open access

https://hdl.handle.net/2115/86677

Testing local adaptations of affiliate freshwater pearl mussel, Margaritifera laevis, to its host fish, Oncorhynchus masou masou

英語

parasites

2021-09

John Wiley & Sons

Ecological Research

36(5)

803-814

Understanding the limiting factors of the reproduction process in host-affiliate relationships is a high priority. We examined the effects of habitat location on the reproductive process of freshwater pearl mussels Margaritifera laevis (Bivalvia, Unionida) as a parasite using sympatric and allopatric Oncorhynchus masou masou (Actinopterygii, Salmoniformes) as a host fish. Initial infection rates of parasitic larvae (glochidia) and transformation rates to cysts (encysted glochidia) were examined for all parasite-host combinations from three habitat locations (a total of nine combinations) to test the hypothesis that sympatric pairs of mussels and fish result in the highest success rates of glochidia infection and encystment. Measurements of glochidia-infected fish reared in flow-through experimental indoor tanks were taken at the initial infection point as well as at encystment, 2 weeks after the infection. Results disagreed with our hypothesis. Instead, an unexpected heterogeneity in a pathological deformity in gills explained a greater amount of variance in these processes. This deformity was responsible for reducing the initial infection rate and increasing the metamorphosis rates of initially attached glochidia to cysts. The field-measured prevalence of the gill deformity was low in all habitat locations, indicating that the deformity occurred during the acclimation period before infection for relatively small-sized host fish more susceptible to infection. Our results did not show the local adaptation of parasitic freshwater mussels to host fish but shed light on one of the least studied factors, providing an empirical underpinning of the importance of pathologically diversified host conditions in the reproductive processes of unionid mussels.

学術雑誌論文

Accepted Manuscript

This is the peer reviewed version of the following article: Hitoshi Kitaichi, Junjiro N. Negishi, Daisetsu Ito, Kazuki Miura, Hirokazu Urabe. Testing local adaptations of affiliate freshwater pearl mussel, Margaritifera laevis, to its host fish, Oncorhynchus masou masou. Ecological Research. 2021; 36(5), 803-814, which has been published in final form at https://doi.org/10.1111/1440-1703.12245. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.

0912-3814

1440-1703

AA10667816