Most people don't like mosquitoes, given their rather annoying habit of inflicting painful bites that turn into itchy, red welts. Mosquitoes also transmit serious and sometimes deadly diseases, including malaria, yellow fever, dengue, and West Nile virus. Pets, too, are at risk of mosquito-borne diseases, like heartworm.
And yet, despite the fact that nearly every person on the planet has up close and personal experience with mosquitoes, many people can't tell the difference between mosquitoes and their other, harmless cousins. Just because it looks like a mosquito doesn't mean it is.
Let's take a look at the differences between mosquitoes and two insects commonly mistaken for mosquitoes – midges and crane flies. All three of these insects belong to the same insect order, Diptera, also known as the true flies.
Note: Click on any image to see a larger version.
This is a mosquito. Only female adult mosquitoes bite, because they require a bloodmeal to produce viable eggs. Male mosquitoes are perfectly harmless to us, and spend their days sipping nectar from flowers, much like bees and butterflies. Actually, some female mosquitoes sip nectar, too. They just need blood when they're producing eggs.
If an insect that looks like this lands on your arm and bites you, that's a pretty good indication that it's a mosquito. But how do you identify a mosquito without enduring a bite? Look for these characteristics:
- long wings - The wings on a mosquito are typically longer than its body.
- a proboscis - Both males and females have an elongated proboscis which extends forward from the mouthparts.
- "fringed" wings - A mosquito's wings bear scales which create a fringe-like border on the trailing or posterior edge.
- "humpback" appearance - A mosquito holds its body away from the substrate on which it is resting, as in this image.
Midges, Family Chironomidae
This is a midge. To the untrained eye, midges look very similar to mosquitoes. Midges, however, do not bite. They do not transmit diseases. Midges do tend to swarm, and are extremely attracted to lights, including bug zappers. The piles of dead "mosquitoes" you think you find in your bug zapper are actually mostly harmless midges.
Notice these characteristics of the midge, which differentiate it from the mosquito above:
- shorter wings - The midge's wings do not extend beyond the end of its body.
- no proboscis - There is no visible proboscis extending from the midge's mouth.
- smooth-edged wings - Because the midge's wings are not covered in scales, there is no visible "fringe" along the edge of each wing.
- straight appearance - When at rest, the midge's body will be straight, with its thorax low to the substrate on which it rests.
Crane Flies, Family Tipulidae
This is a crane fly. People often think these are giant mosquitoes. Admittedly, many crane flies do kind of look like mosquitoes on steroids, but they're completely harmless, just like midges. They're called crane flies for their incredibly long legs, like those of the similarly long-limbed birds. Many members of this group dwarf the typical mosquito, but not all crane flies are giants.
Look for these clues to differentiate a crane fly from a mosquito:
- long legs - A crane fly typically has very long, slender legs in comparison to its body length.
- Usually lack a proboscis - Most crane flies don't have a proboscis, but even those with elongated mouthparts cannot bite.
- smooth-edged wings - Like midges, crane flies lack the fringed wings that are characteristic of mosquitoes.
- straight appearance - A crane fly at rest will hold its body straight, not in the humpback manner of mosquitoes.
- "Introduction to Mosquitoes (Culicidae)," Medical Entomology for Students, 3rd Edition, Mike W. Service, Cambridge University Press
- Insects Commonly Confused with Mosquitoes, Colorado Mosquito Control, accessed August 30, 2012
- Insects commonly mistaken for mosquitoes - midges, Alameda County Mosquito Abatement, accessed August 30, 2012
- Borror and DeLong's Introduction to the Study of Insects, 7th Edition, by Charles A. Triplehorn and Norman F. Johnson