So why do they do it and what do they want?
Flies are one of the most diverse insect orders, with more than 150,000 species described worldwide in more than 150 different insect families.
In Australia, entomologists (scientists who study insects) estimate there are more than 30,000 species of fly, and yet only 7,700 species have been described.
There are two main types of fly: the Nematocera (which includes mosquitoes and non-biting crane flies) and the Brachycera (which includes house flies, fruit flies, and horse flies).
In Australia, there is only one type of fly that’s attracted to us, rather than our blood: the bush fly (Musca vetustissima, Diptera: Muscidae), which is a non-biting fly and close relative of the house fly (Musca domestica). These flies are after the proteins, carbohydrates, salts, and sugars naturally present on your skin.
All the other flies around you are probably after your blood, and that includes mosquitoes and horse flies. And yes,
unfortunately some people are more attractive to mosquitoes than others.
Although mosquitoes and other blood-feeding insects are attracted to the carbon dioxide we exhale, we know the insect sensory system also helps find exposed skin. Since the skin near our faces is often exposed, that’s one reason flies are always buzzing around your face and hands.
Mouthparts with biteIn the mosquito, the proboscis is sharp and needle-like; in the deer fly (also known as the horse fly, or march fly in Australia), it is a large, wide spike.
This reflects the different feeding styles found in flies: mosquitoes use a hypodermic needle approach, and are so selective about where they bite research has shown they can actually find capillaries underneath the skin.
As most people know, these bites can be very itchy and in rare cases the proteins transferred during a mosquito bite can cause anaphylactic shock.
Horse flies use a “slash and suck” approach, where they cut the skin and then lap up the blood that comes out. These bites are my least favourite of any insect.