If you’ve been spending time in fields and meadows recently you may have been witness to the mass emergence of a species of fly known as the March Fly (Bibio albipennis). Their common name is a misnomer, for they are usually seen in April and May in the Northeast. The hatching of March Fly eggs in the soil produces larvae that feed mostly on decaying organic matter. After the larvae pupate and emerge as adults, you find dozens of flies clinging to grass and other vegetation.
Another species of fly in the same genus is known as “Lovebugs,” due to the habit of the males remaining “plugged into” the females during long copulations. Entomologist Stephen Marshall has this to say about their presence in southeastern U.S.: Even though adult Bibionidae are innocuous non-biting insects, the sheer number of fornicating flies fouling car windshields, pitting paint jobs and clogging up radiators renders Lovebugs a well-known Bible Belt nuisance.
The male and female March Fly are sexually dimorphic, differing in appearance. Like many other flies that form male swarms, the males have large heads with massive eyes. The females’ eyes are much smaller. Both are common on flowers and can be significant pollinators of fruit trees.
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