The insect commonly known as the “mosquito hawk” or “skeeter-eater” is actually the crane fly (family Tipulidae). This nickname is based on a misunderstanding, as the adult crane fly does not consume mosquitoes or other insects. With its long, spindly legs and delicate wings, the adult’s primary function is reproduction. Its lifespan is often brief, and it may only sip nectar or water, or not feed at all.
Defining the Crane Fly and its Life Stages
The crane fly undergoes complete metamorphosis, resulting in two forms that attract distinct sets of predators. The adult stage is the brief, airborne form most people recognize, characterized by a fragile body and elongated legs. Adults typically live only a few days to two weeks, dedicated primarily to mating and egg-laying.
The larval stage, known as the “leatherjacket,” can last for several months or even a year. These legless, grub-like larvae have tough, grey-brown skin and can grow up to 4 centimeters long. They spend their time burrowed in moist soil, leaf litter, or aquatic environments, feeding primarily on decaying organic matter, fungi, and plant roots. The long larval phase makes them a sustained food source in the ecosystem.
Predators of the Adult Flying Insect
The adult crane fly’s ungainly, slow flight and defenseless nature make it an easy meal for a wide array of aerial and terrestrial hunters. Diurnal predators, such as various bird species, actively target the flying insects near their emergence sites. Common insectivores like swallows, flycatchers, and starlings consume large numbers of adults.
Nocturnal hunters, particularly bats, capitalize on the adults’ attraction to lights and their clumsy flight patterns. The sheer size of many crane fly species makes them a substantial target for these nighttime fliers. Larger predatory insects also contribute to population control, including the praying mantis and the dragonfly. Other invertebrate hunters, such as various spider species, frequently capture the fragile adults in their webs or ambush them on foliage.
Predators of the Subterranean Larvae
The leatherjacket larvae, living just beneath the soil surface in moist environments, are extensively preyed upon by specialized terrestrial and semi-aquatic animals. Mammals that routinely forage underground are highly effective predators, including moles and shrews, which tunnel through the soil to locate the protein-rich grubs. Larger mammals like skunks and raccoons also feed heavily on leatherjackets, often leaving behind tell-tale signs of their activity in the form of dug-up patches of lawn or turf.
Various ground-dwelling birds are also significant predators, including crows, rooks, magpies, and starlings, which probe the soil with their beaks to extract the grubs. This foraging activity results in small, rounded holes across infested areas, which is often the first visible sign of a leatherjacket presence. In aquatic habitats, where some crane fly larvae thrive, they become a food source for fish species such as trout and bass, as well as predatory aquatic invertebrates. The larvae’s role as a rich food source means that their presence in high numbers can often attract and sustain a diverse community of wildlife.