Swimming pools and backyard ponds can be inundated by certain insects on occasion. Some of these are true aquatic insects that have a lifestyle associated with water while others are nuisance flying insects that are attracted by outdoor lights and accidentally end up in the water.

Aquatic Insects Are Assets in Backyard Ponds

By “aquatic insects” we generally mean those that spend all, or at least part of their life in water. Insects that are aquatic in the immature stage but not the adult stage include midges, mayflies, dobsonflies, stoneflies, and caddisflies. Technically mosquitoes fall into this category, too, since the larvae develop in water.

For other aquatic insects such as the unique backswimmers, water boatmen, water striders, or aquatic beetles, the adult stage spends most of its time in or on water although it survives just fine out of water as well. In fact backswimmers can fly long distances to get to a suitable body of water. There are a couple of aquatic insects (backswimmer, giant water bug) that will bite if handled.

In ornamental backyard ponds, certain aquatic insects are a good thing. They make entertaining pond residents and they feed on algae and other insects. In my experience, if you have a pond these interesting aquatic insects will find it. You don’t want mosquito larvae in your backyard pond though and as long as your pond is stocked with fish you won’t have that problem.

Flying Insects Are Problems in Swimming Pools

The insects that end up in a swimming pool are generally nuisance flying insects and are not welcomed. They annoy swimmers and make a mess in the pool. Mosquitoes and midges are attracted by bright lights and for egg laying because their immature stages have to develop in water. Midges are probably the most common nuisance pests around swimming pools. These mosquito look-alikes hatch out of nearby water in large swarms and are then attracted to lights (see Swarms of Mosquitoes Are Probably Harmless Midges).

Other insects that can fly and are attracted to lights such as June beetles and even mole crickets might end up in the swimming pool. In scummy pools that are no longer maintained with chlorine, some true aquatic insects can move in and can even establish a breeding population.

There are a number of steps you can take to help keep your swimming pool insect-free. At the very top of the list is managing outdoor lights so as not to draw insects to the pool area. For detailed information on how to avoid swimming with insects, see Keeping Insects Out of Swimming Pools.

Photo Credit : By James Lindsey at Ecology of Commanster, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=7204998