Soler Juan José, Ruiz-Rodríguez Magdalena, Martín-Vivaldi Manuel, Peralta-Sánchez Juan Manuel, Ruiz-Castellano Cristina, Tomás Gustavo
Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas (CSIC), Ctra. Sacramento s/n, La Cañada de San Urbano, 04120, Almería, Spain,
Oecologia. 2015 Sep;179(1):63-74. doi: 10.1007/s00442-015-3322-6. Epub 2015 Apr 26.
Exploring factors guiding interactions of bacterial communities with animals has become of primary importance for ecologists and evolutionary biologists during the last years because of their likely central role in the evolution of animal life history traits. We explored the association between laying date and eggshell bacterial load (mesophilic bacteria, Enterobacteriaceae, Staphylococci, and Enterococci) in natural and artificial magpie (Pica pica) nests containing fresh commercial quail (Coturnix coturnix) eggs. We manipulated hygiene conditions by spilling egg contents on magpie and artificial nests and explored experimental effects during the breeding season. Egg breakage is a common outcome of brood parasitism by great spotted cuckoos (Clamator glandarius) on the nests of magpie, one of its main hosts. We found that the treatment increased eggshell bacterial load in artificial nests, but not in magpie nests with incubating females, which suggests that parental activity prevents the proliferation of bacteria on the eggshells in relation to egg breakage. Moreover, laying date was positively related to eggshell bacterial load in active magpie nests, but negatively in artificial nests. The results suggest that variation in parental characteristics of magpies rather than climatic variation during the breeding season explained the detected positive association. Because the eggshell bacterial load is a proxy of hatching success, the detected positive association between eggshell bacterial loads and laying date in natural, but not in artificial nests, suggests that the generalized negative association between laying date and avian breeding success can be, at least partially, explained by differential bacterial effects.
近年来，探索引导细菌群落与动物相互作用的因素对生态学家和进化生物学家而言已变得至关重要，因为它们可能在动物生活史特征的进化中发挥核心作用。我们研究了含有新鲜商品鹌鹑蛋的天然和人工喜鹊（Pica pica）巢中产卵日期与蛋壳细菌载量（嗜温菌、肠杆菌科、葡萄球菌和肠球菌）之间的关联。我们通过将蛋液洒在喜鹊巢和人工巢上来操控卫生条件，并在繁殖季节探究实验效果。卵破损是大斑杜鹃（Clamator glandarius）在其主要宿主之一喜鹊巢中进行巢寄生的常见结果。我们发现该处理增加了人工巢中的蛋壳细菌载量，但在有孵卵雌鸟的喜鹊巢中却没有增加，这表明亲代活动可防止与卵破损相关的蛋壳上细菌的增殖。此外，在活跃的喜鹊巢中，产卵日期与蛋壳细菌载量呈正相关，但在人工巢中呈负相关。结果表明，喜鹊亲代特征的差异而非繁殖季节的气候变化解释了所检测到的正相关关系。由于蛋壳细菌载量是孵化成功率的一个指标，在天然巢而非人工巢中检测到的蛋壳细菌载量与产卵日期之间的正相关关系表明，产卵日期与鸟类繁殖成功率之间普遍存在的负相关关系至少可以部分地由不同的细菌效应来解释。
