Territory quality,male quality,courtship intrusions,and female nest-choice in the threespine stickleback, Gasterosteus aculeatus

In a recent study (Sargent & Gebler 1980), we allowed male sticklebacks to compete for a limited number of clay flowerpots as nest sites in circular wading pools. Although the males who nested in post enjoyed higher reproductive success (Sargent & Gebler 1980), a further analysis of these data revealed the males in these two classes did not differ significantly with regard to territory size, total courtships, and female rejections of the nest. In the present study, for the first half of the experiment, flowerpots were assigned randomly to half of the males nesting in wading pools; the pots were later taken from those males who first had them and were given to the remaining males for the second half of the experiment. Using paired comparisons, each male's performance was examined with and without a flowerpot. The males received more female nest-choices, and fewer intrusions from other males, when their nests were in flowerpots; however, the females appeared to engage in courtships with males independently of the males' nest site concealment. For the two classes of nest site concealment, the males were not significantly heterogeneous for the number of nest-choices that they received: thus male quality did not appear to directly affect female nest-choice. These results suggest that territory quality, in the form of nest site concealment, was the most important determinant of female nest-choice and male reproductive success in the experiments of Sargent & Gebler (1980). Females appear to minimize the risk of egg-cannibalism by spawning with those males who experience the least amount of courtship interference.