Anthophora bee upside down in Digitalis lanata flower

Digitalis lanata Ehrh. Scrophulariaceae Woolly or Grecian foxglove. Distribution: Eastern Europe. It contains large amounts of cardiac glycosides, such as Digoxin, which are used to treat heart failure by increasing the force of contraction of the heart. Digoxin is now made synthetically and the plant is no longer used. Cardiac glycosides are very toxic and the difference between the therapeutic and the toxic and fatal dose is small. Toxic effects include vomiting, slow heart rate, xanthopsia (vision becomes coloured yellow). It is visited by Anthophora Latreille bees (a tentative diagnosis), and one can find these lying upside down in the flowers, apparently intoxicated. On tapping them out, they fall straight to the ground. If placed onto one's palm they lie upside down until turned upright, where they remain with their wings outspread, not moving except to 'buzz' occasionally for several minutes before flying off. Anthophora bees are solitary bees which live in colonies. Photographed in the Medicinal Garden of the Royal College of Physicians, London.