concentrations and, in older females, 5-monoene compounds predominate. During mating season, males are able to detect these pheromones and preferentially select young females to copulate with. Interaction with other species Diet M. rotundata can feed on nectar and pollen from a variety of plants but prefer Medicago sativa. Females will immediately begin feeding after emergence during the maturation period of their eggs. During feeding, the bee will insert its proboscis into the keel of the plant. In the process, pollen is brushed onto its scopa. Predators Currently, 28 species are known to prey on M. rotundata, all of which have unique ways of invading and destroying their host nests. Some species include Trogoderma glabrum, Trogoderma variabile, Tribolium audax, Tribolium brevicornis, and Trichodes ornatus. T. ornatus is the most formidable predator, with females laying their eggs in cracks between leaf pieces. During development, T. ornatus larvae kill host bee larvae and consume pollen from nest provisions. When it reaches the third stage of development, it burrows into adjacent cells and consumes host larvae irrespective of host larval instar stage. In another case, female T. glabrum females lay eggs in cracks between cells at the back of the nest. As they develop, the larvae begin to consume host larvae, moving towards the front of the nest and eating females first. In a third case, T. variabile attacks M. rotundata when it is in its cocoon or the pupal stage. Parasites Various families of wasps are the primary parasites of M. rotundata. Some species include Pteromalus venustus, Monodontomerus obscurus, Melittobia chalybii, Diachys confusus, and Sapyga pumila. The most formidable predator of this species is P. venustus, a parasitoid wasp in which the female uses her ovipositor to sting a developing M. rotundata larvae or pupae. After stinging to paralyze its host, the female lays her eggs on the host's surface and the development of the parasite offspring takes place. After about 15–20 weeks, adults of P. venustus emerge. Other parasites include several species of Coelioxys and Nemognatha lutea. Coelioxys spp. take advantage of instances when females of M. rotundata are away from the nest, such as during foraging, to lay their egg in the host nest cells. Once a Coelioxys reaches the larval stage, it will kill the developing, host larva and consume all of the provisions that the host female placed in the nest. N. lutea, in contrast, initiate parasitism of hosts