Dr Owen Lewis

I am a community ecologist and conservation biologist with a particular interest in tropical forest ecosystems. My "official" Departmental Web Page can be accessed here.

VOLUNTEERS NEEDED: Why is the small tortoiseshell butterfly declining?

PRESS RELEASE: "Coffee Keeps The Web Of Life Buzzing" (Tylianakis, J.M., Tscharntke, T. & Lewis, O.T. (2007) Nature, 445, 202-205).

BOOK: Stewart, A.J.A., New, T.R. & Lewis, O.T. (eds.) (2007). Insect Conservation Biology. CABI Publishing, Wallingford.

Research Interests

I have wide research interests, but my current research is focused on two main, interlinked themes. I welcome enquiries from well-qualified prospective graduate students interested in working in these areas.

(1) Ecology of tropical forests
I am interested in the processes that maintain and structure the astonishing diversity of tropical forests, and the impact of human activities (including fragmentation and commercial timber extraction) on the diversity and functioning of these ecosystems. I co-supervised NERC-funded DPhil students, Eleanor Slade (DPhil awarded November 2007) and Joe Nunez, working in Sabah (Malaysian Borneo) and in Honduras on the effects of forest management practices on the diversity of selected taxonomic groups, and the implications of variations in biodiversity for ecosystem function. My newest research programme is focused on the role of density dependent seed and seedling mortality in maintaining the diversity of tropical trees (NERC funded, in collaboration with Prof Rob Freckleton (Sheffield) and Prof Sarah Gurr (Plant Sciences, Oxford). Fieldwork for this project is based at the Las Cuevas research station in Belize, Central America, and is run by postdocs Robi Bagchi and Rachel Gallery.

(2) Insect-parasitoid community ecology and food web biology
Food webs involving plants, insect herbivores and their parasitoids account for the vast majority of the earth's biodiversity. Fully quantitative food webs can now be constructed which provide a robust description of community structure, and allow us to make predictions about the implications of adding or removing species from ecological communities. Increasingly, we can use these webs as a tool to better understand human impacts on ecological communities. My current work in the UK is looking at the effects of habitat fragmentation on trophic interactions using a large-scale field experiment on insect food webs in habitat fragments (NERC funded), and focusing on spatial and temporal dynamics of a specialised insect herbivore and its parasitoids on a fragmented resource (Nuffield Foundation funded). I also have an interest in the impact of climate change on trophic interactions (collaboration with Dr Rob Wilson, University of Exeter in Cornwall; plus former DPhil students Dr Chris Grobler and Dr Maartje Klapwijk). This work is addressing the question of how trophic interactions are affected as species shift their geographic distributions northwards in space (or upwards in elevation) and their phenologies forwards in time, as the climate warms.

Selected Recent Publications

(Please see below for a full list of publications)

Tylianakis, J.M., Tscharntke, T. & Lewis, O.T. (2007) Habitat modification alters the structure of tropical host-parasitoid food webs. Nature, 445, 202-205.[Text] [Reprint]

Slade, E.M., Villanueva, J., Mann, D.J., and Lewis, O.T. (2007). Experimental evidence for the effects of dung beetle functional group richness and composition on ecosystem function in a tropical forest. Journal of Animal Ecology 76,1094-1104. Full text

Bell, T., Freckleton, R.P. & Lewis, O.T. (2006). Plant pathogens drive density-dependent mortality in a tropical tree. Ecology Letters 9, 569-574 [Reprint]

Freckleton, R.P. & Lewis, O.T. (2006). Pathogens, density-dependence and the coexistence of tropical trees. Proceedings of the Royal Society, Series B, 273, 2909-2916 [pdf]

Morris, R.J., Lewis, O.T. and Godfray, H.C.J. (2004). Experimental evidence for apparent competition in a tropical forest food web. Nature 428, 310-313 [pdf]

Lewis, O.T., Memmott, J., LaSalle, J., Lyal, C.H.C., Whitefoord, C. & Godfray, H.C.J. (2002). Structure of a diverse tropical forest insect-parasitoid community. Journal of Animal Ecology 71, 855-873. [Reprint]

Research Funding

2007-2010: Natural Environment Research Council (NERC) Standard Grant (lead PI in collaboration with Prof Robert Freckleton (Sheffield) and Prof Sarah Gurr (Plant Sciences, Oxford), £541,230: ‘Plant Pathogens and Tropical Tree Diversity’

2005-2006: Natural Environment Research Council (NERC) Small Grant (lead PI with Prof Robert Freckleton), £30,250: ‘Density dependence and the dynamics of tropical tree seedlings’

2005-2006: Countryside Council for Wales research contract, £1,000: ‘Effects of climate change on host-parasitoid interactions’

2005-2008: Biotechnology and Biological Sciences Research Council (BBSRC) Standard Grant (co-PI with Prof. S. Simpson). £237,475: ‘Optimal foraging for multiple nutrients: a comparison within and between feeding guilds’

2002-2004: Nuffield Awards to Newly Appointed Lecturers (sole PI), £5,000: ‘Host-parasitoid dynamics in a fragmented landscape’

2002-2005: Leverhulme Project Grant (co-PI with Prof. C.D. Thomas), £100,792: ‘Climate change and host-parasitoid interactions’

2002-2005: Natural Environment Research Council (NERC) New Investigators Award (sole PI), £51,056: ‘Effects of habitat fragmentation on insect food webs’

Full List of Publications (please email me for reprints)

(i) Refereed papers in primary journals

Hayes, L., Mann, D.J., Monastyrskii, A.L. & Lewis, O.T. (2009). Rapid assessments of tropical dung beetle and butterfly assemblages: contrasting trends along a forest disturbance gradient. Insect Conservation and Diversity, in press.

Klapwijk, M.J., Gröbler, B.C., Ward, K., Wheeler, D. & Lewis, O.T. (2009). Influence of experimental warming and shading on host-parasitoid synchrony. Global Change Biology, in press.

Paniagua, M.R., Medianero, E. & Lewis, O.T. (2009). Structure and vertical stratification of plant galler - parasitoid food webs in two tropical forests. Ecological Entomology, DOI: 10.111/j.1365-2311.2008.01079.x.

Lewis, O.T. (2009). Biodiversity change and ecosystem function in tropical forests. Basic and Applied Ecology, 10, 97-102.

Lewis, O.T. & Gripenberg, S. (2008). Insect seed predators and environmental change. Journal of Applied Ecology, 45, 1593-159

Lewis, O.T., Martin, M & Czaczkes, T.J. (2008). Effects of trail gradient on leaf tissue transport and load size selection in leaf-cutter ants. Behavioral Ecology, 19, 805-809. Free Access Full Text

Basset, Y., Missa, O., Alonso A., Miller, S.E., Curletti, G., De Meyer, M., Eardley, C., Lewis, O.T., Mansell, M.W., Novotny, V. & Wagner, T. (2008). Changes in arthropod assemblages along a wide gradient of disturbance in Gabon. Conservation Biology, 22, 1552-63. [on-line here]

Basset, Y. Missa, O., Alonso, A., Miller, S.E., Curletti, G., De Meyer, M., Eardley, C., Lewis, O.T., Mansell, M.W., Novotny, V., & Wagner, T. (2008). Choice of metrics for studying arthropod responses to habitat disturbance: one example form Gabon. Insect Conservation and Diversity 1, 55-66.

Gröbler, B.C. & Lewis, O.T. (2008). Response of native parasitoids to a range-expanding moth. Ecological Entomology, 33, 453-463.

Menéndez, R., González-Megías,A., Lewis, O.T., Shaw, M.R. & Thomas, C.D.(2008). Escape from natural enemies during climate-driven range expansion: a case study. Ecological Entomology, 33: 413-421.

Merrill, R., Gutiérrez, D., Lewis, O.T., Gutiérrez, J., Diez, S.B. & Wilson, R.J. (2008). Combined effects of climate and biotic interactions on the elevational range of a phytophagous insect. Journal of Animal Ecology 77, 145-155. Full text

Basset, Y., Corbara, B., Barrios, H., Cuénoud, P., Leponce, M., Aberlenc, H.-P., Bail, J., Bito, D., Bridle, J.R., Castaño-Meneses, G., Cizek, L., Cornejo, A., Curletti, G., Delabie, J.H.C., Dejean, A., Didham, R.K., Dufrêne, M., Fagan, L.L., Floren, A., Frame, D.M., Hallé, F., Hardy, O.J., Hernandez, A., Kitching, R.L., Lewinsohn, T.M., Lewis, O.T., Manumbor, M., Medianero, E., Missa, O., Mitchell, A.W., Mogia, M., Novotny, V., Oliveira, E.G. de, Ødegaard, F., Orivel, J., Ozanne, C.M.P., Pascal, O., Pinzón, S., Rapp, M., Ribeiro, S.P., Roisin, Y., Roslin, T., Roubik, D.W., Samaniego, M., Schmidl, J., Sørensen, L.L., Tishechkin, A., Van Osselaer, C. & Winchester, N.N. (2007). IBISCA-Panama, a large-scale study of arthropod beta-diversity and vertical stratification in a lowland rainforest: rationale, description of study sites and field methodology. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique- Entomologie, 77, 39-69. [ pdf ]

Yackulic, C. & Lewis, O.T. (2007). Temporal variation in foraging activity and efficiency, and the role of hitchhiking behaviour in the leaf-cutting ant, Atta cephalotes. Entomologia Experimentalis et Applicata 125, 125-134.

Tylianakis, J.M., Tscharntke, T. & Lewis, O.T. (2007) Habitat modification alters the structure of tropical host-parasitoid food webs. Nature, 445, 202-205.

Freckleton, R.P. & Lewis, O.T. (2006). Pathogens, density-dependence and the coexistence of tropical trees. Proceedings of the Royal Society, Series B, 273, 2909-2916

Bell, T., Freckleton, R.P. & Lewis, O.T. (2006). Plant pathogens drive density-dependent mortality in a tropical tree. Ecology Letters 9: 569-574

Lewis, O.T. (2006). Climate change, species-area curves and the extinction crisis. Philosophical Transactions of the Royal Society, Series B. 361: 163-171

Morris, R. J., & Lewis, O.T. & Godfray, H. C. J. (2005). Apparent competition and insect community structure: towards a spatial perspective. Annales Zoologici Fennici 42, 449 - 462

Morris, R.J., Lewis, O.T. and Godfray, H.C.J. (2004). Experimental evidence for apparent competition in a tropical forest food web. Nature 428, 310-313

Lewis, O.T., Memmott, J., LaSalle, J., Lyal, C.H.C., Whitefoord, C. & Godfray, H.C.J. (2002). Structure of a diverse tropical forest insect-parasitoid community. Journal of Animal Ecology 71, 855-873.

Thomas, C.D., Wilson, R.J. and Lewis, O.T. (2002). Short-term studies underestimate 30-generation changes in a butterfly metapopulation. Proceedings of the Royal Society of London, Series B 269, 563-569.

Morris, R.J and Lewis, O.T. (2002). The role of indirect interactions in structuring tropical insect communities. Oikos 97, 308-311.

Lewis, O.T. and Thomas, C.D. (2001). Adaptation to captivity in the butterfly Pieris brassicae, and the implications for ex situ conservation. Journal of Insect Conservation 5, 55-63.

Lewis, O.T. (2001) Effect of experimental selective logging on tropical butterflies. Conservation Biology 15, 389-400.

Godfray, H.C.J., Lewis, O.T. and Memmott, J. (1999). Studying insect diversity in the tropics. Philosophical Transactions of the Royal Society, Series B 354, 1811-1824.

Thomas, C.D., Glen, S.W.T., Lewis, O.T., Hill, J.K., and Blakeley, D.S. (1999). Population differentiation and conservation of endemic races: the butterfly, Plebejus argus. Animal Conservation 2, 15-21.

Hill, J.K., Thomas, C.D., and Lewis, O.T. (1999). Flight morphology in fragmented populations of a rare British butterfly, Hesperia comma. Biological Conservation 87, 277-283.

Thomas, C.D., Hill, J.K., and Lewis, O.T. (1998). Evolutionary consequences of habitat fragmentation in a localized butterfly. Journal of Animal Ecology 67, 485-497.

Lewis, O.T., Wilson, R.J., and Harper, M.C. (1998). Endemic butterflies on Grande Comore: habitat preferences and conservation priorities. Biological Conservation 85, 113-121.

Lewis, O.T. and Hurford, C. (1997). Assessing the status of the marsh fritillary butterfly (Eurodryas aurinia Rott.) - an example from Glamorgan (UK). Journal of Insect Conservation 1: 159-166.

Lewis, O.T., Thomas, C.D., Hill, J.K., Brookes, M.I., Crane, T.P.R., Graneau, Y.A., Mallet, J.L.B. and Rose, O.C. (1997). Three ways of assessing metapopulation structure in the butterfly Plebejus argus. Ecological Entomology 22: 283-293.

Hill, J.K., Thomas, C.D. and Lewis, O.T., (1996). Effects of habitat patch size and isolation on dispersal by Hesperia comma butterflies: implications for metapopulation structure. Journal of Animal Ecology 65: 725-735.

(ii) Contributions to symposia and compiled volumes

Klapwijk, M.J. and Lewis, O.T. (2008). Effects of climate change and habitat fragmentation on trophic interactions. In: Tropical Biology and Conservation, edited by Arturo Bonet and Glória Carrion Villarnovo. Encyclopedia of Life Support Systems (EOLSS), UNESCO, Eolss Publishers, Oxford, UK. http://www.eolss.net/

Stewart, A.J.A., New, T.R. & Lewis, O.T.,(eds.) (2007). Insect Conservation Biology. CABI Publishing, Wallingford.

Lewis, O.T. & Stewart, A.J.A. & New, T.R. (2007). Insect Conservation Biology: Progress and prospects In: Insect Conservation Biology (eds A.J.A. Stewart, T.R. New & O.T. Lewis). CABI Publishing, Wallingford.

Lewis, O.T. & Basset, Y. (2007). Insect Conservation in Tropical Forests. In: Insect Conservation Biology (eds A.J.A. Stewart, T.R. New & O.T. Lewis). CABI Publishing, Wallingford.

Thomas, C.D., Baguette, M. and Lewis, O.T. (2000). Butterfly movement and conservation in patchy landscapes. In: Behaviour and Conservation (eds. L.M. Gosling and W.J. Sutherland), pp.85-104. Cambridge: Cambridge University Press.

Thomas, C.D., Jordano, D., Lewis, O.T., Hill, J.K., Sutcliffe, O.L., and Thomas, J.A. (1999). Butterfly distributional patterns, processes and conservation. In: Conservation in a Changing World: integrating progress into priorities for action (ed. by G.M. Mace, A. Balmford and J.R. Ginsberg, pp. 107-138. Cambridge: Cambridge University Press.

(iii) Abstracts and short papers

Lewis, O.T. (2007). Book Review: ‘Ecology and Ecosystem Conservation’, by O.J. Schmitz. Environmental Conservation, in press.

Lewis, O.T. (2007). Book Review: ‘Insect Diversity Conservation’, by Michael Samways. Environmental Conservation, in press.

Lewis, O.T., Lord, A.M. & Baker, P. (2005). New and overlooked herbivores of Bracken (Pteridium aquilinum (L.) Kuhn), including the Vapourer, Orgyia antiqua (L.) (Lep.: Lymantriidae). Entomologists’ Record and Journal of Variation 117, 47-48.

Lewis, O.T. (2005). Book Review: ‘On the Wings of Checkerspots: a Model system for Population Biology’, edited by Paul R. Ehrlich & Ilkka Hanski. Quarterly Review of Biology 80, 122.

Lewis, O.T. (2004). Book Review: ‘Food Webs’, by Stuart L. Pimm. Ecoscience 11, 139-140.

Lewis, O.T. (2003). Book review: ‘Arthropods of tropical forests: spatio-temporal dynamics and resource use in the canopy’, edited by Yves Basset, Vojtech Novotny, Scott E. Miller and Roger L. Kitching. Journal of Insect Conservation 7, 187-188

Lewis, O.T. and Bryant, S.R. (2002). Butterflies on the move. Trends in Ecology and Evolution 17, 351-352.

Lewis, O.T. (2001). Book review: ‘The Encyclopedia of Biodiversity’, edited by Simon A. Levin. Ibis 14, 503-520.