low to the ground, searching for nests to parasitize. Once a nest is found, studies show that Nomada females assess their hosts nests based on three guiding principles: 1) vulnerability and quality of the host cell, 2) threat of a maternal host's presence, 3) competition with other Nomada bees. These three factors are assessed by the bees' olfactory senses to determine if the nest is provisioned with pollen, if a host bee is nearby or in the nest, if the nest has been parasitized before, and if there are other parasitic bees nearby. The role of male and female cuckoos bees in the parasitism process differs. Before mating, male Nomada will fly locally secreting a scent which mimics the host female. Male cuckoo bees will secrete this scent near host nests to help female Nomada find a nest to deposit eggs. Furthermore, when male and female bees mate, there is evidence that part of the male's secreted scent rubs off onto female bees, which will actually provide an advantage to her finding and entering a host nest. Nomada parasitizes their host cells by laying eggs in host nests while the female host bee is foraging for pollen, or nectar. The female Nomada oviposits in the host's cells before host oviposition and nest cell closure. The female cuckoo bee will lay her eggs in the host's nest and leave. Some species are known to bury the egg at right angles into the cell wall, while some only partially insert the egg. Additionally, Nomada may sometimes leave multiple eggs into one host cell, a frequent trait of kleptoparasitic bees. Using their mandibles, the parasite larvae kill the host offspring and any conspecific larvae until only one is alive. This larva then consumes the host's provisions. This type of parasitism is also known as brood parasitism, where the parasite's offspring develop on the nutrients gathered by the host for its own offspring. Mating behavior Observations of Nomada mating are relatively rare, however there are reports of mating behavior as described below. In five species of Nomada, the main component of male odor secretions was identical to the Dufour's gland secretions of the female host species. The female Nomada interact with the male's secretion during the matting process. There is evidence these secretions help the female Nomada bees recognize the host nests. Furthermore, reports of non-lethal and non-threatening interactions between Nomada and the host