Evol Ecol Res 2: 841-855 (2000)     Full PDF if your library subscribes.

Phenotypic variability of physiological traits in populations of sexual and asexual whiptail lizards (genus Cnemidophorus)

Alistair J. Cullum

Department of Ecology and Evolutionary Biology, 321 Steinhaus, University of California, Irvine, CA 92697-2525, USA

Address all correspondence to Alistair J. Cullum, Department of Biology, Creighton University, 2500 California Plaza, Omaha, NE 68178-0103, USA.
e-mail: acullum@creighton.edu


One of the major potential disadvantages to asexual reproduction is believed to be a reduction in phenotypic variability. This study represents an empirical test for such a reduction in the variance of physiological traits in parthenogenetic species of the lizard genus Cnemidophorus. Five performance traits (burst speed, endurance, maximal exertion, standard metabolic rate and evaporative water loss rate) were examined in four asexual species and the sexual species that hybridized to produce them. A phylogenetically controlled analysis revealed less trait variance in asexual species for the first three traits, but no detectable differences between asexual and sexual species for the other two traits. A second analysis examining the average shape of trait distributions in the two types of species suggests that sexual populations produce distributions with more elongate tails than do asexual populations. Thus, part of the reason for increased variance in sexual populations may be a greater tendency for these populations to produce extreme phenotypes.

Keywords: asexuality, Cnemidophorus, genetic variability, locomotion, metabolic rate, phenotypic variability.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2000 Alistair J. Cullum. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.