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Dependence on sunbird pollination for fruit set in three West African montane mistletoe species

Published online by Cambridge University Press:  13 February 2012

Kerry A. Weston*
Affiliation:
School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
Hazel M. Chapman
Affiliation:
School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
Dave Kelly
Affiliation:
School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
Elena V. Moltchanova
Affiliation:
Mathematics and Statistics Department, University of Canterbury, Private Bag 4800 Christchurch, New Zealand
*
1Corresponding author. Current address: Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand. Email: kerry-anne.weston@otago.ac.nz

Abstract:

Theory predicts that not all plant species will be equally affected by disruption to their pollinator mutualisms because traits such as breeding system and mutualism strength can affect their response. We investigated these traits in three species of Afromontane mistletoe Globimetula braunii, Agelanthus brunneus and A. djurensis in Ngel Nyaki Forest Reserve, Nigeria, to test whether the traits were reliable indicators of relative reproductive success and could be used to predict relative vulnerability to pollinator loss. For each mistletoe species, insect and bird visitors were identified during a 160–240-min observation period of 4–10 plants and their roles in flower opening and fruit set were investigated using exclusion experiments applied to 250–500 flowers. We found that all three mistletoes are self-compatible but not capable of autonomous self-fertilization. The pollinator assemblage comprised four species of sunbird (Cyanomitris spp., Cinnyris spp.) and a small social wasp (Vespinae). None of the mistletoes requires birds for flower opening: G. braunii flowers self-opened in the absence of pollinators, whereas insects opened both Agelanthus spp. Irrespective of flower opening, each mistletoe species requires sunbirds for effective pollination and fruit set. Only G. braunii demonstrated pollen limitation (pollen limitation index = 0.504) which may be an early indication of mutualism breakdown. We suggest that mistletoes be considered as indicators of habitat condition and functioning within Afromontane forest ecosystems.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2012

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References

LITERATURE CITED

AGUILAR, R., ASHWORTH, L., GALETTO, L. & AIZEN, M. A. 2006. Plant reproductive susceptibility to habitat fragmentation: review and synthesis through a meta-analysis. Ecology Letters 9:968980.CrossRefGoogle ScholarPubMed
AIZEN, M. A. 2003. Influences of animal pollination and seed dispersal on winter flowering in a temperate mistletoe. Ecology 84:26132627.CrossRefGoogle Scholar
AIZEN, M. A. 2005. Breeding system of Tristerix corymbosus (Loranthaceae), a winter-flowering mistletoe from the southern Andes. Australian Journal of Botany 53:357361.CrossRefGoogle Scholar
AIZEN, M. A. & FEINSINGER, P. 1994. Forest fragmentation, pollination, and plant reproduction in a chaco dry forest, Argentina. Ecology 75:330351.CrossRefGoogle Scholar
ANDERSON, S. H., KELLY, D., LADLEY, J. J., MOLLOY, S. & TERRY, J. 2011. Cascading effects of bird functional extinction reduce pollination and plant density. Science 331:10681071.CrossRefGoogle ScholarPubMed
AZPEITIA, F. & LARA, C. 2006. Reproductive biology and pollination of the parasitic plant Psittacanthus calyculatus (Loranthaceae) in central Mexico. Journal of the Torrey Botanical Society 133:429438.CrossRefGoogle Scholar
BERNHARDT, P., KNOX, R. B. & CALDER, D. M. 1980. Floral biology and self-incompatibility in some Australian mistletoes of the genus Amyema (Loranthaceae). Australian Journal of Botany 28:437451.CrossRefGoogle Scholar
BOND, W. J. 1994. Do mutualisms matter? Assessing the impact of pollinator and disperser disruption on plant extinction. Philosophical Transactions of the Royal Society of London B 344:8390.Google Scholar
BORROW, N. & DEMEY, R. 2001. A guide to the birds of Western Africa. Princeton University Press, London. 816 pp.Google Scholar
BURGESS, V. J., KELLY, D., ROBERTSON, A. W. & LADLEY, J. J. 2006. Positive effects of forest edges on plant reproduction: literature review and a case study of bee visitation to flowers of Peraxilla tetrapetala (Loranthaceae). New Zealand Journal of Ecology 30:179190.Google Scholar
CAMPBELL, D. R. 1985. Pollinator sharing and seed set of Stellaria pubera: competition for pollination. Ecology 66:544553.CrossRefGoogle Scholar
CHAPMAN, H. M. & CHAPMAN, J. D. 2001. The forest flora of Taraba and Adamawa States, Nigeria: an ecological account and plant species checklist. University of Canterbury, Christchurch. 203 pp.Google Scholar
CHAPMAN, H. M., OLSON, S. M. & TRUMM, D. 2004. An assessment of changes in the montane forests of Taraba State, Nigeria, over the past 30 years. Oryx 38:282290.CrossRefGoogle Scholar
CHEKE, R. A. & MANN, C. F. 2001. Sunbirds: a guide to the sunbirds, flowerpeckers, spiderhunters, and sugarbirds of the world. Yale University Press, New Haven. 384 pp.Google Scholar
DOCTERS VAN LEEUWEN, W. M. 1954. On the biology of some Javanese Loranthaceae and the role birds play in their life-history. Beaufortia 4:105205.Google Scholar
DONOVAN, B. J. 2007. Apoidea (Insecta: Hymenoptera). Fauna of New Zealand 57. 295 pp.Google Scholar
EVANS, M. S. 1895. The fertilisation of Loranthus kraussianus and L. dregei. Nature 51:235236.CrossRefGoogle Scholar
EWERS, R. M. & DIDHAM, R. K. 2006. Confounding factors in the detection of species responses to habitat fragmentation. Biological Reviews of the Cambridge Philosophical Society 81:117142.CrossRefGoogle ScholarPubMed
FEEHAN, J. 1985. Explosive flower opening in ornithophily: a study of pollination mechanisms in some Central African Loranthaceae. Botanical Journal of the Linnean Society 90:129144.CrossRefGoogle Scholar
FLEMING, T. H. & MUCHHALA, N. 2008. Nectar-feeding bird and bat niches in two worlds: pantropical comparisons of vertebrate pollination systems. Journal of Biogeography 35:764780.CrossRefGoogle Scholar
GILL, F. B. & WOLF, L. L. 1975. Foraging strategies and energetics of East African sunbirds at mistletoe flowers. American Naturalist 109:491510.CrossRefGoogle Scholar
GROSS, C. L. 1996. Is resource overlap disadvantageous to three sympatric legumes? Australian Journal of Ecology 21:133143.CrossRefGoogle Scholar
GROSS, R. S. & WERNER, P. A. 1983. Relationships among flowering phenology, insect visitors, and seed-set of individuals: experimental studies on four co-occurring species of goldenrod (Solidago: Compositae). Ecological Monographs 53:95117.CrossRefGoogle Scholar
HINGSTON, A. B. & McQUILLAN, P. B. 2000. Are pollination syndromes useful predictors of floral visitors in Tasmania? Austral Ecology 25:600609.CrossRefGoogle Scholar
JOHNSON, S. D. & STEINER, K. E. 2000. Generalization versus specialization in plant pollination systems. Trends in Ecology and Evolution 15:140143.CrossRefGoogle ScholarPubMed
KELLY, D., LADLEY, J. J., ROBERTSON, A. W., ANDERSON, S. H., WOTTON, D. M. & WISER, S. K. 2010. Mutualisms with the wreckage of an avifauna: the status of bird pollination and fruit-dispersal in New Zealand. New Zealand Journal of Ecology 34:6685.Google Scholar
KELLY, D., LADLEY, J. J., ROBERTSON, A. W., EDWARDS, J. & SMITH, D. C. 1996. The birds and the bees. Nature 384:615.CrossRefGoogle Scholar
KELLY, D., LADLEY, J. J., ROBERTSON, A. & NORTON, D. A. 2000. Limited forest fragmentation improves reproduction in the declining New Zealand mistletoe Peraxilla tetrapetala (Loranthaceae). Pp. 241252 in Young, A. G. & Clarke, G. (eds.). Genetics, demography and viability of fragmented populations. Cambridge University Press, Cambridge.CrossRefGoogle Scholar
KELLY, D., BRINDLE, C., LADLEY, J. J., ROBERTSON, A. W., MADDIGAN, F. W., BUTLER, J., WARD-SMITH, T., MURPHY, D. J. & SESSIONS, L. A. 2005. Can stoat (Mustela erminea) trapping increase bellbird (Anthornis melanura) populations and benefit mistletoe (Peraxilla tetrapetala) pollination? New Zealand Journal of Ecology 29:6982.Google Scholar
KIRKUP, D. W. 1993. The structural basis of pollination in African Loranthaceae. Ph.D. thesis, Department of Botany. University of Reading. 169 pp.Google Scholar
KIRKUP, D. W. 1998. Pollination mechanisms in African Loranthaceae. Pp. 3760 in Polhill, R. M. & Weins, D. (eds.). Mistletoes of Africa. Royal Botanic Gardens, Kew.Google Scholar
LADLEY, J. J. & KELLY, D. 1995. Explosive New Zealand mistletoe. Nature 378:766.CrossRefGoogle Scholar
LADLEY, J. J., KELLY, D. & ROBERTSON, A. W. 1997. Explosive flowering, nectar production, breeding systems, and pollinators of New Zealand mistletoes (Loranthaceae). New Zealand Journal of Botany 35:345360.CrossRefGoogle Scholar
LARSON, B. M. H. & BARRETT, S. C. H. 2000. A comparative analysis of pollen limitation in flowering plants. Biological Journal of the Linnean Society 69:503520.CrossRefGoogle Scholar
LUNN, D. J., THOMAS, A., BEST, N. & SPIEGELHALTER, D. 2000. WinBUGS – a Bayesian modelling framework: concepts, structure, and extensibility. Statistics and Computing 10;325337.CrossRefGoogle Scholar
MURCIA, C. 1995. Edge effects in fragmented forests: implications for conservation. Trends in Ecology and Evolution 10:5862.CrossRefGoogle ScholarPubMed
MURPHY, D. J. & KELLY, D. 2001. Scarce or distracted? Bellbird (Anthornis melanura) foraging and diet in an area of inadequate mistletoe pollination. New Zealand Journal of Ecology 25:6981.Google Scholar
OLLERTON, J. 1998. Sunbird surprise for syndromes. Nature 394:726727.CrossRefGoogle Scholar
PAUW, A. 1998. Pollen transfer on birds' tongues. Nature 394:731732.CrossRefGoogle Scholar
PAUW, A. 2007. Collapse of a pollination web in small conservation areas. Ecology 88:17591769.CrossRefGoogle ScholarPubMed
POLHILL, R. M. 1989. Speciation patterns in African Loranthaceae. Pp. 221236 in Holm-Nielsen, L. B., Nielsen, I. C. & Balslev, H. (eds.). Tropical forests: botanical dynamics, speciation and diversity. Academic Press, London.CrossRefGoogle Scholar
POLHILL, R. M. & WIENS, D. 1998. Mistletoes of Africa. Royal Botanic Gardens, Kew. 370 pp.Google Scholar
POTTS, S. G., BIESMEIJER, J.C., KREMEN, C., NEUMANN, P., SCHWEIGER, O. & KUNIN, W.E. 2010. Global pollinator declines: trends, impacts and drivers. Trends in Ecology and Evolution 25:345353.CrossRefGoogle ScholarPubMed
ROBERTSON, A. W., KELLY, D., LADLEY, J. J. & SPARROW, A. D. 1999. Effects of pollinator loss on endemic New Zealand mistletoes (Loranthaceae). Conservation Biology 13:499508.CrossRefGoogle Scholar
ROBERTSON, A. W., LADLEY, J. J. & KELLY, D. 2005. Effectiveness of short-tongued bees as pollinators of apparently ornithophilous New Zealand mistletoes. Austral Ecology 30:298309.CrossRefGoogle Scholar
ROBERTSON, A. W., LADLEY, J. J. & KELLY, D. 2008. Does height off the ground affect bird visitation and fruit set in the pollen-limited mistletoe Peraxilla tetrapetala (Loranthaceae)? Biotropica 40:122126.CrossRefGoogle Scholar
RODGER, J. G., BALKWILL, K. & GEMMILL, B. 2004. African pollination studies: where are the gaps? International Journal of Tropical Insect Science 24:528.CrossRefGoogle Scholar
SEKERCIOGLU, C. H. 2011. Functional extinctions of bird pollinators cause plant declines. Science 331:10191020.CrossRefGoogle ScholarPubMed
WESTON, K. A. 2009. Mistletoe reproductive mutualisms in a West African montane forest. M.Sc. thesis, University of Canterbury.Google Scholar