Floral Ecology of Coastal Scrub in Southeast Jamaica

A group of species, attracting no visitors, was characterized by a very narrow 'pollination gap,' making self-pollination almost inevitable, and heavy fruiting indicated self-fertility.

Abstract

Species flowering during the dry season (late December to early April) form three main pollinator groups, namely, butterfly, solitary bee, and hummingbird flowers. The animal vectors present match these three flower syndromes. The daily and seasonal rhythms of flower opening and pollination activity are synchronized. Butterflies and solitary bees, active chiefly in the morning, visit flowers blooming only half a day. The number of seeds per fruit and the pollencarrying capacity of the pollen vector are correlated. Butterflies, carrying few pollen grains, chiefly pollinate flowers with one to four seeds. Solitary bees, carrying many grains, chiefly pollinate flowers with many seeds per flower. These close links between the flowers and their visitors result in a high degree of successful pollination and a high percentage fruit set. A group of species, attracting no visitors, was characterized by a very narrow 'pollination gap,' making self-pollination almost inevitable. Heavy fruiting indicated self-fertility. Heterocorollary in Cordia sebestena, a double keel in Stylosanthes hamata, and several examples of andromonoecy are recorded for the first time. The presence of the adventive honeybee, Apis mellifera, in the association appeared detrimental to the native pollinators when forage was scarce. The whole scrub association appears balanced with a distinctive pattern of floral ecology. This circumstance, in terms of pollinators, is designated a Butterfly-Solitary bee-Hummingbird association. STUDIES IN PLANT ECOLOGY seldom include any consideration of the floral ecology. Yet this facet of the life cycle can scarcely be ignored if an assessment of the plant association as a whole is to be reached. Indeed, without the floral data, errors in interpretation of the ecological factors involved may be made. In Salvia, isolation between two species was assigned to edaphic and topographical features, when it was really due to differences in floral morphology and insect vectors (Grant and Grant 1964). Although patterns of floral ecology are tacitly acknowledged to