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...

Harvestmen (Arachnida: Opiliones) as Overlooked Predators of Anurans in the Neotropics

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Harvestmen (Arachnida: Opiliones) as Overlooked Predators of Anurans in the Neotropics

ABSTRACT

Arthropods are traditionally viewed as invertebrate prey and as predators of other invertebrates, whereas vertebrates are typically considered their predators. However, this paradigm has increasingly been challenged, particularly among arachnids. While several invertebrates are well documented as frog predators, the capacity of particular groups, such as harvestmen (Opiliones), to prey on vertebrates has remained largely anecdotal. Here we report novel field observations of anuran predation by multiple Cranaidae harvestman species across several Neotropical localities. These records include the active capture and consumption of live frogs, demonstrating their role as opportunistic mesopredators. Our findings expand current knowledge of Opiliones ecology by confirming that vertebrate predation occurs across multiple species and localities. Our results suggest that vertebrate consumption among arachnids may be more taxonomically widespread than previously recognized, highlighting the need to consider Opiliones as potential predators in Neotropical trophic networks.

Calvache, E., Villarreal, O., Ávila-Rojas, C., Bentley, A. G., Brito, K., Correa-Zanotti, C., Gutiérrez-Arboleda, M., Iñiguez, K., Narváez, J. C., Proaño, L., Reyes-Vizcaíno, M., & García, L. F. (2026). Harvestmen (Arachnida: Opiliones) as Overlooked Predators of Anurans in the Neotropics. Ecology and Evolution, 16(4), e73542. https://doi.org/10.1002/ece3.73542