Studies have shown that arachnids prefer cloudy autumn and spring days as the best weather to fly in. Although wingless, a spider ...
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Spiders love to fly. Hundreds can touch down in an acre of land on a day when conditions are right. But before casting out a silk thread and swooping miles through the air, a spider checks the weather just as a human pilot might do during a pre-flight routine.
Spiders somehow consider tradeoffs between wind speed and sunshine, preferring cloudy autumn and spring days as the best flight weather.
Called ballooning, a spider's mode of transport involves casting out a "dragline" of silk thread, which gets carried by the wind, along with the attached critter. Since wind is the fuel and sunshine leads to updrafts helpful for take-off, the best time for a spider to take to the air is on sunny, windy days – perfect ballooning conditions.
While hot summer days will spawn more of the updrafts, the associated lack of breeze would mean the spiders couldn't drift anywhere once aloft. At the other extreme, for instance during winter storms, whipping winds that become too strong would interfere with the updrafts to make any flight impossible.
So how does a spider check the weather? Most feel their way with sensory hairs and pit-like sense organs that cover their limbs, or tarsi. When the spider is ready for lift-off, it simply forms itself into the launch position and jumps.
Both detection of windspeed and temperature is vital for the spider to enjoy a successful flight. Occasionally found in groups, spiders generally take to the air alone, but depending on wind speeds and direction, may well land in close proximity to another spider aviator.
Research found on the spider flying phenomenon could have implications for crop management as spiders prey on agricultural pests, such as mites, aphids and flies, 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. If the farmers can predict the influx of spiders, they can reduce the amount of pesticides accordingly.
Article provided by SDA Pest Control