What can we learn from the history of the gonad-eating parasitic worm?
More than you might think, according to Dr David Aldridge of the Department of Zoology at the University of Cambridge.
Dr Aldridge, who won the Researcher of the Year award last week Cambridge Independent Science and Technology Awards, issued a warning about the risks of moving species as part of conservation strategies.
It follows the study of mussels – one of the most endangered groups of animals on Earth.
They play a crucial role in cleaning the water in many rivers and lakes around the world, and there is growing interest in moving them to new locations to stimulate endangered populations or to act as biological filters to improve quality. some water.
But captive breeding programs that bring together mussels from isolated populations face the major risk of providing fertile ground for the Rhipidocotyle bellflower, the carnivorous parasitic worm. They can leave the molds completely sterile
“We need to be much more careful about moving animals to new places for conservation, as the costs can outweigh the benefits,” said Dr Aldridge, lead author of a new report in Conservation Letters .
“We have seen that mixing different populations of mussels can allow widespread transmission of gonad-eating worms – all it takes is one infected mussel to spread this parasite, which in extreme cases can lead to the collapse of any a population.”
In some cases, the presence of pathogens may pose a lower risk unless combined with other factors, such as a lack of food or high temperatures, which can put a population under pressure and lead to a sudden epidemic,
The research focuses on mussels, but its message is applicable more broadly. Relocations to protect endangered species or restore degraded ecosystems are a well-known conservation strategy.
But the authors say the tactic should only be used when absolutely necessary and using quarantine periods, designed to stop transmission of the most likely pathogens.
Josh Brian, doctoral student in the Department of Zoology and first author of the report. added, “Moving animals to a new location is often used to protect or supplement endangered populations. But we have to consider the risk of this spreading pathogens that we don’t quite understand at all, which could put these populations at even greater risk.
Four key factors are identified in the report to determine the risk of spreading pathogens when moving animals:
- the proportion of infected animals in the source and recipient populations;
- the resulting population density;
- host immunity;
- pathogen life cycle – pathogens that must infect multiple species to complete their life cycle, such as parasitic mites, will only persist if all species are present in a given location.
It is known that adaptations to immune systems have an impact on how different populations respond to infection with the same pathogen.
In Yellowstone National Park in the United States, an endangered wolf pack that had been displaced died because they were not immune to the parasites carried by local canines.
And it’s not just conservation efforts that risk replacing pathogens.
Storing rivers with fish for anglers or sourcing exotic plants for home gardens could also bypass pests or diseases.
Isobel Ollard, a doctoral student in the Department of Zoology, who also participated in the study, said: “Being aware of the risks of disease spreading between populations is a vital first step in avoiding unintentional damage in future conservation work. “
The research was funded by the Woolf Fisher Trust.
Dr Aldridge was chosen as Researcher of the Year for his work on the invention of microencapsulated BioBullets – a method of controlling invasive mussels that block pipes in water plants and power plants, costing industry UK water alone over £ 5million a year.
Cambridge Independent Science and Technology Awards winners revealed
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