Fine-scale differences in diel activity among nocturnal freshwater planarias (Platyhelminthes: Tricladida)

Table 2 Relationship between light and activity

species	r ²	p	type	trend
D. polychroa	0.005	0.87	lin	-
D. tigrina	0.653	<0.01	log	-
P. tenuis	0.0003	0.97	lin	+

Correlations between diel light irradiance and planarian activity, using the values reported in Figure 1 (n = 8 and df = 6 for each correlation). Best fitting correlations are reported for each species; lin = linear and log = logarithmic relationships; positive and negative trends are reported as "+" and "-", respectively.