Miniature queens in stingless bees: basic facts and evolutionary hypothesesMárcia de F. Ribeiroa, Tom Wenseleersb, Pérsio de S. Santos Filhoa and Denise de A. Alvesa
a Depto. de Ecologia, Instituto de Biociências, Universidade de São Paulo, R. do Matão, trav. 14, n. 321, 05508-900 São Paulo, SP, Brazil
b Laboratory of Entomology, Zoological Institute, Catholic University of Leuven, Naamstraat 59, 3000 Leuven, Belgium
(Received 1 November 2005 - accepted 31 February 2006 - published online 22 June 2006)
Abstract - Some stingless bees are known to produce both large queens, reared from larger royal cells, and small "miniature" queens, reared from worker cells. Here we review what is known about miniature queens, and evaluate some major evolutionary hypotheses as to why they are produced. One hypothesis - that miniature queens are females who selfishly evade an intended worker fate - is shown to receive significant support. In particular, there is increasing evidence that the decision to become a miniature queen may be under genetic control of the developing females themselves. In addition, data from several species show that females gain significant fitness benefits from doing so, since miniature queens are frequently observed heading colonies and often are as productive as normal-sized queens. On the other hand, in some species miniature queens have a reduced fecundity or may have lower chances of being chosen as a new queen. This shows that the strategy may also have costs. Queens of the genus Melipona, which are also reared from worker-sized cells, are suggested to have the same evolutionary origins as miniature queens.
Key words: queen dimorphism / miniature queens / stingless bees / caste fate conflict / Apidae / Meliponini
© INRA, DIB-AGIB, EDP Sciences 2006