Abstract
Previous laboratory studies of the lizard
Anolis sagrei have suggested that the alternating pattern of hemipenis use in males may serve to increase sperm transfer if a male copulates at least once a day. In this study, the copulation frequency and pattern of hemipenis use of males housed individually in a seminatural enclosure with different numbers of females was monitored. Behavioural observations began 4 days after the animals were placed into the enclosure. In the first experiment, males were housed individually with three females and were observed during the 12-h light phase for each of 3 consecutive days. In a second experiment, males were housed individually with either one or six females and were observed during the 12-h light phase of 1 day. Males housed with three females copulated at least twice a day for each of the 3 observation days and showed a highly significant alternating pattern of hemipenis use. Males housed with a single female copulated less frequently than did males that were housed with three or six females. These results suggest that male
A. sagrei in the field may copulate with a sufficient frequency to make alternation of hemipenis use of adaptive value in terms of sperm transfer.
