Hornworms, Tobacco Hrnworms, Hornworms and Nutrition
Insects that undergo complete metamorphosis (including egg, larval, pupal, and adult stages) obtain no nutrition in the &me between the last larval stage and emergence from the pupa as an adult. In the final larval stage of burrowing insects, such as the tobacco hornworm (Manduca sexta), larvae wander to find soil or detritus in which to burrow, and then burrow, pupate, emerge as fully-‐formed adults, and return to the surface, relying solely on energy stored during the larval stage. I examined the effects of larval nutri&on on wandering behavior and expected that dietary manipulation would delay wandering in both underfed and overfed treatments. I anticipated that duration of wandering behavior decreases in underfed larvae because they need to reserve energy. I predicted increased wandering behavior in overfed larvae because they could use excess stored energy to be more selective in where they burrow. To manipulate energy reserves, I manipulated diet and measured onset and duration of wandering behavior. Weight varied significantly across treatments, with overfed weighing the most and underfed weighing the least. Onset of wandering also differed, occurring first in the control animals and last in overfed larvae. Underfed larvae wandered for a lower percentage of &me than both control and overfed larvae. This study confirmed that nutrition impacts wandering behavior and demonstrates the balance between energetic cost and nutritional benefit. All
Bentzel, Megan, "Nutrition affects onset and duration of wandering behavior in tobacco hornworms" (2014). Thinking Matters Symposium Archive. 5.