female usually chooses a cavity as its nesting site. If the entrance is too large, a mud wall about 8-9mm thick may first be built in which a hole about in diameter is made. The mud is gathered in small balls by the mandibles, transferred progressively to the fore, mid and hind legs, and deposited in the pollen basket on the hind leg. About six balls make a load, three in each basket and the female flies back to the nest site. Inside the cavity, a pedicel is constructed on which an urn-shaped cell is built. The mud hardens as it dries. Initiation of a nest begins with mud collection for the mud wall, entrance, pedicel, and first brood cell. This process can take up to four days. Therefore, all trips on the very first day of nest construction are devoted to mud collection. After the first brood cell is nearly complete, the female will begin to collect both mud and resin, which will be used to line the cell on the second day. After the cell is lined, almost no mud is collected on the third day. A female will spend almost three quarters of her time foraging for larval food collection, and the rest for resin collection. Once the brood cell is complete, oviposition will occur, the collar will be pushed in, and the cell will be covered with mud. The construction of additional cells follows a similar timeline, although there is less mud collection now that the mud wall and entrance have been built. It was noted by Cameron and Ramirez in a study done on the nest architecture of the E. meriana that less time was required to build successive cells after the first. Some nests were also observed to be reused. Clusters of older cells and decomposing females were found in some of the cells, covered with a layer of mud. Brood cell construction Each brood cell is filled two-thirds of its volume with a pale yellow, sticky pollen/nectar mixture. Females returning to the nest with this sticky substance attached to their corbiculae deposit it into the only open brood cell. The female E. meriana follow a specific ritual after placing this pollen mixture into a cell. They make a rotation with the posterior part of the body inside the cell and forelegs around the resin collar. It is suggested that this allows the pollen