Biology of Reproduction, Vol 22, 237-242, Copyright © 1980 by Society for the Study of Reproduction

Blocked Sexual Receptivity in Grouped Female Golden Hamsters: Independence from Ovarian Function and Continuous Group Maintenance

¹ Department of Biology, Princeton University, Princeton, New Jersey 08544

The block in sexual receptivity resulting from maintaining female hamsters in groups is not dependent upon the presence of ovaries during the period of grouping. Intact female hamsters maintained grouped for 12 h in each 24 h period show a significant fraction of blocked animals; thus continuous 24 h maintenance of the grouped state is not necessary to block sexual receptivity. However, significantly more females grouped during the 12 h light period showed the block than females grouped during the 12 h dark period. Hamsters are nocturnal; thus those grouped during the lights on period spent a significantly greater percentage of time sleeping huddled together. The general body contact which occurs during sleeping may provide the necessary stimulus resulting in blocked sexual receptivity. In addition, the hamsters grouped during the light period displayed a significantly greater amount of ‘tail-pulling’ behavior during which they grab at the tail and hindquarters of other animals and try to pull the animal about. ‘Tail-pulling’ behavior during proestrus is highly effective for induction of a rigid lordotic posture in the animal seized. It is hypothesized that the block in sexual receptivity which is found in grouped females is the result of a purely neural mechanism, the occurrence of habituation to those stimuli which normally are sufficient for induction of the lordotic response.

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ACKNOWLEDGMENTS These studies were support in part by funds from NSF-BSM-75-05720.