Shifts in stable-isotope signatures confirm parasitic relationship of freshwater mussel glochidia attached to host fish

Journal of Molluscan Studies
By: , and 

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Abstract

The parasitic nature of the association between glochidia of unionoidean bivalves and their host fish (i.e. the role of fish hosts in providing nutritional resources to the developing glochidia) is still uncertain. While previous work has provided descriptions of development of glochidia on fish hosts, earlier studies have not explicitly documented the flow of nutrition from the host fish to the juvenile mussel. Therefore, our objective was to use stable isotope analysis to quantitatively document nutrient flow between fish and glochidia. Glochidia were collected from nine adult Lampsilis cardium and used to inoculate Micropterus salmoides(n = 27; three fish per maternal mussel) that produced juvenile mussels for the experiment. Adult mussel tissue samples, glochidia, transformed juvenile mussels and fish gill tissues were analysed for δ15N and δ13C isotope ratios. We used a linear mixing model to estimate the fraction of juvenile mussel tissue derived from the host fish's tissue during attachment. Our analyses indicate a distinct shift in both C and N isotopic ratios from the glochidial stage to the juvenile stage during mussel attachment and development. Linear mixing model analysis indicated that 57.4% of the δ15N in juvenile tissues were obtained from the host fish. This work provides novel evidence that larval unionoideans are true parasites that derive nutrition from host fish during their metamorphosis into the juvenile stage.

Publication type Article
Publication Subtype Journal Article
Title Shifts in stable-isotope signatures confirm parasitic relationship of freshwater mussel glochidia attached to host fish
Series title Journal of Molluscan Studies
DOI 10.1093/mollus/eyt008
Volume 79
Issue 2
Year Published 2013
Language English
Publisher Oxford University Press
Contributing office(s) Coop Res Unit Seattle
Description 5 p.
First page 163
Last page 167
Online Only (Y/N) N
Additional Online Files (Y/N) N
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