Selective feeding in response to depletion of particular reserves was examined in the American cockroach, Periplaneta americana. Animals deprived of specific nutrients and subsequently provided with dietary choices, responded so as to restore their altered reserves. Since two foods of differing energy content were used, the fundamental hypothesis of optimality theory could be tested (i.e. do cockroaches behave so as to maximize energy intake?). Adult male cockroaches were placed in a computer-monitored artificial habitat containing routes to shelter, water, protein and carbohydrate. Measures of behaviour were compared over treatments. Treatments included control cockroaches (no starvation), cockroaches fed agar (originally fed protein and sugar), protein-starved cockroaches (originally fed sugar only) and starved cockroaches (no food in the pre-treatment).
In all treatments, more time was spent feeding than drinking. In controls, feeding on carbohydrate took precedence over protein (for intake and duration). Protein-starved cockroaches showed increased intake (over controls) for protein, as expected, but also increased intake for both carbohydrate and water. Starved and agar-fed cockroaches displayed decreased carbohydrate and water intake while protein consumption increased. The compensatory responses showed large initial peaks that gradually approached control behaviour. The results indicate that feeding behaviour is strongly responsive to reserve state and reserves act as an integral part of a dynamic system which operates homeostatically. The fact that depletion of the protein reserve resulted in increased ingestion of both protein and carbohydrate strongly suggests that reserves are linked. Considerable variation in daily feeding was observed which may be related to overshoot/undershoot responses typical of homeostatic systems where time lags exist. The results are strongly at variance with the predictions of optimal foraging theory. Cockroaches appear to feed to homeostatic set points, largely regulated by reserves. Reserves are largely ignored in optimal foraging theory. Furthermore, the animals regulate intake of nitrogen (protein) and/or energy, and do not simply maximize energy intake. / Thesis / Master of Science (MS)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/23165 |
| Date | 01 1900 |
| Creators | Gunderman, Marvin |
| Contributors | Rollo, C. D., Biology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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