Hunting ecology predicts eye arrangements in the modular visual system of spiders

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  Hunting ecology predicts eye arrangements in the modular visual system of spiders Summary Vision is one of the most important senses used by animals and contributes to fundamental behaviors, including foraging, navigation, and mate detection and selection. 1 Although much is known about how eye position and orientation correlate to ecology in the context of binocularity, 2 animals with multipartite visual systems (more than two eyes) remain comparatively neglected. Spiders are highly successful predators that occupy a range of ecological niches and usually possess eight eyes. Here, we use three-dimensional geometric morphometrics and evolutionary modeling to test whether eye positions, orientations, and interocular angles correlate with hunting strategies in 52 species across the spider phylogeny. We demonstrate that eye configurations diversified from an ancestral medial cluster, as seen in modern trapdoor spiders, to a halo-like configuration in orb-weavers, and to the fronta...

A little goes a long way: a rapid sampling protocol repeated seasonally generates considerable spider biodiversity data in an arid national park

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A little goes a long way: a rapid sampling protocol repeated seasonally generates considerable spider biodiversity data in an arid national park

Abstract

The Richtersveld National Park (RNP) is situated in the extreme north-western part of South Africa and protects a large proportion of the Desert Biome in the country, as well as part of the globally significant Succulent Karoo Biome. Prior to 2021, only 92 spider species had been recorded from the park, but some historical records are misidentified. To generate spider diversity data from the RNP, we carried out sampling in four biotopes using a standardized rapid sampling protocol (RSP), repeated in mid-summer (January 2021) and winter (July 2021) to assess seasonal changes in assemblage composition. In total, 2409 spiders were collected, representing 121 species and 32 families. Spider abundance and species richness were far higher in winter (n = 1546, S = 110) than in summer (n = 863, S = 75). Additional collecting at other sites yielded 60 species in total, of which 13 had not been recorded historically or using the RSP. Of the 92 historically recorded species, 62 were not collected using the RSP or in additional collecting samples. An updated checklist of the spider fauna of the RNP now includes 190 species (53 probably undescribed) in 37 families, more than doubling the historical records, and provides a useful foundation for conducting ecological research in the park. Furthermore, 191 specimens representing 120 species were sequenced for a national DNA barcoding project to aid future identification. Our study highlights the importance of developing appropriate and achievable RSPs to address shortages in biodiversity data, particularly in under-resourced developing countries.

Haddad, C.R., Booysen, R., Vickers, M.E. et al. A little goes a long way: a rapid sampling protocol repeated seasonally generates considerable spider biodiversity data in an arid national park. Biodivers Conserv (2025). https://doi.org/10.1007/s10531-025-03107-9