Biochemical characterisation and substrate-specific proteolytic diversity of venom metalloproteinases in African puff adders

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  By 4028mdk09 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11200575 Biochemical characterisation and substrate-specific proteolytic diversity of venom metalloproteinases in African puff adders Abstract The puff adder ( Bitis arietans ) is a highly venomous viper responsible for many snakebite fatalities in Africa, yet there have been few geographically comprehensive analyses of its venom proteins, particularly of the proteases that play a key role in pathology of envenoming. To address this, we have isolated, identified and characterised the bioactivity of the venom metalloproteases of puff adders obtained from a range of localities. Prominent in all venoms was a PI snake venom metalloproteinase (SVMP), derived from a larger PII precursor. This protein existed as either non-glycosylated (21 kDa) or glycosylated, the latter containing either one (26 kDa) or two N-glycans (30 kDa). All the venoms we tested contained either one or the other form: none had...

Thieves and freeloaders: Argyrodine kleptoparasites invading cobwebs (Theridiidae) in the arid south-western USA

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Thieves and freeloaders: Argyrodine kleptoparasites invading cobwebs (Theridiidae) in the arid south-western USA

Abstract

Obligate argyrodine kleptoparasites (Theridiidae, Araneae) exploit heterospecific spider webs for food and shelter. Argyrodine spiders are a model lineage for the study of kleptoparasitism and related strategies, yet data on the behaviour of the majority of the over 250 argyrodine species is lacking. Here, we help fill that knowledge gap by documenting the natural history of two poorly-known species. We studied Argyrodes pluto and Neospintharus baboquivari in the webs of two other cobweb spiders, the western black widow (Latrodectus hesperus) and Tidarren sisyphoides, across four sites in southern Arizona. Argyrodes pluto completes its life cycle in L. hesperus webs and specialises on host egg sacs, displacing them to the periphery and feeding on eggs and juveniles; this behaviour appears essential for its reproduction. Neospintharus baboquivari occurs gregariously in both host webs, gleaning small prey. In contrast, N. baboquivari is reportedly a solitary araneophage in the colonial orb webs of Philoponella oweni. We quantified egg sac displacement and describe foraging, mating, egg sac construction and interactions with parasitoids and predators. These findings reveal novel natural history information and expand our understanding of argyrodine behavioural plasticity.

Cowles J, Agnarsson I (2025) Thieves and freeloaders: Argyrodine kleptoparasites invading cobwebs (Theridiidae) in the arid south-western USA. Biodiversity Data Journal 13: e172851. https://doi.org/10.3897/BDJ.13.e172851