soda straws. In the wild, females also create nests in small holes in the ground or in available cracks/crevices in trees or buildings. The nests are composed of a string of individual cells, as many as the space will allow. When managed for pollination, the females are induced to nest in paper cylinders similar to drinking straws or drilled blocks of wood. Each cell is made from circular disks cut from plant leaves using the bee's mandibles, hence the name "leafcutter". Females use about 15 leaves per cell, called a concave bottom, overlapping the leaves to produce the thimble-shaped cell. While the bees do not store honey, females do collect pollen and nectar which they store in the cells of their nests. Specifically, females first regurgitate the nectar they have provisioned into the cell and then transfer the pollen that is attached to their scopa on top of the nectar. Each cell contains one pollen and nectar ball, and one egg with each cell containing a 2:1 nectar-to-pollen ratio. The completion of one cell in the nest requires between 15 and 20 provisioning trips. After the female lays her eggs, she seals the cell with circular leaf pieces. Nest dimensions and sex ratio Studies reveal that positioning of male and female progeny in the nest is strategic and that cell size plays a major role in the size of progeny, independent of the mother's size. Females have been observed to lay female eggs in the inner cells and male eggs in the outer cells. With respect to sex ratios, larger cell provisions are correlated with a greater production of female offspring. Two explanations exist for these behaviors in terms of mother's foraging behaviors: 1) The mother brings more provisions to the inner cells because she expects that female progeny will be produced there and 2) the mother chooses to fertilize her egg, and therefore promotes the production of female progeny, because she has to bring larger provision proportions to a larger cell. The sex ratio changes depending on nest size, length, and nesting material. This ratio is controlled by the female. These observations have been made for females that make their nests in tunnels. For example, a 5.5 mm tunnel, diameter is associated with a 3:1 ratio and a 6.0 mm tunnel diameter is associated with a 2:1 ratio of males to females. Shorter tunnels, those that are below 5.0