Jayne Bruce C, Byrnes Greg
Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio.
Department of Biology, Siena College, Loudonville, New York.
J Exp Zool A Ecol Genet Physiol. 2015 Jun;323(5):309-21. doi: 10.1002/jez.1920. Epub 2015 Apr 6.
The surfaces in arboreal habitats have variable diameters, slopes, and branching structure that pose functional challenges for animal locomotion. Nevertheless, many lineages of snakes have independently evolved arboreality. We tested the effects of arboreal habitat structure on the locomotion of a highly arboreal species, the brown tree snake (Boiga irregularis), moving on seven diameters (0.6-21 cm) of cylinders oriented at three slopes (0°, 45°, 90°) and with or without pegs. Intermediate diameters of horizontal cylinders maximized speed, and some of the large-diameter cylinders without pegs were impassable when they were inclined. With increased slope the snakes were slower, and they changed from using lateral undulation with sliding contact and balancing to concertina locomotion with periodic static gripping. The presence of pegs increased the speeds of the brown tree snakes and resulted in them only using lateral undulation. Surface diameter, slope, and the occurrence of pegs also had widespread significant effects on the kinematics of the brown tree snakes. Overall, compared to anatomically less specialized corn snakes, brown tree snakes use more lateral undulation, are usually much faster, and are able to move on a wider variety of surfaces. Unlike some of the trade-offs found previously between two less specialized species of snakes with different stoutness when they used modes of arboreal locomotion that involved either balancing or gripping, the slender-bodied brown tree snakes excel at both. Hence, this species may not only be a "jack of all trades" but also a master of many.
树栖栖息地的表面具有不同的直径、坡度和分支结构，这对动物的移动构成了功能上的挑战。尽管如此，许多蛇类谱系还是独立地进化出了树栖习性。我们测试了树栖栖息地结构对一种高度树栖的物种——棕树蛇（Boiga irregularis）移动的影响，该蛇在三种坡度（0°、45°、90°）且有无木桩的七个直径（0.6 - 21厘米）的圆柱体上移动。水平圆柱体的中间直径使速度最大化，一些无木桩的大直径圆柱体倾斜时无法通行。随着坡度增加，蛇的速度变慢，它们从使用带有滑动接触和平衡的侧向波动转变为带有周期性静态抓握的伸缩式移动。木桩的存在提高了棕树蛇的速度，并导致它们仅使用侧向波动。表面直径、坡度和木桩的存在对棕树蛇的运动学也有广泛的显著影响。总体而言，与解剖学上不太特化的玉米蛇相比，棕树蛇更多地使用侧向波动，通常速度快得多，并且能够在更多种类的表面上移动。与之前发现的两种不太特化的不同粗壮程度的蛇在使用涉及平衡或抓握的树栖移动模式时的一些权衡不同，身体细长的棕树蛇在这两方面都表现出色。因此，这个物种可能不仅是一个“万事通”，而且是许多方面的高手。
