Pollen characterization of the bee flora from a Caatinga area of Northeast Brazil

Abstract

Background: Plants and bees have coevolved throughout geological time, establishing a mutualistic relationship that results in feeding/resource obtention by bees and the reproductive success of angiosperms. Questions and Hypotheses: What is the floristic composition of the vegetation visited by bees in the Caatinga? How are pollen grains from Caatinga bee plant species characterized? Do pollen grains of bee plant species present characters that could be associated with the pollination process? Studied species: We studied the pollen grains of 45 bee plant species belonging to 41 genera and 23 angiosperm families. Among the studied species, 37 % are endemic to Brazil, and eight species are endemic to the Caatinga biome. Study site and dates: Apiary within the Caatinga biome, in the State of Bahia, Brazil. Climate warm semiarid. Fieldwork was carried out between August 2016 and June 2017. Methods: Plants in bloom and being visited by Apis mellifera were collected during biweekly field expeditions, herborized, identified, and deposited at the HUNEB herbarium. Pollen grains were acetolyzed, characterized, and microphotographed under light microscopy. Results: Forty-five bee plants were collected and classified according to field observations and specialized literature. Pollen morphology was variable, and nine species had their pollen morphology described for the first time. The apertures of the studied pollen grains were mainly tricolporate (44 %), pantoporate (15 %), and inaperturate (13 %), and exine ornamentation was mainly (micro)reticulate (46 %) and (micro)echinate (33 %). Conclusions: Our results suggest that bee plants present a set of palynological characters that may favor entomophily. Translate stop   Translate stop