Scoloderus

Abstract: More than one-fourth of the spiders examined for this revision were collected since the neotropical genus Scoloderus was revised in 1976. Thirteen names have been proposed for what appear to be five valid species (Scoloderus cordatus, S. gibber, S. nigriceps, S. tuberculifer, and S. ackerlyi). These species are distinguished by the presence or absence of abdominal humps on the female, the shape of the median apophysis of the male palpus, and the shape of the scape of the female epigynum. Abdominal coloration and pattern are highly variable and unreliable for identification. One new species, Scoloderus ackerlyi, is described on the basis of a single, unique female from Belize.

Abstract: Ladder-webs are built by several orb-web spider species and can be divided into two main groups based on the microhabitat in which they are built, either in open spaces (aerial) or against tree trunks (arboricolous). In Australian ladder-web spiders, Telaprocera, the elongated webs are a highly plastic behavioral response to building in space-limited conditions against tree trunks, while the aerial ladder-webs of Scoloderus are an adaptation for catching moths. However, the relative importance of moth capture in the construction of elongated webs in arboricolous spiders cannot be determined with existing data. We here present observational and experimental data concerning prey capture in the arboricolous spiders T. maudae Harmer & Framenau 2008 and T. joanae Harmer & Framenau 2008. We found that moths make up only a small fraction (, 4%) of the diet of Telaprocera spiders and that the proportions of major prey orders in webs are representative of available prey. Our experiments indicate that these webs do not function well at retaining moths. However, further data are required before more definite conclusions can be drawn regarding whether these webs are more effective at retaining moths than standard orb-webs.

Abstract: Ladder-webs are built by several orb-web spider species and can be divided into two main groups based on the microhabitat in which they are built, either in open spaces (aerial) or against tree trunks (arboricolous). In Australian ladder-web spiders, Telaprocera, the elongated webs are a highly plastic behavioral response to building in space-limited conditions against tree trunks, while the aerial ladder-webs of Scoloderus are an adaptation for catching moths. However, the relative importance of moth capture in the construction of elongated webs in arboricolous spiders cannot be determined with existing data. We here present observational and experimental data concerning prey capture in the arboricolous spiders T. maudae Harmer & Framenau 2008 and T. joanae Harmer & Framenau 2008. We found that moths make up only a small fraction (< 4%) of the diet of Telaprocera spiders and that the proportions of major prey orders in webs are representative of available prey. Our experiments indicate that thes...

Abstract: Summary The South American spider Scoloderus sp. spins a remarkably elongated ‘ladder’ orb web similar to that of an as yet unidentified New Guinean spider except that it is inverted 180°, with the long part above rather than below the hub. The two webs differ in a number of details, some of which may represent alternate solutions to the special problems associated with extremely long radii. Various details of the web building behaviour of Scoloderus sp. differ from the behaviour of species of Araneus and Zygiella. Immature Scoloderus build less elongate webs which are more similar to the standard araneid orb web. Eustala (?) sp. spins a web similar in many respects to that of the New Guinean spider, except that it is much less elongated, and thus forms an intermediate between typical orb webs and ‘ladder’ webs.