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...

Homotypic assortative mating is consistent across temporal scales in the spider Mecynogea lemniscata (Araneidae)

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Homotypic assortative mating is consistent across temporal scales in the spider Mecynogea lemniscata (Araneidae)

Abstract

Identifying patterns of size-assortative mating (SAM) indicates the direction of genetic changes in a population. A reliable method for estimating it in a population is to measure mate assortments within and between breeding seasons¸ as well as describing size variation of males and females between temporal scales to avoid Simpson’s paradox. We assessed sexual size dimorphism, the effects of ontogeny, size differences within each sex, the consistency of SAM within and between seasons, and male mate choice in the spider Mecynogea lemniscata. We collected mating pairs in a Eucalyptus plantation across two breeding seasons and in four periods of the second season. We measured body mass and carapace width of spiders. Males matured earlier than females and guarded subadult partners. Although adults were larger and heavier than subadults, ontogeny did not affect SAM. Females were generally heavier than males in the second season but not in first, but mate assortments were random based on body mass in both seasons. Females showed a smaller carapace width in the first season and a larger one than males in the second season. Despite varying size differences between seasons, SAM remained homotypic based on carapace width across seasons and within the second season. Hence, homotypic SAM was consistent across different temporal scales. Male mate choice was not affected by female size. Unlike other species, temporal variation in the size of M. lemniscata spiders did not disrupt SAM, indicating that a consistent SAM can influence evolutionary changes in body size in this population.
Moura, R. R., Xavier, G. M., De Castro, V. C., Silva, W. D., Valentim, A. M., & Gonzaga, M. O. (2026). Homotypic assortative mating is consistent across temporal scales in the spider Mecynogea lemniscata (Araneidae). Zoologischer Anzeiger. https://doi.org/10.1016/j.jcz.2026.04.009