defending themselves when squeezed or antagonized. So, bee suits, such as those required with honey bees, are not necessary when dealing with these bees. When these bees do sting, however, they do not lose their stingers or die after stinging. Human importance Human assistance in pest control In managing M. rotundata for pollination, such methods as dichlorvos pest strips and ultraviolet lamps placed above liquid traps are effective in killing parasitoids, but not harming M. rotundata. Other methods of preventing parasitoid invasion include physical barriers. For example, the presence of thick artificial cavities separating the exterior from the nest and application of a felt cloth sealing to the back of the nesting board prevents parasitoid access to the nest. Another way that pest are controlled is by opening up the nesting material and cleaning the cocoons. Pollination M. rotundata was intentionally introduced into the United States during the 1940s, and its management as a pollinator leads to increases in seed production of some crops in the U.S. It has been shown to pollinate these plant species: Medicago sativa Brassica napus Trifolium spp. Legumes Vaccinium angustifolium Such behaviors as gregarious nesting, use of leaves and nesting materials that have been mass-produced by humans, efficient pollination of M. sativa, and synchronous emergence of adult bees during alfalfa blooming period provide positive benefits for the use of these bees in agricultural development. When these bees are supplied to farmers for pollinating crops, they are usually supplied in a dormant state called prepupal, and kept in such state by a constant temperature of about . At a time that is appropriate for the crop's flowers, the farmer puts the prepupal form in an incubating environment, a constant temperature around The adult bees emerge from the pupal form after about 25 days at that temperature. Then, the farmer brings the bees to the field. See also List of Megachile species References External links Effectiveness of the Alfalfa Leafcutter Bee as a pollinator of legume forage crops (ISHS membership required) How to Manage Alfalfa Leafcutting Bees for Wild Blueberry Pollination rotundata Insects described in 1787 Taxa named by Johan Christian Fabricius