Evidence of female pheromonal signaling in Paruroctonus utahensis

Those of us that have kept scorpions of both sexes have seen how males sometimes react quite strongly  when touching substrate that previously has been visited by a female. Matthew Taylor and co-workers have now published an interesting study presenting evidence for the existence of a highly stable female pheromone in Paruroctonus utahensis (Williams, 1968) (Vaejovidae) with low polarity. This is an important step in our understanding of how chemical communication guides male scorpion mate-searching behavior.

Abstract:
Behavioral evidence suggests that, in some scorpion species, females deposit a pheromone that attracts mates. To date, however, no pheromone has been identified. The goal of our study was to isolate a pheromone from female desert grassland scorpions, Paruroctonus utahensis (Williams, 1968) (Scorpiones:Vaejovidae). We took in situ cuticular washes from female P. utahensis in a chloroform-methanol solution; the extract stratified into aqueous and organic layers. In controlled laboratory experiments, most males exposed to female extract (aqueous and organic fractions combined) exhibited pre-courtship behavior, whereas those exposed to the solvent control (2:1 chloroform-methanol) showed no change in behavior. When extract fractions were separately tested, males initiated pre-courtship behavior when exposed to the organic fraction but not when exposed to the aqueous fraction. These data are the first experimental evidence of a  female pheromone in this species and are important early steps toward characterizing any scorpion pheromone.

Reference:
Taylor MS, Cosper CR, Gaffin DD. Behavioral evidence of pheromonal signaling in desert grassland scorpions Paruroctonus utahensis. J Arachnol. 2012;40(2):240-4. [Free full text]