Fig. 1. The egg-laying sequence exhibits variable transitions between component actions.

a, Illustrations depicting component actions of the egg-laying behavioral sequence. Components comprising exploration, deposition and reset phases are indicated. The colors used in text and boxes here indicate component actions in all subsequent figures; PE, proboscis extension. b, Order of occurrence of the first instance of each behavioral component depicted as a fraction of total events. Only events including all components were analyzed (169 of 176 events). c, Representative ethograms of egg-laying behavior in five flies (n = 4 events per fly). Here and in e, bend is drawn wider to emphasize that this behavior is maintained throughout burrow, egg out and detach behaviors. Horizontal black dashed lines demarcate data from different flies. Here and in d, t = 0 marks the time of completed egg expulsion (egg out). d, Average time course of the seven annotated behaviors depicted as the instantaneous fraction of total events; n = 176 events from 18 flies. e, Diagram depicting the start-to-start transition probabilities between the seven annotated behaviors. An asterisk indicates transitions occurring significantly higher than chance (P < 0.001, one-sided permutation test; Methods and Supplementary Table 2). Transitions with probabilities less than 0.04 were not significant and were omitted from the diagram. Self-transitions indicate that the behavior started, stopped and started again without the initiation of any other intervening behavior.