January 8, 2009

Study: Insects mistake roads for water

Insects mistake buildings, cars and even roads for water, laying eggs that will never hatch and jeopardizing ecosystems, a U.S. university researcher said.

These ecological traps are caused by polarized light reflecting from windows, asphalt roads -- even plastic sheets and oil spills, Michigan State University research associate Bruce Robertson said.

To some species, the light creates an appearance that mimics the surface of the water, which the insects use to breed and feed, he and colleagues reported in the journal Frontiers in Ecology and the Environment.

Dragonflies, for instance, can be prompted to lay eggs on roads or parking lots, thinking the asphalt is water, the researchers said.

Such aquatic insects are at the center of the food web. A crash of their population can cause changes farther up the food chain, the researchers said.

Besides laying eggs that won't hatch on asphalt, the flies themselves can be killed by a passing car -- and predators following misdirected insect prey can find themselves in danger, they said.

Any kind of shiny, black object -- oil, solar cells, asphalt -- the closer they are to wetlands, the bigger the problem, Robertson said.

The researchers say it is therefore important to build with alternative materials and, when necessary, employing mitigation strategies.

These can include adding white curtains to dark windows or adding white hatching marks to asphalt, they said.