Antiherbivore protection and plant selection by the lynx spider Peucetia flava (Araneae: Oxyopidae) in the Brazilian Cerrado

Abstract

AbstractSpiders are ubiquitous in most vegetation, however very little empirical data are available on specific spider–plant interactions and their reciprocal outcomes. In the Brazilian Cerrado, the plant Mimosa setosa var. paludosa, (Fabaceae) has glandular trichomes in its leaves and stems, commonly entrapping insects (i.e. carrion) as well as hosting the lynx spider, Peucetia flava. We hypothesized that: (1) the damage inflicted by exophytic (leaves) and endophytic (seeds) herbivore insects that overcome the glandular trichomes is lower in plants where the lynx spider is present; and (2) the presence of this predator is positively related to food availability (live insects and/or carrion) and plant size. We performed field observations and an experimental field study in terms of the spider's presence versus absence on the Fabaceae plants. Our results showed that the proportion of damaged foliolules on the Fabaceae plants differed between the spiders‐present and spiders‐absent treatments, and that the absence of spiders led to a 3.3‐fold increase in the number of damaged foliolules. However, there was no significant difference in the proportion of seeds taken by endophytic herbivores from branches with and without spiders. We also found that the presence of Peucetia flava was positively related to the presence of entrapped carrion on plants, and that there was a positive and marginally significant effect of increasing abundance of the spiders on taller plants. The results of this study suggest that it is more common to find lynx spiders interacting with M. setosa var. paludosa in larger plants with higher carrion abundance (food source), and that P. flava and M. setosa var. paludosa interact in a facultative mutualism, in which plants provide entrapped carrion for spiders to feed on and possibly facilitate prey manipulation. In return, lynx spiders decrease the damage inflicted by exophytic, but not by endophytic herbivores. These results also contribute to a better understanding of which ecological factors may affect plant selection by lynx spiders and what the influence of this predator is on the structure of food webs in glandular plants.