Hunting ecology predicts eye arrangements in the modular visual system of spiders

  Hunting ecology predicts eye arrangements in the modular visual system of spiders Summary Vision is one of the most important senses used by animals and contributes to fundamental behaviors, including foraging, navigation, and mate detection and selection. 1 Although much is known about how eye position and orientation correlate to ecology in the context of binocularity, 2 animals with multipartite visual systems (more than two eyes) remain comparatively neglected. Spiders are highly successful predators that occupy a range of ecological niches and usually possess eight eyes. Here, we use three-dimensional geometric morphometrics and evolutionary modeling to test whether eye positions, orientations, and interocular angles correlate with hunting strategies in 52 species across the spider phylogeny. We demonstrate that eye configurations diversified from an ancestral medial cluster, as seen in modern trapdoor spiders, to a halo-like configuration in orb-weavers, and to the fronta...

Neurotoxicity of Sri Lankan Krait (Bungarus ceylonicus) and Common Krait (Bungarus caeruleus) Venoms and Their Neutralisation by Commercial Antivenoms In Vitro

 


Neurotoxicity of Sri Lankan Krait (Bungarus ceylonicus) and Common Krait (Bungarus caeruleus) Venoms and Their Neutralisation by Commercial Antivenoms In Vitro

Abstract

The common krait (Bungarus caeruleus) and the endemic Sri Lankan krait (B. ceylonicus) are two species of krait responsible for envenomings in Sri Lanka that result in progressive neuromuscular paralysis. We characterised the in vitro neurotoxicity of B. ceylonicus and B. caeruleus venoms and studied their neutralisation by two commercially available Indian polyvalent antivenoms (i.e., VINS and BHARAT), Thai banded krait antivenom and Australian polyvalent antivenom using the chick biventer cervicis nerve-muscle preparation. Both venoms displayed concentration-dependent neurotoxicity, showing equipotent pre-synaptic neurotoxicity at 0.03 μg/mL. At a higher concentration (1 μg/mL), both venoms showed post-synaptic neurotoxicity, with B. ceylonicus venom being more potent. VINS was unable to neutralise the neurotoxicity of B. ceylonicus venom, but neutralised both pre- and post-synaptic neurotoxicity of B. caeruleus venom. BHARAT neutralised in vitro pre- and post-synaptic activity of both B. ceylonicus and B. caeruleus venoms. Banded krait antivenom and Australian polyvalent antivenoms were unable to fully neutralise the neurotoxicity of either venom at tested concentrations. In conclusion, B. ceylonicus venom shows pre- and post-synaptic neurotoxicity similar to B. caeruleus venom. BHARAT effectively neutralises both pre- and post-synaptic neurotoxicity of B. ceylonicus venom. Both Indian polyvalent antivenoms effectively neutralise neurotoxicity induced by B. caeruleus venom.

Galappaththige, J., Isbister, G. K., Maduwage, K., Hodgson, W. C., & Silva, A. (2025). Neurotoxicity of Sri Lankan Krait (Bungarus ceylonicus) and Common Krait (Bungarus caeruleus) Venoms and Their Neutralisation by Commercial Antivenoms In Vitro. Toxins, 17(9), 439. https://doi.org/10.3390/toxins17090439