Orb-web inclination in uloboridae spiders: the role of microhabitat structure and prey capture

Spider webs are a good example of how phenotypic traits can be adjustable to the physical structure of the environment. Orb-web spiders of the family Uloboridae sometimes form aggregations inside webs of other spider species. In the present study, we focused on the system of Uloboridae associated with webs of the spider Aglaoctenus (Lycosidae). Because of the conformation of Aglaoctenus webs, the direction of prey flow in the central and peripheral positions of the Uloboridae aggregations is vertical and horizontal, respectively. The inclination of Uloboridae orb-webs, in relation to the ground, tends to be closer to horizontal in the centre and vertical in the periphery, whereas other characteristics of the orb-webs and spiders do not differ between the positions. Structural differences between centre and periphery were not enough to explain the inclination pattern of the orb-webs, at least regarding the method we used to measure the micro-habitat structure in this study. Our results support the view of intraspecific variability in orb-web inclination as a case of foraging optimisation strategy and, possibly, of adaptive plasticity. © 2016 Dipartimento di Biologia, Università di Firenze, ItaliaSpider webs are a good example of how phenotypic traits can be adjustable to the physical structure of the environment. Orb-web spiders of the family Uloboridae sometimes form aggregations inside webs of other spider species. In the present study, we focu295474489CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOPNPD/15334828321/14-007/57294-5159631/2011-4We thank Antônio Brescovit for identifying the spider species. We thank the municipal government of Araguari, the environmental department, and the employees of the John Kennedy Woodland Park (Parque Bosque John Kennedy) for their assistance in this stud