Monday, March 23, 2015

Blogging Elsewhere

Apologies for the long periods between posts, but I do have an explanation, if not an excuse. I have been working on a mini field guide to common bees and wasps of Ohio that will be published by the Ohio Department of Natural Resources in early 2016. The text is now complete, though there may well be changes as things progress. I have also been contracted to write content for the blog page of a client I will reveal at a later date.

Additionally, I will be reviewing signage and creating supplemental content for the soon-to-open Missoula Butterfly House and Insectarium in Montana.

I must also prepare a presentation for the inaugural Pikes Peak Birding and Nature Festival in Colorado Springs, Colorado on Saturday, May 9, at the Bear Creek Nature Center. The topic will be "Colorado's Watchable Bugs."

I have been donating plasma the last couple of months and expect that twice-weekly routine to continue. Ironically, it helps establish something of a routine that better structures my time as well as providing a few extra dollars each month.

Meanwhile, I have been grossly neglecting the field guide to common U.S. spiders that I am contracted to write for Princeton University Press. I really need to break through the stagnation and make significant progress. Pronto.

Thank you for understanding that paying assignments take priority right now. I will do what I can for this blog as time permits, but I must look for still more work to keep us afloat financially. I always welcome suggestions for markets I can write for, nature festivals I can speak at, workshops I can lead, and other opportunities. I appreciate your help and support.

Saturday, March 14, 2015

Picture-winged Flies

One of the more interesting insects I have found early in the spring this year is a picture-winged fly, Ceroxys latiusculus. Picture-winged flies belong to the family Ulidiidae, and they are among the more common, ornate, and entertaining of all Diptera, thanks to their lovely wing patterns and cute courtship behaviors.

Ceroxys latiusculus from Fountain, Colorado

The Ulidiidae once went by the family name Otitidae, and this is where you will find them in older references. There are roughly 40 genera and 133 species known from North America north of Mexico. They are relatively average in size for flies, from 3-12 millimeters, depending on the species of course. Most have some kind of pattern of spots, bars, or lines on the wings, and at least a few have metallic bodies.

Pseudoseioptera albipes from Massachusetts

Many picture-winged flies can be reliably found on certain plants, dung, logs, rails of unfinished wooden fences, or the trunks of trees. These locations serve as food sources, basking sites, or display sites for courtship. Below is a video of behavior typical of picture-winged flies, though flies in other families also exhibit the wing-flicking thing.

Ceroxys latiusculus on tree trunk, Penrose, Colorado

Ceroxys latiusculus is common throughout western North America, especially in spring and fall. In the larval stage it develops in the seed heads of plants in the genus Senicio, known as groundsels or ragworts. The adult flies apparently invade homes and other buildings in the fall, seeking winter shelter.

Delphinia picta from Illinois

Back in the eastern U.S., Delphinia picta, 7-8 millimeters, is perhaps the most common picture-winged fly. It breeds in decaying organic matter such as compost. Consequently, it is a common fixture in gardens, as well as forest edges. Look for it on foliage or the ground.

Idana marginata from Massachusetts

Idana marginata is our largest species, about 10-12 millimeters, and it is not uncommon in the northeast quarter of the U.S. Look for it at fresh bird droppings (yum!), or fermenting sap oozing from wounds in trees. At its size, it can easily be mistaken for a fruit fly (family Tephritidae), or some other dipteran. The larvae develop in compost.

Stictomyia longicornis from Colorado Springs, Colorado

One of the more bizarre picture-winged flies is Stictomyia longicornis, which is found almost exclusively on prickly-pear cacti in the southwest U.S., and possibly elsewhere cacti occur. Indeed, it has been reared from rotting cactus pads. The adult flies are only 4 millimeters long, but look more like true bugs or beetles than flies. The wings are short and plastered to the back of the fly. They rarely take wing, either, preferring to dodge between bundles of cactus spines.

Physiphora alceae from Colorado Springs, Colorado

Physiphora alceae is rather atypical in that it lacks bold markings on the wings. This species, about 5 millimeters long, is not native, but its exact point of origin is not easily defined. It is now considered "cosmopolitan," and likely to turn up anywhere in the U.S. Look for the adults on flowers. The larvae feed in decaying plant matter or animal dung.

Pseudotephretina sp. from Tucson, Arizona

The two species of Pseudotephretina closely resemble Ceroxys in size and appearance, but the bars on the wings are more "tiger-striped" and complete than in Ceroxys. These flies are closely associated with poplar and willow trees, but look on the trunks of cottonwoods as well.

One of the more common and attractive ulidiids to be found in southern Arizona is Diacrita costalis. It also ranges into southern California, New Mexico, and Texas. I typically found it in shaded situations during the day, such as under rock overhangs, or covered patios. They are also attracted to bird feces.

Diacrita costalis from Tucson, Arizona

Perhaps the most adorable species are in the genus Callopistromyia. They are only 3.5-5.5 millimeters (usually on the lower end of that spectrum), but absolutely captivating in their behavior. Males can be seen on fence rails or logs where they erect their patterned wings perpendicular to their bodies, then sidle this way and that. C. annulipes is called the "Peacock Fly" in reference to this display. Here's a brief video that illustrates the behavior. The larvae live under bark, but their diet is apparently unknown. Look for these insects throughout the northern U.S. south to northern Georgia, Louisiana, Oklahoma, northern Utah, and Washington state. C. strigula occurs in Canada and the northeast U.S.

Callopistromyia annulipes from Lynx, Ohio

I think you get the "picture," pun fully intended. This is a diverse family of flies that for a change are rarely, if ever, pests (the six Tetanops spp. live as larvae in the roots of living plants), and that have unique behaviors and lifestyles. Enjoy hunting for them.

Tetanops sp. from Colorado Springs, Colorado

Sources: Marshall, Stephen A. 2006. Insects: Their Natural History and Diversity. Richmond Hill, Ontario: Firefly Books Ltd. 732 pp.
McAlpine, J.F. (ed.). 1987. Manual of Nearctic Diptera Vol. 2. Ottawa: Agriculture Canada. pp. 675-1332..

Wednesday, March 4, 2015

Facebook: An Expanding Portal to Entomology

The internet has made the scientific community vastly more accessible to the general public, but social media has taken that to yet another level. Whereas it once took hours, if not days, of research to get an answer to a question, or the identification of an organism in an image, success can now be had in minutes. Facebook in particular has exploded with specialized "groups."

No matter how offbeat your entomological interest there is no doubt a Facebook group devoted to it. Are you a moth fanatic? Ha, so are over 3,300 other people who have already joined the "Mothing and Moth-watching" group.

You might worry that the membership represents a "blind leading the blind" assortment of amateurs or newbies, but most of the time there are plenty of professional entomologists and experienced citizen scientists offering help, sharing announcements of new research, or simply posting stunning images. Take the "Hymenopterists Forum," for example. I have queried this group a number of times with images of wasps, bees, or ants that I was having trouble identifying. I am always met with courtesy and respect, though I am careful not to post too much, too often.

Are your interests regional in nature? New groups continue to sprout which are regionally-centered geographically. I know because I have started four of them myself. Maybe you want to know more about dragonflies and damselflies of the southeast U.S. Voila! "Southeastern Odes" is at your service.

One of the most wonderful aspects of Facebook groups is that they usually have a global membership, and you can always stand to learn from others in far-flung locations around the world. The "Friends of Coleoptera at the Natural History Museum" group reflects beetle experts at the museum in London, England, for example, but they are incredibly friendly to everyone, and highly knowledgeable of beetles from all over the planet.

Still can't find a group that suits you? The answer is easy: create your own. Facebook makes the process of founding a group very easy and relatively intuitive. Do pay attention to the settings ("public," "closed," "secret"), and be mindful that as an administrator you will need to be vigilant to welcome new members, delete spam and its originators, and post regularly to keep your group on the Facebook radar.

I had to be metaphorically dragged into social media back in 2009, but I could not be more grateful to those who nudged (pushed?) me into it. Through Facebook I have made many new friends in the truest sense, learned more than I could have imagined, and helped others. I highly recommend taking full advantage of social media avenues in your own pursuits.

Thursday, February 26, 2015

Green-eyed Wasps, Tachytes

Identifying wasps in the field is often problematic for a number of reasons. Wasps move quickly, and often you only get a glimpse. Mimicry complicates matters and you may actually be looking at a fly, moth, beetle, or true bug. "Field marks" are seldom visible, at least without a magnifying lens. One exception is the genus Tachytes, in the family Crabronidae. The larger species in the genus often have huge green eyes.

Tachytes from South Deerfield, Massachusetts

These insects have been referred to as "sand-loving wasps" in some literature, but they nest in a variety of soil types. I think they deserve the name "green-eyed wasps" because that character is more vivid, even if it does not apply to every species. Males in particular have very large eyes, the better to detect passing females or rival males while scanning the landscape from their perch on a stone, leaf, flower, or twig.

Male Tachytes defending territory from perch in Colorado

Interestingly, one of the hallmarks of the Larrini tribe within the Crabronidae is the reduction of their "simple eyes" (ocelli) to the point of being mere "scars." In Tachytes, the ocellar scars are shaped like golf clubs, having long "tails" running part way down the head. The image below shows the scars between the compound eyes, at the point where they begin to diverge from one another.

Close-up of Tachytes from Colorado

The female wasps excavate burrows in the ground, the tunnels ranging from 7 centimeters to nearly one meter in length, and to a depth of 7.5 to 70 centimeters. Several individual cells are arranged along the length of the burrow, or at the end of tunnels that branch from the main shaft. Some species dig their nests just inside the entrances of burrows made by other organisms such as rodents, lizards, or cicada killer wasps; and at least one species works at night.

All North American species provision those cells with immature grasshoppers (Acrididae), pygmy grasshoppers (Tetrigidae), katydid nymphs (Tettigoniidae), or pygmy mole "crickets" (Tridactylidae). The female wasp paralyzes the victim with her sting, then straddles it, grasps it by the antennae with her jaws, and flies it back to her nest. There, she deposits her prize in one of the cells. One to thirteen victims are placed in each cell, and an egg is laid on the last one.

Male Tachytes atop female in Colorado

Males employ two strategies to find mates. They emerge before females, so at first they defend small territories in the vicinity of areas where females are likely to emerge. Later in the season they defend territories around nesting sites. I have observed them defending territories around nectar resources, too, namely a solitary blooming saltcedar tree (Tamarix sp.) in a large expanse of degraded shortgrass prairie here in Colorado Springs.

The male pounces on the back of a female, pinning her wings to her body, and then beginning courtship behavior. Apparently this amounts primarily to waving his antennae frantically over the female's face, as shown in the short video below. This behavior may not hold true for all Tachytes species, and certainly the duration of courtship and copulation can vary dramatically.

Should the female be receptive, mating ensues. The image below clearly shows a male deploying his....um....ahem...."junk" in preparation for mating. Ok, the technical term is "aedeagus," composed of two "penis valves," and it is the blunt, central structure protruding from the tip of the abdomen in the image. The longer, more slender appendages framing the aedeagus are the "gonostyles." The "volsella" is a shorter spur at the base of each gonostyle. Insect genitalia are complex organs designed to work as a female "lock" and male "key" to prevent cross-breeding with similar species. Indeed, dissection of the male genitalia is often required for species identification in many insects.

Tachytes pair from Colorado

There are 35 species of Tachytes in North America north of Mexico. They are among our more common solitary wasps, easily observed as they feed on flower nectar, though they flit rapidly from blossom to blossom. Males also land on foliage, stones, or the ground, usually returning repeatedly to the same perch or one very close by. This represents the territorial defense behavior, and it allows for great photographic opportunities provided you don't make sudden movements. Happy wasp watching.

Sources: Bohart, Richard M. 1994. "A Key to the Genus Tachytes in America North of Mexico with Descriptions of Three New Species (Hymenoptera, Sphecidae, Larrinae)," Proc. Entomol. Soc. Wash. 96(2): 342-349.
Bohart, R.M. and A.S. Menke. 1976. Sphecid Wasps of the World. Berkeley: University of California Press. 695 pp.
Krombein, Karl V. and Paul D. Hurd, Jr. 1979. Catalog of Hymenoptera in America North of Mexico Vol. 2 Apocrita (Aculeata). Washington, DC: Smithsonian Institution Press. pp. 1199-2209.
Kurczewski, Frank E. and Margery G. Spofford. 1986. "Observations on the Nesting Behaviors of Tachytes parvus Fox and T. obductus Fox (Hymenoptera: Sphecidae)," Proc. Entomol. Soc. Wash. 88(1): 13-24.
Kurczewski, Frank E. and Edmund J. Kurczewski. 1984. "Mating and Nesting Behavior of Tachytes intermedius (Viereck) (Hymenoptera: Sphecidae)," Proc. Entomol. Soc. Wash. 86(1): 176-184.
Kurczewski, Frank E. and Edmund J. Kurczewski. 1971. "Host Records for Some Species of Tachytes and Other Larrinae," J. Kansas Entomol. Soc.. 44(1): 131-136.
Kurczewski, Frank E. 1966. "Behavioral Notes on Two Species of Tachytes That Hunt Pygmy Mole Crickets (Hymenoptera: Sphecidae, Larrrinae)," J. Kansas Entomol. Soc. 39(1): 147-155.
O'Neill, Kevin M. 2001. Solitary Wasps: Behavior and Natural History. Ithaca: Comstock Publishing Associates (Cornell University Press). 406 pp.