SEX DETERMINATION IN BEES. IV. GENETIC CONTROL OF JUVENILE HORMONE PRODUCTION IN MELIPONA QUADRIFASCIATA (APIDAE)

Warwick Estevam Kerr ¹, Yukio Akahira ¹, and Conceição A. Camargo ¹

¹ Department of Genetics, Faculdade de Medicina, Universidade de São Paulo—14100—Ribeirão Preto, S.P., Brazil

Cell number and volume of corpora allata was determined for 8 phases of development, the first prepupal stage to adults 30 days old, in the social Apidae Melipona quadrifasciata. In the second prepupal stage a strong correlation was found between cell number and body weight ( r=0.651^**), and cell number and corpora allata volume in prepupal stage (r=0.535^*), which indicates that juvenile hormone has a definite role in caste determination in Melipona. The distribution of the volume of corpus allatum suggest a 3:1 segregation between bees with high volume of corpora allata against low and medium volume. This implies that genes xa and xb code for an enzyme that directly participates in juvenile hormone production. It was also concluded that the number of cells in the second prepupal stage is more important than the weight of the prepupa for caste determination. A scheme summarizing the genic control of sex and caste determination in Melipona bees in the prepupal phase is given.