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Unformatted text preview: Burrow decorations as antipredatory devices Jennifer L. Williams, a,b Jordi Moya-Laran o, a,c and David H. Wise a a Department of Entomology, S-225 Agricultural Science Building-North, University of Kentucky, Lexington, KY 40546-0091, USA, b Department of Entomology, University of Arizona, Forbes 410, PO Box 2100: (36), Tucson, AZ 85721-003, USA, and c Estacio n Experimental de Zonas A ridas, CSIC, General Segura 1, Almera 04001, Spain 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. Key words: antipredatory mechanisms, burrowing wolf spiders, coexistence, decorations, intraguild predation, Scorpiones. [Behav Ecol 17:586590 (2006)] A nimal decorations are usually thought to function as sig- nals of quality (e.g., Andersson 1994; Soler et al. 1998; Madden 2002). However, web decorations are widespread among araneoid spiders (Herberstein et al. 2000). A recent hypothesis proposes that in this group these decorations can function as devices to attract prey (e.g., Craig and Bernard 1990; Craig et al. 2001). Recent evidence suggests, however, that rather than attracting prey these devices make spider silk cryptic to prey, thereby increasing the chances that flying insects are intercepted by the web (Blackledge and Wenzel 2000). Older hypotheses suggest that in some clades decora- tions could also serve an antipredatory function (Hingston 1927; Schoener and Spiller 1992; Blackledge 1998). Among these hypotheses, the one that enjoys the strongest empirical support is that which states that web decorations prevent pred- ators from detecting the spider in the center of the web (Blackledge and Wenzel 2001; Eberhard 2003; Chou et al. 2005). However, other studies have failed to support this hy- pothesis (Herberstein et al. 2000; Craig et al. 2001). Some visually hunting spider predators may actually use the decora- tions as cues to locate the spiders (Bruce et al. 2001; Seah and Li 2001)....
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