Pollination and breeding system of a neotropical palm Astrocaryum vulgare in Guyana: a test of the predictability of syndromes

A pollination and breeding system study was conducted on a neotropical palm , Astrocaryum vulgare, in Guyana, South America, to better understand its r eproductive character evolution, and test the predictability of pollination syndromes. The pollination syndrome approach was used because it integrate s characteristics of flowers and their pollinators into an evolutionary fra mework that allowed experimental testing of predictions. The flowers of A. vulgare displayed traits that were typical of both beetle and wind pollinat ion syndromes. The protogynous inflorescences produced heat and odour durin g nocturnal anthesis, had numerous stamens with copious, light pollen, and were visited by hordes of beetles that used the inflorescences as feeding, mating and oviposition sites. In contrast, some of these features, such as numerous stamens with copious, light pollen, a high pollen to ovule ratio, and no obvious production of visitor rewards, were also typical of the wind pollination syndrome. However, floral rewards appeared to be tissues of th e fleshy staminate petals and pollen that were readily devoured by the beet les. In addition to the Colcoptera, insect visitors to A. vulgare infloresc ences included several species of Hymenoptera, Diptera and Orthoptera. Howe ver, only Nitidulidae and Curculionidae beetles were effective insect polli nators. Pollination treatments showed that wind pollination was possible, b ut fruit set was significantly higher for female flowers visited by beetles . Although a pollen/ovule ratio of 50000:1 and outcrossing index confirmed an outcrossing breeding system, pollination experiments suggested that A. v ulgare had the potential for self pollination. Therefore, the breeding syst em might be best classified as facultatively xenogamous (cross fertilizing) . The predictive value of potential pollinator agents for A. vulgare was in adequate because its floral traits were indicative of both cantharophilous and anemophilous pollination syndromes.