What do plants tell spiders about disturbances in grasslands?

Grazing and mowing constitute two important ways of reducing vegetation structure, which causes mechanical injuries in plants. In response to these injuries, plants emit herbivore-induced plant volatiles (HIPVs) that can act as recruitment signals for arthropod predators. Among these arthropods, spiders have been suggested to respond to HIPVs. It is unknown, however, if spiders make microhabitat choice based on the detection of those HIPVs or based solely on the availability of vegetal structure. In this study, we investigated microhabitat choice of the orb-weaver spider Argiope trifasciata (Forsskål, 1775) and its potential relationship with impacted and not impacted vegetation structure availability. Our major results corroborate other findings that microhabitat choice in orb-weaver spiders is driven not by HIPVs, but rather by vegetation structure. Habitat structure influences a variety of ecological factors such as predation risk, prey availability, and mate finding in orb-weavers. The mechanisms underlying assessment by A. trifasciata of the vegetative structure remains unknown, and future studies might investigate their capacity to perceive light and shade and/or their assessment of vertical positioning. Practically, our results can be useful in evaluating the impact of land management on spider populations and their resilience to these impacts.