The Rusty patch bumblebee (Bombus affinis) is the first continental US bee to be declared endangered. US Fish & Wildlife said in its announcement that the bee's population has shrunk by 87% since the late 1990's. There are several species of bees on Hawaii that are also endangered. Loss of wild habitat is the main reason for the bumblebee's decline. Approximately 40% of Earth's land area is used by man to produce food. Bees play an enormously important roll growing food plants pollinating about 35% of them, from tomatoes to blueberries. Without the services of pollinating insects such as the bumblebee and monarch butterfly laborious hand pollination will be required. According to the Xerxes Society about 25% of bumblebees in North America are at risk of extinction.
Unlike honeybees, bumblebees live in colonies underground and only live for a year except the queen who remains dormant underground during the winter then emerges in the spring to found a new colony with eggs prepared in the fall. Back in the 30's it was popularly thought that the flight of the bumblebee was aerodynamically impossible--its short, stubby wings not exerting enough lift for its rotund body. Today, science has solved that problem thanks to high speed photography. Writing in the journal of the National Academy of Sciences in 2005, Michael Dickinson of the University of Washington, observed that rather than flapping their wings up and down, bumblebees flap their wings back and forth creating a low-pressure, wing-tip vortex that provides the necessary lift force.