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...

Shedding light on the embryogenesis and eye development of the troglophile cave spider Tegenaria pagana C. L. Koch, 1840 (Araneae: Agelenidae)

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Shedding light on the embryogenesis and eye development of the troglophile cave spider Tegenaria pagana C. L. Koch, 1840 (Araneae: Agelenidae)

Abstract

Background

Relatively little is known about the diversity of embryonic development across lineages of spiders, even though the study of embryonic development is a primary step in evo-devo studies and essential for understanding phenotypic evolution. Practically nothing is known about embryogenesis in cave-dwelling spiders, animals which play an important role in cave ecosystems and may have remarkable adaptations to aphotic habitats such as loss of eyes.

Results

Here, we describe embryogenesis and study the expression patterns of several genes of the Retinal Determination Network (RDN) in the troglophile (species that have pre-adaptations to life in caves, and can complete their life cycle in caves, as well as in epigean habitats) eye-bearing funnel-web spider species Tegenaria pagana C. L. Koch, 1840, using fluorescent staining and confocal microscopy. We discuss the characteristic features of T. pagana embryogenesis and key RDN genes. Although in many respects the embryonic development of different species of entelegyne spiders is similar, we found differences in the rate of development, and the details of the opisthosoma, respiratory system, and brain morphogenesis in comparison with established spider model species. Our data supports the hypothesis of a conserved role of sine oculis gene in the eye formation of arachnids.

Conclusions

Given the recent discovery of congeneric cave species with different degrees of eye reduction throughout Israel, these data sets provide a foundational point of comparison for studying eye reduction and eye loss events in the spider genus Tegenaria.



Propistsova, E.A., Gainett, G., Chipman, A.D. et al. Shedding light on the embryogenesis and eye development of the troglophile cave spider Tegenaria pagana C. L. Koch, 1840 (Araneae: Agelenidae). EvoDevo 16, 2 (2025). https://doi.org/10.1186/s13227-025-00238-6