Innate food preference in the larval tobacco hornworm, Manduca sexta

Food preference can drive an organism to seek a specific food source even if another food, which can provide needed nutrition, is easier to obtain. Food preference can develop in different ways, including innate preference, i.e., organisms display food preference at birth, or learned preference, i.e., organisms develop food preference after previous experience with that food. The tobacco hornworm, Manduca sexta, shows learned preference; however, we lack information about innate food preference in Manduca. Manduca sexta larvae eat many different foods until they feed on a solanaceous plant, when they become more specific in their diet. This study focused on naive Manduca sexta larvae to determine if they show innate food preferences. Because early juveniles seek out solanaceous plants if they hatch on a different family of plants, I predicted that Manduca sexta prefer solanaceous plants over artificial food designed for captive animals. Based on trends seen in other studies, I also predicted that Manduca prefer plants that have not been fed upon previously. To test my predictions, Manduca sexta were allowed to choose from live plants with damaged leaves (to simulate previous feeding by other insects), live plants with undamaged leaves, or lab food. I recorded which food source Manduca approached first and latency to select food. I found that there is no significant difference between latency time, or between the plant and lab food trials. There was a significant difference between the damaged and undamaged plant