Grouping rule in tadpole: is the numerical quantity or size-assortative more critical?

Abstract

The ability to perceive group size and discriminate the ontogeny of conspecifics would play a crucial role in the grouping behavior of animals. However, the relative importance of numerical quantity and size-assortative preferences in shaping grouping rules remains poorly understood. In this study, I examined the responses of Miyako toad (Bufo gargarizans miyakonis) tadpoles to number quantity and size discrimination by choice tests at different ontogenetic stages (small, medium, and large). The results revealed that small-sized tadpoles in early developmental stages significantly preferred larger numbers (4) compared to smaller ones (1). However, this preference was not observed in later developmental stages (medium and large). And interestingly, when there was no group size bias, size discrimination was not observed in tadpoles, irrespective of their ontogeny. These findings suggest that Miyako toad tadpoles possess innate numerical competence but demonstrate ontogeny-dependent utilization of this ability. Understanding the interplay between numerical quantity and size-assortative preferences in grouping behavior will provide esteemed insights into the adaptive value of number sense in vertebrates and sheds light on evolutionary processes.