Table 1. A list and description of all behavioural attributes used for locomotion analysis in this study.

Name	Unit	Description	Cluster
Bending	$\circ$	The bending angle (BA) is the angle between the larva’s tail vector and a vector from the middle of the larva to its head. Positive values indicate the larva bending to the left, negative values bending to the right. ‘Bending’ in this study refers to the absolute, i.e., direction-independent BA.	1
Bending bias		The absolute of the average of all BA values of a larva, divided by the average of all absolute BA values: $\text{abs}\left(\overline{BA}\right)/\left(\overline{abs\left(BA\right)}\right)$. The bending bias is constrained between 0 and 1, with 0 indicating a larva was bending equally to left and right, and 1 indicating a larva was only bending into one direction (no matter which direction).	3
HV angular speed	$\frac{\circ }{s}$	The head vector angular speed (HVAS) is the angular speed of the head vector (HV) through the head of the larva. Positive values indicate movement of the head to the right, negative values to the left. ‘HV angular speed’ in this study refers to the absolute, i.e., direction-independent HVAS.	1
HV angular speed bias		Calculated analogous to the bending bias. Constrained between 0 and 1, with 0 indicating a larva was moving its head equally fast to left and right, and 1 indicating a larva was moving its head only into one direction.	3
HV angular acceleration	$\frac{\circ }{s^2}$	The absolute angular acceleration of the head vector (HV).	1
TV angular speed	$\frac{\circ }{s}$	The tail vector angular speed (TVAS) is the angular speed of the tail vector (TV) through the rear half of the larva. Positive values indicate movement to the right, negative values to the left. ‘TV angular speed’ in this study refers to the absolute, i.e., direction-independent TVAS.	1
TV angular speed bias		Calculated analogous to the bending bias. Constrained between 0 and 1, with 0 indicating a larva was moving its tail equally fast to left and right, and 1 indicating a larva was moving its tail only into one direction.	3
TV angular acceleration	$\frac{\circ }{s^2}$	The absolute angular acceleration of the tail vector (TV).	1
HC rate	$\frac{HC}{s}$	The number of head casts (HC) per second. HCs were defined as events of an HVAS larger than 35 °/s or smaller than –35 °/s, respectively.	1
HC rate bias		The HC rate of HCs to the left minus the HC rate of HCs to the right, divided by the total HC rate. Constrained between 0 and 1, with 0 indicating a larva had equal HC rates to left and right, and 1 indicating a larva was making HCs in only one direction.	3
HC angle	$\circ$	The head cast angle (HCA) indicates how much the orientation of the animal changes upon each HC. It is defined as the difference between the BA at the end and the beginning of the HC. Positive values indicate that the larva changes its orientation to the left, negative values that it changes its orientation to the right. ‘HC angle’ in this study refers to the absolute, i.e., direction-independent HCA.	1
HC angle bias		Calculated analogous to the bending bias. Constrained between 0 and 1, with 0 indicating a larva was making equally large HCs to left and right, and 1 indicating a larva was making HCs in only one direction.	3
Distance travelled	$bl$	The distance of the complete path a larva travels during the observation period (measured in body lengths [bl]).	2
Midpoint speed	$\frac{bl}{s}$	The speed of the larva’s midpoint, irrespective of direction.	2
Midpoint acceleration	$\frac{bl}{s^2}$	The absolute acceleration of the larva’s midpoint.	2
Tail velocity	$\frac{bl}{s}$	The velocity of the larva’s tail point in a forward direction, i.e., in the direction of the tail vector.	2
Tail acceleration	$\frac{bl}{s^2}$	The absolute acceleration of the larva’s tail in the direction of the tail vector.	2