A study of female and male mating behavior and female mate choice in the sharp-tailed grouse, Tympanuchus phasianellus jamesi
Abstract
The mating behavior of sharp-tailed grouse was studied at four leks from 1983 to 1986 in southeastern Montana to (a) describe female behavior, (b) determine whether females choose mates, tend to aggregate on the lek arena, and/or copy the mating decisions of others, and (c) identify correlates of male mating success that may influence female mating decisions. A mean of from 4.5 to 37.5 females attended each lek. On average, individual females attended a lek four times and visited five different males during the season. Three females attended more than one lek. Evidence that at least some females chose mates includes (a) most females rejected all males but their eventual mate; (b) the few females that solicited and/or mated more than once usually did so with the same male; and (c) some patterns of behavior suggest that females may be sampling males. Inter-female aggressive interactions did not appear to affect mating decisions. Experiments with taxidermic mounts and observations both indicated that females will aggregate. Possible copying behavior included females mating with the male they saw mate most often in 8 of 21 copulations; other tests neither strongly supported nor excluded the possibility that females copied. Territory location, male size, and male behavior, but not male age, were correlated with male mating success. The correlation between proximity of a male's territory to the lek center and mating success was apparently a consequence of the rearragement of territories caused by some males' relocating their territories, and not of female preference for central males. This conclusion challenges the hypotheses of male lek social dynamics that assume female preference based on territory location. Surprisingly, males with shorter wing chord lengths mated more. Mated males also had higher rates of agonistic interactions and lower rates of sitting, standing, and comfort behavior than unmated males. Male display rate was not correlated with mating success, perhaps because males tend to display synchronously in the presence of females. Overall this study provides evidence that female aggregation, copying, mate choice, and male-male competition may simultaneously influence male mating success in lekking species.
Degree
Ph.D.
Advisors
Howard, Purdue University.
Subject Area
Ecology
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