Thriving in an arid environment: High prevalence of avian lice in low humidity conditions
Thriving in an arid environment: High prevalence of avian lice in low humidity conditions
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DOI：
10.2980/1195-6860(2007)14
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发表时间：
2007-01-01
期刊：
影响因子：
1.3
通讯作者：
Moreno, Eulalia
中科院分区：
文献类型：
--
作者：
Carrillo, Carmen M.;Valera, Francisco;Moreno, Eulalia
据报道，非生物因素会导致宿主种群之间寄生虫压力的变化，但这种关系尚未得到详细研究，并且关于这些关系的性质存在相互矛盾的证据。在这里，我们研究了鸟类、喇叭雀（Bucanetes githagineus）咀嚼虱寄生的种群内和种群间差异，以及环境湿度对寄生虫负载的影响。我们发现，即使在特别干燥的年份，2 种咀嚼虱子的患病率也很高，而且湿度对月度患病率有积极影响。尽管如此，我们的结果清楚地表明，虱子在低环境湿度条件下会大量繁殖，并且环境中的鸟类不一定比潮湿地区的鸟类承受较低的外寄生压力。我们建议，虱子可以通过将抵抗力更强的阶段（卵）与相对湿度最低的时期（即夏季）同步来调整其生命周期，以克服最关键的时期。我们强调，生态因素对寄主-寄生虫关系影响的研究应考虑后者生命周期的具体方面以及寄生虫不同阶段的主要生物学特征。
Abiotic factors have been reported to cause variation in parasite pressure among host populations, but such relationships have not been studied in detail, and conflicting evidence exists about the nature of these relationships. Here we study within- and between-population variation in chewing lice parasitization in an and bird species, the Trumpeter finch (Bucanetes githagineus), and the influence of ambient humidity on parasite load. We found a high prevalence of 2 chewing lice even in particularly dry years and a positive effect of humidity on prevalence at a monthly scale. Nonetheless, our results clearly reveal that lice can become abundant at low ambient humidity conditions and that birds in and environments are not necessarily under lower ectoparasitic pressure than birds in humid regions. We suggest that lice may adapt their life cycle to overcome the most critical period by synchronizing the more resistant phase (eggs) to the period when relative humidity is lowest (i.e., summertime). We stress that studies on the effect of ecological factors on host-parasite relationships should consider detailed aspects of the life cycle of the latter and the main biological traits of the different stages of the parasites.