The effects of food availability and the presence of the parasite, Plagiorchis elegans, on the probability of Aedes aegypti preimagos to transform from one immature stage to the next over consecutive 24- or 48-hour periods of time were determined. Under conditions of low food availability, 24- and 48-hr transition probabilities of all larval instars, to the next were reduced. Increases in food availability reversed this process, causing significant decreases in same-stage transition probabilities. However, as transition to successive stages increased among first, second, third and fourth instars, there was concomitant significant increase in first and fourth preimago mortality. Addition of Plagiorchis elegans cercariae caused significant decreases in the 24 and 48-hour same-state probabilities for all pre-imago stages. Successive stage transitions for first, second and third instars were significantly increased while those of fourth instars and pupae were significantly decreased following exposure to the parasites. The mortality of all preimago stages significantly increased with exposure to parasite, but was highest among fourth instars and pupae. There were strong food-by-parasite interaction effects among first, second and third instars. Differences in transition probabilities increased with increasing food levels between controlled and parasite-exposed groups. The opposite was true for fourth instars and pupae. While there was no significant interactive effect between food and the presence of the parasite on pupae regardless of food concentration, this was not true for mortality probabilities among fourth instars. Significantly more fourth instars died in response to parasite exposure and there were significant interactive effects of food and parasites on the probability of fourth instars transformation to pupae over 48 hrs.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.20597 |
| Date | January 1998 |
| Creators | Nguyen, Duyen. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Natural Resource Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001642392, proquestno: MQ44231, Theses scanned by UMI/ProQuest. |
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