In order to maintain exploratory search behavior in a fly larva without starving it, the robot automatically delivers a drop of apple juice (≈0.1 g/mL sugar concentration). The larva is allowed to eat for 1−2 min, after which the robot uses water and air to rinse the larva, which then continues roaming freely. This protocol allows for continuous observation of larval behavior over developmental time scales. (A) The larva’s trajectory over a 30 hr duration, with its path (green) stitched together by matching each corresponding robot pick-up and drop-off positions (orange markers) by translation (no rotation, e.g. up is always toward same edge of agar) to produce a continuous trajectory. The larva begins at the top right and ends its run at the bottom (purple markers). (B) A ×20 magnification on a small section of the path, showing the scale of the path compared to the larva’s body (black bar, ≈ 1 mm). (C) We plot a number of behavioral features observed during its search trajectory, including its speed (red), body bend angle (orange), trajectory curvature (green), turn rate (blue), turn size (purple), and turn handedness (olive). Turn handedness is calculated as , such that a handedness of 1.0 indicates all left turns, and a handedness of −1.0 indicates all right turns. Dotted gray lines indicate time of robot pick-up events.