Of 8 species of a seasonally flowering species of bee plant studied, Cocos nucifera, Veitchia merrillii, Tecomaria capensis, Vitex pubescens and Antigonon leptopus were assessed as having good potential for supplying nectar during dearth flowering periods.
Eight bee plants (Table 20) that flower throughout the year and are much visited by bees were studied to assess their potential as nectar sources, especially for the dearth flowering periods between June and July and between December and January.
Floral characters that affect nectar production include: (a) exposed nectaries result in the nectar drying quickly after which it is not visited by bees (e.g. palm flowers) (b) nectaries with a well-developed vascular system tend to produce dilute nectar (e.g. Callistemon and Coffea) and (c) not surprisingly large nectaries (e.g. Asystasia, Coffea, Cocos, Tecomaria, Veitchia and Vitex) produced more nectar than small nectaries.
For the pattern of nectar flow, all species had a major peak mid-morning (the only exception was Antigonon that had a single peak in the afternoon) and all except the palms had a smaller peak in the afternoon. In palms nectar flow started at 0600 hours and declined steadily until 1200 hours when the nectar of the exposed flower dried up and was not available to bees.
The sugar values for the eight species (Table 20) indicate that the high nectar producers are the female flowers of coconut and the Veitchia palm and flowers of Tecomaria capensis. Taking into account the numbers of flowers produced on a single plant (where short flying distances would reduce the amount of energy expended by the bee), the following species are recommended as better nectar sources, particularly for the dearth flowering periods: Cocos nucifera, Veitchia merrillii, Tecomaria capensis, Vitex pubescens and Antigonon leptopus.
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