Sunday, July 8, 2007

Lord of the Flies or Pollinators?

By Billie A Williams
“Time’s fun when you’re having flies,”
Lynn Havsall, Environmental Educator at the College of the Atlantic

For most of us, bees or butterflies are the only insects we think of when we think pollinators. Would you believe a much more prolific pollinator, the ordinary Diptera (fly) is really a contender? Some of them resemble bees so of course we attribute even that to the bee.

In a recent article in (July –August 2007) issue of Audubon Magazine an article on flies caught my attention. Apparently “… scientists recognize flies as key players in ecosystems, recycling carcasses, dung, and plant debris while themselves serving as vital food in the life cycles of many kinds of birds, bats, and fish. Some rival bees as pollinators of domestic crops. Other flies are powerful tools for helping geneticists unravel the nature of life, the police in solving violent crimes, or pollution control specialists in assessing the quality of our waterways.”

A tall order for such tiny creatures you say. Me too! Ogden Nash is credited with saying “God in His wisdom made the fly/And then forgot to tell us why.”

Reading the in-depth wonderful article by Frank Graham Jr. really gave me pause to think about flies in a whole new light. The family names boggle my mind and classing mosquitoes, dragonflies, damselflies in the same group as black fly, horse fly or blow fly boggles my mind. To tell them apart the four winged Dragonfly from the two winged bottle fly is simple when you read the names — those four winged critters have the fly attached to the name – the two winged have the fly separate from the name. J I feel so very clever knowing that.

The first four-winged insects appear in the fossil records dating back more than 350 million years. “The two-winded flies show up 215 million years ago, having evolved the tiny, clublike hind wings called halteres to make flight with the front pair more efficient.”

Another distinction is made regarding the type of antennae the insects have. The long variety such as the mosquito has or the short-horned flies like the house fly. While the mosquito has serious and lethal names to describe their various disease bearing qualities there are only a few flies with lethal characteristics. Contrary to folk entomology, the common house fly does not bite. His mouthparts are designed as sponge-like usurpers of liquefied meals. If you believe you were bitten by a house fly the perpetrator was probably the dreaded, but similar stable fly. The tiny midges (Chironomid midges) not the biting kind, are always present around water and thus become one of the most reliable barometers of the water’s quality.

I may have to enlist the blow files (sometimes called blue bottles, green bottles etc.) in my next mystery as they are the star witnesses when it comes to presenting evidence in court about the time of death of a victim. They are attracted to the corpse shortly after death. They lay their eggs in various body openings. The maggots hatch in a matter of 24 hours and feed internally, hastening decomposition. Entomologists are able to identify maggots that are present on a body and can gauge their stage of development in the contents of environmental conditions — establishing the time, place and successive whereabouts in the time before the body was discovered. Perhaps it was killed in one place and transported to another – the flies in one place (say shoreline) may not be consistent with the flies that would be found elsewhere (say a city dump).

There is some fascinating reading in this issue of Audubon and I may have to revisit it in the next article perhaps looking at the methane gas emitted by cows by burping, creating 18 percent of the greenhouse-gas emissions that contribute to global warming.

Visit for more information.

Feel free to pass on this article as long as you leave the resource box attached.

No comments: