Pollination and breeding system of a population of Tall Coconut Palm Cocos nucifera L. (Arecaceae) on the Gazelle Peninsula of Papua New Guinea

Abstract

Tall Coconut Palms Cocos nucifera L. on the Gazelle Peninsula of Papua New Guinea are almost exclusively (96.3%) insect pollinated. Pollination is most likely to occur in the late afternoon when the number of insect visitors to pistillate flowers increases. Two species of halictid bees, Homalictus cassiaef/oris and H. dampieri, are most likely responsible for most of the pollination. On Gazelle Peninsula Coconut Palms, the pistillate receptive phase partially overlaps with the staminate phase in the subsequently produced inflorescence, and on average 27.8% of fruits are a result of self-fertilization, indicating a mixed breeding system. The self-fertilization rate varies between individuals and with time of the year, and is related to the degree of fertile staminate and pistil ate phase overlap between inflorescences. The flexibility in the breeding system appears to confer potential adaptive flexibility on Coconut Palms because they are able to self-pollinate if individuals become established in areas devoid of other Coconut Palms.