Rob Knell Research
Research Interests
Male Proagaderus watenebei showing his horns, photographed in Danum Valley, Sabah. Photo (c) Rob Knell 2015
I am interested in a variety of different aspects of ecology and evolution, mainly to do with either parasites, immune systems, sex or all three. Recent research has been focusing on the role of sexual selection in determining population-level phenomena such adaptation rates and extinction, with some recent high profile work whereby we’ve linked these processes into selective harvest systems such as trophy hunting. If you want to know more you can hear my dulcet tones explaining this on BBC Radio 4, or if you want to read the paper, this is a copy of the manuscript.
This work on sexual selection and macroevolutionary processes has spilled over into a growing interest in phenomena such as sexual selection in extinct animals, which I have been working on in collaboration with Dr Dave Hone. We’ve published a number of papers on this, including one on the horns and frills of Ceratopsian dinosaurs like Triceratops which recently gained a fair amount of media interest.
More generally, I am interested in the evolution of mating systems and especially of sexual ornamentation. I am particularly interested in the function and evolution of the weapons used by male animals in contests with rivals. Most such weapons are used more for show than as actual weapons, so why is it usually the case that the male with the larger horns, antlers, dewlap or eyestalks usually wins when it comes to a fight. What properties of the male are being signalled by these traits? Recent research in my lab is bringing this and my interest in environmental change together to ask how sexual selection affects adaptation rates and vulnerability to extinction, using both experimental and theoretical approaches.
My interest in the links between parasites and mating systems has led me to some research in the ecology and evolution of sexually transmitted diseases (STDs) and their effect on the evolution of host mating systems. As part of a recent NERC funded project in collaboration with colleagues at the University of Liverpool we studied the effects of temperature on the transmission dynamics of sexually transmitted mite parasites of ladybird beetles - the results from this research are being published at the moment.
Publications
Index
Infectious disease ecology
Ecological Immunology
Sexual selection
Other
Popular science, reviews, other self-aggrandisement
Recent papers (since 2016)
Parrett, JM, Mann, DJ, Chung, AYC, Slade, EM & Knell RJ (2019) Sexual selection predicts the persistence of populations within altered environments. Ecology Letters, published online 29th July 2019, https://doi.org/10.1111/ele.13358 pdf of final manuscript version here supporting information here
O’Sullivan, JD., Knell, RJ & Rossberg, A. (2019) Metacommunity-scale biodiversity regulation and the self-organized emergence of macroecological patterns. Ecology Letters, published online 27th June 2019, https://doi.org/10.1111/ele.13294 Preprint on BioRXiv here
Laughton, A & Knell, RJ (2019) Warming at the population level: effects on age structure, density, and generation cycles. Ecology and Evolution 9, 4403-4420. Open access
O’Brien DM, Allen CE, Van Kleeck, MJ, Hone, D, Knell RJ, Knapp A, Christiansen S & Emlen, DJ 2018 On the evolution of extreme structures: static scaling and the function of sexually selected signals Animal Behaviour 144, 95-108. pdf here
Thorburn DMJ, Knell RJ & Parrett, JM 2018 Sperm morph and remating frequency in the Indian meal moth, Plodia interpunctella Biology letters 14 (8), 20180304 pdf here
Parrett, JM. & Knell, RJ 2018 The effect of sexual selection on adaptation and extinction under increasing temperatures Proceedings of the Royal Society B: Biological Sciences. Published online 18th April 2018. DOI: 10.1098/rspb.2018.0303 pdf here
Knapp, A, Knell, RJ, Farke, A, Loewen, D & Hone, DWE 2018. Patterns of divergence in the morphology of ceratopsian dinosaurs: sympatry is not a driver of ornament evolution. Proceedings of the Royal Society B: Biological Sciences. Published online 21st March 2018. DOI: 10.1098/rspb.2018.0312 Open access
Knell RJ, MartÃnez-Ruiz C 2017. Selective harvest focused on sexual signal traits can lead to extinction under directional environmental change Proc. R. Soc. B 284 (1868) pdf here
Matsumoto K, Knell RJ 2017 Diverse and complex male polymorphisms in Odontolabis stag beetles (Coleoptera: Lucanidae) Scientific reports 7 (1), 16733 Open access
Laughton, AM, O’Connor CO & Knell RJ 2017 Responses to a warming world: Integrating life history, immune investment, and pathogen resistance in a model insect species Ecology and evolution 7 (22), 9699-9710 Open access
MartÃnez-Ruiz C, Knell RJ. 2017. Sexual selection can both increase and decrease extinction probability: reconciling demographic and evolutionary factors. J Anim Ecol 86:117–127. pdf here
Weevil with very long rostrum photographed in Danum Valley, Sabah. Photo (c) Rob Knell 2015
Littlefair JE, Laughton AM, Knell RJ. 2017. Maternal pathogen exposure causes diet- and pathogen-specific transgenerational costs. Oikos 126:82–90. pdf here
Littlefair JE, Knell RJ. 2016. Within- and Trans-Generational Effects of Variation in Dietary Macronutrient Content on Life-History Traits in the Moth Plodia interpunctella. PLOS ONE 11:e0168869. Open access
Littlefair JE, Nunn KA and Knell RJ. (2016). The development of a synthetic diet for investigating the effects of macronutrients on the development of Plodia interpunctella. Entomol Exp Appl 159:305–310. pdf here
Knell, RJ and Thackerey, SJ (2016) Voltinism and resilience to climate-induced phenological mismatch. Climatic Change 137: 525-539. pdf here
Guignard, M, Nichols, RA, Knell RJ, Macdonald, A, Romila, C-A, Trimmer, M, Leitch, IJ and Leitch, AR (2016) Genome size and ploidy influence angiosperm species’ biomass under nitrogen and phosphorus limitation New Phytologist, Early online.
Hone, DWE, Wood, D and Knell RJ (2016) Positive allometry for exagerated structures in the ceratopsian dinosaur Protoceratops andrewsi supports socio-sexual sigalling. Palaeontologia Electronica 19: 1-13 Open access
The full list
(cunningly including the ones already listed above so that it looks like more)
Infectious disease ecology and evolution
Knell, R.J., Begon, M. and Thompson, D.J. (1996) Transmission dynamics of Bacillus thuringiensis infecting Plodia interpunctella: a test of the mass action assumption with an insect pathogen. Proceedings of the Royal Society of London Series B (Biological Sciences), Vol.263 pp 75-81. Download pdf
Knell, R.J., Begon, M. and Thompson, D.J. (1996) Comparative transmission dynamics of two insect pathogens. In: Frontiers of Population Ecology (Floyd, R.B., Sheppard, A.W. and De Barro, P.J., eds.), CSIRO publishing. pp 269-276.
Knell, R.J., Begon, M. and Thompson, D.J. (1998) Host-pathogen population dynamics, basic reproductive rates and threshold densities. Oikos Vol. 81 pp 299-308. Download pdf
Knell, R.J., Begon, M. and Thompson, D.J. (1998) Transmission of Plodia interpunctella Granulosis Virus does not conform to the mass action model. Journal of Animal Ecology Vol. 67 pp 592-599. Download pdf
Knell, R.J. (1999) Sexually transmitted disease and parasite mediated sexual selection. Evolution Vol 53 pp 957-961. Download a not very high-res pdf
Boots, M. and Knell, R.J. (2002) The evolution of risky behaviour in the presence of a sexually transmitted disease. Proceedings of the Royal Society of London Series B (Biological Sciences), Vol.269 pp 585-589. Download pdf
Knell,, R.J. (2004) Syphilis in Renaissance Europe: rapid evolution of a virulent sexually transmitted disease? Proceedings of the Royal Society of London Series B (Biological Sciences): Biology Letters, Vol 271, pp. S174-S176 Download pdf
Knell, R.J. and Webberley, K.M. (2004) Sexually transmitted diseases of insects: distribution, evolution, ecology and host behaviour. Biological Reviews 79, 557-581. Download pdf
Ryder, J.J., Webberley, K.M., Boots, M. and Knell, R.J. (2005) Measuring the transmission dynamics of a sexually transmitted disease. Proceedings of the National Academy of Sciences of the USA, 102, 15140-15143. Download pdf.
Hurst, G.D.D., Webberley, K.M. and Knell, R.J. (2006) The role of parasites of insect reproduction in the diversification of insect reproductive processes. Pages 205-230 in Fellowes, M.D.E., Holloway, G.J. And Rolff, J. (eds.) Insect Evolutionary Ecology: Proceedings of the Royal Entomological Society’s 22nd Symposium. CABI publishing, Wallingford, Oxon. UK.
Ryder, J.J., Hathway, J. and Knell, R.J. (2007) Constraints on parasite fecundity and transmission in an insect-STD system. Oikos 116, 578-584. Download pdf
Ryder, J.J., Miller, M.R., White, A., Knell, R.J. and Boots, M. (2007) Host parasite population dynamics under combined frequency- and density-dependent transmission. Oikos 116, 2017-2026. Download pdf
Staves, P.A and Knell, R.J. (2010) Virulence and competitiveness: testing the relationship during inter- and intraspecific mixed infections. Evolution 64, 2643-2652 Download pdf
Ryder, JJ, Pastok, D, Hoare, MJ, Bottery, MJ, Boots, M, Knell, RJ, Atkinson, D and Hurst, GDD (2012) Spatial variation in food supply, mating behavior, and sexually transmitted disease epidemics. Behavioral Ecology 24, 723-729. Download pdf
Pastok D, Hoare M-J, Ryder JJ, Boots M, Knell RJ, Atkinson D, Hurst GDD. 2015. The role of host phenology in determining the incidence of an insect sexually transmitted infection. Oikos, online July 2015. Copy of the manuscript here.
Ryder JJ, Hoare M-J, Pastok D, Bottery M, Boots M, Fenton A, Atkinson D, Knell Robert J., Hurst GDD. 2014. Disease Epidemiology in Arthropods Is Altered by the Presence of Nonprotective Symbionts. The American Naturalist 183:E89–E104. pdf here.
Ecological immunology
Wilson, K., Knell, R.J., Boots, M. and Koch-Osbourne, J. (2003) Group living and investment in immune defence: an inter-specific analysis. Journal of Animal Ecology 72, 133-143. Download pdf
Pomfret, J.C. and Knell, R.J. (2006) Immunity and the expression of a secondary sexual trait in a horned beetle. Behavioral Ecology 17, 466-472 Download pdf
Reaney LT, Knell RJ (2010) . Immune activation but not male quality affects female current reproductive investment in a dung beetle. Behavioral Ecology 21, 1367-1372 Download pdf
Triggs AM, Knell RJ (2012) . Interactions between environmental variables determine immunity in the Indian meal moth Plodia interpunctella. Journal of Animal Ecology 81, 386-394. Download pdf
Triggs, A.M. and Knell, R.J. (2012) Parental diet has strong transgenerational effects on offspring immunity. Functional Ecology 26, 1409-1417 Download pdf
Littlefair JE, Laughton AM, Knell RJ. 2017. Maternal pathogen exposure causes diet- and pathogen-specific transgenerational costs. Oikos 126:82–90. pdf here
Large male Chalcosoma moellenkampi in the rain Kuala Belalong Field Studies Centre Brunei Darussalaam. Photo (c) Rob Knell 2014
Sexual selection
Knell, R.J., Fruhauf, N. and Norris, K.A. (1999) Conditional expression of a sexually selected trait in the stalk-eyed fly Diasemopsis aethiopica. Ecological Entomology Vol 24 pp 323-328. Abstract
Al-Khairulla, H., Warburton, D. and Knell, R.J. (2003) Do the eyestalks of female diopsid flies have a function in intrasexual aggressive encounters? Journal of Insect Behavior, Vol. 16, pp 679-686 Download pdf
Knell, R.J., Pomfret, J.C. and Tomkins, J.L. (2004) The limits of elaboration: curved allometries reveal the constraints on mandible size in stag beetles. Proceedings of the Royal Society of London Series B (Biological Sciences), Vol. 271, pp 523-528 Download pdf
Knell, R.J. and Fortey, R.A. (2005) Trilobite spines and beetle horns: sexual selection in the Palaeozoic? Biology Letters 1, 196-199 Download pdf
Lailvaix, S.P., Hathway, J., Pomfret, J.C. and Knell, R.J. (2005) Horn size predicts physical performance in the beetle Euoniticellus intermedius (Coleoptera: Scarabaeidae). Functional Ecology 19, 632-639. Download pdf
Pomfret, J.C. and Knell, R.J. (2006) Sexual selection and horn allometry in the dung beetle Euoniticellus intermedius. Animal Behaviour, 71, 567-576. Download pdf
Pomfret, J.C. and Knell, R.J. (2008) Crowding, sex ratio and horn evolution in a South African beetle community. Proceedings of the Royal Society of London, Series B (Biological Sciences) 275: 315-321 Download pdf
Knell, R.J. (2009) On the analysis of non-linear allometries. Ecological Entomology, 34, 1-11. Download pdf
Knell, R.J. (2009) Population density and the evolution of male aggression. Journal of Zoology, 278, 83-90. Download pdf
Knell, R.J. and Simmons, L.W. (2010) Mating tactics determine patterns of condition dependence in a dimorphic horned beetle. Proceedings of the Royal Society of London, Series B (Biological Sciences) 277:2347-2353 Download pdf
Knell, R.J. and Sampson, S. (2011) . Bizarre structures in dinosaurs: species recognition or sexual selection? A response to Padian and Horner. Journal of Zoology 283, 18-22. Download pdf
Knell, R.J. (2011) . Male contest competition and the evolution of weapons. Ecology and Evolution of Dung Beetles, Editors: Simmons, LW, Ridsdill-Smith, TJ, Wiley-Blackwell. You can download a proof of this chapter here, or you can purchase a copy of this wonderful volume here.
Knell, R. J., Naish, D., Tomkins, J. L., & Hone, D. W. E. (2013). Sexual selection in prehistoric animals: detection and implications. Trends in Ecology & Evolution 28, 38-47 Download pdf
Reaney, LT and Knell, RJ. 2015 Building a beetle: how larval environment leads to adult performance in a horned beetle. PLOS One 10:e0134399.
Hone, DWE, Wood, D and Knell RJ (2016) Positive allometry for exagerated structures in the ceratopsian dinosaur Protoceratops andrewsi supports socio-sexual sigalling. Palaeontologia Electronica 19: 1-13
Knell RJ, MartÃnez-Ruiz C. 2017. Selective harvest focused on sexual signal traits can lead to extinction under directional environmental change Proc. R. Soc. B 284 (1868) pdf here
Knapp, A. Knell, RJ, Farke, A, Loewen, D & Hone, DWE. 2018. Patterns of divergence in the morphology of ceratopsian dinosaurs: sympatry is not a driver of ornament evolution. Proceedings of the Royal Society B: Biological Sciences. Published online 21st March 2018. DOI: 10.1098/rspb.2018.0312 Open access
Parrett, J.M. & Knell, R.J. 2018 The effect of sexual selection on adaptation and extinction under increasing temperatures Proceedings of the Royal Society B: Biological Sciences. Published online 18th April 2018. DOI: 10.1098/rspb.2018.0303 pdf here
Knapp, A. Knell, RJ, Farke, A, Loewen, D & Hone, DWE. 2018. Patterns of divergence in the morphology of ceratopsian dinosaurs: sympatry is not a driver of ornament evolution. Proceedings of the Royal Society B: Biological Sciences. Published online 21st March 2018. DOI: 10.1098/rspb.2018.0312 Open access
Thorburn DMJ, Knell RJ & Parrett, JM. 2018 Sperm morph and remating frequency in the Indian meal moth, Plodia interpunctella Biology letters 14 (8), 20180304 pdf here
O’Brien DM, Allen CE, Van Kleeck, MJ, Hone, D, Knell RJ, Knapp A, Christiansen S & Emlen, DJ. 2018 On the evolution of extreme structures: static scaling and the function of sexually selected signals Animal Behaviour 144, 95-108. pdf here
Parrett, JM, Mann, DJ, Chung, AYC, Slade, EM & Knell RJ (2019) Sexual selection predicts the persistence of populations within altered environments. Ecology Letters, published online 29th July 2019, https://doi.org/10.1111/ele.13358 pdf of final manuscript version here supporting information here
Female stenogastrine wasp building her nest. Tasek Merimbun, Brunei Darussalaam. Photo (c) Rob Knell 2014
Other
Knell, R.J. (1998) Generation cycles (review paper). Trends in Ecology and Evolution Vol. 13 No. 5 pp 86-190. Download pdf
Tomkins, J.L., Simmons, L.W., Knell, R.J. and Norris, K.A. (1999) Correlates of ball size and rolling speed in the dung beetle Kheper nigroaeneus (Coleoptera: Scarabaeidae). Journal of Zoology Vol 248 pp 483-487.
Martinez-Levasseur LM, Gendron D, Knell RJ et al. (2011) . Acute sun damage and photoprotective responses in whales. Proceedings of the Royal Society of London, Series B (Biological Sciences). 278 1581-1586. Download pdf
Stevenson MD, Rossmo K, Knell RJ et al. (2012) . Geographic profiling as a novel spatial tool for targeting the control of invasive species. Ecography 8, 704-715. Downlad pdf
Martinez-Levasseur, LM, Gendron, D, Knell, RJ and Acevedo-Whitehouse, K (2013). Control and target gene selection for studies on UV-induced genotoxicity in whales. BMC Research Notes 6: Article 264
Martinez-Levasseur, LM, Birch-Machin, MA, Bowman, A, Gendron, D, Weatherhead, E, Knell, RJ and Acevedo-Whitehouse, K (2013) . Whales use distinct strategies to counteract solar ultraviolet radiation. Scientific Reports 3: Article 2386
Guignard, M, Nichols, RA, Knell RJ, Macdonald, A, Romila, C-A, Trimmer, M, Leitch, IJ and Leitch, AR (2016) Genome size and ploidy influence angiosperm species’ biomass under nitrogen and phosphorus limitation New Phytologist 210, 1195 - 1206. Download pdf
Littlefair JE, Knell RJ. (2016). Within- and Trans-Generational Effects of Variation in Dietary Macronutrient Content on Life-History Traits in the Moth Plodia interpunctella. PLOS ONE 11:e0168869.
Littlefair JE, Nunn KA and Knell RJ. (2016). The development of a synthetic diet for investigating the effects of macronutrients on the development of Plodia interpunctella. Entomol Exp Appl 159:305–310. pdf here
Knell, RJ and Thackerey, SJ (2016) Voltinism and resilience to climate-induced phenological mismatch. Climatic Change 137: 525-539. pdf here
Popular science, editorials, book reviews, other self-aggrandisement
Inside Science on Radio 4 with me talking about research into trophy hunting
Article about trophy hunting in stressed populations
Article about sexual conflict and brain evolution
New gene, new disease. Commentary in Heredity
R and markdown
Want to learn R? I have a book available which should help you get started.
Work in progress: Introductory R Markdown: a beginner’s guide to creating reproducible documents, reports and presentations, a book on producing reports and documents using R Markdown. Completely revised draft posted 11th August 2019.
Some youtube videos to help people with analyses in R:
Ordination using NMDS in R
Regression and linear model coefficients in R
Species accumulation curves
Work with me?
Job and fellowship opportunities, postgrad work etc.
Potential PhD students, postdoc fellows etc. are always welcome. QMUL has specific fee waiver programmes for potential PhD students from Brazil and China but get in touch if you’re from elsewhere as well.
Some positions currently available:
3 year postdoc available working on sexual selection and population dynamics, based at Adam Mickiewicz University in Poznan, Poland. NCN funded project led by Jacek Radwan (AMU), Tom Cameron (University of Essex) and me.
PhD studentship, modelling mating systems and how they affect population dynamics, also at Adam Mickiewicz University in Poznan and funded by the same NCN grant as the postdoc above.
3 year postdoc, working on sex ratio distorters and the evolution of pesticide resistance. BBSRC funded project based at QMUL led by myself, Tom Proce (Liverpool) and Mike Bonsall (Oxford).