Aposematic Coloration in Adults and Larvae of Lygaeus equestris and Its Bearing on Müllerian Mimicry: An Experimental Study on Predation on Living Bugs by the Great Tit Parus major

Abstract

Aposematic forms gain mutual protection from predation as long as they share some striking feature, e.g., a red and black or yellow and black color pattern. To test whether a bird generalizes between adults and larvae of L. equestris (both instars were colored red and black), 18 great tits, P. major, were offered either adults or larvae in 4 consecutive trials, and the opposite instar in 4 subsequent trials. The bugs were attacked in 45% of the trials, but only 2 were completely consumed; 69% of the adults and 33% of the larvae survived an attack. The number of attacks increased between trials 4 and 5, and birds attacked the 2nd presented instar as fast and as frequently as the instar first presented. Although similar proportions of adults and larvae were attacked during trials 1-4 and 5-8, overall mortality was lower during the last set of trials, but only significantly so for the larvae (larvae: P = 0.028; adults: P = 0.261). It does not suffice for 2 Muellerian mimics, or 2 aposematic forms, to possess some striking feature in common to gain mutual protection from predation. Two aposematic forms must be very similar to gain full mutual protection. Results add to the understanding of the reason for the close resemblance so commonly encountered not only between Batesian mimics and their aposematic models but also between Muellerian mimics.