PhD Exit Seminars: Keryn Bain and Alicia Guerrero Vega
Rountree Room, D26, UNSW
(Supervisor: A/Prof Alistair Poore)
Predicting herbivore diets: The importance of intrinsic and extrinsic factors.
Consumer prey interactions have important consequences on the structure and composition of ecological communities. In the field, consumer diets vary widely both among and within species. This variability can be attributed to intrinsic factors acting on individuals that alter preferences and extrinsic factors that alter their ability to obtain resources. As a consequence, what is consumed by an individual at a given time often does not reflect the total dietary niche of that species or even the life span of that individual. For this research, I use a common generalist herbivore, the marine gastropod Lunella torquatus, as a model consumer to examine the intrinsic and extrinsic constraints on diet choice. First, I establish a method using near infrared reflectance spectroscopy (NIRS) to measure the diets herbivores in the field and then use a combination of field surveys and lab experiments to identify how extrinsic and intrinsic factors impact the diets of marine herbivores. Given the slow mobility of this herbivore relative to others, we examine the impact of macro algae availability across temporal and spatial scales and we assessed the effect of recent diet on subsequent foraging patterns and behaviours.
ALICIA GUERRERO VEGA
(Supervisor: A/Prof Tracey Rogers)
The dietary and thermoregulatory role of blubber as revealed by fatty acids
The development of a specialised fat tissue, or blubber, was crucial for mammals to enter the water. Blubber serves as an energy reservoir, where surplus energy is deposited in the form of fatty acids (FAs). I have used FA analysis to understand the dietary and thermoregulatory roles of blubber in marine mammals.
I analysed FAs in two Antarctic seals to obtain long-term dietary information and conducted a meta-analysis including 48 mammals in order to understand the role of FAs in thermoregulation.
I found that FAs are good indicators of diet, particularly in specialist predators. However, mammals also regulate their FAs to fulfil their thermal needs. Semi-aquatic mammals, for example, regulate their FAs according to the latitudinal region they inhabit. This can improve the quality of their blubber without making it extremely thick; which keeps them warm in the water but also allows them an agile movement on land.
Refreshments will be provided after the seminars in the Wilton Tearoom, Level 1, Samuels Building