Comparative study in stingless bees (Meliponini) demonstrates that nest entrance size predicts traffic and defensivity - Couvillon, M. J; Wenseleers, T; Garófalo, Carlos Alberto; Imperatriz-Fonseca, Vera Lucia; Nogueira Neto, Paulo; Ratnieks, F. L. W (Journal of Evolutionary Biology, 2008)