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...

Environmental adaptation and functional diversity of calcin peptides from the venom of East Asian scorpions

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Environmental adaptation and functional diversity of calcin peptides from the venom of East Asian scorpions

Abstract

Toxins as naturally occurring hazardous substances, have evolved as a defense mechanism in organisms for survival. The expression of toxins is profoundly influenced by environmental factors, and the investigation of their correlation holds significant implications for understanding toxin-induced harm and developing protective measures. Scorpions are a significant venomous species, and the relationship between the variability in scorpion toxin expression and environmental factors remains unclear. By conducting transcriptome profiling of scorpion samples collected from eight distinct climatic and environmental regions in East Asia, we successfully identified two distinct scorpion species. Furthermore, we found that the divergence in toxin composition, specifically the expression of two recently discovered calcins are closely aligned with the environmental humidity of their respective habitats. These calcins exhibited varying capacities to modulate the binding affinity of [3H]ryanodine to ryanodine receptors, inducing prolonged subconductance states. Our findings demonstrate that the distinct toxin arsenals of these scorpions reflect long-term adaptive evolution to their specific climatic niches. This study underscores the importance of considering ecological factors in understanding the evolutionary diversification of venomous species, providing a theoretical foundation for the rational exploration of natural toxins in traditional Chinese medicine and drug discovery.
Hua, X., Yang, Z., Xiao, L., Gao, S., Yang, F., Tao, B., Wang, Y., Wang, J., Valdivia, C. R., Chen, W., Jiang, W., Sun, H., Wu, D., Pozzolini, M., Chen, L., Valdivia, H. H., & Xiao, L. (2026). Environmental adaptation and functional diversity of calcin peptides from the venom of East Asian scorpions. Ecotoxicology and Environmental Safety, 310, 119781. https://doi.org/10.1016/j.ecoenv.2026.119781