Distribution of Peucetia viridans (Araneae: Oxyopidae) on Croton ciliatoglandulifer.

Peucetia viridans (Hentz) lives almost exclusively on Croton ciliatoglandulifer (Ortega) in the dry forests of western Mexico. This spider is usually found on pubescent shrubs. Within their host plants, P. viridans has been associated with plant height and cover, as well as with number of flowers or inflorescences in anthesis. Flowers can be used as cues of good habitat conditions or because they attract prey detected by the spider. In this study, we assessed the importance of flowers, plant cover, and plant exposure (sun/shade) on the spider distribution in five 50-plant transects. In a field experiment, we also compared the number of spiders between controls, plants from which inflorescences were removed, and plants with artificial inflorescences. The results from the transects indicate that, when the number of flowers per spider is high, spiders were more abundant in exposed locations, which presumably offer better microclimatic conditions; when flowers become scarce, food may be more difficult to find and the spider distribution become strongly associated with the number of flowers, where they are more likely to find prey. Spider abundances on the experimental plot decreased on plants from which flowers were removed in comparison to control plants. Spider abundance increased on those in which artificial inflorescences were added. The similarity between plants with natural and artificial inflorescences suggests that spiders use flowers as cues of good microhabitats instead of prey visitors, which are significantly less abundant on artificial inflorescences.