| dc.description.abstract | Animal behaviours, from foraging to build sufficient energy stores to the depletion of resources in the pursuit of increased reproductive success, relate to energetics. In this thesis, together with collaborators, I explored how extrinsic environmental factors and intrinsic individual traits, including physiology, are associated with animal behaviours in an endangered population of loggerhead sea turtles (Caretta caretta). In Chapter 2, I specifically examined the link between foraging ecology and reproductive success. I show that higher-quality foraging environments result in increased body condition in the form of fat reserves, a proxy for energetic resources, to be invested into reproduction. I also show that feeding ecology and infection status by a leech parasite (Ozobranchus margoi) were associated with transgenerational carry-over effects, altering offspring performance in fitness tests. Then, in Chapter 3, I endeavoured to examine the interplay between environmental and genetic determinisms of foraging strategy. As expected, environmental factors strongly correlated with stable isotope ratio variation. I found evidence, however, for indirect links between heritability (mtDNA lineage), turtle size, and foraging strategy. In Chapter 4, I focused on specific dive behaviours determined from tri-axial accelerometer and depth sensors deployed on nesting turtles. After classifying dives and their functions, I found that dive behaviours correlated with island-specific conditions as well as turtle physiology, whereby infected individuals adopted behaviours associated with reduced energy expenditure. Finally, in Chapter 5, I evaluate the development of an economical GSM-related GPS tag to record and send high-resolution, real-time positional information to examine habitat use by nesting turtles. I identified coastal areas of high use and explored connections between turtle physiology and movements. Interestingly, across all studies, turtle behaviour varied with parasite infection, likely because of the trade-offs involved between maintaining an active immune system and the energetic demands associated with foraging specifically and movements in general. This work therefore highlights the importance of considering individual health in future movement and foraging ecology research. Overall, this thesis uses a comprehensive approach to identify the underlying physiological conditions that drive the evolution of life-history traits in a wild population and presents findings that can impact future conservation decisions. | en_US |
