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Cousins of the Common House Fly Aren’t So Bad

The housefly, Musca domestica, is the most common domestic fly in Wakulla County and just about everywhere else on the planet. It accounts for about 90 percent of all flies in areas of human habitations.

It has the notoriety of being one of the most widely distributed insects and is universally loathed.  The housefly is considered a disease carrying pest which can be the vector for some serious bacterial infections.

Any insect which is labelled a fly becomes an immediate target for annihilation. There is a whole industry which produces flyswatters, flypaper, and fly baits and is committed to the wholesale destruction of the fly.

In Wakulla County the housefly has two insect cousins which have many of the same negative personal habits, but a few positive attributes which warrant consideration.  The soldier fly and the robber fly are not nearly as well known, but frequent many of the same locales as the housefly.

The scientific name for the soldier fly, Stratiomyidae, is derived from the Greek word for soldier. Variations of this insect are also found in Europe, too, where the Germans refer to it as an armed fly.

The soldier fly’s appearance is somewhat wasp-like which is considered a form of defensive mimicry, confusing potential predators into believing that a sting will accompany any close encounter.

They are identified with black and yellow or sometimes metallic green markings. The soldier flies are often seen in their inactive state which is usually resting with their wings placed one above the other over the abdomen.

Soldier fly larvae are found in varying environments, most commonly in damp soil, sod, under bark, in animal manures, compost and in swamps. The larvae are mainly scavengers, consuming the organic scraps and castoffs of other animals and insects.

Like many scavengers, their importance is in converting waste products into usable form for plants.  The larvae are dark earth tone and may be confused with leaf litter, unless they wiggle.

Adults usually are found near the larval habitats. They have distinctive three segment antennae and have a maximum length of about three fourths of an inch.

The adult soldier flies sustain themselves on wildflower nectar, which is easy to locate most of the year in north Florida.  The remainder of their short lives is committed to finding the ideal site for their eggs.

The robber fly is slightly smaller than the soldier fly.  It too has antennae with three segments, but its behavior is quite different.

They are tiny predators which attack and feed on a long list of insects and spiders.  If traditional prey is in short supply, they will feed on each other.

The robber fly bayonets its victims it with its short, strong beak or proboscis.  The target is injected with saliva containing digestive enzymes and a neurotoxin to immobilize it.

The unlucky insect or spider is quickly paralyzed as the robber fly’s venom dissolves its internal structure.  The liquefied material is syphoned through the robber fly’s proboscis and the search for a new mark begins.  Luckily, humans are not on the menu.

To learn more about flies in Wakulla County, call 850-926-3931 and remember to “like” Wakullaextension on Facebook.


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