The distribution, spatial clustering, and density of trapdoor spiders in two California coastal dune ecosystems

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  The distribution, spatial clustering, and density of trapdoor spiders in two California coastal dune ecosystems Abstract Coastal dune ecosystems support endemic trapdoor spiders, yet population data for these species are limited. We conducted the first coastal dune trapdoor spider population estimation surveys at Moss Landing State Beach (California) and for Aptostichus stephencolberti Bond 2008 at Sunset State Beach using randomly selected 1m 2 quadrats across ~26,000 m 2 per site. Burrow densities were similar between sites (Sunset: 0.287 burrows/m 2 ; Moss: 0.453 burrows/m 2 ), yielding estimated population sizes of ~35,206 and ~30,959 individuals, respectively. However, spatial analyses revealed contrasting patterns of burrow distribution. At Sunset State Beach, burrow presence was strongly associated with vegetation and occurred closer to plants, despite vegetation being randomly distributed. In contrast, no vegetation–burrow association was detected at Moss Landing, alth...

Desiccation resistance of the spider Sicarius thomisoides (Walckenaer, 1847) (Araneae: Sicariidae) to different temperatures

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Desiccation resistance of the spider Sicarius thomisoides (Walckenaer, 1847) (Araneae: Sicariidae) to different temperatures

Abstract

Desert spiders generally are tolerant or resistant to desiccation, as they must develop strategies to live in high temperatures and prevent continued water loss. However, in extreme conditions, as the temperature increases, their metabolism increases, so they could lose water as the temperature rises. The objective of this work was to determine the effect of temperature on water loss in the spider Sicarius thomisoides. Spiders were subjected to different temperatures: 20 °C, 30 °C and 40 °C. Our results indicate that this spider has excellent resistance to desiccation, since, on average of the three temperatures, losing only 77.25 ± 3.14% of the initial weight at 40 °C, being able to resist extremely high temperatures. In addition, we could not determine a significant effect of body size. Water loss was similar among individuals of different stage of development.

Berríos, C., Martínez, M., & Taucare‐Ríos, A. (2026). Desiccation resistance of the spider <em>Sicarius thomisoides</em> (Walckenaer, 1847) (Araneae: Sicariidae) to different temperatures. Revista Chilena De Entomología, 52(1), 51–58. Retrieved from https://www.biotaxa.org/rce/article/view/88431