Book Description

The giant hairy desert scorpion, Hadrurus arizonensis, is a long-lived species of North American scorpion that is presented here as an important model for research in mating systems evolution and sexual selection. Many behaviors found in this species were undocumented and are described here for the first time. This thesis includes studies of the following aspects of H. arizonensis behavior: 1) a description of courtship and mating behavior, 2) an empirical study of variance in courtship success among males and females as an indicator of mate choice in both sexes, 3) a descriptive and empirical study of aggression and agonistic behaviors in non-reproductive inter- and intrasexual interactions, and 4) an observational study of intrasexual competition over mates in both males and females. Experiments were performed in the laboratory and behaviors observed were videotaped for data collection and analysis. All subjects used in this study were field-captured prior to use in behavioral experiments. This species exhibits both reproductive and aggressive behaviors that are stereotyped and can be quantified, either by ranking their intensity, or measuring in terms of time. H. arizonensis is a polygamous species with external sperm transfer (via a spermatophore). Both males and females appear to exhibit mate choice. Large females elicit more intense courtship behavior from males, and males may preferentially court larger females to increase their own reproductive success. Furthermore, both males and females interfere in the courtship of conspecific pairs, indicating that both sexes potentially compete intrasexually for mates. Such findings may be attributable to the substantial contributions each sex makes in reproduction. This species also exhibits complex aggressive behaviors during agonistic interactions that may function in both species recognition and competition.