Some of them produce glycol, which acts like antifreeze. Others seek protected sites, such as under bark or rocks, in rodent burrows or in our homes to avoid extreme winter cold. In addition, the number of insects found later in the year depends on the number of predators, such as beetles, she said. Also, insects called parasitoids lay their eggs on other insects. When the eggs hatch, the young devour the hapless insect.
Diseases can also infect insects and lower their numbers.
Weather also plays a factor. Immature stages of mosquitoes need water to survive. Ticks and fleas are susceptible to drying out. Mowing opens the canopy to let air get in and dry out the ticks and fleas. Vail said fleas haven't been much of a problem in the last few years.