Spiders . . . . . . and Butterflies

"I have tasted all my butterflies, just crunched on them a bit," says Deane Bowers, assistant professor of biology and curator of Harvard's vast lepidoptera collection. Deep in the heart of the Museum of Comparative Zoology, her office is filled with frame after frame of the insects, and butterfly earrings dangle whimsically from her ears. "Checkerspots," she notes with a grin, "have a really bitter taste."

Because checkerspots--a species which Bowers specializes in--feed on plants which contain secondary compounds called iridoid glycosoids, they are highly unpalatable to birds as well. These chemicals, Bower explains, may be toxic to some insects, but checkerspots have evolved mechanisms to excrete them quickly, sequester them in their exoskeleton or detoxify them. Thus the plant protects itself from most predators, and the butterflies render themselves "bitter" and in some cases nauseating. After feeding on members of these specialized species birds often throw up.

"What I think is going on is that the caterpillars are storing the iridoid glycosids as they are feeding which is carried over their adult stage," Bowers explains. This summer, one of her projects will be to determine precisely what role the iridoid glycosoids--which are found in snapdragons and other plants, and may serve as a feeding stimulant for certain caterpillars--play in the unpalatability of the checkerspots.

Bowers, who is currently researching the interaction of insects and host plants, has been "into butterflies" since childhood. She first began her journey into their winged world during graduate school at the University of Massachusetts. She had been interested in entomology as an undergraduate at Smith, and decided to pursue her inclination to research after realizing that the life of a vet or an M.D. was not for her. She solidified her interest in lepidoptera during grad school where she could do field work on the Baltimore checkerspots.

An avid collector since the age of seven--she grew up in Florida surrounded by insects--Bowers still goes out into the fields of Western Massachusetts once or twice a week to collect checkerspots. "These guys are a real pain in the neck," she says, pointing affectionately to the orange and black striped furry caterpillars stacked in plates in her lab. Checkerspots take a full year to mature from the larval stage to the butterfly stage, and Bowers must collect specimens every week or so in order to follow the insects throughout their life cycle.

Bowers also studies buckeye butterflies, a species native to California. Although buckeyes also feed on plants which contain iridoid glycosoids, unlike checkerspots they are not unpalatable. Brown, drab and cryptic, they also look very different from checkerspots which are brightly colored and tend to be gregarious.

"I'm interested in whether or not the buckeyes differ from the checkerspots in their ability to sequester iridoid glycosoids from the plants that they feed on," Bowers animatedly explains. Her experiments this summer will focus on this problem First she will test the butterflies for the iridoid glycosoids, then examine how birds respond to pure iridoid glycosoids as opposed to the entire butterfly--both the checkerspots and the buckeye species.

Other aspects of Bower's research combine evolutionary, ecological and behavioral problems. "I'm going to start playing around this summer with a moth species that feeds on catalpa trees which contain large amounts of iridoid glycosoids," she says. The larvae of this species are gregarious and warningly colored but the adults are drab and cryptic. This type of life history suggests that the larvae are unpalatable but as they molt and become adults they are no longer unpalatable. "I don't exactly know what's going on with these guys, but I'm really psyched--it's really unusual to have a colored larva and a cryptic adult." The checkerspots, buckeyes and catalpas are all ingesting the same compounds, yet exhibit different life history strategies to deal with them.

Bowers divides her time between teaching, research and caring for the Museum of Comparative Zoology's lepidoptera's collection, the largest university collection in the world with 6 million insect specimens. The collection needs constant revision since scientists all over the world request samples of different species. The assistant professor taught two courses this past year in insect biology, in addition to enlarging her own personal butterfly collection. One of her favorite butterfly-related activities is feeding her checkerspots, because she can watch their abdomens slowly fill up with the sugar solution that makes up their daily meal.