Helping Researchers Study Dragonflies
Dragonflies are, in my opinion, tied with hummingbirds as the coolest fliers ever.
I recently listened as Dr. Michael May, a retired Rutgers University professor of entomology, spoke to a small group of raptor enthusiasts hosted by Dr. Laurie Goodrich at Hawk Mountain Sanctuary. Goodrich is Senior Researcher for Hawk Mountain Sanctuary and Assistant Chair of Hawk Migration Association of America. May’s topic was unfamiliar; he spoke about dragonfly migration, a relatively new and little studied field.
The unique dragonfly study is being undertaken by the Migratory Dragonfly Partnership, a small group of government and private organizations from Canada, Mexico and the United States. The Xerces Society is coordinating the cutting-edge program; they are involved with the conservation of invertebrates.
Partnerships determine much of the success of wildlife conservation. The Feds partner with states, and states partner with counties, as well as with: local, state, national and international conservation groups. Many wildlife species are difficult to work with, in part because some species migrate across state and international borders; dragonflies cross United States north and south borders.
Dr May provided additional information during my follow-up phone call. When asked, “What’s the purpose of trying to determine the migration routes of dragonflies”, May answered simply, “We want to study dragonflies because of their beauty and aesthetics.”
May’s statement’s simplicity stopped me in my tracks because his answer is pretty much why I spend so much time watching raptors. The miracle and mystery of both dragonfly and raptor migration can be added to our particular interest.
May said dragonflies have a place in the food-chain, and in different situations dragonflies have either more or less importance. Nevertheless, dragonflies are a plus in nature, and lovely to observe.
Here is a basic life history of the dragonfly. Adults lay eggs in ponds, preferably in ponds with very few fish. Eggs hatch into larvae, and some live underwater for five or six months, though one year is more typical. Since fish eat dragonfly larvae, fewer fish in the pond mean more larvae morph into adult dragonflies. After the larvae morph into dragonflies and live seven – ten days, the newly created adult dragonflies are able to breed. After breeding the female lays her eggs in fish free (hopefully) ponds and the cycle of life continues. Some dragonflies migrate and some do not.
Now things get complicated, even for May, though it is not his fault. The problem is caused by lack of information, just the kind of information May is hoping to get from hawk-watchers, as well as entomologists.
Adult dragonfly’s lifetimes are not totally known because many species migrate and leave their birthplace. The problem starts because different species travel different routes and distances to different regions.
The wintering place for migrating monarch butterflies was unknown for years. Now it is known that most of “our” monarchs’ winter in a small area of mountainous Mexico. There has long been concern among scientist that if a serious weather event hit the monarch’s wintering home, most-to-all monarchs could be destroyed. A catastrophe!
“It is a benefit having dragonflies winter in different regions so an extreme winter in one region wouldn’t kill them all,” said Mays, “but it would also help to have a better idea just where they are,” he said with a chuckle. That is what he hopes to discern from hawk-counters.
May, Goodrich and their associates’ hope that hawk-counters at various hawk-watches can count and report migrating dragonflies they observe.
Using newly created data sheets, counters will record and report dragonfly numbers starting during this fall’s raptor (now) migration. Both their raptor and dragonfly reports will go to the citizen scientist from the Hawk Migration Association of North America. HMANA’s data is used by scientist, researchers and raptor lovers worldwide. The dragonfly data will go to the Xerces Society and their partners. The partnership plans to track five dragonfly species.
Dragonflies captured on their wintering grounds can indicate where they were born by testing isotopes found in their body. The captured migrating dragonfly’s isotopes will determine where aquatic plants eaten by the water-bound larvae stage of the dragonfly was found. Scientists can map those locations, at least in terms of longitude (north and south). It’s pretty slick, actually.
May suggested interested naturalists look at: Dragonflies Through Binoculars, by Sid Dunkle, and Dragonflies of the East (U.S.), by Dennis Paulson for assistance identifying dragonflies.
Goodrich finished, saying, “HMANA will do a pilot dragonfly count program this fall, and willing hawk-watchers will count and record dragonflies seen. It will be tweaked as we progress, and flexible.”