The potential for invertebrate-vertebrate intraguild predation: the predatory relationship between wolf spiders (Gladicosa pulchra) and ground skinks(Scincella lateralis)

Intraguild predation is described as predation among organisms that exploit similar resources. As wolf spiders (Araneae, Lycosidae) are generalist pre dators that share habitat and food resources with the ground skink Scincell a lateralis, we conducted a series of laboratory experiments to determine i f wolf spiders are capable of preying upon ground skinks. Wolf spiders (Gla dicosa pulchra) successfully preyed on skinks during 3 of 20 encounters, bu t did not overtly respond to chemical stimuli from the skinks. Skinks emplo yed antipredatory behaviors (i.e., immobility) when exposed to visual and c hemical stimuli from spiders, providing evidence that they recognize spider s as predators prior to an encounter. In an additional experiment, the hypo thesis that increased skink movement would lead to an increase in spider at tacks was tested. Skinks exhibited high levels of movement in this experime nt, with spider predation occurring during 4 of 10 encounters. The presence of structural refugia played a significant role in this predator-prey inte raction by increasing the amount of time required for a spider to prey upon a skink. Our results indicate that G. pulchra can prey upon S. lateralis, and that skinks may recognize cues deposited on the substrate by spiders. T hese data indicate that these two species may interact in an ecologically m eaningful manner.