Pollination Ecology of Caesalpinia crista (Leguminosae: Caesalpinioideae)

Abstract: The flowering phenology, pollination ecology and breeding system of Caesalpinia crista L. were studied in Dinghushan Nature Reserve, Guangdong, China. The species started blooming in February or March, then last till late April. It took about one week from first flower appearance to its full blooming, which lasted for 2-4 d. The pollen-ovule ratio was 18 000±500. The breeding system was self-incompatible, and protogynous xenogamy. Hymenoptera constituted the major group of pollinators. The pollination type is ambophily, the species could be pollinated by wind if the pollinators were unavailable: this is the first record of ambophily in the genus Caesalpinia. The floral structure adaptation to the pollinating behavior of carpenter bees was described. The influences of artificial treatments in pollination biological studies on the flowering and fruiting of the plants were also discussed. Key words: pollination; ambophily; breeding system; flowering phenology; Caesalpinioideae; Caesalpinia crista Plant reproductive ecology is a vital and highly produc-tive field within modern biology (Lovett Doust and Lovett Doust, 1988; Richards, 1997; Geber et al., 1999). Caesalpinia is a pantropical genus with 120-150 species of trees, shrubs, and lianas, but the study of pollination ecology of the ge