Jeff Green | Aug 11, 2005
Feature article, August 11, 2005
Feature article August 11, 2005LAND O' LAKES NewsWeb Home
Contact UsNature Reflections - Summer Pests
There is much talk across the country of West Nile virus and the dangers of mosquito bites which might be carrying this sometimes fatal disease. We live in a country where the mosquito is common, and their bites as well as their habits, particularly that hum of an invader in the bedroom as you try to fall asleep, are annoying. West Nile has added another dimension to that annoyance.
For me, the mosquito is not nearly the problem of a summer in the Canadian countryside as is the Deer Fly. I love my flower garden and I can spend hours out it it trying to keep ahead of the invasive weeds, but the attack of a single Deer Fly will send me indoors for protection, as the bite of one of these pests will raise a large welt that must be treated quickly to overcome the itch and take the swelling down.
Almost world-wide in distribution the Deer and Horse Flies are unreported in Hawaii, Greenland, and Iceland - maybe I should move to one of these, but I suppose they have other pests with which to contend. So I stay here in the countryside I love, and in the garden in the cool hours of cool early mornings before the Deer Flies have warmed up sufficiently to be active.
Deer Flies with brightly-colored eyes and pictured wings are usually smaller and more colorful than Horse Flies and both of these are called Tabanids. Adult tabanids vary in their periods of activity. My sources tell me Deer flies are usually most active in the early morning and late evening, but they harass me all day long. Horse flies are active all day long - and yes, their bite is equally annoying. Female tabanids are blood feeders and are the biting pest. Male tabanids feed on plant juices or excretions.
Hunting primarily by sight, though odor and carbon dioxide also attract, the female Deer Fly will attack any large, dark, moving object - witness how it will follow my car as I drive down the country roads. It seems to me they almost always target the head, and I have found that a hat really helps. Without a hat the insect zeroes in - often landing in the hair, but equally often finding an exposed area of skin, where it quickly slices into the skin with its strong mandibles, inserts some saliva-like material to keep the blood from clotting and laps up the blood.
It is no relief to know it is only the females that bite - they need the blood to develop their eggs - while the males are enjoying the nectar of the flowers. That one female can lay between 100 and 1000 eggs on vegetation over water or wet ground, and the emerging larvae will fall into the water or damp soil. Larva live for several months to a year, and will then pupate in drier soil, emerging as the adult.
With the arrival of the Deer Fly season my hobby of bird-watching changes from walking to driving, as I find that even though the Deer Flies invade the car they do not bite once inside, but spend all their time trying to get out again. So with windows open I can watch and hear the birds, and the Deer Flies that congregate in the back window of the car as I drive along will not bite me or an animal again.