Bug Blog

Why Are There So Many Mosquito-Like Bugs With Long Legs Within And Around Southern Arizona Homes This Spring? (Crane Flies)

For the past several weeks, many Tucson residents have noticed what appear to be mosquitoes with long legs flying around their porch lights and even within their homes. These nuisance insects are commonly known as “crane flies,” and more than 15,000 species of these flies have been documented. Crane flies belong to the Tipulidae family in the Diptera order, and entomologists with the University of Arizona state that these flies frequently become abundant following wet winters.

Crane Fly

Crane flies spend the vast majority of their lives as larvae dwelling in wet soil, wet leaves and around water bodies. In fact, their larval stage can last as long as three years, and while adults are considered a nuisance within and around homes, larvae are considered beneficial due to their habit of  recycling decaying organic matter within soil, such as dead vegetation. Heavy winter and early spring rain see large numbers of crane fly larvae develop within large fields and residential lawns, especially heavily irrigated lawns. After developing into the adults that Tucsonians are seeing now, they live for a short time for the sole purpose of mating and laying eggs. Occasionally, adults will drink water or feed on nectar, but they are not known for biting humans.

November, December and January saw unusually frequent bouts of rainfall, which contributed to the growth of grass and wildflowers throughout Tucson. This vegetation and the consistently moist soil allowed larvae to develop rapidly, and in great numbers, which is why massive numbers of adults are now active throughout the city. During dry years, larvae remain dormant in soil, and they can remain dormant for multiple consecutive years until moist conditions allow them to develop into winged adults. 2018 was a particularly dry year in southern Arizona, so it is no surprise that a large number of adult crane flies emerged following the wet 2019/2020 winter and early spring season.

Have you been experiencing nuisance issues with crane flies within and/or around your home? Just vacuum them up, they are harmless 🙂