Scorpions Use Strongest Defense Mechanisms When Under Attack.sciencedaily.com. November 13, 2013. Scorpions tend to use their strongest defense mechanisms, according to new research published November 13 in the open-access journal PLOS ONE by Arie van der Meijden and colleagues at Centro de Investigação em Biodiversidade e Recursos Genéticos (CIBIO) in Vairão, Portugal. When attacked by a predator, a scorpion can choose to use either its pincers or its venomous stinger to defend itself. The performance of either the pincers (pinch force) or the stinger (venom strength) can depend on scorpion physical characteristics, like size and shape. But the actual mechanism that the scorpion chooses to use when defending itself — it can use the pincers, the stinger, or both — can depend on other evolutionary adaptations, so it’s not clear whether their behavioral responses are actually correlated with maximum performance ability.

The authors here tested this hypothesis by comparing behavioral responses, performance measurements of pincers and stingers, and scorpion physical characteristics in individual scorpions. They found that pinch force and venom strength were highly variable but did correlate with specific physical characteristics of pincers and stingers. Scorpion behavioral defense responses were also highly variable, but importantly, also correlated with both the physical characteristics and performance measurements of pincers and stingers. Scorpions usually selected their strongest defensive behavior; for instance, species with strong pincers more often used their pincers in defense.The researchers conclude that in situations when survival calls for maximum performance, scorpion behavior is correlated with performance. Van der Meijden sums up: "We found clear relationships between shape, performance, and behavior, even when taking their evolutionary history into account. When it comes to defense, it seems scorpions choose their best weapons. I managed to not even get stung once during this research."
Journal Reference: Arie van der Meijden, Pedro Lobo Coelho, Pedro Sousa, Anthony Herrel. Choose Your Weapon: Defensive Behavior Is Associated with Morphology and Performance in Scorpions. PLoS ONE, 2013; 8 (11): e78955 DOI: 10.1371/journal.pone.0078955

Read also related: A New Scorpion Species from Ancient Lycia.sciencedaily.com. November 08, 2013. Scientists discover and describe a new species of scorpion, Euscorpius lycius, coming from the area of ancient Lycia, nowadays the regions of the Muğla and Antalya Provinces in Southwestern Turkey. With the new discovery, the scorpions from this genus found in the country go up to a total of five known species. The study was published in the open access journal ZooKeys.Euscorpius is a genus of scorpions, commonly called small wood-scorpions. As their name suggest these scorpions don’t impress with a large size, the biggest representative being around 5 cm long. The group is widespread in North Africa and across Europe. Euscorpius scorpions are relatively harmless, with poison that has effects similar to a mosquito bite.The new species is named after the historical region of Ancient Lycia, which is referenced in Egyptian and Ancient Greek myths. Like the mystical history of the region the new species is rather secretive and can be found mainly in pine at night hidden away in pine forests, crawling on rocks or sitting on stone garden walls. All localities where the species was found were humid and cool, with calcareous stones covered with moss.The new scorpion is a relatively small representative, reaching a size ranging between two and two and a half centimeters. The color of the adult representatives is pale, between brown and reddish, with pedipalps, or claws, usually darker than the rest of the body."A total of 26 specimens belonging to the new species were collected from Antalya and Muğla Province, in the south-west of Turkey." explains Dr. Yağmur, the lead author of the study. "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."
Journal Reference:Ersen Yagmur, Gioele Tropea, Fatih Yeşilyurt. A new species of Euscorpius Thorell, 1876 (Scorpiones, Euscorpiidae) from south western Turkey.. ZooKeys, 2013; 348: 29 DOI: 10.3897/zookeys.348.5943
A female Euscorpius lycius. (Credit: Ersen Aydın Yağmur; CC-BY 3.0)