Horse fly larvae

Asset 20.png
crayfish.jpg
 

SCIENTIFIC NAME: Tabanidae

Number Of Species/Distribution

There are over 4,500 species in the tabanidae family.

  • These include the deer fly and the horse fly.

  • They are distributed throughout the world and are common in North America during the summer months.

  • Adult horse flies are more prevalent around aquatic habitats, as that is where they grow into adults.

Diet/Feeding

Tabanidae larvae are predators, collectors, and are even cannibalistic.

  • Mostly, the larvae eat small organisms such as insects, crustaceans, snails, earthworms, and other small invertebrates.

  • Tabanidae larvae will also eat other tabanidae larvae.

  • Although mostly predatory, deer flies also feed on organic debris from animals or plants that is deposited among the substrate.

  • The larvae have chewing or tearing mouthparts for feeding.

  • Adults feed mainly on plant nectar and other plant juices in order to obtain energy for flying.

  • Additionally, female adults require blood from mammals for reproduction.

  • The blood-sucking bites from the adult females can be very painful to mammals.

Habitat

Tabanidae larvae can commonly be found in ponds, marshes, and streams. 

  • They can also be found in salt marshes, swamps, bogs, shallow lakes, and along the water's edge (a region called the 'riparian zone' of freshwater habitats.

  • They survive by burrowing down into the sand or gravel substrate of the water body they inhabit.

  • They can usually be found in areas where the water is slow-moving (called pools), although some species can be found in fast-flowing areas (called riffles).

deer flies.png

HORSE FLY: INTERESTING FACTS

  • Horse fly bites can cause health problems to humans, such as severe lesions, high fever, and even disability.

  • Some people are allergic to the horse and deer flies' saliva, which they inject into the hosts' bodies in order to prevent blood clotting around the area being bitten.

  • Female horse flies usually bite during the day. They are attracted to mammals by movement, carbon dioxide (which mammals breathe out), warmth, and shiny surfaces.

  • Horse flies have beautiful eyes; they are often brightly coloured and sometimes have patterns and stripes.

  • The antennae of horse flies have five segments and are thick at the base, getting thinner at with each segment. Deer fly antennae are long and thin throughout.

  • The wings of horse flies are usually completely dark or completely clear. Conversely, deer fly wings are patterned.

Life Cycle

Tabanidae undergo complete metamorphosis, which involves passing through 4 complete life stages. These are the egg, the larvae, the pupa, and the adult stages.Egg

  • The egg mass laid by the female can contain anywhere from a few eggs to several hundred.

  • The mass is usually deposited on the vegetation that hangs over the water.

  • The eggs appear dark and shiny, and are shaped like spindles.

  • They hatch within five to twelve days, and the larvae drop into the water or moist soil.

Larvae

  • Once the larvae have dropped into the water after hatching, they burrow in the river substrate or the ground along the river bank, spending the winter in these burrows.

  • Sometimes the larvae take one to three years to complete the 6 to 13 stages of development (known as 'instars') that are typical in the Tabanidae life cycle.

  • In late spring, the larvae migrate towards dryer soils and progress into the next life stage, which is the pupal stage.

Pupae

  • The length of the pupal stage depends on the species and temperature, but may range from six to twelve days.

Adults

  • When Tabanidae adults emerge from their pupal stage they immediately begin mating and blood feeding.

  • Adults are great fliers, and search for their mates visually.

  • Most species of horse and deer flies have only one generation per year.

Sources

  • Field Guide to Texas Insects (1999).  Irina Brake, The Diptera Site (2010). About the Tabanidae. Available here.

  • The Canadian Biodiversity Website (2010). Horse Flies and Deer Flies.University of Kentucky College of Agriculture, Department of Entomology (2010). Horse Flies and Deer Flies. Available here.

  • University of Minnesota; Guide to Aquatic Invertebrates of the Upper Midwest (2004). Diptera. Available here.

  • University of Rhode Island (1999). Deer and Horse Flies.BugGuide (2016). Tabanidae? Tabanus mularis.  Available here.