Research


Sarcoptic mange in red foxes: the role of fox behaviour

A PhD study by Eleanor Devenish-Nelson, based at Durham University. Funded by the Durham Doctoral Fellowship and supervised by Dr Philip Stephens (Durham University), Prof. Stephen Harris and Dr Carl Soulsbury.


collared fox
© Mammal Research Unit
Photo by Jane Bowry

Introduction

Studying behaviour patterns is important as it helps us to understand how certain traits contribute to the persistence of populations under different ecological circumstances. The way in which an individual develops and adapts during their life cycle has significant impacts on the properties of the population of which they are part. One way in which this can be analyzed is through a combination of population dynamics and models of how certain behaviours and interactions affect demographic fundamentals such as birth and death rates, migration and mortality. Such an approach can be particularly useful to understanding and predicting the response of mammal populations to disease cycles, and determining how populations persist in the face of such stochastic events.

Few wild mammalian populations have been studied as long and intensively as the Bristol red fox Vulpes vulpes population. The 30-year dataset collated from the long-term study of Bristol's urban foxes provides a valuable opportunity to investigate the dynamics of this population. In 1994 an outbreak of sarcoptic mange caused the fox population in Bristol to decline by more than 95%. Mange is a highly contagious skin disease, caused by the mite Sarcoptes scabiei, which in severe cases can lead to death. It is rare to have detailed population data from before, during, and after a disease outbreak, including detailed data of individual fitness and behaviour. The way in which individuals respond to such disturbances is a useful way of determining factors that are important for the persistence of populations, so this project provides a unique opportunity to examine how key behaviours affect the transmission of the disease in its wild mammalian host and how the species behaves under different ecological and social conditions. Disease outbreaks have the potential to shape the dynamics, structure and functioning of host populations and previous studies have demonstrated that mange does affect density, dispersal, reproduction and recruitment of Bristol's foxes.

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Logo and link to The Fox Website

Aims

Using the outbreak as a starting point, I intend to develop a series of models to identify parameters that play crucial roles in the population ecology of Bristols' fox population. Matrix models will be used to explore basic population dynamics and deterministic models, such as the SEIR, will be used to identify factors that influence the persistence of the disease. As the data set includes detailed radiotracking data, this can be used to construct individual-based models of fox behaviour. Individual-based models in particular enhance basic demographic approaches as they take into account the idiosyncratic differences that determine the properties of the population. The changes that have occurred in key behaviour traits, including territoriality and dispersal, following the disease outbreak have implications for social organization, reproductive potential of both males and females, and the dynamics of the population. Using these models, I will test hypotheses about the mechanisms that have shaped the spread of mange, and the population's response and recovery.

Outcome

The findings from this study will give an insight into the role of behavioural mechanisms and social organization in the spread of disease within group-living mammals. Given that mange affects over 100 species of both wild and domestic animals, and that management strategies are often hampered by lack of basic information concerning disease dynamics in free-ranging host populations, this study has implications that extend to economic, conservation and welfare issues associated with management of this disease.

Contact details

Ellie Devenish-Nelson
Mammal Research Unit
School of Biological Sciences
University of Bristol
Woodland Road
Bristol BS8 1UG, U.K.

Telephone: 0117 9287593
Email: Ellie Devenish-Nelson