The Breeding System and Pollinators of Melastoma affine (Melastomataceae); A Pioneer Shrub in Tropical Australia

Abstract

Melastoma affine D. Don. (Melastomataceae) is a pioneer species of rain forest and wet-sclerophyll habitats in the Australasian region. The breeding system and pollen vectors of Melastoma affine in the Mt. Spec region, North Queensland, were investigated over two seasons. Melastoma affine is self-compatible but does not produce fruit via autogamy or apomixis, i.e., pollen vectors are required for fruit set. The colonizing success of this species is thus dependent on the presence of a pollinator population. Eight bee species were commonly recorded at the nectar-less flowers of M. affine; although only Lestis bombylans, Nomia sp., Amegilla anomola, and Xylocopa near gressitti consistently contacted the stigma during foraging. When sunny weather prevails natural fruit set in M. affine reaches 90 percent, reflecting high visitation and subsequent pollination by such pollinators (...)