The creature often called a “mosquito hawk,” a “skeeter eater,” or sometimes a “daddy long-legs” is actually an insect from the family Tipulidae, commonly known as the Crane Fly. This large, gangly insect frequently inspires questions about its diet, particularly the belief that it preys on other insects like mosquitoes or spiders. This article will clarify the true nature of the Crane Fly and definitively answer whether this seemingly fearsome flyer consumes spiders as part of its natural diet.
Identifying the Crane Fly
Crane flies are easily recognizable by their long, delicate legs and slender bodies, which give them a superficial resemblance to an oversized mosquito. Most species range in size from one-half to over an inch long, excluding their legs, and are typically brown or yellowish-gray in color. A defining characteristic for identification is a distinct V-shaped groove located on the dorsal side of the thorax. Despite their intimidating appearance, adult crane flies are completely harmless to humans and do not bite or sting. The misleading common name “mosquito hawk” is more accurately applied to true predators like dragonflies or robber flies, which actively hunt flying insects.
The Adult Diet
The short answer to whether adult crane flies eat spiders is unequivocally no, as they are not predatory insects. Most adult crane flies have a primary focus during their brief lifespan, which is mating and laying eggs. Many species do not feed at all, relying instead on the energy reserves they stored during their larval stage. Those that do consume anything are limited to a liquid diet, typically sipping nectar from flowers or simply drinking water. Adult crane flies lack the specialized, powerful mouthparts, such as mandibles, necessary to capture, kill, or consume any solid prey, including spiders or mosquitoes.
The adult stage is often short, sometimes lasting only a few days. Rather than being a predator of spiders, the adult crane fly is often prey itself, serving as a common food source for various animals. Bats, birds, lizards, and even spiders rely on the slow-moving crane fly as part of their own natural diet. This role as a non-predatory food source highlights their true ecological position.
What Larvae Eat
The feeding habits of the Crane Fly are most pronounced during its immature stage, known as the larva, or more commonly, the “leatherjacket.” This name comes from the larvae’s tough, grayish-brown skin, which gives them a leathery appearance. Unlike the adults, the larvae are voracious eaters, but their diet consists primarily of decaying organic matter found in moist soil. They function as decomposers, feeding on fungi, decomposing leaves, and other vegetative debris.
The leatherjackets’ diet also includes the roots and crowns of various plants, such as grass and seedlings. This is the stage where crane flies may be considered pests, as large populations feeding just beneath the soil surface can sometimes damage lawns and turf. While the vast majority of larvae are detritivores, some aquatic species of crane fly larvae are known to be opportunistic predators. These specific species may consume small invertebrates and the larvae of other insects, including mosquito larvae.