August peak season for lake animals

by KEVIN STRAUSS

August with its hot weather may seem like a slow time for us as we battle 90-degree temperatures and 90 percent humidity. But in the lake, everything is going full tilt. This is the time in the summer where the algae is growing and providing food for the tiny plankton creatures. The plankton provides food for the insects the insects provide food for the small fish and the small fish provide food for the big fish that we all love to catch.

At the same time, insect populations are at their highest on surrounding lands and young birds have fledged from the nests and are now hanging around in the forest and yards of the northland.

Insects and animals may not “know” that winter is coming, but they are probably biologically programmed to grow fast and reproduce during this season of plenty.

One of the easiest places to see this summer “traffic jam of life” is on the lake surface where insects are far more common than in other seasons.

Backswimmer insects are one species that you see a lot this time of year. Unlike most insects that swim on their bellies, these half-inch-long oval insects swim on their dark backs while showing their white bellies to the sky. They use a pair of long legs to paddle through the water and look like they have tiny rowboat oars on their bodies.

Adult backswimmers overwinter and lay eggs in the spring. Female backswimmers lay eggs on underwater plant stems before dying in the spring. The young hatch and grow into adults in about two months. So the adults we see now were this spring’s young.

Backswimmers often hang motionless with their tails at the water’s surface and their heads pointing down at a 45-degree angle into the water. Even though they are aquatic insects, the adults don’t have gills and they can’t breathe underwater. Instead, adult backswimmers trap air bubbles in the hairs along their bodies. These air bubble “scuba tanks” allow adult backswimmers to stay underwater for hours.

One of the the reasons that backswimmers want to stay underwater is to catch their prey: insects, small tadpoles and small fishes. Backswimmers use their long oar-like back legs to chase prey, grab prey with their front legs and then stab prey with their sharp beaks. The backswimmer then pumps digestive fluid into the creature’s body. That fluid kills the prey and breaks down its innards. Then the backswimmer sucks out the animal’s digested organs and muscles. While that may seem gross to us, we’re not backswimmers. Be careful if you try to handle backswimmers. Despite their small size, they can inflict a painful bite with their long beak-like mouths. use large ladles or cups for a close-up look at these creatures.

While backswimmers are predators, larger fish and insects will also eat them for food.

Along with being aquatic insects, adult backswimmers can also fly and will disperse to new areas in swarms at night. You might notice them swarming around nighttime streetlights near water.

Insects like backswimmers remind us how productive our area lakes are this time of year. Be sure to take time to notice all of the life at your local lake.