Learning to survive and thrive: oviposition learning and memory in gravid Manduca sexta and Drosophila melanogaster

Insect learning in foraging and oviposition shows adaptability. This thesis investigates the impact of learning on oviposition behavior, exploring how different insect species associate sensory cues with food sources or predators and how social learning enhances survival strategies. This research's findings show that moths and flies altered their oviposition preferences upon learning. Despite their innate preferences (e.g., tobacco hawkmoth for Datura, flies for parsnip), both species showed learned preferences for less preferred (e.g., Nicotiana for moths, apple for flies) after training, suggesting learning plays a critical role in oviposition decisions. One notable finding is the difference in learning efficiency between moths and flies. Moths, specifically Manduca sexta, displayed a faster learning rate, adjusting oviposition behavior after a single egg-laying experience, whereas flies required multiple experiences. Both species retained learned information for 24 hours in moths and four days in flies. This thesis also investigated the phenomenon of oviposition constancy in female hawk moths, analogous to flower constancy in pollinators. Results showed hawk moths preferred the same plant type for egg-laying after initial use, even with other options available. This behavior likely enhances efficiency by allowing quick location of familiar plants, conserving energy and time. The motivation for ovipositional learning remains unclear. In foraging learning, it is established that nectar serves as the reward, but there is a scarcity of understanding reward in oviposition learning. Overall, understanding experience-based learning in insect behavior is essential for predicting species responses to environmental changes, understanding evolutionary pressures, informing pest management strategies, and supporting effective conservation strategies for vulnerable species.