Exploration of refuge preference in the Arizona bark scorpion (Scorpiones: Buthidae)

The ongoing difficulty in understanding how Centruroides sculpturatus (Ewing) uses the built environment has prompted this study in exploring refuge choices in a school environment and in laboratory behavioral assays. Radio telemetry tags were used at an urban site heavily populated with C. sculpturatus to track scorpions for a period of 21 d from 1 to 21 August 2013. Complimentary laboratory work tested scorpions in refuge choice arenas targeting variables of four crevice widths--14.0, 9.3, 7.0, and 4.6 mm--or of a vertical versus horizontal orientation preference. These crevice sizes were picked as a response to crevices being naturally used in the field. Telemetry and observations tallied significant preference for artificial structural harborage. Ninety-five percent of the structure refuge use occurred in hollow block walls. Vegetative harborage, debris, and underground burrows were not selected with any significance compared with each other or structures. Generalized additive models (GAMs) indicated the strongest predictive power from individual preference. The behavioral choice assays yielded a significant preference for the largest of crevice widths offered, 14.0 mm and to a lesser extent 9.3 mm, both horizontally and vertically. GAMs for these assays indicated size as the strongest predictive factor in choices. The orientation tests and GAMs showed individual preference driving choice favoring vertical planes. Observations about negative geotaxis in assay and refuge use details from the field are also reported.