The sight of crane flies tends to elicit fear. With their long bodies and even longer legs they look more like massive mosquitos than flies, but don’t be fooled by their intimidating appearance – they are harmless to humans and animals. Crane flies actually play a crucial role in ecosystem decomposition, breaking down organic matter in soil and acting as a food source for spiders and birds. Although crane flies don’t sting, spread illness or bite, they are still annoying to have flying around the house. The question is, are crane flies harmful or helpful?
What are Crane Flies?
Crane flies are large insects that thrive in warm, temperate climates and are most often seen during spring. They are often referred to as mosquito hawks or eaters because of the common misconception they eat mosquitos. You may notice an abundance of them after an especially rainy winter season because the moist soil creates the perfect conditions for their eggs and larvae to thrive. Overly watered lawns produce the same outcome and are a hot spot for crane flies to take up residence.
What do Crane Flies Eat?
While crane flies are often mistaken for oversized mosquitos, they do not share the same feeding habits as mosquitoes. Rather than an affinity for blood, crane flies sustain themselves by feeding on decaying organic plant matter and small insects. Their feeding habits change depending on which phase of the life cycle they are in.
Each phase has a unique set of needs. For example, adult crane flies don’t eat anything at all because the adult stage is so short. In contrast, crane fly larvae eat a lot to prepare for adulthood. At this stage, they seek out seedlings, decomposing wood, and some species even eat mosquito larvae and small insects.
The Crane Fly Life Cycle
Crane flies go through four distinct phases during their lifetime:
Egg
Crane flies start out as eggs, but only stay in this phase for a few days. Similar to mosquitoes, moist climates are ideal for their growth and development, so adult crane flies lay their eggs underwater or near a water source.
Larva
This phase is the longest and can last up to a few months. While in the larva phase, crane flies resemble tan or gray legless grubs. They spend most of their time near water sources seeking out food like decaying plants, plant roots, mosquito larvae and small insects.
Pupa
This is the phase where the crane fly transforms from a worm-like creature to a flying insect. The larva creates a cocoon just below the soil surface and stays in it for 5-12 days until it emerges in its final adult form.
Adult
The final phase in the crane fly lifecycle is the adult phase. Adult crane flies only live for a few days. Their sole purpose as adults is to mate and reproduce. As soon as they accomplish this task, they die.
Are Crane Flies Helpful?
Yes, crane flies play an important role in maintaining a healthy ecosystem. As larvae and adults, they are the primary food source for many insectivores like frogs and swallows. Since crane fly larvae almost exclusively feed on decomposing organic matter, they also play a large role in the process of decomposition in nature.
Are Crane Flies Harmful?
Yes and no – crane flies don’t harm people or animals because they don’t bite or sting. However, an abundance of crane fly larvae can cause significant lawn damage. Lawns may start to appear dead or patchy because the larvae feed on the roots and crowns of the turf. Until they are adults, crane flies exist as eggs, larvae and pupae hidden in water or damp soil. This is why they like lawns so much and why most people don’t even know they are there.
If crane flies are negatively affecting the yard or their flying around starts to become a nuisance around the home, we have some solutions to prevent or get rid of crane flies around the house.
Preventing Crane Flies
As with many common pests, prevention is the best course of action to keep crane flies away. The most common reason to prevent crane flies is to maintain a healthy lawn. If a lawn tends to get patches of brownish-yellow dead grass, crane fly larvae could be at fault.
Here are a few steps you can take to prevent crane flies:
Avoid Overwatering
Watering lawns is crucial to maintain healthy green grass, especially in the Southwest where nature doesn’t typically do the job for you. However, it is equally as important to keep from overwatering lawns. This attracts crane flies and other pests like mosquitos and termites, who are all attracted to moisture.
Mow Regularly
Regularly mowing the lawn is another easy practice that deters crane flies. Long grass provides a place to hide from humans and animals and creates a safe environment for reproduction and egg-laying. Keeping the grass cut down to three or four inches tall takes away much of that protection and crane flies will look elsewhere to reproduce.
Bring in the Birds
Most birds think crane flies are delicious. Hanging up a birdfeeder, birdhouse or birdbath can attract birds to your lawn. Birds need shelter, running water and food, and having all three in one place creates a bird’s paradise. Even with a birdfeeder, birds still love to snack on insects and will eliminate crane flies and many other unwanted that tend to roam around the yard.
Eliminating Crane Flies
If crane flies already invaded the lawn or you’re seeing them buzzing around backyard gatherings, there are a variety of products that can help. Typically, the best way to eliminate adult crane flies is by hanging an LED insect trap. Since adult crane flies don’t eat, they aren’t attracted to typical baits and traps, but they are attracted to light. Not only will these traps lure and kill crane flies, but they take care of most flying insects in the area. Another solution is to spray surfaces where crane flies tend to land with a control spray that kills insects on contact but is safe for humans and pets. There is also a wide variety of lawn insecticides to choose from that can rid lawns of crane fly larvae.
While crane flies are necessary for a healthy ecosystem, we still don’t want them buzzing around yards or eating up lawns. To find the best combination of products for your specific needs, stop by one of our Valley-wide Bug & Weed Mart locations, and one of our experts will help you find a safe, economical solution to conquer crane flies.