Wednesday, June 15, 2005

Musseled Out

Gulliver's Travels Revisited

Hagenius brevistylus larva with attached Zebra mussels, Photo by P. Myers.

Remember how the Lilliputians tied down Gulliver? They were small, but many. Zebra Mussels, are small, but they have tied down many a structure in the Great lakes due to their enormous numbers of individuals that accumulate. This latest blog entry was inspired by Phil Myers from the UM Museum of Zoology, currently teaching a summer course at the UM Biology Station at Douglas Lake. Phil has been the main force behind the Animal Diversity Web Project here at UM, and has been going wild with photographing insects with his Nikon digital SLR. At this point, he has far surpassed me in the number of insect photographs he has taken.

Phil was shooting odes around Douglas Lake, and saw that there were many Hagenius brevistylus (dragonhunter) trying to emerge and dying at the water's edge, when they could not break free from the coating of Zebra Mussels (Dreissena polymorpha) from the final larval instar. For a mobile hunter like the dragonhunter, the added weight of these mussels has to be a detriment. Of course, if they are covering the exoskeleton where the integument splits along the top of the thorax, the emerging adult will be trapped and die. We do not know how much of a detrimental factor the zebra mussels are to a population of lake-based dragonflies, and this could be a very interesting research project for a student at the Bio Station. This has to have a short-term negative impact on larger species that take longer to reach maturity (1-3 years for Hagenius).
In 2001, Margi Chrisincke wrote about Didymops transversa and Dromogomphus spinosus in Otter Lake that were encrusted by zebra mussels. About that time, I saw a Dromogomphus spinosus exuviae with a Zebra Mussel on the shore of Burt lake, just a few miles away from Douglas lake.

I encourage anyone else to share their observations on this phenomenon.


CHRISCINSKE, M. 2001. Zebra mussels observed on dragonfly larvae in Otter lake. Williamsonia 5(4):9.

WEIHRAUCH, F. & J. BORCHERDING, 2002. The zebra mussel, Dreissena polymorpha (Pallas), as an epizoon on anisopteran larvae (Anisoptera: Gomphidae. Corduliidae, Libinellulidae)  Odonatologica. 31(1):85-94

Sunday, June 12, 2005

Entomology Book Meme

Entomology Books

Thanks to Nannothemis, she convinced me, or rather railroaded me into doing this book meme thing.

I have been an entomologist for over 30 years, counting my teenage years when I was a budding bugologist. Obviously, I have read many entomology books, some cover to cover; others, just a page when I need to refer to something. In college at the SUNY College of Environmental Science and Forestry, I took every entomology course offered, which came out to something like 40 credits worth... of the books used then, the one I have remained faithful to has been Borror, Delong, and Triplehorn's An Introduction to the Study of Insects, 4th Ed.

In my high school years, two books set me on the path -- How to Know the Insects by H.E. Jaques, and The Golden Guide to Insects by Zim. Later, the book that was a big help was Peterson's Guide to the Insects of North America by Borror and White. The Peterson guide was my main insect book until in college, when I started adding to my collection. I was quite poor until I left for college, so any book I purchased was with my own money, and I used to borrow many an entomology book from the library at St. Lawrence University in Canton, NY while in high school. I remember being enthralled with E.O. Essig's book on Entomology and a pile of other early entomology texts.

Books that really influenced me during my early years:

Rau and Rau - Wasp Studies in the Field.

H.E. Evans - Life on a Little-Known Planet

H.E. Evans - Wasp Farm

J.H. Comstock - An Introduction to Entomology

R.E. Snodgrass - Insects and Their Ways and Means of Living

Believe it or not -- I studied solitary wasps extensively from college until about 1994 -- published a lot of papers on their behavior and distribution, and I credit Howard Evans' works for that influence.


I have to admit that early on, I was dissatisfied with the early books on Odonata that I had access to. Too many damn wing vein things, etc. Then, when I really got going with them around 1995/96, there still was not the flood of books that we have today. However, I credit the following:

Needham and Westfall - Dragonflies of North America

Walker's 3 volume series on the Odonata of Canada and Alaslka

Corbet, P.S. - A Biology of Dragonflies (I have a real copy)

Since then, I have amassed quite a few Odonata works, and the ones I use the most are:

Dragonflies of the Northwoods by Kurt Meade

Damselflies of the Northeast by Ed Lamm

Walker's three volumes

Westfall and May's Damselflies of North America

I don't read that many popular insect books anymore, possibly because I'd rather read things other than what I am already familiar with. However, of some relatively recent popular books would be the one by Sue Hubbell, Broadsides From the Other Orders that is a favorite. How many entomology books do I have? I'm not really sure, because a good many are in my office at the UMMZ, and I have quite a few at home. I'll just estimate somewhere between 150 and 250...

Monday, June 06, 2005


GOMPHUS SPICATUS (courtesy of Phil Myers, UMMZ)

Gomphid dragonflies are predominantly dwellers of moving water, but a few (Arigomphus, the pond clubtails, and this species) are lake dwellers. Gomphus spicatus is one such dragonfly -- larvae are found mostly in lotic situations, and where they are found in streams, they tend to be encountered in slow moving slough-like habitats. This one is doing what this species seems to do best- bask on the ground. It has been out and flying for the past few weeks in lower Michigan.