Some context

My stay in Colombia was a great opportunity to experience neotropical fauna and flora for the first time in the wild. After long hours of working with butterflies, I would often head to the forest at night. Lit by the faint glow of a UV flashlight, I spent countless hours looking for scorpions. I eventually found some — and it turned out that my little patch of forest hosted two undescribed species. Remarkably, disturbing one of these scorpions had me realise that it was capable of venom spraying, a behaviour only known from two other genera. I characterized this behaviour, compared it to previous data, and described both species.

To compare the new species to other spraying scorpions, I recorded venom squirting behaviour in 10 specimens using high-speed video. After extracting initial projection velocities, heights and angles from the video data, it is relatively easy to reconstruct full trajectories according to:

With initial height hi​, initial angle θi​ and initial velocity $v$.

Main findings:

Published at the Zoological Journal of the Linnean Society

• Tityus (Tityus) achilles employs two types of remote defenses (single droplet or continuous stream) with distinct velocities, ranges, and volumes.
  

• Venom can be delivered at a distance of up to 35 cm, targeting the sensitive tissues (eyes, respiratory systems) of a potential predator
  

• Venom spraying behaviour is associated with comparatively light stimuli VS. other venom-spraying scorpions
  

• Overall, the venom expenditure strategy of the new species is markedly different to that of other spitting scorpions, with a large reserve of metabolically inexpensive secretion used for airborne delivery
  

• The convergent evolution of venom squirting in scorpions may be underpinned by very different selection pressures