Drake, Donald R. , Postelli, Katherine A. , Plentovich, Sheldon M. , Thompson, Tommy L. .
Patterns of nectar feeding by birds on Lobeliad flowers in montane forests in Hawai'i.
Hawaiian Lobeliads (Campanulaceae) and honeycreepers (Drepanidinae) are widely believed to be ecologically interdependent, with the plants providing nectar to the birds in exchange for pollination. With the decline and extinction of many honeycreeper species, it is important to determine whether the remaining native (and alien) birds are likely to be functional pollinators of Lobeliads. We spent 116 hours observing flowers and quantifying bird behavior on three Lobeliad species in montane forests on Kaua'i. A different combination of bird species visited each Lobeliad species, and the way each bird species foraged at the flowers differed among Lobeliads. Cyanea leptostegia was visited mainly by alien Japanese White-eyes (Zosterops japonicus), which inserted their heads in the corollas and likely effected pollination. Trematolobelia kauaiensis was visited mainly by the endemic Kaua'i 'Amakihi (Hemignathus kauaiensis), which always took nectar from the bases of the flowers without pollinating, and less frequently by the endemic 'I'iwi (Vestiaria coccinea), which always inserted their heads in the corollas and likely effected pollination. Clermontia fauriei was visited by five species, most commonly Kaua'i 'Amakihi (always nectar robbing), and White-eyes and 'I'iwi (both sometimes nectar robbing, sometimes pollinating). Although the three Lobeliads offer nectar of similar sugar concentrations (9.6-13.2 % sucrose equivalents, w/w), each is visited by a different set of birds. Whether a particular bird species is a nectar robber, pollinator, or both, depends on the plant species. Surprisingly little quantitative data exist on honeycreeper-Lobeliad interactions, and our observations suggest that the traditional view of coevolved mutualisms between the two groups does not fully reflect their current relationships.
Log in to add this item to your schedule
1 - University of Hawaii, Botany Department, 3190 Maile Way, Honolulu, HI, 96822, USA
2 - University of Hawaii, Zoology Department, Honolulu, HI, 96822, USA
Presentation Type: Poster:Posters for Topics
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM