Has male Euscorpius scorpions "date drugs" in their venom?

 

Differences in the venom composition of scorpions have been reported for many tears, both within the same species and between species. In addition, different venom types have been related to different purposes (e.g. the findings of prevenom in some species). 

Sex-specific differences in venom composition have been demonstrated for several arthropod taxa(e.g. in spiders where males of the infamous Sydney funnel web spider has a venom lethal to humans, while the female venom is not dangerous). Less is known about this in scorpions, but many species use sexual stings during courship and it has been suggested that the male venom used for this may sedate females to make them less aggressive.

Jonas Krämer and co-workers have recently published an interesting study analyzing the venom composition of male, female and juvenile Euscorpius italicus (Herbst, 1800) (Euscorpiidae). This species uses sexual sting during courtship. Their study shows that the male venom has marked differences in venom composition from females and juveniles. The authors suggest that this may cause a reduced toxic effect on females during the sexual sting. Other suggested effects may be a reduced agggressivity in females and also physiological effects that improove the success of the mating.

More studies are necessary to understand more about this fascinating connection between venom and courtship behavior.

Abstract:
In the animal kingdom, intraspecific variation occurs, for example, between populations, different life stages, and sexes. For venomous animals, this can involve differences in their venom composition. In cases where venom is utilized in the context of mating, the differences in composition might be driven by sexual selection. In this regard, the genus Euscorpius is a promising group for further research, as some of these scorpions exhibit a distinct sexual dimorphism and are known to perform a sexual sting during mating. However, the venom composition of this genus remains largely unexplored. Here, we demonstrate that Euscorpius italicus exhibits a male-specific venom composition, and we identify a large fraction of the substances involved. The sex specificity of venom peptides was first determined by analyzing the presence/absence patterns of ion signals in MALDI-TOF mass spectra of venom samples from both sexes and juveniles. Subsequently, a proteo-transcriptomic analysis provided sequence information on the relevant venom peptides and their corresponding precursors. As a result, we show that several potential toxin precursors are down-regulated in male venom glands, possibly to reduce toxic effects caused to females during the sexual sting. We have identified the precursor of one of the most prominent male-specific venom peptides, which may be an ideal candidate for activity tests in future studies. In addition to the description of male-specific features in the venom of E. italicus, this study also includes a general survey of venom precursors in this species.

Reference:
Kramer J, Pommerening R, Predel R. Equipped for Sexual Stings? Male-Specific Venom Peptides in Euscorpius italicus. Int J Mol Sci. 2022;23(19). [Open Access]