Episodic correlations in behavioural lateralization differ between a poison frog and its mimic

Sensory and behavioural lateralization is thought to increase neural efficiency and facilitate coordinated behaviour across much of the animal kingdom. Complementary laterality, when tasks are lateralized to opposite sides, can increase the efficiency of multitasking, but predictable behaviour may increase predation risk. Laterality is, however, variable in its scale, existing at both the population and individual level. Population level lateralization is thought to facilitate coordination of social behaviours whereas individual level biases may promote behavioural efficiency. We studied behavioural lateralization in sympatric wild populations of two terrestrial frog species: the Ecuador poison frog, Ameerega bilinguis, and its Batesian mimic the sanguine poison frog, Allobates zaparo. We used a multivariate approach to study lateralization across four different behaviours: two social behaviours (interactions with conspecifics and heterospecifics) and two nonsocial behaviours (interactions with prey and a simulated predator). We investigated three questions: (1) at what scale is behaviour lateralized, (2) are behaviours lateralized in a complementary manner, and (3) are social and nonsocial behaviours lateralized at different scales? We found no evidence of population level lateralization nor complementary laterality, and limited evidence for individual level lateralization in Al. zaparo but not Am. bilinguis. We found only weak evidence for differences in lateralization between social and nonsocial behaviour and only in Al. zaparo, although counter to our prediction, social behaviour was not lateralized but nonsocial behaviour was weakly lateralized at the individual level. However, we did detect robust, species- and task-specific within-individual correlations. Specifically, Am. bilinguis showed shared side use in individuals for certain tasks between consecutive trials, while Al. zaparo showed alternating side use in individuals for certain tasks between consecutive trials. Our results suggest that lateralization may be more variable than previously thought and manifest in an episodic fashion under certain conditions.