McBrayer Lance D, Wylie Jessica E
Department of Biology, PO Box 8042, Georgia Southern University, Statesboro, GA 30460, USA.
Zoology (Jena). 2009;112(5):370-8. doi: 10.1016/j.zool.2009.01.001. Epub 2009 Jun 6.
Foraging behaviors exist along a continuum from highly sedentary, ambush foraging, to more continuous searching, or active foraging. Foraging strategies, or modes, are defined based upon locomotor behaviors (e.g. percent time moving, moves per minute). In lizards, traits correlated with ambush and active foraging have been of interest for some time; however, general patterns of correlated evolution between locomotor morphology and locomotor behavior have only recently begun to be quantified. In this study, variation in hindlimb morphology is investigated in a model group of lizard species that vary between active foraging and more sedentary (or mixed) foraging mode. Canonical variates analysis reveals that the two active foraging species occupy similar regions of the morphospace, while the two more sedentary species occupy different regions. The active foraging species have a narrow pelvis with shorter tibia and femora. The more sedentary species have a wide pelvis, long tibia and femora, and slightly longer metatarsals. Phylogenetic patterns of trait variation were examined through ancestral character state reconstruction and show morphological shifts in concert with foraging mode in these species. The observed shifts in locomotor morphology are discussed in light of published data on sprint speed and endurance in these species. Together, the data show that linking morphological variation to variation in stride length and stride frequency is critical to understanding the evolution of locomotor performance. Much more stride length and frequency data are needed among ambush, mixed, and active foraging species because these parameters, and their morphological components, are likely correlated with variation in food acquisition mode.
觅食行为存在于一个连续体中，从高度久坐的伏击式觅食到更持续的搜索式或主动觅食。觅食策略或模式是根据运动行为来定义的（例如移动时间百分比、每分钟移动次数）。在蜥蜴中，与伏击式和主动觅食相关的特征已经被关注了一段时间；然而，运动形态与运动行为之间相关进化的一般模式直到最近才开始被量化。在这项研究中，对一组蜥蜴物种的后肢形态变异进行了调查，这些蜥蜴物种在主动觅食和更久坐（或混合）觅食模式之间存在差异。典型变量分析表明，两种主动觅食的物种占据形态空间的相似区域，而另外两种更久坐的物种占据不同区域。主动觅食的物种骨盆狭窄，胫骨和股骨较短。更久坐的物种骨盆宽阔，胫骨和股骨较长，跖骨略长。通过祖先特征状态重建检查了性状变异的系统发育模式，结果表明这些物种的形态变化与觅食模式一致。根据这些物种已发表的短跑速度和耐力数据，对观察到的运动形态变化进行了讨论。总之，数据表明将形态变异与步长和步频变异联系起来对于理解运动性能的进化至关重要。在伏击式、混合式和主动觅食物种中，还需要更多的步长和频率数据，因为这些参数及其形态组成部分可能与食物获取模式的变异相关。
