Can Ornithophilous Hawaiian Lobeliads Produce Seeds in the Absence of Pollinators? A Test UsingClermontia kakeanaandCyanea angustifolia(Campanulaceae)

Abstract

The native Hawaiian bird-pollinated flora is primarily composed of five ornithophilous lobeliad genera, collectively containing approximately 140 species. Historically, these genera were believed to have been pollinated by at least some of the 10 specialist nectarivorous bird species endemic to Hawai‘i. However, since human colonization, both bird and ornithophilous native plant species have undergone wide-scale declines and extinctions, resulting in the potential loss of pollination for this component of the native flora. In an attempt to assess if lobeliad species can produce viable seeds in the absence of pollinators, two pollination treatments (open control and pollinator exclusion) were applied to two Hawaiian lobeliad species [Clermontia kakeana Meyen and Cyanea angustifolia (Cham.) Hillebr.] in single populations of each species on O'ahu. In each lobeliad species, mean seed counts were not significantly different in fruits resulting from open-pollinated and pollinator-excluded flowers. This suggests that both species are capable of autogamy and can produce seeds in the absence of pollinators.