Nectar characteristics and pollinators for three native, co-occurring insectpollinated

TORRES, C.; DAMBOLENA, S.; ZUNINO, P.; GALETTO, L.

The international journal of plant reproductive biology

The Society of Plant reproductive biologists

Lugar: Agra; Año: 2012 vol. 4 p. 121 - 126

0975-4296

Floral biology, nectar traits and pollinators were studied in different species of Passiflora, co-occurring in their southern area of distribution. Volume, concentration, and sugar amount of nectar per flower were measured in the native, insect-pollinated Passiflora caerulea, P. foetida and P. suberosa (Passifloraceae). Qualitative and quantitative nectar sugar composition were determined and compared between species. Pollinators were recorded and related to both floral and nectar traits. Flowers of the three species display the usual floral sexual phases described for the genus. In general, nectar traits were variable between species but relatively constant within each one. Nectar sugars were glucose, fructose and sucrose in relatively constant proportions among samples of the same species, but each species showed a particular sugar composition (P. foetida, P. caerulea and P. suberosa with lower, intermediate and higher proportion of sucrose, respectively). Bombus spp. and Xylocopa splendidula were recorded as the main pollinators for P. caerulea; Bombus opifex, Melissoptila sp., and Thygater sp. for P. foetida, and different species of wasps for P. suberosa. Bees seem to prefer larger amounts of nectar with hexose predominance, while wasps less amount of almost pure sucrose nectar. These species of Passiflora need pollinators to assure high fruit and seed sets. On the other hand, plants of these species mature many birddispersed fruits every season indicating that plant-pollinator interactions are healthy although the actual high rates of deforestation in the region.Passiflora, co-occurring in their southern area of distribution. Volume, concentration, and sugar amount of nectar per flower were measured in the native, insect-pollinated Passiflora caerulea, P. foetida and P. suberosa (Passifloraceae). Qualitative and quantitative nectar sugar composition were determined and compared between species. Pollinators were recorded and related to both floral and nectar traits. Flowers of the three species display the usual floral sexual phases described for the genus. In general, nectar traits were variable between species but relatively constant within each one. Nectar sugars were glucose, fructose and sucrose in relatively constant proportions among samples of the same species, but each species showed a particular sugar composition (P. foetida, P. caerulea and P. suberosa with lower, intermediate and higher proportion of sucrose, respectively). Bombus spp. and Xylocopa splendidula were recorded as the main pollinators for P. caerulea; Bombus opifex, Melissoptila sp., and Thygater sp. for P. foetida, and different species of wasps for P. suberosa. Bees seem to prefer larger amounts of nectar with hexose predominance, while wasps less amount of almost pure sucrose nectar. These species of Passiflora need pollinators to assure high fruit and seed sets. On the other hand, plants of these species mature many birddispersed fruits every season indicating that plant-pollinator interactions are healthy although the actual high rates of deforestation in the region.