Underwing Moths

I am going to “cheat” a little here by offering a link to an article in lieu of a blog entry. The Missouri Conservationist magazine published a shortened version of an article on underwing moths that they paid me for a few years ago. Changes in editorial staff and the format of their publication were the reasons for the delay. I am delighted to say that the new Managing Editor, Nichole LeClair Terrill, has been a joy to work with. I am looking forward to contributing more articles in the future. I would also like to thank photographer Donna Brunet for providing such a fantastic image to illustrate this current piece.

Bee Flies

The title above is not a noun and a verb, but the common name for the family Bombyliidae. Bee flies get that name from their obvious resemblance to bees, but it is a diverse family and not all of them are covered in fuzzy hairs or iridescent scales. Their life histories are likewise variable, and for most species are unknown. At least 800 species occur in North America north of Mexico. More await naming and description by scientists.

Spring is a great season to see bee flies. Look for them in open areas on sunny days, or even sunny spots in wooded areas. Many species, like the “greater bee fly,” Bombylius major, shown above, hover so perfectly as to appear to be levitating. Male bee flies in particular exhibit this behavior, perhaps defending small territories or displaying for females. You might easily hear one of these flies before you see it.

Many bee flies have elongated mouthparts, causing some people to fear them as blood-suckers. The proboscis is for probing flowers for nectar, though, and the flies are totally harmless to people and pets. Bee flies are probably mostly “flower visitors” rather than pollinators.

The larval stages of bee flies are definitely not harmless to other insects, and this makes them beneficial allies in the war against pests. At least some members of the genus Geron, shown above on an aster in western Massachusetts, are parasites of the caterpillars and/or pupae of bagworm moths in the family Psychidae. Bombylius major, a widespread species illustrated near the top of this article, is somewhat less helpful. Its offspring are parasitic in the nests of solitary bees that nest in the soil. This and related species are known as “bombers” because the female will hover over the entrance to a bee’s burrow and lob eggs into it with a flick of her abdomen. The larvae that hatch then seek out the host bee’s larvae, becoming external parasites upon them.

Members of the genus Villa, like the unidentified specimen from Arizona pictured here, are villains only to caterpillars of butterflies and moths, again functioning as parasites in the flies’ larval stages.

Larvae of Hemipenthes are hyper-parasites. That is to say they are “parasites of parasites.” They live as parasites of the larvae of ichneumon wasps, tachinid flies and other insects that are themselves parasites of caterpillars of butterflies and moths. How bizarre is that? I photographed this Hemipenthes eumenes (below) a little over a week ago here in Arizona.

Try looking for bee flies yourself next time you are out and about. You might also surf the ‘net to get a feel for what they look like. Start by browsing the images BugGuide.net for a great overview of the North American fauna. See more stunning images from all over the world at this Flickr search. You’ll be amazed by the beauty of these delicate insects.

Hatched!

Remember the “Carpet Cocoon” story I did back in March, and the one on the “Carpet Caterpillar,” too? Well, the story has come full circle now.

Sometime last night, an adult moth emerged from the pupa that the caterpillar formed in the yogurt cup I had it in. I remember thinking that I needed to put a paper towel or tissue around the inside of the smooth cup so the moth could climb up and fully expand its wings for a successful molt. Naturally, I had the lid off the cup, covering a small, live beetle on my drafting table last night….So, this is what I found this morning:

An empty cup, with a now empty pupal case (and caterpillar head capsule at the left). No moth to be seen anywhere. Terrific. I looked high and low, and finally, by sheer luck, discovered the surprisingly large, perfectly healthy moth tucked neatly in the door jamb of the front door, at about ankle level. It had managed to eclose (the scientific term for emerging as an adult insect from a pupa) perfectly, in the most imperfect circumstance, with no further intervention from me. Astounding.

The comments I received on my initial post about the caterpillar were mostly directed to my assertion that the moth was nothing much to behold. I only had images from BugGuide.net to go by, and I was not impressed. Suffice it to say that seeing the living creature has changed my opinion. It seems to have actually transformed the carpet fibers into the shimmering scales on its wings.

I had errands to run today and was in and out of my apartment frequently. On the last, late afternoon return home, the moth flew out the door. Ah, freedom! Well-deserved, too, I might add.

More Hilltopping Insects

I finally got the full effect of a hilltopping experience on March 25 when I hiked to the summit of Sentinel Peak (“A” Mountain), just west of downtown Tucson, Arizona. At only 2, 897 ft. (883 meters) above sea level, and rising a mere 522 feet off the desert floor, it is more of a butte than a mountain. Still, its relative isolation makes it an effective magnet for hilltopping insects.

“A” Mountain is named for the immense concrete letter on its eastern slope, painted in the red, white, and blue colors of the University of Arizona. Most folks visit the top for the spectacular panoramic view of Tucson and its surrounding mountain ranges. It can be a romantic setting at dusk, too. Male insects of many species come there for romance as well, but usually have to defend territories or otherwise repel rival males in the process.

Among those insects are bumble bee-sized bot flies, Cuterebra austeni. The big, black and white adults are not often seen during their brief existence. They have no functional mouthparts and are fueled only by burning the fat reserves they accumulated in the larval stage. As larvae they are subdermal parasites of either rodents or rabbits, depending on the species. I’ll spare you the gory details.

The male flies conserve their energy and will allow you to approach extremely closely if you do so carefully. Once startled, or when they detect a rival or a female, they jet off at warp speed. Eventually they return to the same spot, or very close by.

A more typical, larger, and colorful hilltopping insect is the black swallowtail, Papilio polyxenes. These butterflies are in seemingly constant motion, flying swiftly across the summit and only pausing to perch for very brief periods.

They are incredibly aggressive, chasing each other mercilessly. You can actually hear their wings and bodies colliding, so violent are their aerial duels.

Perhaps the most unexpected and unusual insect I discovered was the pollen wasp Pseudomasaris maculifrons. Pollen wasps are solitary insects in the same family as potter wasps, mason wasps, and the social hornets, yellowjackets, and paper wasps. While her cousins feed their larval offspring with other insects, the female pollen wasp stores pollen and nectar in her mud nest.

Males are easily recognized by their peculiar antennae: long and clubbed. Females have much shorter, clubbed antennae. Males of this particular species are known to perch repeatedly in the same small area, day after day, for as long as 29 days (Alcock, John. 1985. “Hilltopping Behavior in the Wasp Pseudomasaris maculifrons(Fox),” Journal of the Kansas Entomological Society, 58(1), pp 162-166). Between February and May, different generations of males occupy the same locations in different years. They are very active insects, but do not appear to be nearly as belligerent as bot flies or black swallowtails.

It turns out the top of the peak also attracts other insect photographers. I crossed paths there with my friend Philip Kline, who I hadn’t seen in probably two years! We had a great time catching up, and helping each other identify the insects we were seeing.

May your own hilltop experiences be just as rewarding and enjoyable. You could very well discover something new (especially regarding bot flies), to yourself or the scientific world.

Sometimes you become the best perch on the peak!