While many insect pests are well known for posing a nuisance during the spring and summer months, most people would agree that mosquitoes and flies are the most annoying of all. Mosquitoes and flies belong to the Diptera order of insects, and around 20,000 of these insects have been documented in the United States. Everyone knows that mosquitoes bite humans in order to collect blood-meals, but not everyone is aware that numerous fly species do the same thing. However, the manner in which biting flies and mosquitoes collect human blood-meals differ.
Mosquitoes and other bloodsucking insects are attracted to the carbon dioxide that humans exhale, and Diptera fly species have evolved to sense the heat emitted from the human body. Mosquitoes inflict bites by injecting a very narrow needle-like mouthpart into the skin, which often makes their bites undetectable until they become irritated. This needle-like mouthpart is known as the “proboscis,” and it is designed to efficiently suck blood. Studies have found that mosquitoes instinctively insert their proboscis directly into capillaries beneath the skin, and some individuals are allergic to the mosquito saliva transmitted into the bloodstream during bites. Surprisingly, cases of anaphylactic shock have occurred in response to mosquito bites.
Deer flies also possess a needle-like mouthpart for sucking blood, only theirs is wider and is outfitted with a spike, which makes their bites particularly painful. Horse fly bites are largely considered to be the most painful of all bites inflicted by Dipteran insects, as they possess scissor-like mouthparts that rip away flesh. Once blood begins to flow from the lacerated bite wound, horse flies use sponge-like mouthparts called the “labella” to lap up the blood. Biting midges are common insect pests that possess elongated mandibles outfitted with sharp teeth designed to lacerate skin, but they also possess a bloodscuking proboscis. Only female biting midges suck blood, and their bites are tremendously painful. In some parts of the world, biting midges transmit disease, but in the US they are mainly a nuisance pest.
Have you ever sustained a bite from a biting midge?