Understanding the habitat selection and natural history of the spider Deinopis cf. cylindracea (Deinopidae)

Compreendendo a seleção de habitat e a história natural da aranha Deinopis cf. cylindracea (Deinopidae)

Abstract

Habitat choice is fundamental for an animal foraging, defense, and reproduction. Ogre-faced spiders are known for their unusual morphology, natural history, and rarity. They are sit-and-wait predators that build net-like webs that are manipulated by spiders and thrown at their prey. Hunting behavior includes selecting microhabitats for web construction that reduces the likelihood of damage or entanglement in the substrate during prey capture. Therefore, we expect that Deinopis cf. cylindracea selects smooth surfaces to forage on. We observed D. cf. cylindracea associated with smooth trunks of Plinia cauliflora (Myrtaceae) in the natural environment and actively selecting smooth trunks over rough trunks or litter in controlled experiments. Such selection is likely to maximize the foraging strategy of launching the web towards the substrate. Aggregations had occurred more often in the 50 cm trunk closest to the ground, where the prey community is largest. During the day, this spider appears to choose sites where it can adopt a stick-like posture upon the vegetation near the ground. Hunting at night and resting cryptically during the day appears to be shaped by natural selection for the survival and reproduction of this spider species.

Keywords:
Atlantic Forest; camouflage; vertical stratification; Plinia cauliflora