Tasmanian devil die‑off appears to be affecting genetics of fellow predator

The spotted-tail quoll, a carnivore marsupial native to Australia. Photo by Ken Griffiths on iStock.
The spotted-tail quoll, a carnivore marsupial native to Australia. Photo by Ken Griffiths on iStock.

Population declines in the Tasmanian devil, a top predator species, caused by a transmissible cancer, may be affecting the evolutionary genetics of a subordinate predator species, the spotted-tailed quoll, research published in the journal Nature Ecology & Evolution reports.

Top predator declines are occurring globally and have cascading ecological effects, one of which is to reduce competition and enable increased activity of subordinate mid-range predators in an ecosystem, known as mesopredators. The Tasmanian devil population is declining owing to the transmissible devil facial tumor disease (DFTD), a rare example of an infectious cancer. This has changed the resource use and activity patterns of the spotted-tailed quoll, a mesopredator marsupial native to Australia. It is not known whether evolutionary processes are also affected in the quolls.

Washington State University researcher Andrew Storfer, his PhD student Marc Beer and colleagues collected genome marker data from 345 quolls over the course of 15 generations. The researchers looked for evidence of genetic variation and natural selection associated with differences in DFTD prevalence and geographical location. They found that quolls in areas with similar prevalence of the disease were genetically more similar than those located in areas with different DFTD prevalence and Tasmanian devil population densities, which may indicate selective dispersal and/or selection against individuals from different environments.

The researchers also found evidence for decreased gene flow and increased population structure in quolls overall, likely resulting from reduced competition. Finally, they showed evidence of selection acting on genes for muscle development, locomotion and feeding behavior that was linked to differences in DFTD prevalence and devil population densities. They suggest that these traits may be involved in competition between quolls and devils and therefore selected differently when devil numbers decline.

The authors conclude their “community landscape genomics” approach may be used in general to enable greater understanding of the evolutionary consequences of global predator declines.

This story was adapted from a press release by the journal Nature Ecology & Evolution. 

By Communications staff, WSU Insider