Plasma Testosterone Levels Are Related to Various Aspects of Locomotor Activity in Wild-Caught Male Meadow Voles ( Microtus pennsylvanicus)

Abstract

PERROT-SINAL, T. S., D. INNES, M. KAVALIERS AND K.-P. OSSENKOPP. Plasma testosterone levels are related to various aspects of locomotor activity in wild-caught male meadow voles (Microtus pennsylvanicus). Physiol Behav 64(1) 31–36, 1998. The relationship between plasma testosterone levels and locomotor activity in wild-caught sexually mature male meadow voles ( Microtus pennsylvanicus) was assessed in the laboratory. Several aspects of locomotor activity were monitored for 1 h on two consecutive days using the automated Digiscan activity monitoring system. Plasma testosterone levels were determined immediately following the second day of activity monitoring. Significant Pearson correlations were obtained between plasma testosterone levels and total distance traveled [ r(10) = 0.55, p < 0.05] and amount of time spent in movement [ r(10) = 0.55, p < 0.05] on the second day. The wild voles showed a reduction in activity levels from the first to the second day of activity monitoring, which is indicative of habituation to a novel environment. This study provides direct evidence for a significant correlation between laboratory measures of behavioral activity and plasma testosterone levels in a wild-caught rodent. These findings indicate that previous assessments of hormone–behavior relationships in laboratory-bred rodents are consistent with the relationship between hormones and behavior in wild rodents.