Evidences that genetically determined melipona queens can become workers.

IHERING (1903) suggested that caste determination in Melipona (Hymenoptera Apidae) was not phenotypic but was possibly determined by some mechanism before the egg was laid. On the basis of observations by many authors, we can say that in all genera of social Apidae, except Melipona, caste determination is controlled by quantity or quality of food or both. KERR (1946) found in four colonies of Melipona quadrifasciata Lepeletier and one of Melipona marginata Lepeletier that workers and queens emerged from the same type of cells. Queens were randomly scattered and emerged in a fixed proportion. This proportion appeared to be 12.5% in M . quadrifasciata and 25% in M . marginata. It was postulated that M . quadrifasciata queens are heterozygous for three genes and M . marginata queens for two. By this hypothesis, homozygosis for 1, 2, or 3 genes would cause the insect to be a worker. During the winter the percentages of queens produced dropped to 3.45 in M . quadrifasciata and 6.50 in M . marginata. Four other papers have since been published on the subject of caste determination in Melipona. KERR (1948) gave data on five additional colonies of M . quadrifasciata, two of M . marginata and one each of Melipona nigra Lepeletier, M . melanouenter Schwarz and M . rufiuentris Lepeletier. M . rufiuentris, M . nigra, and one colony of M . quadrifasciata gave proportions of queens closer to 25% than 12%. KERR (1950a) gave more information on two colonies each of M . quadrifasciata and M . interrupta Latreille and one colony each of M . melanoventer and M . fauosa (Fabricius). KERR (1950b) proposed tentatively that caste had been determined phenotypically in the ancestors of Melipona and that a succession of gene mutations resulted in the genotypic mechanism. It remained to be explained why queens are not produced in winter, or in poorly fed colonies. KERR, STORT, and MONTENEGRO (1966) examined this problem to find whether caste determination was purely environmental, or if genetic factors contributed as well. They concluded that the following factors have no bearing on caste determination: (1 ) temperature; (2) eggs eaten by the queen; (3) time spent by the queen feeding herself from the brood cell; (4) number of eggs laid by the queen in the same brood cell; (5) increase of protein ratio within the nest. They found that each alveolus is normally filled by four to 11 workers and the entire operation takes from 15 to 64 seconds. Queens emerged from cells provisioned by four to eight