Seasonal and spatial dynamics of ectoparasite infestation of a threatened reptile, the tuatara (Sphenodon punctatus)
Seasonal and spatial dynamics of ectoparasite infestation of a threatened reptile, the tuatara (Sphenodon punctatus)
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受威胁爬行动物大蜥蜴（Sphenodon punctatus）体外寄生虫感染的季节和空间动态
DOI：
10.1111/j.1365-2915.2008.00751.x
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发表时间：
2008
影响因子：
1.9
通讯作者：
N. Nelson
中科院分区：
文献类型：
--
作者：
S. Godfrey;C. Bull;N. Nelson
摘要 保护受威胁的脊椎动物及其受威胁的寄生虫需要了解影响其分布和动态的因素。这对于高密度保护区内的物种尤其重要，因为宿主之间接触的增加可能导致寄生率增加。蜥蜴 (Sphenodon punctatus) (Reptilia: Sphenodontia) 是一种受威胁的爬行动物，在新西兰斯蒂芬斯岛的森林中以高密度生存（约 2700 只蜥蜴/公顷），在牧场和灌木丛中以较低密度生存（< 200 只蜥蜴/公顷）。我们在 2004 年 11 月至 2007 年 3 月期间在三个森林研究样地进行标记重捕研究，调查了两种体外寄生虫（斑蜥蜱、Amblyomma sphenodonti 和螨螨、Neotrombicula sp.）感染的生命周期和季节动态，并比较了 2006 年 3 月不同生境类型的感染水平。蜱负荷在夏季最低，从深秋达到峰值。 （五月）直到早春（九月）。雌性蜱虫的交配和充血量在春季最高，幼虫蜱虫数量随后在初秋（三月）增加。若虫蜱数量在 9 月份增加，成虫蜱数量在 5 月份增加。我们的研究结果表明，大蜥蜴蜱的生命周期为 2 至 3 年。螨虫负荷在夏季和秋季最高，并在三月达到峰值。不同栖息地的蜱虫流行率（受感染宿主的比例）和密度（每公顷寄生虫的估计数量）相似，但牧场中的蜱虫数量（每个宿主的寄生虫数）高于森林和灌木丛。森林中螨虫的流行率和密度高于牧场或灌木丛，但栖息地之间的螨虫负荷相似。我们认为，森林中蜥蜴密度较高可能会通过稀释效应减少个体的体外寄生虫负荷。了解宿主-寄生虫动态将有助于宿主及其寄生虫的保护管理。
Abstract The conservation of threatened vertebrate species and their threatened parasites requires an understanding of the factors influencing their distribution and dynamics. This is particularly important for species maintained in conservation reserves at high densities, where increased contact among hosts could lead to increased rates of parasitism. The tuatara (Sphenodon punctatus) (Reptilia: Sphenodontia) is a threatened reptile that persists at high densities in forests (∼ 2700 tuatara/ha) and lower densities in pastures and shrubland (< 200 tuatara/ha) on Stephens Island, New Zealand. We investigated the lifecycles and seasonal dynamics of infestation of two ectoparasites (the tuatara tick, Amblyomma sphenodonti, and trombiculid mites, Neotrombicula sp.) in a mark‐recapture study in three forest study plots from November 2004 to March 2007, and compared infestation levels among habitat types in March 2006. Tick loads were lowest over summer and peaked from late autumn (May) until early spring (September). Mating and engorgement of female ticks was highest over spring, and larval tick loads subsequently increased in early autumn (March). Nymphal tick loads increased in September, and adult tick loads increased in May. Our findings suggest the tuatara tick has a 2‐ or 3‐year lifecycle. Mite loads were highest over summer and autumn, and peaked in March. Prevalences (proportion of hosts infected) and densities (estimated number of parasites per hectare) of ticks were similar among habitats, but tick loads (parasites per host) were higher in pastures than in forests and shrub. The prevalence and density of mites was higher in forests than in pasture or shrub, but mite loads were similar among habitats. We suggest that a higher density of tuatara in forests may reduce the ectoparasite loads of individuals through a dilution effect. Understanding host–parasite dynamics will help in the conservation management of both the host and its parasites.