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For many tropical forests a tendency for fruit production to fluctuate seasonally has been established, with pronounced peaks of abundance and periods of fruit scarcity during which a few important resources maintain frugivore communities. However, there is a lack of studies in subtropical forests on community phenology and on the identification of important resources. In this study, community-wide fruit availability and its use by the local frugivore community was investigated in the subtropical coastal dry forest of Oribi Gorge Nature Reserve, South Africa over 13 mo from July 1997 to July 1998. Along 19.5 km of phenology trails, 940 individuals of 96 plant species bearing fleshy fruits were monitored twice per month and fruit-eating animals observed. Although some fruit was available all year round richness of both fruiting species and fruit abundance showed a seasonal pattern with peaks at the end of August to beginning of October (i.e. before the rainy season) and March to May (i.e. after the rainy season). Periods of fruit scarcity were found in July and August (i.e. during the long dry season) and in November and December (i.e. during the rainy season). Fruits of 23 plant species were observed being eaten by 18 species of bird and two of monkey. Highest animal numbers were attracted by Ficus thonningii, a species that fruited asynchronously during most of the year and during periods of fruit scarcity, and provided high overall fruit biomass. The importance of this species as a potential keystone resource for the frugivore community is discussed.

The evolution of pollination systems has been investigated in Zaluzianskya section Nycterinia (Scrophulariaceae), a group characterized by very long‐tubed flowers (up to 60 mm) that open either only at night (19 species) or during the day (one species). Field observations of three species: Z. natalensis, Z. elongata and Z. pulvinata, revealed that their flowers are pollinated shortly after dusk by hawkmoths. Further observations showed that Z. microsiphon, the sole species to have flowers that open only during the day, is pollinated exclusively by long‐proboscid flies belonging to the family Nemestrinidae. A phylogenetic analysis of Z. sect. Nycterinia based on morphological characters indicates that Z. microsiphon evolved within a clade of night‐flowering species. The shift from hawkmoth to long‐proboscid fly pollination in Zaluzianskya was probably facilitated because long corolla tubes, white petals and dilute nectar in hawkmoth‐pollinated flowers are pre‐adaptations for pollination by long‐proboscid flies. However, the autapomorphic features of Z. microsiphon, such as zygomorphy, diurnal flower anthesis and lack of scent, can be regarded as adaptations for long‐proboscid fly pollination. Breeding system experiments on Z. natalensis and Z. microsiphon revealed the existence of genetic self‐incompatibility. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 138, 17–27.

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