Crane flies are often seen as bothersome insects, frequently appearing indoors with peculiar flight patterns. Despite their sometimes startling appearance and behavior, these insects are largely harmless to humans.
What Makes Them Seem Annoying
Crane flies possess physical characteristics and behaviors that contribute to their perceived annoyance. Their large size, with some species reaching over an inch in length and a wingspan of up to three inches, makes them highly noticeable, especially indoors. These insects have slender bodies and exceptionally long, gangly legs, which can easily detach if caught, adding to their awkward appearance.
Their flight patterns also contribute to their perceived nuisance. Crane flies are not strong fliers, often described as clumsy and erratic. They tend to flutter aimlessly, bumping into walls, windows, and light fixtures, particularly when attracted to indoor lights at night. This uncoordinated movement, combined with their sudden appearance indoors, can be startling and unsettling.
The Truth About Their Bite
A significant reason for the widespread apprehension towards crane flies stems from the misconception that they are giant mosquitoes capable of biting humans. This belief is unfounded; crane flies do not bite humans or animals. Their mouthparts are not designed for biting or sucking blood. Instead, they are adapted for consuming nectar or are often vestigial, meaning undeveloped or non-functional.
The resemblance to mosquitoes is purely superficial, as crane flies belong to a different family of insects. Unlike mosquitoes, which have piercing mouthparts, adult crane flies either do not feed at all or only consume nectar and water. This fundamental difference in feeding habits means they pose no threat of biting or transmitting diseases.
Their Benign Nature
Beyond the misconception about biting, adult crane flies are harmless to humans and property. They have a very short lifespan as adults, living only for a few days to two weeks, with their primary purpose being reproduction. During this brief adult stage, they do not transmit diseases.
While adult crane flies are benign, their larvae, often called “leatherjackets” due to their tough skin, can affect lawns. These larvae live in moist soil and feed on decaying organic matter and grass roots, which can lead to thinning or brown patches in turf. However, adult crane flies play a beneficial role in the ecosystem as decomposers and as a food source for various animals like birds and bats.