Evidence of Chemical Signaling in the Sand Scorpion, Paruroctonus mesaensis (Scorpionida: Vaejovida)

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Abstract
This study presents evidence of intraspecific chemical communication in scorpions. The subject of our investigation was the nocturnal sand scorpion, Paruroctonus mesaensis. During the mating season, mature males show a sex‐specific wandering behavior ostensibly directed at locating conspecific females that remain in the vicinity of their home burrows. Searching behavior was stimulated in the laboratory by releasing males onto substrates that had previously been occupied by females. Receptive males exhibited changes in locomotory behavior that favored occupation of the female‐exposed area. Males occasionally displayed a precourtship behavior, called juddering, indicating the presence of a pheromone on the substrate. Juddering, and two newly described behavior patterns, tail‐wagging and pedipalp‐reaching, were also induced by solvent extracts of female cuticle. Most behavioral responses began vigorously within the first few s of stimulus contact and gradually adapted within 10 min. The potential importance of specialized sensory appendages, the pectines, for mediating chemosensitivity is discussed. These results are consistent with the hypothesis that mate identification and localization in sand scorpions are mediated in part by a contact sex pheromone.