Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon

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  Beyond Venom and Constriction: Bite Performance and Trophic Ecology in the Genus Drymarchon Abstract Snakes exhibit extreme cranial kinesis that facilitates ingestion of prey with large cross-sectional area, but this ability is widely predicted to reduce bite performance due to decreased structural rigidity. Consequently, most large-bodied snakes rely on envenomation or constriction to subdue prey prior to ingestion. Species within the genus Drymarchon represent a notable exception: these large, non-venomous, non-constricting snakes routinely consume a wide range of prey, including large and potentially dangerous vertebrates, using only simple seizing and pinioning behaviors. Here, we quantify bite performance in three species of Drymarchon ( D. corais, D. couperi, and D. melanurus ), examine morphological predictors of biting performance, compare biting pressure to constriction pressure in similarly sized snakes, and synthesize dietary records across the genus. Our results sh...

Understanding urbanization impacts on spiders’ (Arachnida, Araneae) diversity in Armenia

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Understanding urbanization impacts on spiders’ (Arachnida, Araneae) diversity in Armenia

Abstract

The impact of urbanization on biodiversity has become a prominent area of investigation, highlighting the need for comprehensive research in this field. This study focuses on assessing the variation in spider diversity across an urban landscape (Urban area with gardens, urban without gardens, and city gardens). Our investigation took place in Yerevan City and suburbs with increasing urbanization, where we aimed to elucidate the diversity of spider species along transects extending from the city center to Jrvej suburb area. Through a combination of observational data and specimen collection, we observed a discernible pattern: The total species richness was 111 species belonging to 72 genera, and 21 families. The family Theridiidae had the highest diversity (17 species). The total abundance of spiders was 276, with the highest abundance in the urban zone with a garden (187 specimens). The most abundant species were: Pholcus phalangioides (Fuesslin, 1775) (33 specimens) (Pholcidae), Steatoda paykulliana Walckenaer, 1805 (20 specimens) (Theridiidae), and Oecobius nadiae (Spassky, 1936) (8 specimens) (Oecobidae). The highest diversity of spiders was found in the urban zone with a garden (buildings with a garden) (85 species). During our study, we identified 36 spider species new to Armenian Araneofauna. These findings contribute to the expanding body of knowledge indicating the importance of vegetation cover spaces within urban areas in preserving biodiversity amidst urbanization pressures, based on the spider diversity in pure building and the green areas were less than the mixed habitat in the urban environments.

Zarikian, N. H., Kosyan, A. M., & Marusik, Y. M. (2026). Understanding urbanization impacts on spiders’ (Arachnida, Araneae) diversity in Armenia. Journal of Urban Ecology, 12(1). https://doi.org/10.1093/jue/juaf018