Do syntopic host species harbour similar symbiotic communities? The case of Chaetopterus spp. (Annelida: Chaetopteridae)

• Published in: PeerJ (San Francisco, CA) Vol. 5; p. e2930
• Main Authors: Britayev, Temir A, Mekhova, Elena, Deart, Yury, Martin, Daniel
• Format: Journal Article
• Language: English
• Published: United States PeerJ. Ltd 02.02.2017; PeerJ, Inc; PeerJ Inc
• Subjects: Analysis; Annelida; Behavior; Biodiversity; Biology; Brachyura; Carapidae; Chaetopteridae; Chaetopterus; Community structure; Coral reefs; Crustacea; Dominance; Ecology; Evolution; Hypotheses; Interspecific; Laboratories; Marine Biology; Morphology; Phylogenetics; Physiology; Pinnotheridae; Polychaeta; Porcellanidae; Science; Sediments; Specialization; Species composition; Species richness; Studies; Symbionts; Symbiosis; Symbiotic community structure; Tergipedidae; Zoology; Vietnam; Competition; Carapidae; South China Sea; Vietnam; Polychaeta; Tergipedidae; Pinnotheridae; Symbiotic community structure; Porcellanidae
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.2930

To assess whether closely related host species harbour similar symbiotic communities, we studied two polychaetes, sp. (  = 11) and cf. (  = 83) living in soft sediments of Nhatrang Bay (South China Sea, Vietnam). The former harboured the porcellanid crabs cf. and sp., the pinnotherid crab sp. and the tergipedid nudibranch sp. The latter harboured the polynoid polychaete , the carapid fish and the porcellanid crab , all of which, except , seemed to be specialized symbionts. The species richness and mean intensity of the symbionts were higher in sp. than in cf. (1.8 and 1.02 species and 3.0 and 1.05 individuals per host respectively). We suggest that the lower density of sp. may explain the higher number of associated symbionts observed, as well as the 100% prevalence (69.5% in cf. ). Most sp. harboured two symbiotic species, which was extremely rare in cf. , suggesting lower interspecific interactions in the former. The crab and nudibranch symbionts of sp. often shared a host and lived in pairs, thus partitioning resources. This led to the species coexisting in the tubes of 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 cf. 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.