Increases in ground-level ozone, especially in rural areas, may interfere not only with predator insects finding host plants, but also with pollinators finding flowers, according to researchers from Penn State and the University of Virginia.
"Ozone pollution has great potential to perniciously alter key interactions between plants and animals," the researchers said in a recent issue of Environmental Research Letters.
The animal tested in this case was the striped cucumber beetle, a predator of cucurbits -- cucumber, squash, pumpkin and melons. These insects dine on the plants from the moment they emerge from the ground and when fruit forms, they eat that as well.
"Insects detect odor with olfactory receptors located on their antennae," said Jose D. Fuentes, professor of meteorology, Penn State. "These receptors sense plant-emitted volatile organic compounds in very small amounts -- as low as six molecules hitting an antenna."
However, ozone, which is a very reactive substance, degrades the volatile organic compounds when they mix to the point where they no longer stimulate the olfactory system.
Fuentes, working with John Zenker, Penn State undergraduate in meteorology, and T'ai H. Roulston, research associate professor and curator, Blandy Experimental Farm, University of Virginia, tested the beetles in an enclosed Y-tube apparatus so that the insect could choose which branch to take. Researchers collected the insects from pumpkin and squash plants. They tested the insects using buffalo gourd plants, a naturally growing wild gourd that likes semiarid areas.
Separate air streams flowed into the two branches of the Y-tube. Choices of air in each tube were ambient filtered air, ambient filtered air plus up to 120 parts per million ozone, ambient filtered air plus volatile organic compounds, or air plus up to 120 parts per billion ozone and volatile organic compounds from the plant. To obtain this mix, or only ozone or volatile
|Contact: A'ndrea Elyse Messer|