That's Not an Ant?!

It is always best to avoid making assumptions about insects in the field. I was reminded of that on three seperate occasions this month, all of them involving mimicry of ants by small longhorned beetles in the family Cerambycidae. Early spring is apparently the season for these wood-boring insects, at least here in Kansas. Their resemblance to ants is uncanny, and highly convincing.

Cyrtophorus verrucosus

While exploring our yards and looking for insects on April 2, I noticed what I thought was a carpenter ant climbing on the exterior of our detached garage. I was about to dismiss it, but decided to document it anyway, as it would be new for the year. Imagine my surprise and delight to discover it was instead an adult Cyrtophorus verrucosus. This species has no common name, which is unfortunate given its uniqueness.

The beetle averages only 9 millimeters in body length. Larvae bore in a variety of host trees, including maple, hickory, oak, elm, birch, chestnut, dogwood, Eastern Redbud, American Beech, and even pine. The adult beetles are active from March to July, but are most abundant in early spring. Cyrtophorus verrucosus ranges over most of the eastern U.S., and Canada as far west as Alberta. This was a new species for our property.

I was invited to present the keynote address for a joint meeting of the Kansas Academy of Science, and Central States Entomological Society, in Wichita, Kansas on April 5, and Heidi and I stayed over to go exploring on Sunday, April 6. I reached out to a Facebook and iNaturalist friend, Ryan Philbrick, and we met at the Kansas Wildlife Exhibit in Central Riverside Park. From there we went to Keeper of the Plains, and walked the nice concrete trail along the Arkansas River. At one point, Ryan turned over a small, broken tree limb on the ground. He noticed millipedes and a small "ant" crawling over the bark.

Euderces pini

I trained my camera on the ant and discovered it was another species of longhorned beetle, Euderces pini. At only 7-8 millimeters, and slender, it is even more ant-like than other species. The larval host trees include Flowering Dogwood, Pecan, Winged Elm, and American Beech, but there are several other hardwoods on the menu.

The adult beetles are frequently found on flowers, feeding on pollen and nectar. Even dandelions will suffice until native trees start blooming. Euderces pini occurs in the southern half of the eastern United States, and appears as an adult from March to June.

Currant-tip Borer

Back home, yesterday, April 13, I happened to notice a small ant-like insect on the central air-conditioning unit in the back yard. It was even smaller than the other beetles, but at least it had a common name: the Currant-tip Borer, Psenocerus supernotatus.

Despite its name, this 4-millimeter beetle has been reared from plants other than currant: Green Hawthorn, Tulip Tree (aka Tulip Poplar, Yellow Poplar), and Black Willow. This beetle is widespread in North America, east of the Rocky Mountains, and the adults are found from April to June.

None of these three beetles are considered pests, maybe because they do not affect crops or orchard trees. Their earthtone colors make them rather cryptic, but they are quite active, running rapidly, and flying well.

An actual ant

It is interesting to note the convergence in body shape and coloration between the different genera. They each have white streaks or bars designed to suggest body segmenation where there is none. Ants show marked constrictions between the head, thorax, and abdomen. In these beetles, the thorax may be mistaken for the enlarged head of an ant, and the elytra (wing covers), "divided" into thorax and abdomen by those white markings. The true head of the beetle is relatively small, and in the case of the Currant-tip Borer, directed downward and nearly hidden by the thorax.

There are even more ant-mimicking longhorned beetle species. Give that "ant" a second glance, especially if you see it in isolation, with no other ants nearby. It may turn out to be a beetle instead.

Sources: Lingafelter, Steven W. 2007. Illustrated Key to the Longhorned Woodboring Beetles of the Eastern United States North Potomac, Maryland: Coleopterists Society, Special Publication No. 3. 206 pp.
Yanega, Douglas. 1996. Field Guide to Northeastern Longhorned Beetles (Coleoptera: Cerambycidae). Champaign, Illinois: Illinois Natural History Survey, Manual 6. 174 pp.

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.

Wasp Mantisfly

Maybe I am simply excitable in general, but I was ecstatic to find a truly astonishing insect species earlier this week here in Colorado Springs. I spied what I thought was an ordinary paper wasp (Polistes sp.) on the underside of a sunflower blossom, but something wasn't quite right. Short, quivering antennae finally betrayed it as the Wasp Mantisfly, Climaciella brunnea. These bizarre insects are most closely related to antlions and lacewings in the order Neuroptera.

As I wrote in the Kaufman Field Guide to Insects of North America, mantispids "resemble a science experiment gone horribly wrong. Imagine shrinking a praying mantis, then attaching its front end to the hind end of a lacewing, and you have a mantispid."

In the case of C. brunnea, the body form has been further modified to look like a paper wasp. The resemblance is uncanny. The base of the abdomen is constricted into a "wasp waist," and the wings are rotated such that they fold over the back instead of pitched roof-like as in other mantispids. Even more amazing, the leading half of each wing is darkened, to resemble the longitudinal fold in the wings of vespid wasps. When startled, the Wasp Mantispid even splays its wings like an agitated paper wasp.

Wasp Mantisfly in defensive pose

An actual paper wasp, Mischocyttarus flavitarsis

As if the adult insect is not strange enough, the life cycle is simply mind-boggling. The adult female C. brunnea deposits clutches of literally hundreds, even thousands of eggs, each on a short filament, usually on the underside of leaves. The tiny larvae that emerge probably drop to the ground. They then adopt a posture whereby they are standing more or less upright, on their hind end, swaying, and legs waving in the air. They aim to glom onto passing spiders. Only one larva per spider will survive, and competition must be keen. Assuming only one larva boards a given spider in our example, the story progresses this way: The larva clings to the margin of the spider's carapace (top part of the cephalothorax), waiting for the spider to reproduce. Should the spider be a male, the larva must transfer to a female during mating. The mantispid larva must then wait until the female begins constructing an egg sac.

Before the female spider finishes closing her egg sac, the mantispid larva must enter the sac. The larva cannot penetrate an egg sac that is completely enclosed in silk. Once inside, the larva begins feeding on the spider eggs.

At least three wolf spider hosts have been recorded for C. brunnea: the Rabid Wolf Spider, Rabidosa rabida, and two unidentified members of the genus Schizocosa (Redborg and Redborg, 2000) in Illinois. The entire life cycle from egg to adult requires at least one year.

Look for the adult mantispids on flowers, especially sunflowers, thistles, and milkweed, where they wait to ambush other insects. I found a total of five specimens in quick succession on sunflowers at the edge of a big vacant field of shortgrass prairie on August 13, 2014, and three more on August 15 in the same location. So, they can be very localized in abundance.

Apparently the males live but a very short time, less than a week. Females persist for about a month. Emergence times vary, between May and October, but the overwhelming majority seem to be seen in June, July, and August.

This species is widely distributed, and while considered scarce is probably more common than we realize. It is recorded from southern Canada and nearly every state except the Pacific coast states, Idaho, and Nevada, then south through most of Central America.

Sources: Boyden, Thomas C. 1983. "Mimicry, Predation, and Potential Pollination by the Mantispid Climaciella brunnea var. instabilis (Say) (Neuroptera: Mantispidae)," J. NY Entomol. Soc. 91(4): 508-511.
LaSalle, Mark W. 1986. "Note on the Mantispid Climaciella brunnea (Neuroptera: Mantispidae) in a Coastal Marsh Habitat," Entomol. News 97: 7-10.
Leckie, Seabrooke. 2010. "Mantisfly," The Marvelous in Nature.
Redborg, Kurt E. and Ellis G. Macleod. 1983. "Climaciella brunnea (Neuroptera: Mantispidae): a mantispid that obligately boards spiders," J. Nat. Hist. 17(1): 63-73.
Redborg, Kurt E. and Annemarie H. 2000. "Resource Partitioning of Spider Hosts (Arachnida, Araneae) by Two Mantispid Species (Neuroptera, Mantispidae) in an Illinois Woodland," J. Arachnol. 28(1): 70-78.

Wasp Wednesday: Not Wasp IX

I have recently begun participating in “Project Noah,” and as a result find yet another demand for identification of mystery bugs, like this one posted just yesterday. The subject of the image is a Red-necked Ash Borer, Neoclytus acuminatus, a type of longhorned beetle in the family Cerambycidae.

The person who posted the image says he calls them “crickabees” because they have “legs like a cricket….and stripes like a bee.” Most folks mistake these beetles for wasps, though. They can be fast-moving insects, a trait not always associated with beetles. Couple that with their bold markings, and it would be easy to assume they are a stinging insect.

Despite its name, this beetle bores in virtually any hardwood tree during its larval stage, though it does seem to favor ash. It has also been recorded from woody vines and shrubs. I have noticed the adults on freshly-cut trees, but also on older logs. While dead, dying, or weakened trees are most commonly exploited by the Red-headed Ash Borer, it is also a serious pest of healthy black locust trees planted as windbreaks or on farm woodlots. It may also attack recently-planted trees. So, trees stressed in some way are going to be vulnerable to this beetle.

References indicate that the normal flight period for Neoclytus acuminatus is between May and August in the northeast U.S., and from February to November in the southeast. There may be up to three generations each year in the south, usually only one in the north. Firewood brought indoors in late winter or early spring may yield adult beetles emerging inside your home.

This species is widespread, found almost everywhere east of the Rocky Mountains (and into Idaho). It is not one of the larger longhorned beetles, adults measuring only 4-18 millimeters in length.

Sources: Shour, Mark. 2008. “Red-headed Ash Borer Also a Threat to Ash Trees,” Extension News.
Solomon, J.D. 1995. Guide to Insect Borers of North American Broadleaf Trees and Shrubs. Agric. Handbk. 706. Washington, DC: U.S. Department of Agriculture, Forest Service. 735 pp.
Yanega, Douglas. 1996. Field Guide to Northeastern Longhorned Beetles (Coleoptera: Cerambycidae). Illinois Natural History Survey Manual 6. 184 pp.

Wasp Wednesday: Wasp/Not Wasp

Previously on “Wasp Wednesday” we featured keyhole wasps of the genus Trypoxylon. Like most stinging insects, these wasps are models for other harmless insects that escape predators by pretending to be something more dangerous than they are: a sheep in wolf’s clothing if you will. Meet Pseudodoros clavatus, a near perfect imposter of a keyhole wasp.

A biologist friend once cautioned me on jumping to conclusions about which insects serve as models for various mimics, but just look at this fly. The elongated abdomen even has pale markings to make it appear narrower than it actually is. At 7-12 millimeters long, it is also similar in size to many Trypoxylon wasps. Besides looking like the wasp, the fly even behaves like it. Male keyhole wasps often hover in front of vertical objects, and the fly hovers just as well, if not better than, the wasp.

Ok, so how do you tell them apart, anyway? Above is the wasp. Note that it has two pairs of wings (though connected to each other they are usually still discernible as separate). The antennae of the wasp are thick and relatively long. They eyes are large, but do not take up the entire head or face of the wasp. Now look at the fly below. It has only one pair of wings. The antennae are so short they are scarcely visible. The eyes cover most of the head of the fly, and are not notched on the inner margin like those of the wasp.

Pseudodoros clavatus is a member of the family Syrphidae, collectively known as “flower flies” (“hover flies” in Europe). They are frequent, abundant visitors to flowers of all kinds. While they may be insignificant pollinators, they play their part in perpetuating wildflowers. Their good deeds extend to the larval stage as well. The maggots of Pseudodoros are voracious predators of aphids.

Seeing one of these slug-like larvae on your rose bush might lead you to think that it is also eating the plant, but watch one closely and you will see it methodically slaying aphids, seizing the tiny sap-suckers and hoisting them off the stem. The fly larva then sucks the hapless pest dry and discards the empty husk of its exoskeleton.

Look for this species from coast to coast in the United States and southern Canada. It may be confused with the similar genera Baccha and Ocyptamus in some parts of its range, but Ocyptamus species have at least faint dark markings on the wings (if only a bold leading edge to the wing). Baccha is more difficult to distinguish, but at least one species has a distinctly banded abdomen. The image below is still a Pseudodoros.