Fig. 1: Perturbation of the butterfly compass.
From: Neural representation of goal direction in the monarch butterfly brain
a Schematic drawing of the flight simulator (modified from ref. 6). b Virtual flight trajectories of three butterflies. The red dot represents the starting point. c For a consistent goal direction relative to the sun, butterflies follow a sun displacement of e.g., 180°. d The flight heading of one butterfly before and after sun displacement. Magenta lines represent the mean heading. e The butterflies (N = 32) followed the sun displacement as indicated by ratios between change in heading and sun displacement clustering around one. f The butterfly brain (anterior view78;) with the central complex highlighted. g The neurons’ mean vector length (MVL) of tuning was longer than for shuffled data (n = 113, p < 10−5, W = −10878, two-sided Wilcoxon test). Boxes and whiskers show 25th/75th and 5th/95th percentile respectively and the median. h Angular tuning of two neurons (green and blue) before (left) and after (right) a 180° sun displacement. Black lines indicate the neurons’ preferred firing directions (pfds). (Right) The MVL of the neurons (gray dotted lines) and a distribution of calculated MVLs from shuffled data are shown. i Angular tuning of compass neurons and putative goal direction (GD) neurons before (left) and after (right) compass perturbation. For each neuron, the tuning of the two most directed flights are shown. Neurons are ordered according to their pfds before compass perturbation. Each neuron’s firing rate (FR) is normalized against its peak firing rate. j Correlation of the angular tuning before and after compass perturbation (p = 0.001, U = 1027) and k heading offset variances in response to compass perturbations (p = 0.0054, U = 1113) for putative GD (blue, n = 58) and compass (green, n = 55) neurons (two-sided Mann–Whitney U test). Low heading offset variances indicate that the pfds were linked to the butterfly’s heading. Error bars in (j) and (k) represent the interquartile range (middle line indicates the median). l The distributions of pfds of compass (left) and putative GD neurons (right) uniformly tiled the angular space (Rayleigh test). Source data file: datasource.xlsx Fig. 1.
