Pollination ecology ofZizyphus mauritiana (Rhamnaceae)

Abstract

At Visakhapatnam (17°42′N-82°18′E)Zizyphus mauritiana Lam. blooms twice a year, once during September–January (first season) and again during March–June (second season). The flowers are compatible to geitono and xeno pollen. They are strongly protandrous and pass through distinct developmental stages. While the first 2 flowers of umbel are invariably complete, the succeeding ones either develop up to the male stage or continue through the female. The flowers in the 2 stages are more numerous in the first season than in the second. They decrease as the seasons progress. Two plant types occur. In one, the flowers anthese at 0600 h (early) and in the other at 1000 h (late). The stigmas of the late type receive pollen in the latter half of their receptive period, first from the early and then from the both. Those of the early type receive pollen of the late type in the beginning of receptive period, and in the last quarter first from the early and then of the both. A population with only one plant type has the stigmas receiving pollen in the last quarter of their receptive period. Pollen in the male stage and nectar in the female constitute the reward to the insect visitors that included bees, wasps, flies, ants and butterflies. The former 3 groups proved to be effecting pollination, among whichApis florea, Ceratina sp.,Trigona sp.,Ropalidia spatulata, Chrysomya megacephala andSarcophaga sp. are the major pollinators.