DOES FLUCTUATING ASYMMETRY REFLECT THE IMPORTANCE OF TRAITS IN LITTLEBROWN BATS (MYOTIS-LUCIFUGUS)

Small random deviations from perfect bilateral symmetry define fluctua ting asymmetry, and these deviations reflect an individual's inability to genetically control the development of a particular trait. Natural selection should act to minimize fluctuating asymmetry in traits that are most functionally important to an organism. Temperate-zone bats f orage in night and therefore symmetry of wing bones should be very imp ortant to fitness. Bats use their hind limbs only for hanging in roost s, therefore asymmetry in the main leg bone, the tibia, should not be as significant to a bat's fitness. We predicted that there would be le ss fluctuating asymmetry in the forearms than in the tibia. We measure d the forearms and tibias of 119 little brown bats (Myotis lucifugus), and as predicted, forearm length did show less fluctuating asymmetry than tibia length. This result supports the hypothesis that traits can be ranked in order of functional importance according to the degree o f fluctuating asymmetry found for each.