Chemical Secretion Use Varies Among Species but Lacks a Straightforward Relationship With Other Defenses in Neotropical Opiliones

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  Chemical Secretion Use Varies Among Species but Lacks a Straightforward Relationship With Other Defenses in Neotropical Opiliones ABSTRACT Chemical secretion deployment is a widespread defensive strategy in arthropods, typically aimed at surviving encounters with predators. However, the ecological forces shaping variation in its use across species remain unclear. We quantified chemical secretion behavior in 11 sympatric species of Prionostemma within the understudied arachnid order Opiliones. We surveyed species in two distinct forests in Costa Rica and tested their secretion propensity when stimulated, and whether these differences correlate with interspecific variation in morphology, leg-loss levels, or social behavior. We found that species varied in their tendency to release chemical secretions, forming a continuous gradient from taxa that rarely secreted to those that secreted in nearly all encounters. However, this variation was not explained by body size or leg loss. Spec...

Microclimate of cemetery habitats and nest site selection of Eresus kollari (Araneae: Eresidae) in South Korea

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Microclimate of cemetery habitats and nest site selection of Eresus kollari (Araneae: Eresidae) in South Korea

Abstract

Nest site selection and construction are important life history events for many animals. These decisions are largely governed by abiotic factors such as temperature, humidity, and solar radiation. Eresus kollari—a burrowing spider that excavates its own nest and rears its offspring within—likewise faces important decisions when choosing where to build. In South Korea, the species often occupies sun-exposed, dome-shaped burial mounds. To understand the behavioral decision-making that leads the species to occupy mound habitats, we conducted field surveys and laboratory experiments. Field surveys showed that 75.6% of all E. kollari nests were found on mound surfaces, with the highest density near the mound center (3.98 nests/m2). Across the hemispherical mound, nests were concentrated on the eastern, central, and western sectors and displayed a slight overall bias toward the south. Mean soil temperature was ~19°C and did not differ between the mound and adjacent ground. In contrast, the mound surface was markedly drier (soil moisture = 4.7%) than the surrounding soil (7.5%). These spiders formed highly localized clusters within their habitats; this clustering pattern resembled a parent–offspring aggregation and also suggested that individuals exhibit preferences for specific environmental conditions. Laboratory selection tests corroborated the field patterns: Spiders preferentially moved away from moist substrates and displayed a strong attraction to illuminated directions. Collectively, these results suggest that E. kollari prefers sunny, dry mound surfaces as nesting sites and settles there to construct nests.

Choi, J. H., Oh, D., Kim, N. H., Lee, J. K., & Kim, K. W. (2026). Microclimate of cemetery habitats and nest site selection of Eresus kollari (Araneae: Eresidae) in South Korea. Ecosphere, 17(7), e70708. https://doi.org/10.1002/ecs2.70708