Burrow decorations as antipredatory devices

Abstract

Animal decorations are normally interpreted as signals of quality. In spiders, however, decorations may have different functions, including the attraction of prey to the web or making the spider cryptic to predators. To date, there is scant evidence for the latter hypothesis. Here we use the burrow-decorating wolf spider Lycosa tarantula to test whether turrets around the burrow serve to prevent burrow invasion and predation from the Occitan scorpion Buthus occitanus. We located spiders and scorpions in field enclosures and manipulated the presence or absence of decorations or turrets. We found that the presence of the turret decreases the rate of burrow invasion and improves spider survival, possibly because the turret makes the burrow cryptic to scorpions. In addition, a field survey showed that burrows with larger decorations had a lower chance of being invaded by scorpions. These results provide evidence that the decoration has an antipredatory function in nature. Copyright 2006.