Figure 2.

Locomotor Behavior of robo Mutant Larvae

(A–F) Characteristic tracks of first instar larvae. OrR (A) and heterozygous robo mutant alleles (D–F) explore by alternating straight movements with turns. robo mutant larvae perform circular crawls (B and C).

(G and H) Representative crawling patterns depicted by perimeter stacks. OrR larvae perform pause turns (G) (asterisk) by bending the anterior part of the body. robo mutants crawl in circles without performing turns (H). See also Movies S1, S2, S3, and S4 and Figure S2 for a detailed description of the behaviors.

(I) Number of forward and backward waves per minute.

(J) Duration of forward and backward waves in seconds.

(K) Distribution of duration of forward peristalsis for all waves analyzed. The gray box highlights the duration of waves in OrR larvae. Binning is 200 ms; OrR n = 375; robo¹/robo² n = 471; robo²/robo⁸ n = 319.

(L) Number of pause turns per minute.

(M) Number of rearing events per minute.

(N) Proportion of transitions. The number of pauses turns + rearing movements divided by the number of forward waves + backward waves was calculated. There are no significant differences between any genotype.

A Kruskal-Wallis test with Dunn’s multiple comparison was used in (I), (J), (L), (M), and (N). Forward and backward waves were compared independently. Asterisk (^∗) indicates comparison with robo²/+; + indicates comparison with the other heterozygote control; and # indicates comparison with OrR. ^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗p < 0.001; ⁺⁺⁺p < 0.001. 32–41 larvae were evaluated per group. Boundaries of boxplots represent first and third quartiles; the middle line indicates the median. Whiskers indicate the highest and lowest value of each experimental group.