Fernández-González Sofía, Pérez-Rodríguez Antón, de la Hera Iván, Proctor Heather C, Pérez-Tris Javier
Departamento de Zoología y Antropología Física, Universidad Complutense de Madrid, Spain.
Departamento de Zoología y Antropología Física, Universidad Complutense de Madrid, Spain.
Int J Parasitol. 2015 Aug;45(9-10):655-62. doi: 10.1016/j.ijpara.2015.04.003. Epub 2015 May 14.
Obligate symbionts (including parasites, commensals and mutualists) often share host species and host-based food resources. Such symbionts are frequently distributed unequally among hosts with different phenotypic features, or occupy different regions on a host. However, the processes leading to distinct within-host symbiont distributions remain obscure. We aimed to test whether distinct in-host symbiont distributions arise as the outcome of species-specific habitat preferences or interspecific competition, and how host phenotype influences such processes. To this end, we studied the distribution within and among individual bird hosts of two feather mites (Proctophyllodes sylviae and Trouessartia bifurcata) of migratory and sedentary European blackcaps, Sylvia atricapilla, wintering in sympatry. Trouessartia bifurcata was mostly restricted to resident blackcaps, while P. sylviae was abundant on both host types. Within hosts, each species tended to settle on different feather sectors (proximal or distal, respectively), which they filled by spreading on the wing following ordered but opposite patterns, thereby supporting the view that spatial segregation was primarily the outcome of dissimilar space preferences. However, we also found evidence of competition finely tuning mite distributions: when P. sylviae increased abundance and expanded onto the range of T. bifurcata, abundances of the two species were negatively correlated in the shared areas. In addition, the presence of T. bifurcata on a host was associated with a more restricted distribution of P. sylviae. Our results show that both species-specific preferences and interspecific interactions contribute to shaping mite distributions among and on individual hosts, a situation likely mirrored by other host-multi-symbiont systems.
专性共生体（包括寄生虫、共栖生物和互利共生生物）通常共享宿主物种和基于宿主的食物资源。这类共生体在具有不同表型特征的宿主之间分布往往不均等，或者占据宿主的不同区域。然而，导致宿主内共生体分布差异的过程仍不清楚。我们旨在测试宿主内共生体的不同分布是否是物种特异性栖息地偏好或种间竞争的结果，以及宿主表型如何影响这些过程。为此，我们研究了在同域越冬的欧洲黑顶林莺（Sylvia atricapilla）的两种羽螨（Sylviae Proctophyllodes和Trouessartia bifurcata）在单个鸟类宿主内部和之间的分布情况，其中黑顶林莺有迁徙型和留居型。Trouessartia bifurcata主要局限于留居型黑顶林莺，而Sylviae Proctophyllodes在两种宿主类型上都很丰富。在宿主内部，每个物种倾向于定居在不同的羽毛区域（分别为近端或远端），它们通过以有序但相反的模式在翅膀上扩散来占据这些区域，从而支持了空间隔离主要是不同空间偏好结果的观点。然而，我们也发现了竞争对螨类分布进行精细调节的证据：当Sylviae Proctophyllodes数量增加并扩展到Trouessartia bifurcata的分布范围时，这两个物种在共享区域的数量呈负相关。此外，宿主上存在Trouessartia bifurcata与Sylviae Proctophyllodes分布更受限有关。我们的结果表明，物种特异性偏好和种间相互作用都有助于塑造螨类在单个宿主之间和之上的分布，这种情况可能在其他宿主 - 多共生体系统中也存在。
