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...

Delayed Cannibalism in the Litter-Dwelling Scorpion Mesotityus pusillus (Pocock, 1893) (Scorpiones, Buthidae): Evaluating Kin Recognition as a Possible Explanation

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Delayed Cannibalism in the Litter-Dwelling Scorpion Mesotityus pusillus (Pocock, 1893) (Scorpiones, Buthidae): Evaluating Kin Recognition as a Possible Explanation

Abstract

The small size and limited defensive capacity are factors responsible for the high mortality of juveniles. Thus, offspring recognition is an important trait for juvenile survival, especially in generalist predators. In this study, we investigated aspects related to offspring discrimination in females of the scorpion Mesotityus pusillus. A total of 172 juveniles from 32 females were divided into two groups: females with their own offspring and females with unrelated juveniles. Predation events were recorded daily for 20 days. Predation occurrence and the proportion of juveniles consumed did not differ significantly between groups. Females with their own offspring tended to take longer to initiate predation than females exposed to unrelated juveniles, although this difference was not statistically significant. Our results reveal differences in the timing of cannibalistic behavior without providing clear evidence for consistent avoidance of cannibalism. While kin recognition cannot be excluded as a possible explanation, alternative mechanisms, such as familiarity, prior association, or environmental cues, may also contribute. These findings highlight a potential role of temporal offspring discrimination in shaping cannibalistic behavior, which may influence juvenile survival and reproductive success in M. pusillus.

Rodríguez-Medina, L.S., de Araujo Lira, A.F. & Pordeus, L.M. Delayed Cannibalism in the Litter-Dwelling Scorpion Mesotityus pusillus (Pocock, 1893) (Scorpiones, Buthidae): Evaluating Kin Recognition as a Possible Explanation. J Insect Behav 39, 20 (2026). https://doi.org/10.1007/s10905-026-09915-3