Api-TRACE: A System for Honey Bee Tracking in a Constrained Environment to Study Bee Learning Process and the Effect of Lithium on Learning

Learning is an adaptive behavior that improves the performance of bees in foraging, dance communication, predator avoidance, and other tasks. Any deficiencies in learning could be detrimental to the long-term survival of the bee colony. Passive avoidance task is a fundamental procedure for investigating learning. We introduce Api-TRACE, a computer vision-aided system to analyze the avoidance assays. Api-TRACE tracks individual bees from the video footage of the assay and detects the moments when they were exposed to a stimulus. The algorithm provides stimulus exposure duration and learning profiles of each individual bee, enabling fast and detailed analysis of the results. Electric shock avoidance assay is one of the most common experimental methods to assess learning. We designed an apparatus for the electric shock avoidance experiments using within-reach hardware and 3D-printed components. We used Api-TRACE and experimental apparatus to investigate the effect of lithium on bee learning success in passive avoidance and reversal learning paradigms through an electric shock avoidance assay. Lithium is a potential chemical for combating Varroa, a bee (Apis) parasite, and a well-known medication for treating bipolar disorder. It has been known that lithium alters learning in humans and other animals. Before the experiment, we treated the bees with a sucrose solution with 0, 5, 25, and 125 mM LiCl ad libitum. Our results indicated that a decrement in learning performance emerged with increasing lithium doses in the reversal phase but not in the acquisition of the electric shock avoidance assay.