Effect of forest fires on a Mediterranean Odonata assemblage

Abstract

Despite a high number of incidental online records of spiders predating upon dragonflies/damselflies, studies on these interactions are scarce. Here, we describe the predatory behavior of Argiope trifasciata on the two most common odonate species in the study area, and whether various factors (web width, web length, spider body length, odonate body length, distance of the web from the edge of water body, and height of the web above ground) are related to the number of odonates captured. Argiope trifasciata employed stalking and frontal approaches as Odonata predation strategies. Our findings showed that larger Odonata are preyed upon by larger spiders. The greatest numbers of prey were caught in wider, higher webs, whereas narrow webs closer to the ground caught more small prey. Capturing success by A. trifasciata was similar in webs at different distances from the water for both species. Contrary to our hypothesis, there was no relationship between capturing success in either prey species and the distance of the web from the water. Habitat architecture may be more important to this interaction, as vegetation attracts both spiders (for anchoring webs) and odonates (as perch sites).