Figure 2.

Larval movements in response to 46° probe.

(A) Sequence of larval movement during a stereotyped roll. The tail and head curl in (first image on left), and the body rotates in the opposite direction (2^nd, 3^rd, and 4^th images) until right side up again (5^th image). (B) Example images of aversive behaviors quantified in figures 3 and 4. These include: rapid and simultaneous contraction of the head and/or tail (1^st image); repetitive backwards crawling (2^nd image); lifting and flailing of the head or tail (3^rd and 4^th images); or an incomplete roll (last image).