‘Good Heavens what insect can suck it’- Charles Darwin, Angraecum sesquipedale and Xanthopan morganii praedicta

In this review we provide a detailed description of Darwin's prediction of the coevolution of a long-spurred orchid, Angraecum sesquipedale, and a long-tongued moth, his correspondence on the subject, the history of the moth and the subsequent literature. On seeing the long spur of A. sesquipedale, Darwin predicted that its pollinator would be a moth with a long proboscis. For more than a century following Darwin's prediction this was assumed to...