When an animal rotates (whether it is an arthropod, a fish, a bird, or a human) a drift of the visual panorama occurs over its retina, termed optic flow. The image motion is stabilized by compensatory behaviors (driven by the movement of the eyes, head or the whole body depending on the animal) collectively termed optomotor response (OR). Dipteran lobula plate has been consistently linked with optic flow processing and the control of optomotor responses. Crabs have a neuropil similarly located and interconnected in the optic lobes, therefore referred to as a lobula plate also. Here we show that the crab’s lobula plate is required for normal optomotor response since the response was lost or severely impaired in animals whose lobula plate had been lesioned. The effect was behavior-specific, since avoidance responses to approaching visual stimuli were not affected. Crabs require simpler optic flow processing than flies (because they move slower and in 2D instead of 3D), consequently their lobula plates are relatively smaller. Nonetheless, they perform the same essential role in the visual control of behavior. Our findings add a fundamental piece to the current debate on the evolutionary relationship between the lobula plates of insects and crustaceans.

The full description of how animals were prepared are described in the methods section. OR was video taped (videos not included due to large size but could be provided if needed) and tracked. Here we present all the individual tracking files (e.g. 1339.csv) for the three experimental groups (derived from six different batches of animals, collected from their natural environment). For AR we present the individual files (up to 4 animals per file because we had 4 behavioral set ups running in parallel, e.g. yy023.csv) . 

Raw files were further processed (e.g. EXPERIMENTO 10.R) to obtain summary measurements in each batch (e.g. output experimento 10 RO - todo el trial.csv for OR and medidas_resumen_RE_exp15.csv for AR). Finally, these were gathered to produce the final statistical analysis and figures using R software (Todo junto RE y Correlaciones - Trial total.R and Todo junto RO - Exps 10 a 16 - Trial total.R).