Thesis
Biological rhythms and valve gape behaviour of Mytilus galloprovincialis in Western Australia
Honours, Murdoch University
2022
Abstract
Molluscs of the class Bivalvia are ideal subjects for behavioural studies as they are sedentary, abundant and have a hard external shell to which behaviour recording sensors may be attached. Bivalves open their shell (which consists of two valves) in order to feed and undergo aerobic respiration, and may close their valves as an anti-predation measure or when surrounding water conditions are suboptimal. The recording of bivalve behaviour is known as valvometry. Valvometry can be used to monitor and detect pollution, fluctuations in environmental conditions and in the exploration of biological rhythms. A systematic literature review of 172 valvometry studies, published between 1928 and 2021 was performed. Data on eleven variables, including method, location, study purpose and study duration, were extracted for comparison. The studies were conducted in 35 countries, on 59 different bivalve species. The majority (75%) of these studies were conducted in Europe and North America, while only 2 were completed in Australia, both of which were carried out in a laboratory setting. Overall, only 26% of the valvometry studies were conducted in situ. While laboratory valvometry studies do provide important information, this review confirms the need for further in situ studies to be conducted in currently understudied regions, such as Australia.
The second component of this study involved measuring the valve gape behaviour of Mytilus galloprovincialis at two sites in Western Australia between November 2021 and January 2022. The valvometer data demonstrated that the mussels displayed a bimodal circadian rhythm, consisting of a strong daily 24-hour rhythm and a weaker 12-hour rhythm. The mussels were typically open most of the time (90%) with an overall trend of valve openness during the day and valve closure during the night. Some of these results vary from findings in other similar published studies, which highlights that, while also driven by endogenous genetic mechanisms, the biological rhythms of bivalves are highly linked to specific local environmental conditions. As environmental conditions are being altered on both a global and local scale, such as increasing sea surface temperatures and instances of extreme weather events, the behavioural rhythms of bivalves are likely to be impacted.
Details
- Title
- Biological rhythms and valve gape behaviour of Mytilus galloprovincialis in Western Australia
- Authors/Creators
- Katelyn M Fox
- Contributors
- A. Cottingham (Supervisor) - Murdoch UniversityJames Tweedley (Supervisor) - Murdoch University, Centre for Sustainable Aquatic EcosystemsMike Van Keulen (Supervisor) - Murdoch University, Centre for Sustainable Aquatic Ecosystems
- Awarding Institution
- Murdoch University; Honours
- Identifiers
- 991005548667907891
- Murdoch Affiliation
- College of Science, Health, Engineering and Education
- Resource Type
- Thesis
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