SIZE OR SYMMETRY - AN EXPERIMENT TO DETERMINE WHICH OF THE 2 ACCOUNTSFOR MATING SUCCESS IN MALE MIDGES

It has repeatedly been demonstrated that size, or its correlates, dete rmine the mating success of male animals. Recently a second character, fluctuating asymmetry, has been identified as important in this regar d. Thus, there may be two components to success for the male, size and symmetry. The question is the relative importance of the two. Here an experiment is described, designed to address this question. The midge Chironomus plumosus L. is the test organism. Swarms of males in the w ild were manipulated to increase the average wing asymmetry of the swa rm. An unmanipulated swarm provided a control. By this means the effec ts of size and fluctuating asymmetry were uncoupled. The outcome is th at symmetry alone appears sufficient to account for mating success amo ng males of this midge.