BEIJING, April 13 (Xinhuanet) -- And you thought only Spider-Man could fly. Turns out a cloudy fall or spring day can be full of flying -- or ballooning -- spiders looking for a tasty bug and a place to touch down, according to a new study.

Called ballooning, a spider's mode of transport involves casting out a "dragline" of silk thread thatgets carried by the wind, taking the spider for a ride. Since wind is the fuel and sunshine leads to updrafts helpful for take-off, scientists figured sunny, windy days would make for perfect ballooning conditions.

But a team of biologists and mathematicians with Rothamsted Research in England calculated travel distances under a range of conditions for wind and sun levels. A resulting computer model revealed the best flight weather corresponds with real-life peaks in spider ballooning on cloudy fall and spring days.

While hot summer days will produce more of the updrafts, the associated lack of breeze would mean they couldn't drift anywhere once aloft, the scientists think. And strong windsduring winter storms would interfere with the updrafts to make any flight impossible.

So how does a spider feel wind velocity? Most feel their way with sensory hairs and pit-like sense organs that cover their limbs, or tarsi.

"The literature on spider sensing points to tarsal organs and hairs as having roles in, respectively, the detection of temperature and wind speed," lead author Andy Reynolds told LiveScience.

The research, published online recently by the journal Biology Letters, could have implications for crop management. Spiders prey on agricultural pests, such as mites and aphids, acting as natural alternatives to the chemical pesticides used by farmers.

"Each day of the growing season, around 1,800 spiders land in each hectare (about 2.5 acres) of arable farmland after ballooning," Reynolds said. "If the farmers can predict the influx of spiders, they can reduce the amount of pesticides accordingly."

(Agencies)