Technical Abstract: Several Osmia (Osmia) species, O. cornifrons, O. cornuta, O. lignaria, O. ribifloris, O. rufa, have been studied and developed as crop pollinators.These species share several biological traits that facilitate their management at the commercial scale. They all nest in pre-established cavities, readily accept artificial nesting materials, and the larvae spin thick multi-layered cocoons that provide protection during management. All of these species also share a common life cycle. They are univoltine, early-flying bees, that over-winter as adults. Females nest for about a month in late-winter or spring, and immatures develop throughout spring-summer. In late-summer or early-fall they reach adulthood and remain inside their cocoons as dormant adults that will emerge the following spring. Recent studies have investigated the respirometry and developmental biology of O. cornuta in Spain and O. lignaria in the USA. These studies have established temperature requirements for the development and wintering of these species, and allowed us to improve prediction and manipulation of emergence periods. The possibility of advancing or delaying emergence facilitates the use of these pollinators on a variety of crops flowering at different times of the year. Improved artificial control of Osmia development and emergence is potentially important for pollination of crops whose blooming period is advanced under artificial heat conditions in greenhouse environments.