Great Basin Naturalist


An investigation to elucidate some facets of the biology and ecology of Paruroctonus boreus (Girard), in southeast Idaho, was conducted from 21 March to 13 October 1972. Three hundred and eighty-five observations were made on 202 scorpions captured in covered pitfalls and by ultraviolet light.

The greatest activity occurred at 2130 hours. Surface activity was not observed when ambient temperature was below 10 C, and, as ambient temperature increased, an increase in surface activity was noted. Male scorpions frequently moved as much as 30 m between observations, while females seldom moved more than five m.

Sex ratios varied considerably depending on time of year and method of sampling. Of 142 scorpions observed by blacklight, 92 were males, and 50 were females (1.84 males/female). Limited data suggest a mean litter size of 34 ± 11.