ectotherms. Body size can influence many aspects of an individual’s physiology, while temperature and nutrition are two major variables that influence an animal’s body size. Obtaining the appropriate amount and ratio of nutrients is vital for development, while temperature affects an animal’s physiology through its impact on biochemical reactions. Additionally, body size and temperature may affect the quantity and ratio of nutrients an animal needs through their effect on metabolic rate. This thesis investigated the interaction of body size, temperature and nutrition using two species of Australian locusts (Orthoptera: Acrididae), Chortoicetes terminifera and Locusta migratoria.ududChapter 2 tested whether the nutritional requirements of an individual differed with body size and temperature. The results showed that body size and temperature interacted to affect the thermal limits of an individual and subsequently the ratio of nutrients consumed. Chapter 3 investigated whether body size and temperature influence an individual’s ability to supply themselves with the required nutrients while eating grass (rather than synthetic food). Larger locusts were less efficient at extracting and absorbing nutrients than smaller locusts. Results also indicated that the anatomical structure of the grass and locust mandible structure were both important. Chapter 4 examined whether body size would influence thermoregulatory behaviour, as thermoregulation can be used to adjust metabolic rates and consequently nutritional needs. The smaller locusts spent the majority of their time at the hotter temperatures in a thermal gradient arena, while the larger locusts spent most of their time at both the hotter and cooler temperatures. These results suggest that body size influences the physiological processes that individuals prioritise through temperature selection.
展开▼
