The role of nectar production, flower pigments and odour in the pollination of four species of Passiflora (Passifloraceae) in south-eastern Brazil

Abstract

The pollination biology of four species of passionflower was studied in south-eastern Brazil, specifically the importance of chemical features of floral nectar, pigments and odours. All species required pollinators to produce fruits: I! alata was pollinated by bees, l? speciosa by hummingbirds, and l? galbana and l? mucmnata by bats.Pollinators consumed nectar as a food source. The activity of vertebrate pollinators reflected resource availability: they foraged when large amounts of nectar were available and when quantitative resource predictability was greater. The nectar of the vertebrate-pollinated species was richer in cholesterol and phospholipids, and had a potassium-sodium ratio higher than 1.0. For all species, the light absorption of flowers was paralleled by the pollinators' visual spectral sensitivity. This first report on Passiflora floral volatile compounds showed that there was a greater chemical class diversity among the species pollinated by animals with an acute olfactory sense, such as bees and bats. Benzenoid alcohols were the most represented compounds. The fragrances contained compounds that occur in other plant species and in the exocrine secretions of bees. This study shows a strong association between pollinators and the attracting and rewarding features of flowers.

Reproductive biology and pollination of Aechmea distichantha Lem. (Bromeliaceae)

“…On the other hand, concentration was greatest early, at the beginning of anthesis, and gradually declined. Th is suggests that the fl ower reabsorbs the solutes, as has been observed in other hummingbirds pollinated species (Freitas & Sazima 2001;Varassin et al 2001) including Bromeliaceae (Canela & Sazima 2003). While concentration was independent of volume in A. distichantha, in A. pectinata both varied during anthesis (Canela & Sazima 2003).…”

Influência de abelhas africanizadas na concentração de açúcares no néctar de soja (Glycine max L. Merrill) var. Coodetec 207

“…Tal comportamento é influenciado pelas características florais, tais como a morfologia, características químicas e recompensas (VARASSIN et al, 2001). O néctar é considerado a principal recompensa para o polinizador (DELAPLANE;MAYER, 2000) e sua Acta Scientiarum.…”

Produção de néctar e visitas por abelhas em duas espécies cultivadas de Passiflora L. (Passifloraceae)

“…Para abelhas Xylocopa Latreille, 1802 e Bombus Latreille, 1802 a quantidade de recurso disponível afeta o número e a freqüência de visitas (Kawai & Kudo 2008). Em Passifl ora, foi observado que a produção de néctar pode estar associada ao comportamento de seus polinizadores (Varassin et al 2001). A produção de frutos em P. edulis e P. alata é diretamente dependente dos serviços de polinização, uma vez que as espécies são auto-incompatíveis (Akamine & Girolami 1959;Hoff mann et al 2000).…”

“…A produção de néctar durante o período diurno da antese ocorre em várias espécies de Passifl ora (Varassin et al 2001, Fischer & Leal 2006, Longo & Fischer 2006. Em ambas as espécies de maracujá, as abelhas X. frontalis e B. morio, em parte de seu período de atividade, parecem responder à reposição contínua de néctar visitando as fl ores de forma constante.…”