Colony size, habitat structure, and prey size shape the predation ecology of a social pseudoscorpion from a tropical savanna

Predation strategies are driven by habitat structure, prey’s nutritional value, and/or by predator characteristics such as developmental stage. Here, we evaluated the feeding habits of the social pseudoscorpion Paratemnoides nidificator in two areas of a Brazilian Cerrado savanna. These pseudoscorpions live under tree bark trunks of varying sizes; habitat structure could interfere with pseudoscorpion ambushing behavior and prey accessibility. We therefore assessed the hypotheses that (i) small and large colonies of P. nidificator will capture prey of distinct amounts and sizes; (ii) habitat structure will limit the captured prey size; (iii) there will be an age-dependent prey choice in P. nidificator. We evaluated the prey items, colony composition, and habitat structure of pseudoscorpions and determined whether P. nidificator presents age-dependent feeding preferences by offering prey items of different sizes. Colonies with more individuals captured more prey items and those prey presented a wider size variety. P. nidificator can capture a high variety of prey sizes by using openings in tree bark as a trap; however, only tree barks of intermediate size amplitude may be used for trapping most prey. Nymphs showed no preference for prey size, while adults mainly fed on larger ants. Tree bark may play a role as a phenotype extension by easing the process of large prey capture, which is considered a crucial factor for social species. Small prey might be a complementary food resource for nymphs, reducing intraspecific competition and their exposure to larger, dangerous prey. SIGNIFICANCE STATEMENT: Habitat structure and prey’s traits such as size affect the predation strategies of several animals. How these features interfere in the feeding habits and prey accessibility of social arachnids is a matter of question. We showed that habitat structure and colony size drive the prey size preference of a social pseudoscorpion. Paratemnoides nidificator lives under tree trunk barks that vary in size, depth, and shape. The tree bark openings may play a crucial role by easing the capture process of different prey sizes, including large prey, which is considered a crucial factor for social species. According to the prey size hypothesis, social species require, collectively, higher amounts of food energy. Thus, we propose that the bark openings are related to the evolution of P. nidificator’s social behavior as they potentially allow the capture of larger and more nutritious prey.