Tuesday, May 30, 2017

Window-winged Moths

One is not accustomed to thinking of moths as day-flying creatures, but a surprising number are indeed diurnal. You may simply not always recognize them as moths. A good example are the window-winged moths in the family Thyrididae. They are named for square or rectangular translucent spots in their wings, which may appear to be white or amber in color.

I encountered one of these diminutive insects just the other day, Monday, May 29, in Aiken Canyon Preserve, a property of The Nature Conservancy that features mixed conifer (mostly Ponderosa Pine and juniper) forest, impressive sandstone bluffs and formations, and extensive glades of prairie grasses, yucca, cacti, and herbs. The trail crossed a dry stream bed at one point and I caught sight of something I first thought was just another fly. It landed briefly and revealed itself to be Thyris maculata, a relatively uncommon western insect, but much more widespread in the eastern U.S.

The little moth was perhaps seeking water and/or minerals and was barely pausing, preventing me from getting really crisp images. When I returned home I did a bit of research and found that there are only twelve (12) species in the family Thyrididae known in North America, and few of those are western. The family is mostly pantropical (Old World and New World tropics), and the total number of world species exceeds 760. There are, in fact, over 400 additional species awaiting description at the London Museum of Natural History alone. While our domestic species have a wingspan varying from 6-16 millimeters, many tropical species are larger, with wingspans of 26-34 millimeters.

Thyris maculata from Massachusetts

Thyris maculata does visit flowers for nectar, as I observed in the town of Athol in western Massachusetts in 2015. Even then, the little moths defy attempts to get in-focus pictures. You are more apt to find at least some species, like the "Mournful Thyris," Thyris sepulchralis, licking animal scat. Fresh dung is a real treasure to lots of insects, including many butterflies and true bugs.

What do they eat in the caterpillar stage? They are surprisingly cosmopolitan in their tastes, being generalist feeders. Among their host plants are beans, grapes, cotton, and thoroughworts. The larvae typically roll the leaves of the host plant and tie them with silk; some species bore in the stems or twigs of the host. Thyris maculata has been reared from Clematis and Houstonia. This might explain the moth's extensive range, from Ontario and Quebec south and west to Georgia, Texas, Missouri, New Mexico, Colorado, and even Idaho and Montana. The adult flies anytime between March and October, but especially May through July. Samuel Johnson, a friend and moth expert here in Colorado deduced from my record yesterday that the species has two broods in the Pikes Peak region of Colorado. His own record is from August, 2003.

Dysodia sp. from Rio Rico, Arizona

Yet another genus of window-winged moths that I have come to know is Dysodia. These are slightly larger, heavier-bodied moths which are nocturnal. I have seen them attracted to lights in southern Arizona and the Lower Rio Grande Valley in southernmost Texas. The caterpillars typically roll the leaves of their host plant, forming both a shelter and a comfortable place to dine. There are at least four species of Dysodia in the U.S., and the one in south Texas is likely an undescribed species. So much yet to learn....

Thyris maculata from Massachusetts

Sources: Beadle, David and Seabrooke Leckie. 2012. Peterson Field Guide to Moths of Northeastern North America. Boston: Houghton Mifflin Harcourt. 611 pp.
Covell, Charles V., Jr. 1984. A Field Guide to Moths of Eastern North America. Boston: Houghton Mifflin Company. 496 pp.
Powell, Jerry A. and Paul A. Opler. 2009. Moths of Western North America. Berkeley: University of California Press. 369 pp.

Tuesday, May 16, 2017

Another Rarity: Nysa Roadside-Skipper in Colorado

This is what you get for exploring, observing, recording, and being curious: Surprises. I am not well-versed in things butterfly, but I do know when I haven't seen a particular species before. Even if I cannot say anything about a creature in the field, I can go and research it later. Such was the case of the Nysa Roadside-Skipper encountered on Monday, May 15, in Lamar, Prowers County, Colorado.

It always starts innocently enough, and sometimes results from disappointment over something else. I would much rather find interesting wasps, beetles, grasshoppers, and true bugs instead of butterflies, but it so happened that recent bad weather (a cold snap a couple weeks ago and heavy rains more recently) left little to find besides Lepidoptera in Lamar. Some Lepidopterist out there is going to make me envious by finding a cool wasp now.

So, my wife, Heidi, and our mutual friend Jill White Smith, took the field looking for birds and whatever other wildlife we could see. Jill is a very accomplished photographer. You can see her work at Nature Made Photography on Facebook, in fact. She does "people photography," too, as she puts it. She is also very generous and welcoming, and eagerly showed us around to her favorite haunts.

One of those habitats is an abandoned, unpaved road that is quickly becoming part of a dune or sandhill adjacent to the riparian corridor of Willow Creek, south of the Lamar Community College campus. Flies, damselflies, a few bees, and butterflies flew up every few steps. I happened to notice one small one land in the road, and I focused my camera. I could tell it was a skipper, but not one I had ever seen before. I had left my field guides at home, but that only served to build suspense.

We got home from the three-plus hour drive around eleven at night. After unloading the car, I consulted my Kaufman Field Guide to Butterflies of North America. Thanks to Jim Brock and Kenn Kaufman, I quickly found my mystery skipper: the Nysa Roadside-skipper, Amblyscirtes nysa. The only "problem" was that the range map for the species does not include Colorado. Heidi did a bit more research and found only one Colorado record online at Butterflies and Moths of North America (BAMONA), and no Colorado records on Bugguide.net. I consulted an old book, Butterflies and Moths of the Rocky Mountain States, and found no historical records for Colorado.

What do we know about this insect? Its known range is from Mexico, southeast Arizona, southern New Mexico, and the western two-thirds of Texas north and east through Oklahoma and the eastern two-thirds of Kansas, barely crossing into Missouri. There are between one and three generations ("broods") each year, depending on the geographic location of a given population. The caterpillars feed on grasses. The Kaufman guide adds: "Males perch in wash bottoms, road depressions, or along trails very early n the morning before retiring to shade for the afternoon." This guy was overdue for a nap, then, at almost 10:00 AM.

We also saw what I thought was a small Common Sootywing, but it turns out what I saw was the dorsal (top) view of this same skipper. I narrowly missed an opportunity to get a shot, but here is one of a specimen in Arizona:

© Philip Kline via Bugguide.net

Lastly, while taking images of the skipper, I noticed what might be the cutest beetle ever. I had to bring it home to get images. As near as I can tell, it is a darkling beetle in the genus Edrotes, for which there are also no Bugguide records for Colorado.

Discoveries like these await you, too. You do not have to know what you are looking at to enjoy the moment, capture it in pixels or digital video, and share it with others. You explore and observe often enough and long enough, and you are almost guaranteed to find something truly unusual, or even unknown.

Sources: Brock, Jim P. and Kenn Kaufman. 2003. Kaufman Field Guide to Butterflies of North America. Boston: Houghton Mifflin Co. 384 pp.
Ferris, Clifford D. and F. Martin Brown. 1981. Butterflies of the Rocky Mountain States. Norman: University of Oklahoma Press. 442 pp.