School of Biological, Biomedical and Environmental Sciences

Evolutionary Biology Group

Evolutionary Biology Group

Dr Lori Lawson Handley's research

Department of Biological Sciences

  • Profile
  • Research
  • Key Publications
  • Additional

Profile

My research interests span quite a diverse range of topics within the general realm of ecological and evolutionary genetics, but basically I use population genetics approaches to understand the fundamental evolutionary and demographic processes that determine the genetic make-up of populations.

Since moving to Hull in September 2007, my research has focused on the ecology and evolutionary biology of invasive alien species, and in particular, the harlequin ladybird. My group are trying to elucidate the source populations and invasion routes of this highly invasive species, and to understand why it is such a successful invader. We are part of the UK ladybird research group and ladybird survey, and are part of a global consortium of researchers working on different aspects of the biology of invasive arthropods.

Keywords: ecological genetics, invasive alien species, evolutionary genetics, landscape genetics, dispersal, biological invasions,  natural enemies, endosymbiont bacteria.


Lab news

  • Congratulations to Cathleen Thomas for passing her PhD viva (March 2012)
  • New book on invasive arthropod predators and parasitoids published by Springer(Oct 2011)
  • "Ecological genetics of invasive alien species" review published in BioControl (Sept 2011) 

Research

Ecological Genetics of Invasive Alien Species

Biological invasions are a major threat to global biodiversity, agriculture, the economy and human health. They also allow biologists an excellent opportunity to study evolution in action. I am particularly interested in integrating genetics with ecology in the context of biological invasions, which is crucial, since the two are explicitly linked: ecological conditions in a new environment may be considerably different from the native range, and this can present major adaptive challenges for an invasive population. My group uses molecular genetic tools to 1) decipher source populations and invasion routes, 2) understand the role of genetic variation in invasion success, 3) investigate the causes and consequences of dispersal and range expansions, and 4) investigate the interactions between invasive species and their native and recipient communities, including host-parasite and predator-prey relationships. We recently published a review of this field in a special issue of the journal BioControl, which can be accessed from the following link:

Lawson Handley LJ, Estoup A, Evans D Thomas C, Lombaert E, Facon B, Aebi A, Roy H. (2011) Ecological genetics of invasive alien species. Biocontrol 56, 409-428.

The harlequin ladybird as a model invasive species

Since 2007, work in my group has focused on the model invasive species, the harlequin ladybird, Harmonia axyridis. This species is currently invading the British Isles and posing a potentially devastating risk to native ladybird populations. We hope that this unique case study will contribute significantly to our understanding of the evolutionary biology of species invasions. The harlequin, which is native to Asia, was first found in the UK in 2004. Since then it has become widespread throughout south-east England, and is now found as far as Cornwall, Wales, Lancashire, and North Yorkshire. The harlequin has been monitored rigorously since its initial discovery in the UK by our collaborators as part of “The Harlequin Ladybird Survey”. Records sent in by the general public are validated and collated within a main database. This information is essential so we can follow the pace and spread of the invasion, so please do keep on sending your records and samples. More information and an on-line recording form can be found at the Harlequin Survey Website.

We are lucky to be part of an excellent network of researchers interested in multidisciplinary aspects of the biology of H. axyridis. In particular, we collaborate with Dr Helen Roy (Centre for Ecology and Hydrology), Dr Pete Brown (Anglia Ruskin University), Dr Arnaud Estoup (University of Montpellier), Dr Alex Aebi (Agroscope, Zurich), and Dr Jason Chapman (Rothamsted Research). Our recent work has contributed to understanding the global distribution and spread of the harlequin ladybird (Brown et al. 2011; Lombaert et al. 2011), and its relationship with its natural enemies such as parasitoid wasps and flies (e.g. Roy et al. 2011). Work is ongoing, together with graduate students Cathleen Thomas and Dan Jeffries, to investigate dispersal abilities in the native and invasive ranges, and the impact of endosymbiont bacteria on invasion success.

Patterns, causes and consequences of mammalian sex-biased dispersal

Dispersal is arguably one of the most important events in an organism’s life and is influenced by interactions among kin, such as competition for mates or resources, cooperation, and inbreeding avoidance. I am interested in understanding the relative importance of these factors in determining which sex disperses, and their influence on the timing and distance of dispersal (see Lawson Handley and Perrin 2007). Consistent with evolutionary predictions, dispersal is male-biased in the majority of species. Investigations of exceptional species can therefore be particularly enlightening for studying the evolution of dispersal. We recently provided genetic evidence for female-biased dispersal in Hamadryas baboons, which is contrary to predictions based on this species’ polygynous mating system, and likely to be linked to its’ unique hierarchical social structure, with which dispersal has evolved (Hammond et al. 2006). Dispersal is also a trait that evolves in response to natural selection. An area of my current interest is therefore to understand the effects of landscape and environmental variables on dispersal over different spatial scales, since this has important implications due to changing climatic conditions and increased habitat fragmentation.

Human migration and settlement history

Geography has played a crucial part in determining the genetic make-up of human populations. In fact, distance from East Africa (the cradle of modern humans) can explain most of the variation within and between human populations, as demonstrated by the smooth decline in neutral genetic diversity, and increase in genetic distance with increasing distance from Africa (See figure below). These “clines” are consistent with a single exit of anatomically modern humans out of Africa and essentially continuous gene-flow over limited distances. I am interested in using these simple patterns as null models to investigate natural selection at particular regions of the genome, and in using geographically explicit frameworks to investigate the influence of geography, environment and culture on global and regional-scale patterns of human genetic variation. This was reviewed in the September 2007 issue of Trends in Genetics.

Key Publications

  • Lombaert E, Guillemaud T, Thomas CE, Lawson Handley LJ et al. (2011) Inferring the origin of populations introduced from a genetically structured native range by approximate Bayesian computation: case study of the invasive ladybird Harmonia axyridis. Molecular Ecology online early
  • Elnagdy S, Majerus M, Lawson Handley LJ. (2011) The value of an egg: fitness compensation through resource reallocation in ladybirds (Coleoptera: Coccinellidae) infected with male-killing bacteria. Journal of Evolutionary Biology online early.
  • Lawson Handley LJ, Estoup A, Evans D Thomas C, Lombaert E, Facon B, Aebi A, Roy H. (2011) Ecological genetics of invasive alien species. Biocontrol 56, 409-428.
  • Brown P, Thomas C, Lombaert E, Jeffries D, Estoup A, Lawson Handley LJ. (2011) The global spread of Harmonia axyridis (Coleoptera: Coccinellidae): distribution, dispersal and routes of invasion. Biocontrol 56, 623-641.
  • Roy H, De Clercq P, Lawson Handley LJ, Poland R, Sloggett J, Wajnberg E. (2011) Alien arthropod predators and parasitoids: an ecological approach. Biocontrol 56, 375-382.
  • Roy H, Lawson Handley LJ, Schonrogge K, Poland R, Purse B (2011) Can the enemy release hypothesis explain the success of invasive alien predators and parasitoids? Biocontrol 56, 451-468.
  • Lawson Handley LJ (2010) Heritable artificial sex chromosomes in medaka: a leap forward towards real-time observation of sex chromosome evolution. Heredity 105: 245-246.
  • Balloux F, Lawson Handley LJ, Liu H, and Manica A. (2009) Climate shaped the worldwide distribution of human mitochondrial DNA sequence variation. Proceedings of the Royal Society B-Biological Sciences 276: 3447-3455.
  • Romero IG, Manica A, Goudet J, Lawson Handley, LJ, and Balloux F. (2009). How accurate is the current picture of human genetic variation? Heredity 102: 120-126.
  • Lawson Handley LJ, Byrne K, Santucci F, Townsend S, Taylor M, Bruford MW, and Hewitt GM (2007) Genetic structure of European sheep breeds. Heredity 99: 620-631.
  • Lawson Handley LJ, Goudet J, Manica A, Balloux F. (2007) Going the distance: Human population genetics in a clinal world. Trends in Genetics. 23:432-439
  • Lawson Handley LJ, Perrin N. (2007) Advances in our understanding of mammalian sex-biased dispersal.  Molecular Ecology 16:1559-1578
  • Ashrafian-Bonab M, Lawson Handley LJ, Balloux F. (2007) Is urbanization scrambling signals of human genetic diversity? A case study. Heredity 98:151-156
  • Lawson Handley LJ, Berset-Brandli L, Perrin N (2006) Disentangling Reasons for Low Y Chromosome Variation in the Greater White-Toothed Shrew (Crocidura russula). Genetics 173:935-942
  • Lawson Handley LJ*, Hammond RL*, Emaresi G, Reber A, Perrin N (2006) Low Y chromosome variation in Saudi-Arabian hamadryas baboons (Papio hamadryas hamadryas). Heredity 96:298-303. (*Joint first authors)
  • Hammond RL*, Lawson Handley LJ*, Winney BJ, Bruford MW, Perrin N (2006) Genetic evidence for female-biased dispersal and gene flow in a polygynous primate. Proceedings of the Royal Society B-Biological Sciences 273:479-484 (*Joint first authors)
  • Lawson Handley LJ, Perrin N (2006) Y chromosome microsatellite isolation from BAC clones in the greater white-toothed shrew (Crocidura russula). Molecular Ecology Notes 6:276-279
  • Sazanov AA, Sazanova AL, Stekolnikova VA, Trukhina AV, Kozyreva AA, Smirnov AF, Romanov MN, Lawson Handley LJ, Malewski T, Dodgson JB (2006) Chromosomal localization of the UBAP2Z and UBAP2W genes in chicken. Animal Genetics 37:72-73
  • Brändli L, Lawson Handley, LJ, Vogel P, and Perrin N (2005) Evolutionary history of the greater white-toothed shrew (Crocidura russula) inferred from analysis of mtDNA, Y, and X chromosome markers. Molecular Phylogenetics and Evolution 37: 832-844
  • Lawson Handley LJ, Ceplitis H, and Ellegren H (2004) Evolutionary strata on the chicken Z chromosome: Implications for sex chromosome evolution. Genetics 167:367-376
  • Lawson LJ, and Hewitt GM (2002) Comparison of substitution rates in ZFX and ZFY introns of sheep and goat related species supports the hypothesis of male-biased mutation rates. Journal of Molecular Evolution 54: 54-61

Additional

PhD and MSc Students:
  • Cathleen Thomas (Evolutionary genetics of harlequin ladybirds) NERC funded PhD student, Jan 2008-present.
  • Dan Jeffries (Dispersal in harlequin ladybirds) Departmental funded MSc by research student, Oct 2009-June 2011

Collaborators:

Ladybirds:

  • Dr Helen Roy, Centre for Ecology and Hydrology
  • Dr Pete Brown and Dr Alison Thomas, Anglia Ruskin University
  • Dr Remy Poland, Clifton College, Bristol
  • Dr Jason Chapman, Dr Judy Pell, Dr Jason Baverstock and Miss Trish Wells, Rothamsted Research
  • Dr Arnaud Estoup and Mr Eric Lombaert, University of Montpellier and INRA
  • Dr Alex Aebi, Agroscope, Zurich
  • Dr Sherif Elnagdy, University of Cairo

Other main collaborators:

  • Dr Francois Balloux, Imperial College London
  • Prof Nicolas Perrin, University of Lausanne, Switzerland
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