Host-parsite co-evolution and co-infection of invasive parasitic Mytilicola copepods in blue mussel hosts

• Main Author: Feis, Marieke E.
• Format: Thesis
• Language: unknown
• Published: 2018
• Subjects: Pacific oyster; Copepods
• Online Access: https://epic.awi.de/id/eprint/48494/; https://hdl.handle.net/10013/epic.1549eac4-9fbc-4475-87ad-1ffd890525dd

Parasites are ubiquitous in nature and the strong natural selection pressures they impose on their hosts are predicted to elicit rapid evolutionary adaptive responses of hosts towards their parasites, leading to antagonistic host–parasite co-evolution. While most of what we know about these processes stems from laboratory studies with a restricted set of model organisms, much less is known about host–parasite co- evolution in the wild, largely due to logistical challenges of experimental manipulations on an ecosystem scale. Biological invasions represent excellent opportunities to overcome these logistical issues and study host–parasite interactions and co-evolution in non-model species in the wild, as they can be seen as “natural experiments” in which different invasion scenarios lead to different ecological and evolutionary dynamics. This dissertation utilises the invasions of two parasitic copepods Mytilicola intestinalis and Mytilicola orientalis in the Wadden Sea to address the study of host–parasite co-evolution and co-infection in non-model species in the wild. This conceptual approach and the biological system are introduced in Chapter 1. Validation of the presumed origins and invasion routes of both parasites were still lacking, therefore my first aim was to confirm them. This was done through an extensive literature review, in combination with invasion genetics (Chapter 2), which resulted in the validation of Japan as the native and North America and Europe as the invaded ranges of M. orientalis (where it was co-introduced with the Pacific oyster Magallana gigas), while it remained unclear whether the Mediterranean Sea is really the native range of M. intestinalis. The biological invasion of M. intestinalis and later M. orientalis created a situation in which two congeneric species co-occur and share the same novel host in their invaded range. The two parasites have different degrees of host specificity in the Wadden Sea, as M. intestinalis only infects blue mussels Mytilus edulis, while M. orientalis ...