Cameron Lab - Systematics and Biology of Social Hymenoptera

Evolution of mimicry pattern in bumble bees

Mimicry, as defined by the dual hypotheses of Bates (1868) and Müller (1879) that edible and inedible (repulsive) species gain a selective advantage by sharing similar color patterns, has been an exciting evolutionary theme since the last century— Darwin considered it one of the more convincing arguments in favor of natural selection.  Through the following century, the theory generated considerable controversy, and arguments were put forth as evidence and counter-evidence.  However, since Wickler’s (1968) eloquent synthesis of the underlying principles of mimicry, one could imagine that the subject is “done”.  Far from it!  We are just now in a position to shed true light on mimicry through recent research on phylogeny, genetics and development in natural populations. 

The new research on developmental and genetic mechanisms of color pattern variation for mimicry as well as other signaling systems, in combination with robust phylogenies of the organisms, is spearheading a synthesis in our understanding of the evolution of phenotypic diversity, its function and selective value.

My lab has completed a comprehensive worldwide phylogeny of Bombus (step 1 in understanding the evolution of mimicry patterns) and is mapping the aposematic color patterns in bumble bees worldwide (step 2).  With a phylogeny for the entire genus and worldwide distribution maps of each species, we can demonstrate the multiple independent, convergent color patterns comprising Müllerian mimicry rings— intraspecific polymorphism allows additional tests of mimicry.

The phylogenetic pattern allows insights into whether there are constraints on phenotypic variation in color pattern, and what they might be. 

A color sport of B. impatiens, in which reddish-brown abdominal stripes have replaced the normally all black hairs of tergites 2 - 5.

   (c) Lorenzo Rodriguez