Reproductive biology of the Ilex species (Aquifoliaceae) in Hong Kong, China

Abstract

Fourteen wild species of shrubs and trees in the dioecious genus Ilex occur in Hong Kong (22°N, 114°E). All species flowered and formed fruits once each year. Sex ratios at flowering were male biased in all but one large population studied and, in most cases, this bias could not be explained by earlier flowering in males or higher female mortality. Apis cerana accounted for >87% of flower visits in all species and there was a significant positive relationship across species between the number of visits per flower per hour and the estimated mean number of flowers on a plant. The large green fruits of Ilex chapaensis Merr. were consumed only by masked palm civets, Paguma larvata, while the red or black fruits of other species were consumed by birds. The rate of fruit removal across species was positively related to sugar content and negatively related to phenolic and saponin contents. The mean number of pyrenes per fruit was 4.0-6.2 and the mean percentage of pyrenes containing seeds was 49%-90%. Most embryos were immature (heart shaped) at fruit maturity, but <50% of embryos developed further in some species. Floral investment was 0.93-5.84 times higher in male plants, but total reproductive investment was 0.62-8.3 higher in females.