Inter-individual variability in equine antibody responses to African snake venoms follows heavy-tailed distributions with implications for antivenom production

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  Inter-individual variability in equine antibody responses to African snake venoms follows heavy-tailed distributions with implications for antivenom production Abstract Variability in the antibody response of horses used for snake antivenom manufacture is well recognized, yet its statistical structure and implications for industrial productivity remain poorly characterized. In this study, we quantified antivenom antibody titers by ELISA in a cohort of 14 horses immunized with venoms from the clinically most important snakes in sub-Saharan Africa. To integrate antibody levels with plasma availability, we calculated the Cumulative Plasma Productivity (CPP) by converting individual plasma volumes into titer-corrected equivalents and sequentially pooling these volumes according to their corrected contribution. Distributional analysis revealed right-skewed, heavy-tailed patterns better approximated by a log-normal model than by a strict Pareto (power-law) form, with approximately 20–3...

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