What’s This Bug? The Crane Fly.

Here in Tucson, we are in the middle of Crane Fly season and it's creeping people out all over the city. These gangly insects are everywhere – and I mean everywhere; I even found a dead one in my purse. This phenomenon happens every year, but the numbers are greater when the area experiences wet weather late in the previous year. This was the case for our city in late 2019 and into early 2020. Crane Fly larvae grows best in damp soil and the accumulated rain triggered growth in wildflowers and grasses, which provided a stable food source for the root-eating larvae. With all that organic matter to feast on, the larvae population grew and thrived. Which leads us to this moment, when large numbers of adults have grown from that larvae and are now out looking for mates.

People around here have to run a gauntlet of  these quivering critters to get through their front doors. Like many other insects, Crane Flies are attracted to light; so avoiding these clusters can be tricky. You can turn off the light by your door, but they will still see the light leaking out from inside. So, unless you turn all your lights off, you will probably just have to deal with them and wait them out - they will only be around a couple of weeks.


Crane Flies must be one of the most wrongly identified insects out there. They are most commonly mistaken for mosquitoes, and for many people they spark a sort of primal fear of that particular insect. But, Crane Flies are not mutant mosquitoes plotting to suck you dry of blood. They are not mosquitoes at all or even closely related –they are members of the fly family (Tipulidae spp.) and only share a passing resemblance to mosquitoes.

It is not only misidentification that plagues Crane Flies, but widespread misunderstanding of their capabilities and motivations in life. Hence the Mosquito-eating monikers like “Mosquito Hawk”. Crane Flies do not, despite the deepest desires of some people, eat mosquitoes. In fact, they do not have the mouth parts to eat anything (or bite – more on that in a minute). Some have a visible proboscis, which some scientists say they use to suck up flower nectar. Other scientists dispute this feeding claim and believe they do not eat at all as adults and survive by living off the fat stores accumulated in their larval stage. Lending credence to the not-eating, energy-conserving hypothesis is their activity level; they don’t fly around endlessly. They sort of bump-jump-fly and then find a spot to cling to.

Because they do not have the proper mouth parts or stingers, Crane Flies are harmless to people. They cannot (so will not) bite, sting or suck on people. For all these reasons, they also do not carry diseases. Their Daddy-Long-Legs-combined-with-mosquito looks and their twitchy movements may give you the willies, but they pose no danger.

While adult Crane Flies are completely harmless, the same cannot necessarily be said for their voracious larval form (which is 95% of their lives). Crane Fly larvae are great decomposers; they consume all sorts of organic material in the soil. However, they will not discriminate between unwanted organic matter and desirable plant roots. So, for those in search of the perfect lawn, they can be seen as a problem. Keeping your lawn healthy will discourage excessive feeding (check out our lawn products here) and treating the area with beneficial nematodes (we recommend NemAttack™ Steinernema feltiae) should keep their numbers down. For more on controlling Crane Fly larvae, read this article.

If you are still convinced that the current Crane Fly situation in Tucson is horrific, consider what it must be like in the Sichuan province of China. Back in 2017, outside the city of Chengdu, a monster-sized Crane Fly was captured. It has since been confirmed to be the world’s largest. Read more here.

There are some people who see Crane Flies as deeply spiritual beings and their appearance as a blessing. This site gives more details on this unique vision of a unique creature.

Here's a video for more general information on Crane Flies.

Adult Crane Flies may be aesthetically challenged, but they serve a purpose beyond their own reproduction. They are a bounty to insect-loving animals in our environment. Birds, bats, lizards and other wildlife are currently having their own version of Thanksgiving over-eating. I can envision them in their homes, contentedly sleeping off their feast – just like Uncle Fred on the couch after too much turkey.                                                     

Submitted by Pam