REPRODUCTIVE ECOLOGY OF AN EVERGREEN DRY SEASON-BLOOMING TREE SPECIES, WALSURA TRIFOLIATA (A. JUSS.) HARMS (MELIACEAE)

Abstract

Walsura trifoliata is an evergreen dry season-blooming hermaphroditic tree species. The flowers are nectariferous and characterized by urceolate androecium, strong protandry and secondary pollination mechanism, protruded bifid stigma displaying receptivity, self-compatibility and facultative xenogamy without the function of spontaneous autogamy. The floral traits indicate generalist pollination syndrome and adaptation for entomophily, with bees effecting mostly geitonogamy and wasps and butterflies effecting mostly xenogamy. Fruit-set is highest in xenogamy. Fruit is a globular drupe with 1-2 seeds embedded in fleshy aril. Seed dispersal modes include zoochory, barochory and hydrochory. The study shows that the function of generalist pollination syndrome, entomophily, facultative xenogamy and polychory enable this tree species to achieve highest fruit-set, maintain genetic variation through cross-pollination, and disperse its seeds to different distances in the forest ecosystem.