If black flies with hanging legs appear in the garden in spring, many hobby gardeners worry about the "infested" plants. And the question arises, "To fight or not to fight?"
In a nutshell
- March flies are actually mosquitoes
- don't sting
- harmless to humans
- March flies are classified as beneficial insects
- mass appearance of native insects between March and May to find pairs
March flies
If you encounter a swarm of insects with black, hanging legs, they are March flies. Because the typical feature of the males are the hanging legs in flight. The March fly is a species of hairy midge (Bibionidae) family. The scientific name of the March hair midge, as the March fly is also known, is Bibio marci. The term "flies" comes from the fact that the mosquitoes are very similar in appearance to flies. March flies
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- are native to Europe
- appear in swarms
- are the most common type of mosquitoes
Characteristics and Occurrence
In addition to the hanging legs in the flight of the males, you can recognize the "flies" with the naked eye by the following features:
- jet black shiny mosquitoes
- eight to eleven millimeters long
- Females with black wings
- Males with milky wings
- Hair on head, legs and body
March flies occur from March to May. The insects swarm particularly often around April 25th, which is the memorial day of Saint Mark, which is why they are also called St. Mark's fly or St. Mark's hair mosquito. The mosquitoes fly basically every year, but in some years they occur in very large numbers. In the garden these hairy midges are buzzing. a. around shrubs and small plants. They also like to be near bodies of water.
Notice: March flies are harmless to humans because they do not stick.
life cycle
Only one generation of these mosquitoes flies each year. The lifespan of adult animals is short, as they die soon after mating or egg laying. To ensure the conservation of the species, each female lays about 100 eggs in the loose soil. The next generation hatches after 35 to 40 days. The gray larvae, which are about two centimeters in size, develop in the soil and also hibernate there until they swarm out after pupation to find a partner for reproduction. This leads to mass accumulations, which, however, dissipate on their own after mating.
Useful or harmful
March flies are now classified as beneficial insects. Since the adults feed on nectar, they play an important role in pollination. Because they fly when it is still too cold for bees and bumblebees and look for the flowers even in rainy weather.
Whether the larvae of the St. Mark's fly should also be classified as beneficial insects was a matter of debate for a long time. Today they are counted among the beneficials, but this classification is associated with a small "but". Normally, vegetable waste is the food of the larvae. They thus contribute to the degradation processes in the soil and are among the humus-formers. However, if there is a drought and/or there is a mass outbreak, they can also eat live rootstocks, such as those of tomatoes or potatoes. Nevertheless, the usefulness of mosquitoes outweighs that, which is why you should not fight them.
Frequently Asked Questions
There are small black flies in flower pots, what to do?Small black flies, only one to seven millimeters in size, which have settled in the pots of indoor plants, are assigned to the fungus gnats. Since their larvae like to eat the roots of plants, you should fight these insects.
What natural enemies do March flies have?Natural enemies include birds and insectivores. In addition, the insects are plagued by a special parasite that first lives in the animal's head and then pupates in its abdomen.