Pollination biology of Agave horrida (Agavaceae) in the Chichinautzin mountain range, in Central Mexico”

Abstract

Background: the predictability of nectarivorous bats and their greater fecundity efficiency promote specialized pollination systems in columnar cactus in central Mexico. Some authors have suggested the same pollination pattern for Agave genus, and even when recent meta-analysis does not find such pattern, they have suggested this could be due to the lack of descriptive studies of pollination for this genus.
 Hypothesis: according to the chiropterophily syndrome of its flowers, the most efficient pollinator of Agave horrida will be nectarivorous bats leading to a pollination system with a specialist tendency in this agave species.
 Studied species: Agave horrida and floral visitors.
 Study site and years of study: lava field of the Chichinautzin mountain range, in Morelos State in Central Mexico in 2005.
 Methods: we studied the floral biology of A. horrida , its floral offer (density of flowers in a given area), visitor rate, and visitor abundance, and conducted exclusion experiments for diurnal and nocturnal visitors.
 Results: A. horrida has protandric flowers with chiropterophilous characteristics (larger nectar production at night and nocturnal anther dehiscence and stigma receptivity). Nectarivorous bats were the most frequent flower visitors and the guild that most frequently presented pollen on their bodies. Pollinator exclusion experiments show that both birds and bats can successfully pollinate A. horrida . Nevertheless, the predictability and abundance of the nectarivorous bat Leptonycteris nivalis , along with the greater fruit and seed production than birds, makes it the most efficient pollinator.
 Conclusions: our results support the hypothesis of a specialized pollination system towards nectarivorous bats in agaves in central Mexico.