An investigation of the defensive behaviors of the southern unstriped scorpion, Vaejovis carolinianus

 In the last decade there have been several studies looking into sting use and venom use in scorpions in relation to prey capture and defense. Venom metering in scorpions has been well documented, but few studies have focused on the other behavioral options a scorpion has in regard to prey capture or defense.

David Nelson and co-workers have now published a study on the defensive behaviors of Vaejovis carolinianus (Beauvois, 1805) (Vaejovidae) with regards to the scorpion's assessment of risk and refuge availability. The study concludes that V. carolinianus can assess risk and features of the local environment and, therefore, alter their defensive strategies accordingly.

Abstract:
Selection should favor individuals that acquire, process, and act on relevant environmental signals to avoid predation. Studies have found that scorpions control their use of venom: both when it is released and the total volume expelled. However, this research has not included how a scorpion’s awareness of environmental features influences these decisions. The current study tested 18 Vaejovis carolinianus scorpions (nine females and nine males) by placing them in circular arenas supplied with varying numbers (zero, two, or four) of square refuges and by tracking their movements overnight. The following morning, defensive behaviors were elicited by prodding scorpions on the chelae, prosoma, and metasoma once per second over 90 s. We recorded stings, venom use, chelae pinches, and flee duration. We found strong evidence that, across all behaviors measured, V. carolinianus perceived prods to the prosoma as more threatening than prods to the other locations. We found that stinging was a common behavior and became more dominant as the threat persisted. Though tenuous, we found evidence that scorpions’ defensive behaviors changed based on the number of refuges and that these dierences may be sex specific. Our findings suggest that V. carolinianus can assess risk and features of the local environment and, therefore, alter their defensive strategies accordingly.

Reference:
Nelsen DR, David EM, Harty CN, Hector JB, Corbit AG. Risk Assessment and the Effects of Refuge Availability on the Defensive Behaviors of the Southern Unstriped Scorpion (Vaejovis carolinianus). Toxins. 2020;12(9). [Open Access]