Nectar characteristics and pollinators for three native, co-occurring insectpollinated Passiflora (Passifloraceae) from central Argentina

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 theirsouthern area of distribution. Volume, concentration, and sugar amount of nectar per flower were measured in thenative, insect-pollinated Passiflora caerulea, P. foetida and P. suberosa (Passifloraceae). Qualitative andquantitative nectar sugar composition were determined and compared between species. Pollinators wererecorded and related to both floral and nectar traits. Flowers of the three species display the usual floral sexualphasesdescribed for the genus. In general, nectar traits were variable between species but relatively constantwithin each one. Nectar sugars were glucose, fructose and sucrose in relatively constant proportions amongsamples of the same species, but each species showed a particular sugar composition (P. foetida, P. caerulea andP. suberosa with lower, intermediate and higher proportion of sucrose, respectively). Bombus spp. and Xylocopasplendidula were recorded as the main pollinators for P. caerulea; Bombus opifex, Melissoptila sp., and Thygatersp. for P. foetida, and different species of wasps for P. suberosa. Bees seem to prefer larger amounts of nectar withhexose predominance, while wasps less amount of almost pure sucrose nectar. These species of Passiflora needpollinators to assure high fruit and seed sets. On the other hand, plants of these species mature many birddispersedfruits every season indicating that plant-pollinator interactions are healthy although the actual highrates of deforestation in the region.