Do syntopic host species harbour similar symbiotic communities? The case of Chaetopterus spp. (Annelida: Chaetopteridae).
Do syntopic host species harbour similar symbiotic communities? The case of Chaetopterus spp. (Annelida: Chaetopteridae).
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作者：
Britayev TA;Mekhova E;Deart Y;Martin D
为了评估是否密切相关的宿主物种港湾相似的共生群落，我们研究了两个多毛类，Chaetopterus sp.（n = 11）和Chaetopterus cf。apacillulatus（n = 83）生活在越南南中国海Nhatrang湾的软沉积物中。前者窝藏了Porcidid蟹Polyonyx cf. heok和Polyonyx sp.，后者的体内有多毛纲多毛类Ophthalmonoe pettiboneae、背甲纲鱼类Onuxodon fowleri和孔甲纲蟹Eulenaios comparus，除O.福勒里，似乎是专门的共生体。共生体的物种丰富度和平均强度在毛翅虫中均高于毛翅虫。参见无翅小蜂（1.8和1.02种，3.0和1.05头/寄主）。我们认为，毛翅虫的低密度可能解释了观察到的较高数量的相关共生体，以及100%的患病率（69.5%，在C。参见appenciculatus）。大多数毛翅虫都有两个共生种，在C.参见apaculatus，表明较低的种间相互作用在前者。毛翅目的蟹类与裸鳃亚目的共生体通常共享一个宿主，成对生活，从而划分资源。这导致了物种共存于Chaetopterus sp.的管中，建立了一个紧密堆积的群落，表明高物种丰富度和平均强度，以及低物种优势度。与此相反，与C.参见无尾两栖类建立了一个单一物种占优势的共生群落，因此，物种丰富度和平均强度较低。因此，我们认为，种间相互作用决定物种丰富度，强度和优势，而种内相互作用的影响强度和丰度。物种组成可能影响了观察到的群落结构差异。我们假设这两种宿主物种最初可能是异地的。共生群落的进化特化会发生在分离的地理区域，而现有地理障碍的后消会导致重叠分布。
To assess whether closely related host species harbour similar symbiotic communities, we studied two polychaetes, Chaetopterus sp. (n = 11) and Chaetopterus cf. appendiculatus (n = 83) living in soft sediments of Nhatrang Bay (South China Sea, Vietnam). The former harboured the porcellanid crabs Polyonyx cf. heok and Polyonyx sp., the pinnotherid crab Tetrias sp. and the tergipedid nudibranch Phestilla sp. The latter harboured the polynoid polychaete Ophthalmonoe pettiboneae, the carapid fish Onuxodon fowleri and the porcellanid crab Eulenaios cometes, all of which, except O. fowleri, seemed to be specialized symbionts. The species richness and mean intensity of the symbionts were higher in Chaetopterus sp. than in C. cf. appendiculatus (1.8 and 1.02 species and 3.0 and 1.05 individuals per host respectively). We suggest that the lower density of Chaetopterus sp. may explain the higher number of associated symbionts observed, as well as the 100% prevalence (69.5% in C. cf. appenciculatus). Most Chaetopterus sp. harboured two symbiotic species, which was extremely rare in C. cf. appendiculatus, suggesting lower interspecific interactions in the former. The crab and nudibranch symbionts of Chaetopterus sp. often shared a host and lived in pairs, thus partitioning resources. This led to the species coexisting in the tubes of Chaetopterus sp., establishing a tightly packed community, indicating high species richness and mean intensity, together with a low species dominance. In contrast, the aggressive, strictly territorial species associated with C. cf. appendiculatus established a symbiotic community strongly dominated by single species and, thus, low species richness and mean intensity. Therefore, we suggest that interspecific interactions are determining species richness, intensity and dominance, while intraspecific interactions are influencing only intensity and abundance. It is possible that species composition may have influenced the differences in community structure observed. We hypothesize that both host species could originally be allopatric. The evolutionary specialization of the symbiotic communities would occur in separated geographical areas, while the posterior disappearance of the existing geographical barriers would lead to the overlapped distribution.