Biotic versus abiotic pollination in Oeceoclades maculata (Lindl.) Lindl. (Orchidaceae)

Abstract

Geographical variation in the reproductive biology of widespread species often occurs at their distributional boundaries. We sought to determine whether such variation has occurred in an invasive orchid, Oeceoclades maculata, across its naturalized range. We compared its reproductive biology in a Brazilian population with that published for a population on the Caribbean island of Puerto Rico. In the state of São Paulo, O. maculata flowers between December and February, at the height of the rainy season. Similar fruit sets were observed in manual self (76%) and cross (70.4%) pollination treatments. The fruit set of plants protected from both pollinators and rainfall was 6.1%, whereas plants exposed only to rainfall had a fruit set of 41.4%, slightly less than the controls (48.3%). Like the Puerto Rico population, reproduction is primarily through rain-assisted autogamy, but unlike observations made on the island, outcrossing can eventually occur. We observed two butterfly species (Heliconius ethilla narcaea and Heliconius erato phyllis) pollinating O. maculata. Secretory epidermal cells and trichomes of the spur lumen produced 0.7 mL of 25% (sucrose equivalents) nectar per flower each morning, which was stored in a dilated basal portion of the spur and reabsorbed by the afternoon. Thus, geographical variation in reproductive biology exists across the broad invasive range of O. maculata.

Biologia reprodutiva de Campylocentrum micranthum (Orchidaceae, Angraecinae)

“…Na área de estudo os indivíduos de Campylocentrum micranthum florescem no verão, entre dezembro e fevereiro, período no qual as chuvas são mais intensas no interior do estado de São Paulo e muitas espécies são encontradas em flor (Pansarin & Pansarin 2008Ferreira et al 2010;Aguiar et al 2012). Em Chiapas, no México, C. micranthum floresce entre abril e maio, e em novembro (Damon & Salas-Roblero 2007).…”

“…Em Chiapas, no México, C. micranthum floresce entre abril e maio, e em novembro (Damon & Salas-Roblero 2007). A ocorrência de diferenças nos períodos de floração é comum em espécies de ampla distribuição e tem sido documentada para orquídeas que ocorrem desde a América Central até o interior do estado de São Paulo (Pansarin & Amaral 2008;Aguiar et al 2012).…”

“…Lindl. (Aguiar et al 2012). No entanto, em O. maculata o nectário apresenta tricomas na porção apical, onde o néctar fica acumulado (Aguiar et al 2012).…”

“…(Aguiar et al 2012). No entanto, em O. maculata o nectário apresenta tricomas na porção apical, onde o néctar fica acumulado (Aguiar et al 2012). Em Orchidaceae, é comum que o néctar produzido seja secretado para o lúmen do nectário, assim como ocorre em C. micranthum.…”

Floral biology of Sesbania virgata: an invasive species in the Agreste of Paraíba, northeastern Brazil

“…The reproductive success was 55.67% in the control (pollination free from visitors) and 27.34% in the treatment of spontaneous self-pollination. Aguiar et al (2012) reported a mixed reproductive system in Oeceoclades maculate composed of crosspollination and autogamy. Similarly to our study species, this system is probably related to its success in colonizing new and isolated habitats.…”