Kasha Strickland, Menna Jones, Andrew Storfer, Rodrigo Hamede, Paul Hohenlohe, Mark Margres, Hamish McCallum, Sebastien Comte, Shelly Lachish, Loeske E. B. Kruuk

Emerging infectious diseases (EIDs) cause catastrophic declines in wildlife populations, but 2 also generate selective pressures that may result in rapid evolutionary responses. One such EID 3 is devil facial tumour disease (DFTD) in the Tasmanian devil. DFTD is almost always fatal, 4 which likely causes strong selection for traits that reduce susceptibility to the disease, but 5 population decline has also left Tasmanian devils vulnerable to inbreeding depression. We 6 analysed 22 years of data from an ongoing study of a population of Tasmanian devils on 7 Freycinet Peninsula, Tasmania, to (1) identify whether DFTD may be causing selection on 8 body size, by estimating phenotypic and genetic correlations between DFTD and size traits, (2) 9 estimate the additive genetic variance of susceptibility to DFTD, and (3) investigate whether 10 size traits or susceptibility to DFTD were under inbreeding depression. We found a positive 11 phenotypic relationship between head width and susceptibility to DFTD, but this was not 12 underpinned by a genetic correlation. Conversely, we found a negative phenotypic relationship 13 between body weight and susceptibility to DFTD, and there was evidence for a negative genetic 14 correlation between susceptibility to DFTD and body weight. There was additive genetic 15 variance in susceptibility to DFTD, head width and body weight, but there was no evidence for 16 inbreeding depression in any of these traits. These results suggest Tasmanian devils have the 17 potential to respond adaptively to DFTD, although the realised evolutionary response will 18 critically depend on the evolution of DFTD itself.