Interação multualista entre morcegos nectarívoros(Chiroptera) e a pata-de-vaca Bauhinia Holophylla Steud. (Fabaceae) em uma área de cerrado: atração e recompensa

Abstract

(Attraction and reward of nectar-feeding bats (Chiroptera: Phyllostomidae) by the plant Bauhinia holophylla (Fabaceae) in a Brazilian savanna) In facultative mutualisms, species compete strongly with each other for partners. It is expected that sympatric plant species pollinated by the same guild of animals invest heavily in attracting partners. Thus, we investigated interactions between Bauhinia holophylla and bats to test whether: (1) this plant is visited mostly by bats and if it assures attraction of bats through typically chiropterophilic floral traits; and (2) bats adjust their foraging behavior to the temporal pattern of nectar production by flowers. We worked in a Cerrado area in southeastern Brazil, recording floral visitors and their foraging pattern. We determined nectar production and how its concentration varied throughout the night. Three species of bats were the main legitimate visitors. Bauhinia holophylla floral characteristics followed predictions of the chiropterophyly syndrome: brush format, white color, sweet odor, crepuscular anthesis, nocturnal nectar production and flowers exposed on branches. Bats visited flowers more often at dusk, there were differences in the main hours of overflight, reconnaissance flight and visitation. Solute concentration in nectar was always highest at the beginning of the night and fell gradually thereafter. Bats did not visit more flowers when nectar concentration was higher. We conclude that in this interaction dependence is asymmetric, following patters of other facultative mutualisms, because Bauhinia holophylla depends on bats for its pollination, but bats presumably do not depend on it for food.