Ecology

Investigators from Edith Cowan University Release New Data on Zoology

  2012 MAY 18 - (VerticalNews.com) -- According to the authors of a study from Perth, Australia, "Studies of locomotor performance often link variation in morphology with ecology. While maximum sprint speed is a commonly used performance variable, the absolute limits for this performance trait are not completely understood."

  "Absolute maximal speed has often been shown to increase linearly with body size, but several comparative studies covering a large range of body sizes suggest that maximal speed does not increase indefinitely with body mass but rather reaches an optimum after which speed declines. Because of the comparative nature of these studies, it is difficult to determine whether this decrease is due to biomechanical constraints on maximal speed or is a consequence of phylogenetic inertia or perhaps relaxed selection for lower maximal speed at large body size. To explore this issue, we have examined intraspecific variations in morphology, maximal sprint speed, and kinematics for the yellow-spotted monitor lizard Varanus panoptes, which varied in body mass from 0.09 to 5.75 kg. We show a curvilinear relationship between body size and absolute maximal sprint speed with an optimal body mass with respect to speed of 1.245 kg. This excludes the phylogenetic inertia hypothesis, because this effect should be absent intraspecifically, while supporting the biomechanical constraints hypothesis. The relaxed selection hypothesis cannot be excluded if there is a size-based behavioral shift intraspecifically, but the biomechanical constraints hypothesis is better supported from kinematic analyses. Kinematic measurements of hind limb movement suggest that the distance moved by the body during the stance phase may limit maxi-mum speed," wrote C.J. Clemente and colleagues, Edith Cowan University.

  The researchers concluded: "This limit is thought to be imposed by a decreased ability of the bones and muscles to support body mass for larger lizards."

  Clemente and colleagues published the results of their research in Physiological and Biochemical Zoology (Optimal Body Size with Respect to Maximal Speed for the Yellow-Spotted Monitor Lizard (Varanus panoptes; Varanidae). Physiological and Biochemical Zoology, 2012;85(3):265-273).

  For additional information, contact C.J. Clemente, Edith Cowan University, Sch Mkt Tourism & Leisure, Perth, WA 6009, Australia.

  The publisher of the journal Physiological and Biochemical Zoology can be contacted at: Univ Chicago Press, 1427 E 60TH St, Chicago, IL 60637-2954, USA.

  Keywords: City:Perth, Country:Australia, Region:Australia and New Zealand, Chemistry

  This article was prepared by VerticalNews Ecology, Environment & Conservation editors from staff and other reports. Copyright 2012, VerticalNews Ecology, Environment & Conservation via VerticalNews.com.