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...

Arthropod-related vehicle collisions increase harvestmen populations along road verges

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Arthropod-related vehicle collisions increase harvestmen populations along road verges

Abstract

The expansion of road networks has been instrumental in facilitating human mobility and economic development. However, this infrastructure presents significant challenges to ecological systems. While most research focusses on the ecology of vertebrates, the potential effects on invertebrates remain understudied. This study investigated the impact of roads on the abundance and diversity of ground-dwelling arthropods, specifically harvestmen (Arachnida: Opiliones) and ground beetles (Coleoptera: Carabidae). The results showed that the distance from the road positively influenced the abundance (but not diversity) of beetles, while both the abundance and diversity of the harvestmen were highest near the roads. Further analysis revealed that dead insects were significantly more common near high-speed road sections compared to low-speed sections, probably due to increased road collisions. The abundance of harvestmen (but not beetles) was significantly affected by the presence of dead insects. Mediation analysis showed that high speed roads influence harvestmen abundance indirectly through its effect on dead insects abundance. It seems that the carabid beetles avoided the high-speed sections of the roads. Our findings suggest that roads causes mortality of flying insects via collisions but also serve as an important food source for scavengers such as harvestmen. Thus, road collisions with arthropods generate conditions similar to those observed for vertebrate scavengers feeding on roadkill.
Litavský, J., Prokop, P., Majzlan, O., & Žarnovičan, H. (2025). Arthropod-related vehicle collisions increase harvestmen populations along road verges. Acta Oecologica, 128, 104114. https://doi.org/10.1016/j.actao.2025.104114