Document: SHA-3-44-9

Pollination of Bombax ceiba by bats, birds and bees.

MISTRY, S.*

Bryn Mawr College, Bryn Mawr, PA 19010, USA ¹

Abstract:
Tropical tree species are often visited by pollinators of various taxa. While observational inferences of pollination based on visitations can be useful, such observations do not provide an estimate of the relative efficacy of each taxa as pollinators. This study examined the pollination biology of Bombax ceiba, a large deciduous tropical tree, in India. Bombax trees produce large red flowers with copious amounts of nectar. The flowers normally stay open for two days and are visited by birds and bees during the day, and by fruit bats at night. Hand-pollination as well as day and night bagging experiments were conducted to estimate the pollination services of each group by measuring fruit and seed set. Visitation rates and damage to flowers were also measured for each taxon. Although birds visited the flowers significantly more than bats, they damaged fewer flowers during the day than bats did at night. Hand pollination studies indicated that Bombax is a self-incompatible species, with outcrossing being the only successful mode reproduction. It was not possible to ascertain the relative role of bats and birds as pollinators, because soon after the start of the bagging experiment, droves of honeybees emptied the flowers of all nectar and pollen. Much of the bee activity occurred early in the morning, before the stigmas were receptive, and is unlikely to have pollinated the flowers. Fruitset by hand pollination was significantly higher than natural fruitset, but the latter value was probably lowered by the activity of the bees. Measurements of fruitset, seedset and other fruit and seed characteristics were also not significantly different. The results of this study suggest that both bats and birds may be important pollinators of Bombax, but that the behavior of bees is more akin to nectar robbing than pollination.

Keywords: pollination bats birds nectar robbing

This abstract is being presented at: 8:30 AM in session:
Oral Session #6: Pollination Ecology.