Living underground: first record of myrmecophily in a species of tarantula (Mygalomorphae: Theraphosidae: Catumiri Guadanucci, 2004)

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  Living underground: first record of myrmecophily in a species of tarantula (Mygalomorphae: Theraphosidae: Catumiri Guadanucci, 2004) Abstract Myrmecophily is widespread among arthropods but remains poorly documented in spiders, particularly in Mygalomorphae. Tarantulas (Theraphosidae) have not previously been shown to form true myrmecophilous associations, with existing records limited to anecdotal observations. Here, we provide the first robust evidence of myrmecophily in a tarantula, based on combined field and experimental data. Fieldwork in the Ñacuñán Biosphere Reserve (Monte Desert, Argentina) revealed that individuals of a species of Catumiri Guadanucci 2004 inhabit nests of the leaf-cutting ant Acromyrmex lobicornis Emery 1887. Of 45 excavated nests, 16 (35.5%) contained spiders, with a total of 69 individuals recorded. The presence of multiple developmental stages, including early instars cohabiting with adult females, indicates that reproduction and early development ...

Evaluation of the therapeutic window of commercial antivenoms against neurotoxicity induced by Bungarus ceylonicus and Bungarus caeruleus venoms in the chick-biventer cervicis model

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Evaluation of the therapeutic window of commercial antivenoms against neurotoxicity induced by Bungarus ceylonicus and Bungarus caeruleus venoms in the chick-biventer cervicis model

Abstract

Krait (Genus: Bungarus) envenoming is characterised by progressive neuromuscular paralysis. In Sri Lanka, the absence of a species-specific antivenom for envenoming by the endemic Sri Lankan krait (Bungarus ceylonicus) necessitates reliance on Indian polyvalent antivenoms, despite limited evidence of their efficacy. This study investigated the time window during which commercial Indian (BHARAT, VINS) and Australian polyvalent (Seqirus) antivenoms can prevent neurotoxicity induced by Sri Lankan Krait (B. ceylonicus) and Common Krait (Bungarus caeruleus) venoms using the chick biventer cervicis nerve–muscle preparation. Venoms were added at concentrations producing either predominantly pre-synaptic or post-synaptic neurotoxicity, and antivenoms were added 30 or 90 min after venom exposure. When added after venom, all antivenoms showed a consistent, time-dependent decline in efficacy against pre-synaptic neurotoxicity, with only partial prevention when added after 30 min and complete failure when added after 90 min. In contrast, post-synaptic neurotoxicity remained more amenable to neutralisation after a delay; BHARAT partially prevented post-synaptic effects of both venoms at 30 min, while VINS fully prevented post-synaptic neurotoxicity of B. caeruleus at the same time point. These findings support the hypothesis that pre-synaptic toxins rapidly enter motor nerve terminals, limiting antivenom access and reversibility, whereas the effects of post-synaptic toxins are more readily reversible due to their extracellular mode of action.
Galappaththige, J., Hodgson, W. C., Maduwage, K., Isbister, G. K., & Silva, A. (2026). Evaluation of the therapeutic window of commercial antivenoms against neurotoxicity induced by Bungarus ceylonicus and Bungarus caeruleus venoms in the chick-biventer cervicis model. Toxicon, 109258. https://doi.org/10.1016/j.toxicon.2026.109258