cm long, are less favorable. Nest recognition During nest construction, females transfer olfactory cues onto their nests to facilitate nest recognition. Specifically, they transfer these hormones by running their abdomens along the nest or excreting liquid from the tip of the abdomen. The olfactory cues are especially concentrated around the nest entrance. When these olfactory cues were experimentally removed, females of M. rotundata were unable to identify their own nests, revealing the importance of these chemicals. The chemical composition of these olfactory cues includes hydrocarbons, wax esters, fatty aldehydes, and fatty alcohol acetate esters. Colony cycle As a member of the Hymenoptera order, this bee is haplodiploid. Adults emerge by the end of the summer through one of two developmental pathways: larvae will develop by the end of one summer and proceed through the a prepupal diapause phase until the next summer, or larvae, known as "second-generation" bees, skip this phase and emerge as adults in the same summer. The larva transitions through four instar stages before emerging as an adult. During its development, which occurs rapidly, the larva consumes the pollen ball and enters diapause when the pollen is fully consumed. In its progression into the diapause phase, the larva defecates pellets in a ring formation and then spins its cocoon out of silk threads. The next spring, the mature larva pupates, a process that lasts 3–4 weeks, and completes its development. Once the bee is developed, it cuts its way out from the nest by chewing itself out of its cocoon. Upon emergence, females mate immediately and begin constructing their nests after a week. Progeny released via the two alternative pathways for emergence display different sex ratios and sizes. Among adults that emerge during the summer of the same year, the sex ratio is biased towards males. Among the "second-generation bees", however, the sex ratio is female biased. Further, spring-emergent adults weigh more than summer-emergent ("second-generation") adults. These differences have been proposed to be attributed to the chances of survival to mating of the two sexes and the metabolic costs involved in development. Bees that undergo diapause and emerge in the spring must endure the long winter, so require more food stores. As a result, they will be larger when they mature. Another explanation has been that smaller bees mature faster, thus are able to mate more quickly when they emerge in the summer to avoid the cold,