Domhnall Jennings

I have broad interests across the field of animal behaviour, and this is reflected in the nature of the projects currently running in my lab. Investigating fundamental questions on the evolution of behaviour, and in collaboration with members of my lab, we are looking at how reproductive strategies influence the costs of reproduction for individuals, how maternal stress affects maternal investment in her offspring and its impact on survival, the function and benefits of play and how it changes as the individual develops, and decision making by third-party bystanders in relation to intervention behaviour during escalated fights. Therefore, my interests span:

Parental care and stress: Conflict between parents and offspring over parental resource allocation is expected to arise because offspring should demand greater investment than parents are willing or able to give; specifically, this occurs because parents need to allocate resources to future offspring and to their own survival. Theoretical models thus argue that offspring receiving resources for longer should have increased fitness and probability of survival, and conversely, that their parents should have lower subsequent reproductive success. Therefore, the timing of withdrawal of investment is expected to have important implications for both parties. One feature of care that has received limited investigation in wild animals is the role of maternal stress experienced during pregnancy; we still know remarkably little about the fitness consequences of stress during pregnancy on the mother’s behaviour towards it’s offspring, and how the offspring responds to it this to maximise its own probability of survival. We are currently working on these questions using the European fallow deer as the model species.

Play: Play is a distinct feature of juvenile behaviour in many social and solitary mammals, birds and reptiles. Yet we still have limited understanding about why it is that juveniles predominantly engage in play, and what the ultimate benefits of playing are. Because of it labile nature, play has been described generally as a behaviour that (i) is not completely functional as it does not appear to contribute to immediate survival, (ii) is spontaneous, voluntary, pleasurable, rewarding and done for its own sake, (iii) is awkward, exaggerated and involves modified patterns of adult behaviour, (iv) it involves the repetition of behavioural actions during a play bout (v) and occurs when animals are relaxed. Proposed functions of play have explored the idea that play conveys delayed benefits such as physical training, or establishing and maintaining relationships with group members with which an individual will interact with later in life. However, very few studies have systematically tested how different forms pf play change with age, environmental conditions, and parental investment. By studying the behaviour of fallow deer fawns we are exploring the functions of play to address these questions.

Reproductive investment: Capital breeders such as deer severely reduce the amount of time they spend foraging when reproductively active, instead relying on stored energy for reproduction and related activities and for subsequent over-winter survival. We are investigating whether there is a link between day-to-day behaviour (e.g., territory acquisition and defence, aggression, mating success, resting) and decline in body condition of identifiable males during the annual rut. Moreover, the rutting season directly precedes winter with its consequent decline in forage availability and quality. However, we have a very poor understanding of how low-value, scarce winter forage affects survival, maintenance, and energy restocking by individuals in preparation for high-cost outputs such as antler growth and subsequent reproductive effort. We are currently investigating these and related questions in the fallow deer.

Contest behaviour: Aggression is a key component of animal social behaviour caused by the need for individuals to access limited resources. In the main, contests have been studied by focussing on dyadic fights; however, in the wild many of these encounters are disrupted by the actions of third-party bystanders that actively intervene in the ongoing contest. We have studied the costs and benefits of such intervention behaviour, and are currently investigating the decision processes bystanders use when deciding to intervene. Therefore, we are studying the role that correlates of individual quality, i.e., body and weapon size, play in determining whether these attributes are associated with third-party behaviour in the rutting fallow deer.