Latin: Eristalis sp. and Helophilus sp.
Technically, Rat-tailed maggots are not a species. Rat-tail maggots are a term for larvae of hoverflies or drone flies. Hoverflies are also called Syrphidae, but overall, they are the two families Eristalis and Helophilus, when talking about rat-tail maggots. Rat-tail maggots, of course, got their name due to their appearance, which may resemble a rat tail.
Rat-tail maggots may be disgusting animals, but they are as such not pests. Rat-tail maggots live in nutrient-rich puddles, which is a nice way of saying heavily polluted water. One can typically find rat-tail maggots in slurry tanks, sewers, manure puddles and even in rotten hollows in older stumps and trees. Here they live somewhat peacefully until they turn into hoverflies.
Appearance
Rat-tail maggots are only a term for the hoverfly larvae. This larva may look like the regular fly maggots but can be recognized by the special breathing tube at the rear end. The breathing tube is long and thin, giving the rat-tail maggot its special appearance.
When the rat-tail maggot is ready to develop into a hoverfly, it will leave the puddle to pupate. It can only pupate in a dry place. After pupation, the fully grown hoverfly emerges from the pupa. A hoverfly is a large fly, with a hairy body.
Biology and behavior
Rat-tail maggots gather in mud where they feed on microorganisms. They also eat decayed, organic material. This organic material usually decays due to unfavorable conditions, which in short means lack of oxygen or nutrients in the water. Here, the breathing tubes are especially useful. The rat-tail maggot sticks its breathing tube up above the surface of the puddle, to survive the deprived oxygen water. If the puddle provides nutrition and is otherwise not disturbed, rat-tail maggots can occur in surprisingly large numbers.
It is especially normal to experience rat-tail maggots near cattle. This is because they like to be near manure, which is normal near cattle. However, this may lead to farmers finding rat-tail maggots in their milking parlors. Even though it is best to clean the milking parlors for rat-tail maggots, the maggots does not pose a danger to the cattle.
Damage
Although rat-tail maggots may be disgusting, they are not harmful. The long breathing tube may look like a sting, but it is not. The rat-tail maggot cannot sting or harm humans or animals. They do not destroy furniture, woodwork, or masonry like other pests. Adult hoverflies are also quite harmless, although they occasionally are mistaken for bees.
Now and then, one or more rat-tail maggot may find their way into a basement if the basement is located near the maggot’s puddle. If this happens repeatedly, one should find out where they are coming from. Typically, it will be a manure puddle, a sewer, or a decayed tree in which the rat-tail maggots lives. The maggots do seek dry places to pupate, or the puddle may be overpopulated, which can be the reason why one will find them in basements. However, a few rat-tail maggots in the basement should not cause concern.
Prevention and control
Although rat-tail maggots are harmless and does not cause any damage, their presence is a good indicator that there is contaminated water nearby. A few rat-tail maggots in the house can be swept outside again. You should never drink water in which rat-tail maggots are found. Likewise, you should keep pets and farm animals away from stagnated water with rat-tail maggots. I you experience rat-tail maggots in the house, like in sinks, gutters, or wells, clean thoroughly immediately, ensuring that the water can run through the drains. The easiest way to prevent and control rat-tail maggots is simply maintaining hygiene and make sure that water does not stagnate either inside or outside the house.
"Pests in House and Home"
"Bed Bugs - Bites, Stings and Itches"
"Food Pests"
"Husets dyreliv" (Insects Around the House - Only danish)
"Skadedyr i træ" (Timber Pests - Only danish)
"Stuefluen" (Common Housefly - Only danish)