Dragonfly Larva and Ponds

Damselflies look like dragonflies.

Many insects lay eggs and spend their larval stage in ponds, puddles, streams and other bodies of water. Mosquitoes are well-known for breeding in ponds with little water flow. Their predators, including dragonflies, also prefer to breed in and around ponds. Making sure your backyard pond encourages dragonflies and other beneficial aquatic insects, instead of pests such as mosquitoes, can improve your property and eliminate nuisances naturally.

Life Cycle

Female dragonflies lay their eggs near or in the water, often around floating plants. The eggs hatch into nymphs or larvae. Dragonflies can spend several years in the larval stage, catching mosquito larvae, tiny fish and tadpoles and small adult insects. After the nymph stage, the dragonfly climbs up onto a nearby plant, such as a reed, where the air causes it to start breathing and split its skin. The adult dragonfly emerges from the skin and flies off for its first meal. Adult dragonflies feed on airborne insects such as flies, ants, gnats, adult mosquitoes and midges.

Appearance

Dragonfly larvae have large compound eyes in both their adult and larval stages. They vary significantly in size, depending on the species, but all have grasping pincers to catch prey. Most larval dragonflies are brown or green, and blend in with the water and local vegetation. They have six segmented legs and a wide, often oval-shaped abdomen.

Conditions

These insects can breed successfully in even very small ponds. Some species will even lay their eggs in a barrel of water. According to the National Wildlife Federation, however, the ideal dragonfly pond is shallow at the edges and 2 or more feet deep in the middle. The deep water gives dragonfly larvae a place to hide from birds, raccoons and other land-dwelling predators, while the shallow water encourages aquatic plant growth. Avoid ponds with fast-moving water, since dragonflies prefer marshes, still ponds and other slow-moving water sources. Dragonflies do less well in ponds with an existing frog or fish population, since these animals may eat the larvae.

Similar Insects

Ponds suitable for dragonflies are also likely to breed damselflies. These slender insects look a lot like dragonflies, but hold their wings differently when at rest. Damselflies are weaker fliers than dragonflies, but the adults and their larvae are just as effective at destroying mosquito populations. Crane flies, insects that look much like giant mosquitoes, also breed in ponds. Commonly called mosquito hawks, these insects eat mosquitoes only in their larval form. Adult crane flies drink only nectar or do not feed at all.

References

• Oregon State University; Dragonfly; M. Grunberg et al.; April 2007
• Penobscot County Soil & Water Conservation District; Identifying Aquatic Insects From Your Pond; David T. Hansen
• National Wildlife Federation; Attracting Dragonflies to Your Yard; Cynthia Berger; April/May 2002
• "Houston Chronicle"; Dragonflies: Mother Nature's Mosquito Control; Suzy Fischer; July 5, 2008