Biology ETDs

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In order to investigate the nature of cold-hardiness in scorpions, adult Paruroctonus aquilonalis collected in August, 1972 near Albuquerque were exposed to ambient conditions of photoperiod and temperature, or to one of several artificial photoperiod-temperature regimes. Four specific laboratory regimes were established to describe the effect of photoperiod duration and temperature on supercooling point level. Conditions of these regimes were (i) constant photoperiod-constant temperature, (ii) constant photoperiod-decreasing temperature, (iii) decreasing photoperiod-constant temperature and (iv) decreasing photoperiod-decreasing temperature. Experimental conditions were either kept constant, or were decreased in increments from simulated summer conditions (26 C and 13-hr 15-min photoperiod) through the fall and winter. Supercooling points of laboratory scorpions ere measured in late October and late December, as were those of naturally exposed scorpions. In naturally exposed summer scorpions females had both significantly lower per gram oxygen consumption and super­cooling points than did males. These results indicated inherent physiological differences between sexes, and were compared with information available for Diplocentrus spitzeri and Centruoides sculpturatus scorpions. Results of supercooling-point determinations of naturally exposed male and female P. aquilonalis indicated that fall super­cooling points were significantly lower than those of the summer, and that they remained so during the winter. Among the October supercooling-point means of the laboratory groups significant differences were found which could be attributed to the lowering effect on supercooling point of decreasing photoperiod and decreasing temperature conditions. These conditions, however, appeared not to depress supercooling points beyond the late fall and likely serve as useful environ­mental cues of approaching winter in natural populations.

Project Sponsors

I appreciate the identification of the scorpion Paruroctonus aquilonalis by Dr. Herbert L. Stahnke, Arizona State University. I also wish to acknowledge the assistance of Mr. Raymond C. Krehoff for his aid in the construction of environmental chambers, and Miss Leola Gonzales for her help in field excavations. I particularly wish to thank Dr. Clifford S. Crawford for his continued professional guidance and encouragement in the completion of this research. This project was supported in part by National Science Foundation grant GB-31602.



Document Type


Degree Name


Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

Clifford Smeed Crawford

Second Committee Member

Donald Walter Duszynski

Third Committee Member

James Roman Gosz

Fourth Committee Member

Marvin LeRoy Riedesel

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