When a large, gangly insect with unusually long legs appears, many people immediately think of a giant mosquito. This often leads to concern about potential bites or harm. While these insects might resemble mosquitoes, they are distinct creatures that play a different role in the environment.
Meet the Crane Fly
The insect often mistaken for a giant mosquito is most likely a crane fly, belonging to the family Tipulidae. This is a diverse group, with over 15,500 described species worldwide. Crane flies typically have slender bodies, long, thin wings, and exceptionally long, delicate legs that can easily detach. Their body color can range from orange-brown to brown.
Spotting the Differences
Several key characteristics distinguish crane flies from mosquitoes. Crane flies are considerably larger, with many species measuring 0.5 to 1.5 inches in body length, and some can have a wingspan up to 4 inches. Mosquitoes are much smaller, typically 0.15 to 0.4 inches long. A key difference is their mouthparts; crane flies lack the piercing proboscis female mosquitoes use to bite and feed on blood. Instead, crane flies have a snout-like head, and their adult mouthparts are often underdeveloped.
Wings also offer clues. While both have two wings, mosquito wings typically have scales, absent on crane fly wings. Crane flies often rest with wings spread or held at a slight angle, appearing more open, while mosquitoes hold wings folded closer to their body. Crane flies exhibit a more clumsy, wavering flight pattern compared to the agile and precise flight of mosquitoes. Mosquitoes often appear humped due to a bent thorax when at rest, while crane flies maintain a straighter body posture.
Beyond the Bite
A common concern is whether crane flies bite or pose any threat to humans. Adult crane flies do not bite people or animals because their mouthparts are not designed for biting or blood-sucking. This absence of biting is a primary distinction from mosquitoes, whose females require blood meals for egg development. Most adult crane fly species do not feed during their short lifespan (a few days to two weeks), focusing instead on reproduction.
Some adult crane flies sip nectar from flowers or water to stay hydrated. Crane fly larvae, often called “leatherjackets” due to their tough skin, primarily feed on decaying organic matter, plant roots, and grasses in moist soil. While crane fly larvae can sometimes become minor pests to lawns or gardens by feeding on roots, they are not considered a threat to human health and do not transmit diseases.
Crane Flies in Your Home and Garden
Crane flies are commonly found in moist, vegetative outdoor habitats, such as gardens, lawns, and near bodies of water. They are attracted to lights, which can inadvertently draw them indoors, especially during the evening. If a crane fly is found inside a home, it is usually there by accident, often bumping against walls or ceilings while trying to find its way back outside.
Crane flies undergo complete metamorphosis, progressing through egg, larva, pupa, and adult stages. Female crane flies lay eggs in moist soil, often in lawns or along creeks. The larvae (leatherjackets) develop in these moist environments, feeding on organic matter. While adult crane flies are harmless, a large concentration of their larvae can cause damage to lawns by feeding on grass roots, leading to brown patches. Simple measures like ensuring proper lawn drainage and avoiding overwatering can help manage their populations in outdoor areas.