PDF(Pubmed)
Abstract：
Predators must contend with numerous challenges to successfully find and subjugate prey. Complex traits related to hunting are partially controlled by a large number of co-evolved genes, which may be disrupted in hybrids. Accordingly, research on the feeding ecology of animals in hybrid zones has shown that hybrids sometimes exhibit transgressive or novel behaviors, yet for many taxa, empirical studies of predation and diet across hybrid zones are lacking. We undertook the first such field study for a hybrid zone between two snake species, the Mojave rattlesnake (Crotalus scutulatus) and the prairie rattlesnake (Crotalus viridis). Specifically, we leveraged established field methods to quantify the hunting behaviors of animals, their prey communities, and the diet of individuals across the hybrid zone in southwestern New Mexico, USA. We found that, even though hybrids had significantly lower body condition indices than snakes from either parental group, hybrids were generally similar to non-hybrids in hunting behavior, prey encounter rates, and predatory attack and success. We also found that, compared to C. scutulatus, C. viridis was significantly more active while hunting at night and abandoned ambush sites earlier in the morning, and hybrids tended to be more viridis-like in this respect. Prey availability was similar across the study sites, including within the hybrid zone, with kangaroo rats (Dipodomys spp.) as the most common small mammal, both in habitat surveys and the frequency of encounters with hunting rattlesnakes. Analysis of prey remains in stomachs and feces also showed broad similarity in diets, with all snakes preying primarily on small mammals and secondarily on lizards. Taken together, our results suggest that the significantly lower body condition of hybrids does not appear to be driven by differences in their hunting behavior or diet and may instead relate to metabolic efficiency or other physiological traits we have not yet identified.
摘要：
捕食者必须应对众多挑战，才能成功找到并征服猎物。与狩猎相关的复杂性状部分受大量共进化基因控制,可能在杂种中被破坏。因此，对杂交区动物饲养生态的研究表明，杂交动物有时会表现出过犯或新颖的行为，然而对于许多分类群来说，缺乏对杂交区捕食和饮食的实证研究。我们对两种蛇种之间的杂交区进行了首次此类野外研究，莫哈韦响尾蛇（Crotalusscutulatus）和草原响尾蛇（Crotalusviridis）。具体来说,我们利用既定的野外方法来量化动物的狩猎行为，他们的猎物社区，以及新墨西哥州西南部杂交区个体的饮食，美国。我们发现,尽管杂种的身体状况指数明显低于来自任一亲本组的蛇，杂种在狩猎行为上通常与非杂种相似，猎物遭遇率，掠夺性攻击和成功。我们还发现,与C.scutulatus相比，C.viridis在夜间狩猎时更加活跃，并在清晨废弃了伏击地点，在这方面，杂种更像viridis。不同研究地点的猎物可用性相似，包括在混合区内，袋鼠（Dipodomysspp。)作为最常见的小型哺乳动物，无论是在栖息地调查还是与狩猎响尾蛇相遇的频率。对胃和粪便中的猎物残留物的分析也显示出饮食中的广泛相似性，所有蛇主要捕食小型哺乳动物，其次捕食蜥蜴。一起来看,我们的结果表明，杂种的低体状态似乎不是由其狩猎行为或饮食差异驱动的，而是可能与我们尚未确定的代谢效率或其他生理特征有关。
