Parasitism, Family Conflict and Breeding Success
University of Edinburgh
2013
Supervisors: Emma Cunningham and Sue Lewis at Edinburgh University, Francis Daunt and Sarah Burthe at the Centre for Ecology & Hydrology.
Wild animals are almost always infected with large numbers of parasites.
A parasite infection can be expensive for the host to deal with, leading
to negative consequences such as less successful breeding or poorer
survival. By altering these vital rates, effects of parasites on
individual hosts have the potential to scale up and affect the dynamics
of entire populations. However, different hosts suffer these effects to
different extents. Intrinsically, some may be more able to cope with an
infection, for example because they are in better condition or have more
efficient immune systems. Hosts may also be subject to different
extrinsic influences, including both their ecological environment, for
example food availability, and their social environment, that is how
they interact with other individuals. These differences between hosts
could be especially important during breeding, when parents must weigh
up how much to invest in their own parasite defences against investing
in caring for their young, who may be particularly vulnerable to
infection. In my PhD thesis, I investigated how parasite infection of
nestling chicks and their parents influences these trade-offs between
family members and how this affects the outcome of the breeding attempt.
Using experimental anti-parasite treatment of the European shag
Phalacrocorax aristotelis, I examined the role of gut parasites
in chick growth and survival, behavioural interactions between chicks
and their parents, parent condition and parents' behaviour during and
after the breeding season. As a seabird, the shag is an important
indicator of changes in the marine environment, and understanding its
responses to these changes requires a full understanding of its ecology.
Parasitism is an important part of this ecology that has until recently
been overlooked.