Foraging Ecology of Timber Rattlesnakes, Crotalus horridus
Foraging Ecology of Timber Rattlesnakes, Crotalus horridus
复制标题
木响尾蛇的觅食生态学
作者：
H. K. Reinert;Gylla A. MacGregor;M. Esch;L. Bushar;R. Zappalorti
摘要木材响尾蛇的地理范围包括美国东半部的大部分地区。虽然已有很好的文献记载和报道了可怕隐翅虫的总体食物组成，但还没有对当地种群的变异进行研究。我们研究了宾夕法尼亚州和新泽西州四个不同种群的可怕隐翅虫的饮食和觅食行为。在种类和科的水平上，从粪便样本、胃样本和野外观察中鉴定了253种猎物。虽然田鼠(Myodes Gapperi)和小鼠(Permyscus spp.)组成了所有种群的大部分食物，相对猎物种类频率在四个种群之间存在显著差异。这些数据表明，即使在相对较小的地理距离内，可怕隐翅虫的食物习性也有很大的差异。与小型哺乳动物诱捕数据的比较进一步表明，这种埋伏捕食者的食物组成可能不仅仅反映了猎物物种的可用性。对赤眼蜂的无线电遥测观测进一步表明，不同研究地点之间以原木为导向的觅食行为的频率不同。对身体姿势的分析揭示了另一种埋伏觅食姿势(非原木导向姿势)，这种姿势在不同研究地点的频率也有所不同。然而，所有研究地点选定的觅食栖息地的特点是，当地砍伐的原木和其他木质碎屑密度很高(占森林地面覆盖率的6%/m2)。这些发现表明了恐怖梭子蟹觅食生态的地理差异，并表明了对可用猎物的觅食反应具有行为可塑性。
Abstract The geographic range of the Timber Rattlesnake (Crotalus horridus) encompasses most of the eastern half of the United States. Although the overall diet composition of C. horridus has been well documented and has been reported to be very broad, local population variation has not been studied. We examined the diet and foraging behavior of C. horridus from four separate populations in Pennsylvania and New Jersey. A total of 253 prey items from scat samples, stomach samples, and field observation were identified to species or family level. Although voles (Myodes gapperi) and mice (Peromyscus spp.) comprised the bulk of the diet in all populations, relative prey species frequency differed significantly among the four populations. These data indicate that the food habits of C. horridus varied widely even within relatively small geographic distances. Comparisons with small mammal trapping data further suggest that the diet composition of this ambush predator may not simply reflect the availability of prey species. Radiotelemetric observations of C. horridus further indicate differing frequencies of log-oriented foraging behavior among the study sites. Analysis of body posture revealed an alternative ambush foraging posture (non-log-oriented posture) which also exhibited variation in frequency among study sites. However, selected foraging habitats at all study sites were typified by a locally high density of fallen logs and other woody debris (6% of forest-floor cover/m2). These findings indicate geographic variation in the foraging ecology of C. horridus and suggest behavioral plasticity in foraging response to available prey.