Angraecoid orchids and hawkmoths in central Madagascar: specialized pollination systems and generalist foragers

Studies on hawkmoth pollination in a primary forest in central Madagascar indicated that at least five of six flowering, long-spurred angraecoid species exploited the same hawkmoth, Panogena lingens. as a pollen vector. Several other long-tongued hawkmoth species were present, but no evidence was found that they participated in orchid pollination. The pollinaria of Angraecum arachnites, A. compactum, Neobathiea grandidierana, and Jumellea teretifolia were deposited on the basal portion of the proboscis. The latter three species utilized the same dorsal portion of the proboscis, whereas attachment by A. arachnites was ventral. The pollinaria of Aerangis fuscata were deposited on the frons and palps. Hawkmoths frequently carried mixed loads, but at least ethological and mechanical mechanisms seemed to restrict interspecific pollination. The P. lingens-angraecoid orchid relationship may have reached a specialized state before progenitors of other long-tongued Sphingidae colonized or evolved in central Madagascar.