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

Posted by
  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...

Identification and testing of sex pheromone components of the invasive Australian redback spider (Lactrodectus hasseltii)

Posted by

 

By Toby Hudson - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=18357388

Identification and testing of sex pheromone components of the invasive Australian redback spider (Lactrodectus hasseltii)

Abstract

Australian redback spiders Latrodectus hasseltii, known for their strong neurotoxic venom, are a quarantine threat for much of the world. Female redback spiders produce a sex pheromone that attracts males of the species, yet the compounds involved in their attraction remain unresolved. Our project set out to identify these compounds and use them to trap male redback spiders as the first step in the development of a pest management/surveillance tool for these spiders. Headspace volatiles from the silk of virgin and mated female redback spiders was collected by solid phase microextraction and analysed by gas chromatography coupled with mass spectrometry. Silk samples were also solvent extracted for analysis by liquid chromatography coupled with mass spectrometry. Comparison with synthetic standards on multiple column phases identified the candidate volatile pheromone components as 2-methylpropanoic acid, (S)-2-methylbutanoic acid and 2-pyrrolidone, while N-3-methylbutanoyl-O-(S)-2-methylbutanoyl-L-serine was identified as the main candidate short-range cue. Bioassays with a combination of these four compounds showed similar levels of attraction to the natural virgin female’s silk. Field trapping trials using a mixture of all four compounds successfully trapped male redback spiders in New Zealand vineyards.

Twidle, A.M., Sullivan, T.E.S., Arahanga, M.T. et al. Identification and testing of sex pheromone components of the invasive Australian redback spider (Lactrodectus hasseltii). Sci Rep (2026). https://doi.org/10.1038/s41598-026-49837-w