An Unsung Fly Pollinator?

The little guy you see on the flower is a dipteron, that is, it is a member of the order of insects known as the Diptera. The word "Diptera" is formed from two Greek words, di- ("two"), and -pterous ("having wings"). These two-winged organisms are also commonly known as flies, and they are among the most successful organisms on the planet. There are at least 120,000 different species in this order, and the fly on the flower is one of those but, unfortunately, I have no clue which one... having exhausted all the reference works at hand with no success. It is a species that is very common here, and often gets caught in the insect traps we have placed around this area, so we have plenty of specimens to examine. 

My guess is that it has no known economic value, and has not had the misfortune of developing a reputation as a huge pest. To get noticed by the scientific community one or the other of those requirements must first be met. Since this fellow has not done so, little or no research has ever been published on it. That probably means it truly is not a huge pest, because we tend to home in on those with a vengeance. On the other hand, it may very well be a truly great, but unsung benefactor without our knowledge, as we have an uncanny tendency to take those kinds of organisms for granted until some disaster (sometimes of our making) causes them to disappear. 

A number of  other flies, for example, are well known for their ability to pass pollen from one flower to another, like the honeybees (Apis mellifera) do. This results in fertilizing the ovaries of those flowers who receive pollen in this manner, provided, of course, that the pollen received proves to be compatible with their genetic makeup. Generally, this means that the pollen must be from the same species of plant. To be an efficient pollinator, the organism doing the pollen transfer must first enjoy sampling the nectar provided by that flower. Flies with large, awkward, sponging mouthparts, like the common housefly (Musca domestica) may be attracted by the flower's scent but have a hard time getting any of the nectar. 

Other species of flies have mouthparts that may be extended deep into openings of the flower, allowing the fly to suck the nectar out. This particular fly has that ability, but it is lacking one other feature that seems to be very important... its body is glabrous, that is, it lacks conspicuous hairs. The honeybee, which is one of the most efficient pollinators around, has a pubescent, or hairy body, and the pollen from the flowers it visits gets caught in those hairs. Later, at another flower, some of the pollen becomes dislodged. But our mystery fly, without this particular physical accouterment that makes the honeybee so valuable, is probably not a very good pollinator. 

Jerry Cates

jerry.cates@entomobiotics.com

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