Fig. 10. Flow chart diagrams of gap-crossing behaviour. Arrows connect any two elements of behaviour that were performed in direct transition (bigrams), pointing from the first to the second element. The size of arrow (see key) represents the ²-values of the corresponding bigrams (explained in the text; see Materials and methods). Arrows marked by c connect behavioural elements performed by limbs of contralateral body segments (e.g. left antenna and right front leg). Only bigrams that occurred more than twice and with higher probability than expected in a random distribution (P0.001) have been included in the flow chart. `Typical' combinations that represent steps described in the text are schematically displayed on the right side: (A) tentative step, (B) gap-crossing step, (C) gap-crossing step without searching movement. Black, elements and transitions that occur in both the 30 mm and 50 mm trials; red, elements and transitions that occur only in the 30 mm trials; green, elements and transitions that occur only in the 50 mm trials; FL, front legs; ML, middle legs; HL, hind legs; Ant, antennal. For further abbreviations see Fig. 1 (sections of gap crossing) and Fig. 5 (ethogram; elements of behaviour used in the flow chart diagram are printed red).