Limits to learning: effects of predator pattern and colour on perception and avoidance-learning by prey

Abstract Abstract. Animal learning is constrained by the ways in which environmental information is perceived, processed and assimilated into a representation of the animal's environment. Colour and pattern, cues used to learn and remember the location of resources, may also be used to learn and remember the location of predators. Avoidance-learning by stingless bees, Trigona fluviventris , was explored at spider orb-webs that were identical in design but differed in colour and at webs that were similar in colour but different in design. Trigona fluviventris are able to see and learn to avoid spider orb-webs. Their rate of learning, however, varies with web visibility, a function of contrast between the web and its background, and, more specifically, with the spectral properties of the silk. More bees were initially intercepted at webs spun by Argiope argentata than webs spun from unpigmented silks by Nephila clavipes (webs of similar spectral properties but different design). However, bees learned faster to avoid Argiope webs indicating that interception and escape are important components of the learning process. Fewer bees were intercepted at yellow pigmented webs than webs spun from unpigmented silks by N. clavipes (webs of different spectral properties but identical design) even though yellow webs reflected less light. However, bee avoidance-learning was slow at yellow webs. These findings suggest that bee avoidance-learning may be influenced by how chromatic information is processed by insect visual systems. Spiders may have evolved to construct webs that make use of cues that insects strongly associate with food rewards, thereby confounding the insect's ability to learn and remember the web as dangerous.