family as the social yellowjackets. They carry their mimicry to astonishing extremes. Note that the leading edge of their wings is darkened, mimicking the longitudinal folds of a vespid wasp's wings at rest. Wasps have long, reasonably thick antennae, which Temnostoma flies don't have. No worries, the fly compensates by waving its front pair of legs in front of its face, just like wasp antennae. Wh-a-a-a-a-t?! I know! Next time I'll take video.

Male Ancistrocerus sp. mason wasp

Well, lookie lookie, here comes an honest-to-goodness, certifiable mason wasp. This is a male, as the tip of each antenna is hooked, a distinguishing characteristic for many male eumenine wasps. I am a little hard-pressed for a genus, but I suspect it might be Ancistrocerus. Female mason wasps usually nest in pre-existing cavities like old beetle borings in logs, hollow twigs, etc.

Chalcosyrphus piger syrphid fly

Yet another kind of syrphid fly we saw was this Chalcosyrphus species. They are typically assumed to be mimics of solitary wasps in the families Pompilidae, Crabronidae, or Sphecidae. Indeed, some species even flick their wings like wasps while they run around on foliage or the surface of logs. Their larvae live in decaying wood, but at least a few may feed on fermenting sap. This species has a red abdomen, but others are wholly black or otherwise colored differently. There are 22 species in North America, so identification is difficult without putting a specimen under a microscope.

Xylota sp. syrphid fly

Closely allied to Chalcosyrphus is the genus Xylota. Oddly, this specimen reminded me most of a sawfly or an ichneumon wasp, neither of which is usually capable of stinging in self-defense. The adult flies rarely visit flowers, instead feeding on pollen grains from the surface of leaves. The larvae develop in rotting wood.

Mallota posticata syrphid fly

Many syrphid flies use leaves as a platform on which to groom, which explains the yoga-like moves of this specimen of Mallota posticata, a bumble bee mimic. I swear, grooming flies must be the envy of contortionists. As larvae, these flies grow up in rotting holes in trees.

Eastern Yellowjacket queen, a real wasp!

My, my, here we have another actual wasp, a queen of the Eastern Yellowjacket, Vespula maculifrons, pausing from her search for an underground nesting site. She is likewise grooming. This particular species is very likely the "model" for most of the "mimic" flies we were seeing....and arguably the best mimic was yet to come.

Sphecomyia vittata syrphid fly

The syrphid fly Sphecomyia vittata is simply stunning. It is about the same size as a queen yellowjacket, and even has longer, thicker antennae than almost any other fly, the better to resemble its sting-equipped model. This insect even flies like a queen yellowjacket, in the lazy, zig-zag manner of a queen looking for a nesting site. I recall capturing one of these in Cincinnati and being convinced it was a wasp right up until I had it in the jar. I was jaw-droppingly impressed.

Ichneumon wasp

Ah, here is an ichneumon wasp that looks suspiciously like that Xylota flower fly we saw a few minutes ago. At least some members of the subfamily Ichneumoninae can sting, so maybe looking like one is a better strategy than first imagined.

Laphria sp. robber fly

Somewhere along the line my wife spotted this fly, which I never saw. It is obviously a bumble bee mimic, but it is not a syrphid. It is a robber fly in the family Asilidae, genus Laphria. Looking like a bumble bee works to its advantage in two ways: its potential predators assume it stings. Meanwhile the fly's potential prey assume it is a bee seeking flower nectar. Interestingly, Laphria seem to be particularly fond of small, flying beetles, which they spot from their perches, apprehend in mid-air, and return to a leaf or log to feed upon.

Common Gartersnake, Thamnophis sirtalis

What a rewarding rest stop. Oh, and there was this bonus Common Gartersnake, Thamnophis sirtalis, also soaking up some rays. It never moved an inch as we worked around it to take insect images. Thanks to the maintenance crews at this rest stop for recognizing the importance of leaving natural elements intact around the area, including dead wood for insects to feed on, and birds to nest in. May other states follow your example.

Source: Marshall, Stephen A. 2006. Insects: Their Natural History and Diversity. Richmond Hill, Ontario: Firefly Books, Ltd.732 pp.

Saturday, April 30, 2016

Snow Days, Slow Days

I feel the need to apologize for the relative lack of content here lately, but several circumstances are conspiring to reduce the frequency with which I have been posting. Some are beyond my control, others a function of having differing current priorities. For once, these are valid explanations, not merely excuses.

Weather

It literally snowed here yesterday, April 29, and the high temperature was 35° F. You can choose your own expletive for "F." Today is cool and very windy. This is not unexpected for this time of year, but is incredibly frustrating. It is simply useless to go out looking for insects or arachnids, or much of any wildlife, actually. Last year we had a snowstorm on Mother's Day weekend, so....(sigh).

Blowout Tiger Beetles, Cicindela lengi, have been among the few literal bright spots this spring

Those few insects I am finding have been posted more frequently on Facebook than here in this blog. Look me up on Facebook under "Bug Eric," and also the "Arthropods Colorado" group.

Writing Elsewhere

I continue to accrue more paying assignments at other websites and publications, so while this is a very good thing from an income standpoint, it means that I have less time to devote to this blog. Watch this space, though, for announcements of where else my work is appearing. Most of it is going to the After Bite Insectlopedia blog, under my name. I share billing with the anonymous "Professor Bugsbee."

Meanwhile, a brand new website on spiders will be making its debut shortly, and I will be contributing content in the form of articles. Our goal is to produce at least one new article each week, and by the time summer gets here I suspect that site will be getting most of my attention.

Lastly, I am hoping to do more editing and "style consulting" for other writers and their work, especially pertaining to natural history. Please contact me if you or someone you know is looking for helpful criticism and/or help in getting published. I had the good fortune of going over a couple of e-books, one on notable insects and other arthropods of Zion National Park, and another on the same subject for Cedar Breaks National Monument. I very much enjoy the process of book production and helping others.

Lack of Travel

I have already told my wife that I want us to book a vacation in Florida or somewhere else down south next April! I am not going to go six or seven months between out-of-state destinations. Thankfully, we will soon be going away to what we hope are literally greener pastures to the east. That should provide a little more blog fodder, I hope. Meanwhile, I am available for nature festivals, insect identification workshops, speaking engagements, and other events. After expenses are paid for, I am negotiable for honorariums.

Suggestions Always Welcome
Do you have a species of insect or arachnid you would like to see featured here? Maybe there is a topic that you would very much like to learn more about. Perhaps you have images or video of insect behavior that would make a great story? I am open to any and all of these things. While I rarely allow guest bloggers, I always give them due consideration, especially if there is no commercial component or agenda.

Take care friends, enjoy your own explorations and observations!

Saturday, April 23, 2016

What's on Dat Scat?

My last post addressed what kinds of insects can be found in dung, but today I want to show you what can be found on animal poop. While blow flies, family Calliphoridae, are often overwhelmingly abundant on fresh manure, you'd be surprised what else comes in for a taste.

Acmon Blue and Reakirt's Blue enjoying some refreshing scat with broad-headed bugs

Would you believe many butterflies will visit scat? Last year I happened upon this scene on a concrete nature trail in a popular park here in Colorado Springs. There were two species of gossamer-winged butterflies imbibing from some kind of predator poo. The ones with the orange bands on both the front wings and hind wings are Melissa Blues. The one with orange on the hind wing only is an Acmon Blue. The other one, without orange bands, is a Reakirt's Blue.

Melissa Blue joins Reakirt's Blue and broad-headed bugs

Males of many butterflies require mineral supplements that they can pass along to females during mating. Dung is one such mineral-rich resource.

Some butterflies feed mostly on dung, or carrion, and hardly ever visit flowers. Among them are the satyrs like this Northern Pearly-eye that was visiting dung on a bike trail in a suburb of Chicago, Illinois.

Northern Pearly-eye butterfly

The Red-spotted Purple is also notorious for preferring dung and corpses for nourishment, though one usually sees the territorial males perching on the ground or up on leaves in the canopy along stream or river corridors, or forest edges.

Red-spotted Purple butterfly

Other surprising visitors to scat are true bugs that normally feed on ripening seeds or other plant material. Finding so many broad-headed bugs, family Alydidae, sharing the poo-pile with the butterflies was quite surprising. There are at least two species here: Megalotomus quinquespinosus is the brown one, known as the "Lupine Bug." The other, smaller and blacker, is a species in the genus Alydus.

Male Golden Dung Fly

Different kind of excrement seems to attract different kinds of insects, at least to a degree. Fresh cow and horse dung is a favorite breeding ground for dung flies in the family Scathophagidae. The males stake out pats of poo and defend them from other males, while also intercepting females receptive to mating. The female lays her eggs in the manure and the larvae that hatch feed and develop there. You can easily recognize males of the Golden Dung Fly, Scathophaga stercoraria, but their fuzzy, bright golden appearance.

Various blow flies on what is probably bear scat

The blow flies (Calliphoridae) come in two basic varieties: "greenbottles" that are wholly metallic green, mostly in the genus Lucilia, and "bluebottes" that are usually larger, and gray with a metallic blue abdomen. Most of the common bluebottles are in the genus Calliphora. There is also the Black Blow Fly, Phormia regina, that is black or deep metallic blue-black. All can be present at dung.

Black scavenger fly

Tiny and wasp-waisted, black scavenger flies in the family Sepsidae are not easy to see immediately given their size, but their behavior is unmistakable: they walk around "rowing" their wings as if they needed the extra propulsion to get around.

Flesh flies of the family Sarcophagidae are gray with black "pinstripes" on the thorax, and usually red eyes and a red "tail." They are about the size of the blow flies, though some are smaller. The females "larviposit." That is, they lay tiny maggots in dung or carrion, rather than laying eggs. Bypassing the egg stage gives them a head start in exploiting the food resource.

A mating pair of flesh flies

Dung-watching is probably not going to become the next big thing in the world of naturalists, but if you can get over the "yuck factor," you might find some interesting creatures among the clean-up crew. Just make sure you are up wind.

Saturday, April 16, 2016

What's in Dat Scat?

Sometimes you have to literally get down and dirty to find interesting insects. Poking into animal dung, affectionately known as "scat," is a pretty smelly, gross business, but it can yield a diversity of insect life you are unlikely to see otherwise. A case in point came on April 13 when I visited the Bluestem Prairie Open Space along the edge of Johnson Reservoir just southeast of Colorado Springs.

Two half-buried Trox sp. and one red and black dung beetle, Aphodius fimetarius under coyote scat.

While dogs are not permitted in the area, I suspect the locals probably bring them in anyway, judging by the tracks and the scat I come across. Still, the overwhelmingly most common canines are coyotes, and their dung invariably contains lots of fur from their prey. This makes their excrement attractive to beetles more commonly found on carrion and mummified carcasses.

Hide beetle, Trox sp., on coyote scat, facing left

Hide beetles in the family Trogidae normally visit the dried-out remains of an animal body when little is left but skin and bones. Indeed, that is what they eat as adults and larvae, along with feathers, fur, and connective tissue. Apparently coyote dung is the next best thing to a dead body. I found a total of three Trox sp. on just one piece of manure. These beetles are almost invariably caked in gunk so as to be nearly unrecognizable as insects, or animals of any sort, really. When disturbed they go voluntarily comatose, so convincingly that I have given them up for dead, stiff specimens. I've been startled by having them re-animate in a vial or cup after several minutes.

Fully active Trox sp.

Another surprise on this chunk of poop was a skin beetle, Dermestes fasciatus or D. marmoratus, I am not sure which. Again, these beetles are usually much more common on carcasses in advanced stages of decomposition, including wet bones.

Skin beetle, probably Dermestes marmoratus

There were, however, some honest-to-goodness dung beetles in another piece of coyote scat that was a little....fresher, if one can apply that term to anything that doesn't smell the part. Aphodius fimetarius is a little red and black dung beetle that was introduced to North America from Europe probably a century or more ago. It is now widespread and common here, usually in cow pats. The larvae live and feed in the manure, then dig into the soil beneath it to pupate. There is probably one generation per year.

"Tumblebug," Canthon simplex, unfortunately lying trampled on a trail

The other dung beetle I found was one of the dung-rollers or "tumblebugs" as they are affectionately called. This species, Canthon simplex, is relatively tiny, adults measuring only 7-8 millimeters. The adults tear off a pea-sized chunk of poo and roll it into a ball, either females alone or in pairs with males. Rolling the ball away minimizes conflict with other dung beetles. Once a suitable site is located, the female buries the "brood ball" and lays a single egg inside. The grub that hatches feeds inside, eventually pupating within the now hollow sphere.

"Tumblebug," Canthon simplex

While I was looking for the dung beetles, a very small rove beetle, family Staphylinidae, raced up a grassblade and flew off before I had a chance to secure it. Rove beetles are predators of other insects, and many species visit dung and carrion to feed on fly maggots. Rove beetles are slender, almost serpentine, with shortened wing covers (elytra), and so may be mistaken for earwigs at first glance. Staphylinids are so diverse that identifying them is next to impossible for anyone but an expert; and it also frequently involves detailed examination of the male's genitalia.

Typical rove beetle, family Staphylinidae

Maybe you are not "into" dung fauna, at least not if it requires pawing through it with or without gloves and/or various instruments. Ok, no one can blame you; but before you dismiss the power of poo altogether, consider my upcoming post "What's on dat scat?" You will be surprised all over again.

Source: Ratcliffe, Brett C. 1991. "The Scarab Beetles of Nebraska," Bull Univ Nebr State Mus. Vol. 12: 333 pp.