We studied the reproductive biology and pollination ecology of the palm cabecinegro (Manicaria saccifera) in very wet tropical forest, in the Chocó, Pacific region of Colombia. We present data about the phenology, floral morphology, floral biology, reproductive system, and pollination. M. saccifera is monoecious, self-incompatible, lacks apomixis and has dichogamy in the form of protogyny. Flowering occurs all year round with a peak between April and May. A single individual may produce up to five inflorescences in its reproductive period. Each inflorescence has unisexual flowers grouped in dyads and triads; anthesis is diurnal and the flowers may be receptive for 72 h. Flowers are visited by 10 species of insects. The inflorescences in the female-phase do not offer reward and insects are attracted by olfactory mimicry; in the male-phase flowers reward visitors with pollen and a place to oviposit. The most efficient pollinator is Mystrosp cercus (Nitidulidae), the only visitor arriving in abundance during the female-phase. Other insects do not enter the flower because the peduncular bract and the petals act as barriers, blocking the entrance of insects greater than 2 mm. Having one exclusive pollinator which in turn depends on the palm for its survival is an example of extreme specialization and mutual dependence.way [3,4], and finally, palms are culturally important because many species are essential to the cultural development of local peoples [5].Due to this importance, studies on their reproductive biology have increased in the last decades [6]. Initially, most studies focused on cultivated palms or on widely used species [1,7]; however, recent works have focused on a wider range of palms [8][9][10].Research on the reproductive biology of this plant family has increased our knowledge on the great variety of pollination strategies and mechanisms found in plants and on the strong dependence and intimate association that most palm species share with the insects that pollinate them, mainly species of coleoptera belonging to the families Nitidulidae and Curculionidae [9][10][11]. Due to palms economic, ecologic and cultural importance, studies on palms reproductive biology are essential for their sustainable use, conservation and future domestication [10].Manicaria saccifera is a widely distributed species [12], of ecological importance [1,13] and great economic potential [14,15]. It ranks among the most utilized and economically valuable palms for the Afro-American and indigenous communities of the Chocó biogeographic region: [16] reported 36 different uses for this species, evidencing its versatility as a non-timber forest product. The most significant uses of M. saccifera in the Pacific region of Colombia include: the use of the peduncular bract as a source of fiber for crafts and textiles [15][16][17];weaving the leaf veins for basketry [15]; the use of unexpanded leaves for brooms; the leaves for thatch houses; the immature fruits filled with a liquid resembling coconut water are consumed while working in the...