At the very earliest stages of development, an offspring’s environment is created by it’s mother. Much of our research examines how mothers allocate resources to their young at different phases of reproduction, from the allocation of different sperm, through resources provided to the embryonic environment, to later juvenile stages. We then use this information to address how these effects can be altered by maternal age and changes in the mother's environment and the subsequent effects this can have for both wild and domesticated animal populations.

Parental age effects

In many animal species, including humans, reproducing at a later age is thought to correlate with increased risks for both mother and offspring. These risks are generally thought to be due to the senescence of parents; as individuals get older they may suffer from a number of different processes associated with aging. However, as parents get older, the physiological costs and benefits of allocation resources to their offspring can also change. A full understanding of how these parental age effects operate is important not only for those interested in offspring health and fitness but for our understanding of the ageing process. We are examining why maternal age has a negative impact on both sons and daughters.

We use both insect and avian systems with short generation times to investigate these effects and are particularly interested in how parental age affects the ability of offspring to reproduce successfully as well as their ability to survive.

Effects of environmental change

Allocation decisions during prolonged periods of parental care are important in many animal systems. However, many environmental factors can limit how much a parent is able to allocate to young and hence, how a parent should divide resources between family members. We are examining how changes such as large scale climate shifts affects parental ability in animal populations.

Part of this work is in collaboration with The Centre for Ecology and Hydrology, Banchory who have been monitoring the long terms patterns of breeding success of North Sea bird populations. Seabird species are commonly used as bioindicators of the marine environment and together we are combining this long term information with experimental work to assess the impact of recent changes in timing of major biological events and the implications this may have for populations in the future.

Effects of parasitism on allocation

Allocation decisions during prolonged periods of parental care are important in many animal systems. However, many environmental factors can limit how much a parent is able to allocate to young and hence, how a parent should divide resources between family members. We are examining how changes such as large scale climate shifts and changes in parasite density affects parental ability in animal populations.

We have found that in a wild population of seabirds, that the effects of parasite load varies throughout the breeding season and that these differences can account for observed reductions in breeding success by late breeders (Reed et al 2008). This could arise for a number of reasons; late breeders may be of poorer quality and therefore either more susceptible to the effects of parasitism or carry higher parasite loads, there may be seasonal increases in the prevalence of infectious stages of the parasite or there may be seasonal changes in the ability to deal with parasites or seasonal variation in immune responses. Future work aims to untangle the importance of these different effects.

Part of this work is also in collaboration with The Centre for Ecology and Hydrology, Edinburgh.

We also undertake related projects to address specific problems. For example, one field project in Costa Rica is looking at how parasitism affects a mother's overall level of investment in reproduction in tropical birds and the impact this has on host populations which are quickly becoming a pest of cultivated fruit.