A FLY IN SPIDERS CLOTHING - WHAT SIZE THE SPIDER

Many flies of the family Tephritidae have stripes on their wings and b lack markings on their thorax which make them look like jumping spider s (Salticidae), especially when they display their wings horizontally. Previous studies have shown that salticid spiders respond to tephriti ds by displaying and retreating, arguing that tephritids evolved as mi mics of salticids to protect them from predation by the latter. Here I show that the jumping spiders' reaction to a tephritid fly, the Medit erranean fruit fly (medfly) Ceratitis capitata, depends on the spider' s size, age and sex. Large, adult female jumping spiders seem to be th e least confused or intimidated by the medfly. This reduces the benefi ts that may derive from the resemblance of tephritids' wing and thorax patterns and displays to salticids, and leaves some doubt whether the se flies' special characteristics solely evolved to confuse spiders.