Crane Fly

Not a giant mosquito

The crane fly (daddy long-legs in British English) is one of the most frequently misidentified UK insects. It bears superficial resemblance to a mosquito but is completely harmless to humans — adults have no functional mouthparts for biting and do not feed on blood. The widespread belief that it’s a “deadly mosquito” is entirely false.

Adults live only 10–15 days, surviving on fat reserves accumulated as larvae. Their sole purpose in adult life is reproduction.

The V-shaped mark

The crane fly’s wings are held out at rest in a distinctive V or T shape — flat and horizontal, unlike mosquitoes, which hold wings parallel to the body. The abdomen dangles below when flying. Their legs break off easily — an escape mechanism when grabbed.

Leatherjackets

The larvae — called leatherjackets — are grey-brown, cylindrical, legless, and tough-skinned. They spend up to a year in moist soil feeding on grass roots, organic matter, and plant seedlings. In gardens and sports turf, leatherjacket infestations cause patches of yellowing, dying grass — the roots are eaten from below. Starlings and rooks digging up lawns in autumn are typically searching for leatherjackets.

Control

Biological control using the parasitic nematode Steinernema feltiae (applied to moist lawn in autumn when larvae are small) is effective and environmentally preferable to insecticides. Nematodes infect and kill the larvae over 2–3 weeks.