Armed stem to stinger: a review of the ecological roles of scorpion weapons

Abstract

Scorpions possess two systems of weapons: the pincers (chelae) and the stinger (telson). These are placed on anatomically and developmentally well separated parts of the body, that is, the oral appendages and at the end of the body axis. The otherwise conserved body plan of scorpions varies most in the shape and relative dimensions of these two weapon systems, both across species and in some cases between the sexes. We review the literature on the ecological function of these two weapon systems in each of three contexts of usage: (i) predation, (ii) defense and (iii) sexual contests. In the latter context, we will also discuss their usage in mating. We first provide a comparative background for each of these contexts of usage by giving examples of other weapon systems from across the animal kingdom. Then, we discuss the pertinent aspects of the anatomy of the weapon systems, particularly those aspects relevant to their functioning in their ecological roles. The literature on the functioning and ecological role of both the chelae and the telson is discussed in detail, again organized by context of usage. Particular emphasis is given on the differences in morphology or usage between species or higher taxonomic groups, or between genders, as such cases are most insightful to understand the roles of each of the two distinct weapon systems of the scorpions and their evolutionary interactions. We aimed to synthesize the literature while minimizing conjecture, but also to point out gaps in the literature and potential future research opportunities.

Can size make a difference? Cross-predation occurrences between lizards and scorpions in the Brazilian seasonal dry tropical forest

“…through the inoculation of toxins via a stinger (Polis, 1990;Lourenço, 2018;Simone, Van der Meijden, 2021). Therefore, due to their venom, scorpions may capture larger-bodied prey as recorded in our study.…”

Can size make a difference? Cross-predation occurrences between lizards and scorpions in the Brazilian seasonal dry tropical forest

“…through the inoculation of toxins via a stinger (Polis, 1990;Lourenço, 2018;Simone, Van der Meijden, 2021). Therefore, due to their venom, scorpions may capture larger-bodied prey as recorded in our study.…”

New Insights on Genetic and Morphological Divergence Among a Buthus Species Complex From Tunisia With the Identification of a New Species

“… 2018 ; Van Der Meijden et al. 2012 ; Simone and Van Der Meijden 2021 ). Regarding the gradient of ornamentation, it seems that Buthus species try to mimic the substrate's hue to make themselves less noticeable to predators.…”

“…Owing to this habitat gradient, scorpion populations are likely to inhabit areas with different prey, predator and competitor communities, which could expose their morphological traits, notably the size of chela, telson, and carapace, to different selective pressures, inducing the evolution of these traits in varied trajectories. Indeed, these body parts are known to be under high selective pressure, because they are used both in defense and hunting purposes (Coelho et al 2018;Van Der Meijden et al 2012;Simone and Van Der Meijden 2021). Regarding the gradient of ornamentation, it seems that Buthus species try to mimic the substrate's hue to make themselves less noticeable to predators.…”

Transcriptomic Analysis Reveals Diverse Expression of Scorpion Toxin Genes in Mesobuthus martensii

“…Scorpion venom, produced by the vesicle, is crucial in predation and defense against external predators [32]. Transcriptome sequencing analysis of 14 M. martensii tissues revealed higher toxin gene expression levels in the vesicle.…”

Can size make a difference? Cross-predation occurrences between lizards and scorpions in the Brazilian seasonal dry tropical forest

“…through the inoculation of toxins via a stinger (Polis, 1990;Lourenço, 2018;Simone, Van der Meijden, 2021). Therefore, due to their venom, scorpions may capture larger-bodied prey as recorded in our study.…”

New Insights on Genetic and Morphological Divergence Among a Buthus Species Complex From Tunisia With the Identification of a New Species

“… 2018 ; Van Der Meijden et al. 2012 ; Simone and Van Der Meijden 2021 ). Regarding the gradient of ornamentation, it seems that Buthus species try to mimic the substrate's hue to make themselves less noticeable to predators.…”

“…Owing to this habitat gradient, scorpion populations are likely to inhabit areas with different prey, predator and competitor communities, which could expose their morphological traits, notably the size of chela, telson, and carapace, to different selective pressures, inducing the evolution of these traits in varied trajectories. Indeed, these body parts are known to be under high selective pressure, because they are used both in defense and hunting purposes (Coelho et al 2018;Van Der Meijden et al 2012;Simone and Van Der Meijden 2021). Regarding the gradient of ornamentation, it seems that Buthus species try to mimic the substrate's hue to make themselves less noticeable to predators.…”

Transcriptomic Analysis Reveals Diverse Expression of Scorpion Toxin Genes in Mesobuthus martensii

“…Scorpion venom, produced by the vesicle, is crucial in predation and defense against external predators [32]. Transcriptome sequencing analysis of 14 M. martensii tissues revealed higher toxin gene expression levels in the vesicle.…”

Can size make a difference? Cross-predation occurrences between lizards and scorpions in the Brazilian seasonal dry tropical forest

“…through the inoculation of toxins via a stinger (Polis, 1990;Lourenço, 2018;Simone, Van der Meijden, 2021). Therefore, due to their venom, scorpions may capture larger-bodied prey as recorded in our study.…”

New Insights on Genetic and Morphological Divergence Among a Buthus Species Complex From Tunisia With the Identification of a New Species

“… 2018 ; Van Der Meijden et al. 2012 ; Simone and Van Der Meijden 2021 ). Regarding the gradient of ornamentation, it seems that Buthus species try to mimic the substrate's hue to make themselves less noticeable to predators.…”

“…Owing to this habitat gradient, scorpion populations are likely to inhabit areas with different prey, predator and competitor communities, which could expose their morphological traits, notably the size of chela, telson, and carapace, to different selective pressures, inducing the evolution of these traits in varied trajectories. Indeed, these body parts are known to be under high selective pressure, because they are used both in defense and hunting purposes (Coelho et al 2018;Van Der Meijden et al 2012;Simone and Van Der Meijden 2021). Regarding the gradient of ornamentation, it seems that Buthus species try to mimic the substrate's hue to make themselves less noticeable to predators.…”

Transcriptomic Analysis Reveals Diverse Expression of Scorpion Toxin Genes in Mesobuthus martensii

“…Scorpion venom, produced by the vesicle, is crucial in predation and defense against external predators [32]. Transcriptome sequencing analysis of 14 M. martensii tissues revealed higher toxin gene expression levels in the vesicle.…”