Selection of a conspicuous male genitalic trait in the seedbug Lygaeus simulans

摘要

Phenotypic selection of a male genitalic trait based on insemination success in the seedbug Lygaeus simulans, Deckert 1985, was demonstrated in this study. In a laboratory experiment, 97 pairs of virgin animals copulated once. The females consisted of six groups of full sisters, all sisters of a group having been raised in the same box. Related females were used in order to lower the variance of female preferences and to thereby increase the chances of detecting selection of male traits by female choice. The males were independent, i.e. each male descended from a unique pair of parents. Multiple regressions of insemination success on linear and nonlinear terms of a male genitalic trait (processus gonopori length) and male weight revealed stabilizing selection on the genitalic trait. According to functional considerations this selection is most probably the result of female choice of male processus length.