Spatial distribution and microhabitat preference of Psecas chapoda (Peckham & Peckham) (Araneae, Salticidae)

Although spiders generally do not have a strong association with the plants on which they live, the jumping spider Psecas chapoda inhabits and breeds on Bromelia balansae (Bromeliaceae). To understand the relationship between Psecas chapoda and Bromelia balansae. we investigated whether the type of habitat (forest or grassland). the size of the bromeliad and the inflorescence of the host plants affected the preference and/or density of P. chapoda. We also examined how spiders of different ages and their eggsacs were distributed on the leaf layers of the rosette of host plants and whether P. chapoda used other plants in addition to B. balanasae. Psecas chapoda occurred with higher frequency on bromeliads in grasslands to those in forest. In grassland, larger bromeliads had more spiders, but this was not true of bromeliads in the forest. This spider avoided bromeliads with inflorescence. Most of the spiderlings (70%) occurred in the central layer of the rosette leaves, and their distribution pattern suggested that they sought shelter to protect themselves from desiccation or cannibalism, both of which are commonly observed in this species. Older spiders, as well as females without eggsacs. Occurred in the external layers whereas 90% of the females with eggsacs occurred close to the central layers. Deposition of the eggsacs near the center of the rosette can allow the spiderlings to reach their shelter rapidly and to be less exposed to desiccation and cannibalism. The non-detection of A chapoda on non-bromeliad plants, and the stereotyped behaviors on the host-plant suggest that this jumping spider was strongly associated with B. balansae.