Evidence of Xysticus ulmi (Hahn) (Araneae: Thomisidae) Predation on Adult Cassida viridis Linnaeus (Coleoptera: Chrysomelidae)

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  Evidence of Xysticus ulmi (Hahn) (Araneae: Thomisidae) Predation on Adult Cassida viridis Linnaeus (Coleoptera: Chrysomelidae) Tortoise beetles (Chrysomelidae: Cassidinae) have several morphological and behavioral antipredator traits. For example, the soft larvae accumulate their feces and exuviae from previous instars to create a so-called “fecal shield” (Engel 1936; Kosior 1975), which functions as a defense against many predator guilds (Eisner and Eisner 2000; Eisner et al. 1968; Vencl et al. 1999, 2005; Vencl and Srygley 2013). Adults are characterized by their explanate and well-sclerotized pronota and elytra, which cover all soft parts of the body, thereby forming a tortoise-shaped shield (Buzzi 1988; Engel 1936; Jolivet 1997; Jolivet and Verma 2002; Selman 1988; Windsor et al. 1992) (Fig. 1A). Furthermore, the adults are known for their ability to grip firmly to surfaces with both tarsal claws and pads, which renders them difficult to capture (Buzzi 1988; Engel 1936; Joliv...

Machine learning approaches to assess microendemicity and conservation risk in cave-dwelling arachnofauna

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Machine learning approaches to assess microendemicity and conservation risk in cave-dwelling arachnofauna

Abstract

The biota of cave habitats faces heightened conservation risks, due to geographic isolation and high levels of endemism. Molecular datasets, in tandem with ecological surveys, have the potential to precisely delimit the nature of cave endemism and identify conservation priorities for microendemic species. Here, we sequenced ultraconserved elements of Tegenaria within, and at the entrances of, 25 cave sites to test phylogenetic relationships, combined with an unsupervised machine learning approach for detecting species. Our analyses identified clear and well-supported genetic breaks in the dataset that accorded closely with morphologically diagnosable units. Through these analyses, we also detected some previously unidentified, potential cryptic morphospecies. We then performed conservation assessments for seven troglobitic Israeli species of this genus and determined five of these to be critically endangered.

Steiner, H.G., Aharon, S., Ballesteros, J. et al. Machine learning approaches to assess microendemicity and conservation risk in cave-dwelling arachnofauna. Conserv Genet (2024). https://doi.org/10.1007/s10592-024-01627-5