Pollination Requirements and the Foraging Behavior of Potential Pollinators of Cultivated Brazil Nut (Bertholletia excelsaBonpl.) Trees in Central Amazon Rainforest

Abstract

This study was carried out with cultivated Brazil nut trees (Bertholletia excelsaBonpl., Lecythidaceae) in the Central Amazon rainforest, Brazil, aiming to learn about its pollination requirements, to know the floral visitors of Brazil nut flowers, to investigate their foraging behavior and to determine the main floral visitors of this plant species in commercial plantations. Results showed thatB. excelsais predominantly allogamous, but capable of setting fruits by geitonogamy. Nineteen bee species, belonging to two families, visited and collected nectar and/or pollen throughout the day, although the number of bees decreases steeply after 1000 HR. Only 16, out of the 19 bee species observed, succeeded entering the flower and potentially acted as pollinators. However, due to the abundance, flower frequency and foraging behavior of floral visitors, it was concluded that only the speciesEulaema mocsaryiandXylocopa frontaliscould be considered relevant potential pollinators.

Research Article Contemporary pollen and seed dispersal in natural populations of Bertholletia excelsa (Bonpl.).

“…The predominance of outcrossing in B. excelsa was previously reported in a study on the mating system using genetic markers (O'Malley et al, 1988;Wadt et al, 2015). In contrast, a study of the species based on hand pollination showed that self-fertilization did not result in fruit production, suggesting that the species is self-incompatible or presents inbreeding depression (Cavalcante et al, 2012). However, self-incompatibility may be latent or vary by an individual due to genetic mechanisms, meaning that at some stages of tree fertility self-fertilization may occur or some trees may be selfcompatible allowing self-fertilization to occur.…”

“…The IBD pollen dispersal pattern can be explained by the behavior of pollinating bees. B. excelsa is pollinated by medium and large bees of the Bombus, Centris, Xylocopa, and Epicharis genera, as well as some species of Euglossinae (Maués, 2002;Cavalcante et al, 2012). While these species can fly over long distances, they forage within restricted areas when there are many trees flowering, thus resulting in short distance pollen dispersal (Janzen, 1971).…”

“…excelsa is predominantly outcrossing, hermaphroditic species (O'Malley et al, 1988), with a mellitophylous pollination syndrome ; its floral morphology restricts the entry of visiting insects, allowing only those with the physical strength and body size compatible with the flower structure to act as effective pollinators (Maués, 2002). The main visitors and pollinators for B. excelsa are the bees of the genera Bombus, Centris, Xylocopa, and Epicharis, as well as some species of Euglossinae (Maués, 2002;Cavalcante et al, 2012). Flowering occurs in the early rainy season during which there is an abundant supply of nectar and pollen for the pollinators (Maués, 2002).…”

“…Flowering occurs in the early rainy season during which there is an abundant supply of nectar and pollen for the pollinators (Maués, 2002). The fruit set is dependent on natural pollinator activity (Cavalcante et al, 2012), and fruit formation occurs only when there is mating between trees; therefore, despite the possible occurrence of selfing , gene flow may play a key role in fruit production. Fruits are primarily dispersed by barochory, due to their significant weight (0.5-1.5 kg; Costa et al, 2009), and dispersed secondarily by rodents of the genera Dasyprocta and Sciuridae (Haugaasen et al, 2010).…”

Revisiting the ‘cornerstone of Amazonian conservation’: a socioecological assessment of Brazil nut exploitation

“…Since the fungus thrives when nuts remain on the forest floor for extended periods of time (Hudler 1998), Brazil nut producers are encouraged to dry nuts post-harvest to avoid contamination. The construction of drying structures became part of a series of 'best management practices' outlined in the extension literature (Cardó 2000;Wadt et al 2005;APIZ 2008). While FSC standards for Brazil nuts have been developed in Brazil, Peru and Bolivia, there are few experiences of FSC certification on the ground, since it is perceived as costly as it attempts to cover too many forest management dimensions for what is considered a non-destructive harvesting activity (Duchelle et al 2014b).…”