The Saga Concludes

Like I haven’t written enough already about the brown-banded cockroach (see All Grown Up and The “University Roach”), along comes another chapter.

I was visiting the insect collection in the Department of Entomology at the University of Arizona in Tucson yesterday, when in the process of moving a cart to get to a cabinet, I discovered a cockroach, belly-up on the floor. I could tell it was a brown-banded roach even before I turned it over. I had seen another dead one here before (before I had a camera). The neat thing about this one was that it was a male.

Oddly, I have never seen a living adult male of this species. Then again, until I saw live ones at the University of Massachusetts, I had not seen a living example of either gender. I suspect they are less populous than other “domestic” roaches, and maybe more secretive, too.

In any event, Supella longipalpa is an outstanding example of sexual dimorphism in the order Blattodea. While the females are broad-bodied with shortened forewings (called tegmena), males are more slender, with long tegmena and fully-functional hindwings as well.

Other cockroach species have even more dramatic differences between the sexes, males being fully winged and females totally wingless. The sand roaches in the genus Arenivaga come to mind. They occur here in the Arizona outdoors, so maybe I’ll eventually be able to share their story here on my blog as well. For now, though, I can close the book on the brown-bandeds.

All Grown Up

I have no idea whether she is the same individual that I introduced in ”The University Roach” back in November, but on Monday, December 14, I finally spotted an adult female brown-banded roach on the floor in my lab. Since the first sighting I have learned a little more about the species, too.

Ok, maybe what I really learned is just how much we collectively don’t know, like exactly where this species came from in the first place. My initial research concluded that Supella longipalpa is probably native to Africa. According to the second edition of How to Know the Grasshoppers, Cockroaches and Their Allies, by Jacques R. Helfer (Wm. C. Brown Company Publishers, Dubuque, Iowa, 1972), the brown-banded cockroach was known only from Florida from 1903 until at least 1917. The text further states that the species was introduced to Arizona in 1933. An asterisk footnote recognizes that “Supella longipalpa (F.) has been very successful in extending its range and has now turned up in every state.”

The homeland of this species is disputed in Stephen A. Marshall’s tome, Insects: Their Natural History and Diversity (Firefly Books, Richmond Hill, Ontario, 2006). The author states that this species is native to India, and that it is becoming increasingly common in households throughout North America.

David George Gordon, in his highly-readable book The Compleat Cockroach (Ten Speed Press, Berkeley, California, 1996), agrees with the African origin of the species, adding that it wasn’t until troops returned from World War II that brown-bandeds really made inroads in the U.S., and that “By 1967, brownbandeds were reported in forty-seven of the forty-eight contiguous states.”

The Cockroach Combat Manual, by Dr. Austin M. Frishman and Arthur P. Schwartz (William Morrow and Company, Inc., New York, New York, 1980) gives a more detailed description of the African scenario, indicating that this species got to Florida via Cuba (1892), arriving in Key West and Miami in 1903. No word on whether it fled Cuba due to political instability. This book also names Vermont as the sole state to be free of this pest as of 1967.

All authorities do seem to agree that this roach is most likely to be found inside furniture and electrical appliances. They have a fondness for starchy materials, too, and will munch on the paste used in bookbinding, and also on wallpaper paste. Body fluids from molting and deceased specimens can sometimes cause short circuits in televisions and other electronic equipment. Maybe there really is a bug in your computer….

The "University Roach"

Once cold weather sets in, it is more difficult to find wildlife, even insects. Sometimes, though, they find you. Such was the case last week when the nymph of a brown-banded cockroach, Supella longipalpa, crossed my desk at the lab while I was eating lunch.

I have taken to calling brown-banded roaches the “university roach” because that is the only place I’ve ever seen them: Oregon State University, the University of Arizona, and now here at UMass (Amherst). I’m not sure what, if anything, this says about the academic proclivities of the species, but it is certainly more sharply dressed than our other domestic pest cockroaches.

The two-tone coloration of brown-banded cockroaches is especially obvious in the nymphs, before the wings obscure the markings on the abdomen. These are not large roaches, perhaps a little bigger than German cockroaches, but still much smaller than American roaches and other members of the Periplaneta genus.

Like the other domicilatory roaches, the brown-banded is not native to North America. Its origins remain elusive, but perhaps its homeland is somewhere in tropical Africa. Females are flightless, having short, non-functional wings, but it does not deter the mobility of the species. Brown-banded roaches are frequently transported inside of furniture, which may explain the appearance of that nymph on my desktop. Male brown-bandeds are, ironically, quick to fly when disturbed.

Watch for brown-banded roaches in warmer, drier places than other roaches. They may seek shelter behind pictures on the wall, or in appliances. This latter habit has earned them the popular nickname of “TV roach.” I suspect the one exploring my desk normally resides inside the computer tower. Doesn’t seem to affffffffect the….perforMancccce of the thing, though….