Long tongues and loose niches: Evolution of euglossine bees and their nectar flowers

I examined relationships between tongue length of orchid bees (Apidae: Euglossini) and nectar Spur length of their flowers in the genera Calathea, Costus, and Dimerocostus using phylogenctically independent contrasts. Long-tubed flowers have specialized on one or several species of long-tongued euglossine bees, but long-tongued bees have not specialized on long-tubed flowers. Whereas long tongues may have evolved to provide access to a wider variety of nectar resources, long nectar spurs may be a mechanism for flowers to conserve nectar resources while remaining attractive to traplining bee visitors.