Two new arthropod toxins purified from the venom of the Mexican scorpion Centruroides nigrescens

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  Two new arthropod toxins purified from the venom of the Mexican scorpion Centruroides nigrescens Abstract The venom of the slender black scorpion Centruroides nigrescens , from the State of Guerrero México, was fractionated by Sephadex G–50 gel filtration, followed by carboxymethyl cellulose ion separation and high–performance liquid chromatography, permitting to obtain two new peptides toxic to arthropods. The estimate LD 50 of the soluble venom for the insect Acheta domesticus was 11.1 μg/g body weight, and for the arthropod Armadillidium vulgare was 61.1 μg body weight . The amino acid sequence of toxin Cnige1 (toxic to A. domesticus and A. vulgare ) contains 65 amino acids, with a molecular mass of 7273.37 mass units, whereas toxin Cnige2, toxic to A. domesticus , contains 68 amino acids, with a molecular mass of 7548.81 units. Both peptides are well packed, containing 8 cysteines, which in the native venoms are forming 4 disulfide bridges each. The amino acid sequences f...

A bionomic overview of spider parasitoids and pseudoparasitoids of the ichneumonid wasp subfamily Pimplinae

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A bionomic overview of spider parasitoids and pseudoparasitoids of the ichneumonid wasp subfamily Pimplinae

Abstract


The parasitoid way of life (parasitizing and finally killing a single arthropod host) is one of the most successful lifeways in the animal kingdom, sparking an explosive diversification and accompanying numerous parasitoid strategies in insects, especially in the order Hymenoptera. Amongst parasitoid wasps, the Polysphincta group of genera has evolved a highly distinctive parasitoid mode of life, as solitary koinobiont ectoparasitoids of spiders (Chelicerata: Araneae). Some species of polysphinctine wasps have a remarkable ability to control spiders’ web-building behaviour (host web manipulation) to protect the vulnerable wasp cocoons. The group currently consists of 25 genera and 294 extant species worldwide, with 14 genera known to manipulate their host spiders. This study reviews the current species composition, distribution, host utilization and biology of all genera belonging to the Polysphincta group and their ancestral genera of spider egg mass pseudo-parasitoids, highlighting specific offensive approaches for subjugating spider hosts for oviposition and web manipulation against specific spider hosts. There must still be many more unique behaviours to be discovered, given that the life histories of several polysphinctine genera are poorly known or unknown. A tidy correspondence between lineages of polysphinctines and host spiders was recognized, implying the evolutionary history of polysphinctines. Based on the integrated information on behavioural data and host utilization, we suggest some hypotheses determining triggers for host shifts and discuss the possibility of adaptive radiation driven by divergent natural selection on host differentiation. One new taxonomic change is proposed: Zaglyptus idukkiensis (Manjusha, Sudheer & Ghosh, 2019), comb. nov., is transferred from Polysphincta.

Takasuka, Keizo, and Gavin R. Broad. "A bionomic overview of spider parasitoids and pseudo-parasitoids of the ichneumonid wasp subfamily Pimplinae", Contributions to Zoology (published online ahead of print 2024), doi: https://doi.org/10.1163/18759866-bja10053