Dr Stella Watts

The effects of honeybees (Apis mellifera) and nectar robbing flower visitors on hummingbird-plant interactions in south-eastern Peru.

• Introduction
• Objectives
• Publications

Introduction

Recently a number of researchers have pointed to a global pollination crisis. Some authors have reported declines in many pollinator groups, including indigenous birds, bats and insects, and the plant guilds that support them (Kearns and Inouye 1997, Allen-Wardell et al, 1998, Corbet 2000, Kremen and Ricketts, 2000 and Roubik 2000). In the Neotropics, the colonisation by African honeybees (Apis mellifera) has been cited as a possible threat to native plants and their associated pollinators. Honeybees interact with approximately one-fourth of the flora and many of the flower visitors in Tropical America. The possible dangers of honeybees to native pollinators and their plants has been highlighted in the past by Roubik, 1978; Paton, 1993; Leide 1994; Ollerton and Leide, 1997. There is now growing concern that failure to confront the declines in populations of animals providing pollination services could have major implications for the pollination of both wild plant communities and agricultural crops (Allen-Wardell, et al, 1998).

Invasive animal species such as honeybees cause pollinator disruptions by displacing native fauna from plants without effecting comparable pollination (Roubik 2000). In Australia, European honeybees remove pollen from some bird-pollinated plant species, thereby reducing the amount of pollen that nectarivorous birds would subsequently deposit on flowers. In some cases honeybees exacerbate pollination disruption by nectar robbing floral resources. Additionally, a reduction in territories and the number of birds living in a patch has been reported when honeybees were present (Paton, 1993). However, we do not know if the same is true for Neotropical plants and their hummingbird pollinators.

In Peru, work on the effects of possible disruptions from honeybees on the native hummingbird fauna and other flower visitors is non-existent. The Urubamba Valley, Department of Cusco, have high floristic and faunal diversity and include patches of South America's most endangered forest ecosystem-Polylepis. The region has been identified as a key area for endemic and threatened birds (Stattersfield et al, 1998; Wege and Long, 1995. Sixteen species of birds have been listed in the IUCN red data book and are considered endangered. The following species of endemic hummingbirds are of particular interest to this study: Oreonimpha noblis, Chalcostigma olivaceum, and Aglaeactis castelnaudii.

Objectives

The aims of this research are to build on earlier fieldwork undertaken on hummingbird-plant interactions in Peru during 1998-2000.

The objectives of this project are to:

• Understand the relative importance of hummingbirds, native insects and honeybees as pollinators of native plants.
• Document the extent to which honeybees displace hummingbirds from plants which are normally hummingbird pollinated.
• Assess the vulnerability of hummingbird-plant interactions to disruption by honeybees and other flower visitors.
• Make recommendations for sustaining, or restoring pollination systems.
• Establish a long-term monitoring programme (in collaboration with Cusco University), to continue after the project has finished, and assess any changes in diversity and abundance of pollinators.

Publications

Dalsgaard, B., Magård, E., Fjeldså, J., Martín González, A.M., Rahbek, C., Olesen, J.M., Ollerton, J., Alarcón, R., Araujo, A.C., Cotton, P., Lara, C., Machado, C.C., Sazima, I., Sazima, M., Timmermann, A., Watts, S., Sandel, B., Sutherland, W.J., Svenning, J.C. (2011) Specialization in plant-hummingbird networks and the legacy of spatiotemporal climatic stability during the Late Quaternary. PLoS ONE 6(10): e25891. (pdf 210KB)

Watts, S., Huamán Ovalle, D., Moreno Herrera, M. & Ollerton, J. (2011) Pollinator effectiveness of native and non-native flower visitors to an apparently generalist Andean shrub, Duranta mandonii (Verbenaceae). Plant Species Biology in press (pdf 533KB)

Ollerton, J., Alarcón, R., Waser, N.M., Price, M.V., Watts, S., Cranmer, L., Hingston, A. Peter, C.I. and Rotenberry, J. (2009) A global test of the pollination syndrome hypothesis. Annals of Botany 103: 1471-1480. (pdf 588KB)[Appendix 1 (pdf 18KB)] [Appendix 2 (pdf 60KB)] [Appendix 3 (pdf 35KB)] [Appendix 4 (pdf 65KB)]

Ollerton,J., Killick, A., Lamborn, E., Watts, S. & Whiston, M. (2007) Multiple meanings and modes: on the many ways to be a generalist flower. Taxon 56: 717-728 (pdf 283KB)

Ollerton, J. and Watts, S. (2000) Phenotype space and floral typology: towards an objective assessment of pollination syndromes. Det Norske Videnskaps-Akademi I. Matematisk-Naturvitenskapelig Klasse, Avhandlinger, Ny Serie 39: 149-159. (pdf 1.8MB)

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