Fly pollination and pollinator sharing in two synchronopatric species: Cordia multispicata (Boraginaceae) and Borreria alata (Rubiaceae)

Abstract

The floral biology of Cordia multispicata (Boraginaceae) and Borreria alata (Rubiaceae) was studied in naturalpopulations in a fragment of the Atlantic forest in Pernambuco, northeastern Brazil. Both species flower during almost the whole year.Cordia multispicata is a shrubby species with white, distylous and tubular flowers. Borreria alata is a herbaceous species. Its flowersare whitish, tubular and have a polymorphism in relation to the size of their style. Floral anthesis in both species begins at 6:00 a.m.Sugar concentration in the nectar was about 16% in C. multispicata and 30% in B. alata. Nine species of flies, mainly of the genusPalpada (Syrphidae), were observed visiting flowers of the two species. Seven of them were observed visiting and pollinating flowersof both C. multispicata and B. alata. Two species visited only flowers of C. multispicata, whereas no fly was exclusive to B. alataflowers. Both species have similar flowermorphology, flowering time, habitats in the forest and establish populations very close to eachother. These facts can favour the pollinators' sharing and increase pollinator attraction.Foi estudada a biologia floral e a poliniza o por moscas em Cordia multispicata (Boraginaceae) eBorreria alata (Rubiaceae) em popula es naturais em um remanescente de floresta Atl ntica em Pernambuco, Nordeste do Brasil. Asduas esp cies florescem durante quase todo o ano. Cordia multispicata uma esp cie arbustiva, dist lica comflores brancas, pent merase tubulosas. Borreria alata herb cea, tamb m com flores esbranqui adas e tubulosas, apresentando um polimorfismo com rela o aotamanho do estilete, em flores da mesma infloresc ncia. A antese floral em ambas as esp cies inicia s 6 h. A concentra o de a caresno n ctar em m dia de 16% em C. multispicata e de 30%emB. alata. Nove esp cies de moscas, principalmente do g nero Palpada(Syrphidae), foram observadas visitando flores das duas esp cies de plantas, entre as quais sete esp cies foram observadas polinizandoflores de C. multispicata e de B. alata. Duas esp cies foram exclusivas a C. multispicata e nenhuma visitou exclusivamente flores deB. alata. Ambas as esp cies apresentam morfologia floral, "habitat" e per odo de flora o semelhantes, al m de estabelecerempopula es pr ximas umas das outras. Estes fatos podem favorecer a partilha de polinizadores e aumentar o potencial de atra o dasflores dessas plantas.