The microhabitat of Symbion pandora (Cycliophora) on the mouthparts of its host Nephrops norvegicus (Decapoda: Nephropidae)
The microhabitat of Symbion pandora (Cycliophora) was described by recording the prevalence and distribution of two life cycle stages, namely feeding individuals and chordoid cysts on the mouth appendages of 65 Norway lobsters. The commensals infested lobsters with a carapace length >35 mm, while the intensity of the commensals increased with host size up to more than 1,100 feeding individuals and 173 chordoid cysts. Feeding individuals and chordoid cysts were found on all six pairs of mouth appendages, but were rare on Mxp3. A Kruskal–Wallis analysis of variance showed that the distribution of the two stages over individual segments deviated significantly from random expectations (P<0.001). Feeding individuals densely aggregated on a few medial segments, generally those that are pervaded by suspended food particles during host feeding. Chordoid cysts, which arise from non-feeding females occurred in low numbers and were more evenly distributed over the segments, often aggregating on the lateral parts and in the articulations of the segments. Based on these findings we suggest that the feeding activity of S. pandora is synchronized with that of the host.
KeywordsLife Cycle Stage Carapace Length Larval Settlement Bottom Trawl Medial Segment
We would like to acknowledge the financial support from the European Community Programme for the Access to Research Infrastructure (contract grant number: ARI P.17) at Kristineberg Marine Research Station, Sweden. Furthermore we acknowledge the financial support from the DAAD (Referat 313, Kennziffer D/00/20555). We are grateful for the technical support from Else B. Rasmussen and Per G. Henriksen as well as for statistical advice from David Mayntz. We wish to thank two anonymous reviewers for providing comments that helped to improve this manuscript.With regard to the treatment of animals this study has been performed in accordance with the current laws of Denmark and Sweden.
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