Two Types of Phototactic Behaviour in Anuran Amphibians

Abstract

EARLY studies, such as those of Pearse¹ just after the turn of the century, suggested that anuran amphibians face towards and move to light, particularly light from the portion of the visible spectrum that the human observer sees as blue. Muntz has carried out both behavioural² and physiological³ experiments that suggest this phototactic behaviour in species of the genus Rana is a true colour preference, rather than a response based on apparent brightness. Chapman's⁴ experiments confirm this conclusion for Rana catesbeiana. Because the functional significance of this “blue preference” is still a matter of speculation, we undertook to study anurans outside the family Ranidae to see if other sorts of preferences exist in anurans. Although this comparative study has only begun, we have discovered a different sort of phototactic behaviour, which we here compare with our own replications of the previous work on Rana.