Abstract
All organisms have evolved the ability to detect, process, and respond to many different forms of environmental stimuli. These sensory experiences can also be stored and later referenced in the form of memory. The Drosophila larva is a simple model organism that can store associative memories during classical conditioning, and is well-suited for studying learning and memory at a fundamental level. Thus far, the behaviors and neural circuits important for olfactory learning have been identified in D. melanogaster larvae. However, this depth of knowledge is currently underrepresented with regard to other larval sensory systems. Here, we investigate memory formation in larvae treated with a temperaturebased associative conditioning protocol, pairing normally neutral temperatures with appetitive (fructose, FRU) or aversive (salt, NaCl) stimuli. Associative memory was evaluated using linear and radial thermal gradients. We quantified navigation strength towards or away from conditioned temperatures to assess the effectiveness of temperature as a conditioned stimulus. Larvae formed appetitive memories and approached temperatures when they were paired with FRU. Aversive memories were also formed when warmer temperatures were paired with NaCl. Although, larvae approached colder temperatures when NaCl was present or paired with them. These results, especially when combined with future investigations of thermal memory circuitry in larvae, should provide broader insight into how sensory stimuli are encoded and retrieved in insects and more complex systems.