University News for July 5, 2011

An entomologist with the University of Manitoba credits this year's abundance of water for a dramatic increase in dragonfly populations.

The summer of 2011 has seen an abundance of dragonflies.

Dr. Terry Galloway, an entomology professor with the University of Manitoba's Faculty of Agricultural and Food Sciences, says although we don't know much about what affects dragonfly populations, we do know a large amount of water favors them--and we have had lots of water this year.

Clip-Dr. Terry Galloway-University of Manitoba:
We've got about eight or so families in Manitoba, and all of them are aquatic in their immature stages, so the adults lay their eggs in various kinds of aquatic habitats--wetlands, ditches, temporary pools--all kinds of different aquatic habitats right across the province.

The juvenile stages, they are predators and they feed on all kinds of different aquatic organisms, from really small, tiny crustaceans when they're in the early stages, or for the smaller species.

The big ones can even feed on tadpoles and fish, so they're very aggressive predators in these aquatic habitats.

The adults are also predators, and it depends a great deal on the size of the dragonfly.

We have some of the very, very tiny damselflies that will feed on small flying insects, small flies and so forth, and they do tend to catch them from the air.

We have somewhat larger skimmers and so forth that we see around.

They're feeding on somewhat larger insects, larger flies and butterflies, and some the largest of our dragonflies in fact feed on other dragonflies, and these predators can have quite a significant impact actually on other insects.

Dr. Galloway says it's often thought dragonflies feed heavily on mosquitoes, but he says they don't have much of an impact on mosquito populations.

He says when we have large numbers of mosquitoes, even great numbers of dragonflies aren't going to have a dramatic impact.

For UniversityNews.Org, I'm Bruce Cochrane.

*University News is a presentation of the University of Manitoba's Faculty of Agricultural & Food Sciences