Scorpion Choose Most Effective Weapons
November 14, 2013

Scorpions Choose Their Weapons Wisely

Brett Smith for - Your Universe Online

Equipped with sharp pincers and a stinging, venomous tail – scorpions are not a creature to be trifled with. While the size and strength of these weapons vary from one species to another species, the dangerous arachnids tend to use their most effective means of attack or defense when provoked, according to a new study in the journal PLOS One.

The use of either the pincers or the stinger can depend on a scorpion’s physical makeup, and the study researchers said they wanted to see if scorpions’ behavioral responses are correlated with the maximum performance ability of each weapon.

In the study, a team of Portuguese and French researchers compared behavioral responses, performance capacities of pincers and stingers and scorpion physical characteristics for “26 scorpion species [that] were selected to represent a broad range of… morphologies based on their availability,” the study authors wrote in their report.

The study team discovered that pinch force and venom strength varied highly between species and did correlate with the physical characteristics of pincers and stingers. While the scorpions’ defense responses were also highly variable, they did correlate with both the physical appearance and performance of pincers and stingers – meaning the scorpions more often chose their strongest defensive behavior. For example, the most venomous scorpions used their stingers more often than their pincers for defense.

"We found clear relationships between shape, performance, and behavior, even when taking their evolutionary history into account,” said study author Arie van der Meijden, from Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO) in Vairão, Portugal. “When it comes to defense, it seems scorpions choose their best weapons. I managed to not even get stung once during this research."

Last week, a team of Turkish and Italian researchers described a new scorpion species they discovered in southwestern Turkey in a report published by the journal Zookeys. Measuring only about an inch in length, the new species was dubbed Euscorpius lycius and is mostly harmless to humans – with their stingers causing about the same effect as a mosquito bite, the researchers said.

The international team said they gathered about 26 specimens of the new species in humid and shady places such as mossy walls and underneath stones. Adults of the new species range from a pale brown to light reddish color, with pinchers that are darker in coloration.

The new species makes five in the Euscorpius genus, a group of small scorpions common to North Africa and parts of Europe. In total, scientists have described over 1,700 species of scorpions, which can be found on every continent except Antarctica.

"Further studies are in progress to understand the quantity and distribution of the different species and populations of the genus Euscorpius in Turkey and their relationship with the Greek populations," said study author Ersen Yagmur of Celal Bayar University in Turkey.

Because scorpions glow when exposed to ultraviolet light, a hand-held UV lamp has long been a standard tool of biologists for nocturnal field surveys of these arachnids. This fluorescence is a byproduct of the process that forms the scorpions’ exoskeleton and each successive stage of that development brings about an increase in intensity.