Functional dioecy and moth pollination in Cabralea canjerana subsp. Canjerana (Meliaceae).

Abstract

Cabralea canjerana subsp. canjerana is a common species in the Atlantic Forest, occurring in several areas of this biome. Yet, little is known about its reproductive strategies. This study aims to understand the reproductive biology of this subspecies, including floral biology, sexual system, and pollination biology. Male and female plants have morphologically similar flowers, but male plants have larger inflorescences with more flowers than female plants. Female flowers remain open and receptive for two days, whereas male flowers last only one day; thus, compensating for the imbalance of the number of flowers per plant between the two sexes. Morphologically similar male and female flowers, as observed in C. canjerana subsp. canjerana , are rare among dioecious species. The high frequency of moths visiting the flowers, the timing of flower opening (anthesis) and the production of nectar suggest that moths are the pollinators of this subspecies. In contrast to the floral dimorphism found in C. canjerana subsp. polytrica , variations in floral morphology are unrelated to the plant sex in subsp. canjerana . This and other results found in this study suggest that the subspecies of C. canjerana might be different species.