Sex Determination and Caste Production

Abstract

Like all Hymenopterans, bees are holometabolous; they pass through a series of anatomical and physiological changes, from larva to adult, called metamorphosis (Savard et al. Genome Res 16:1334–1338, 2006; Fig. 4.1). In holometabolous insects, there are five main stages in the ontogenetic development: egg, larva, prepupa, pupa, and adult or imago. After the larva hatches, it experiences a rapid growth. Because the rigid outer cuticle prevents the expansion and growth of the body, the larva needs to shed it in a series of molts or ecdysis. The regulation of growth and the ecdysis is under the effect of various hormones, the most important being the juvenile hormone (JH), insulin, and ecdysone (Hartfelder et al. Apidologie 37:144–163, 2006; Nijhout and Callier. Annu Rev Entomol 60:141–156, 2015). During the larval phase of the bee, there are four molts and five stages (Dade. Anatomy and dissection of the honeybee. International Bee Research Association, 1985). There is also a fifth molt between the prepupal and pupal phases, plus a final one between the pupal and the imago phases, making a total of six molts throughout the ontogenetic development.