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EASTBIO: Evolution of dispersal and host plant adaptation during range expansion in the global crop pest seed beetle Callosobruchus maculatus

  • Full or part time
    Dr G Bocedi
    Dr L Lancaster
    Prof MG Ritchie
  • Application Deadline
    Sunday, January 05, 2020
  • Funded PhD Project (European/UK Students Only)
    Funded PhD Project (European/UK Students Only)

About This PhD Project

Project Description


Dr Greta Bocedi (University of Aberdeen)

Dr Lesley Lancaster (University of Aberdeen)

Professor Mike Ritchie (University of St. Andrews)

Herbivorous insects play important roles in regulating plant communities and have large effects on agro-ecosystems as pests on food crops. In recent years, we have witnessed repeated outbreaks of ‘super-pests’, generalist herbivores that have rapidly colonised new regions and are capable of feeding on novel plant types. However, the mechanisms by which insects switch their host plant feeding strategies (between specialism and generalism) are largely unknown. We also know, from theory and previous experiments, that during range expansion, dispersal abilities increase, thus potentially accelerating the colonization of new regions. However, we do not know how adaptation to new hosts and evolution of dispersal interact, and how range expansion may proceed where populations are faced with novel plant types. Thus, it is now timely and critical to discover how these two fundamental mechanisms (adaptation to novel hosts and dispersal) underpinning invasions interact, in order to predict and contain emerging pest outbreaks. This PhD project will employ experimental evolution in a spatially-explicit range expansion setting, and genetically- and spatially-explicit modelling, to understand the dynamics and feedbacks between evolution of dietary specialisation and generalization, and evolution of dispersal during invasions, in both single and multi-species setting (to discover how range expansion and adaptation to novel hosts may proceed in a competitive environment).

Experiments will be run using the model system Callosobruchus maculatus, a worldwide pest on stored legumes with well documented host shifts in its phylogeographic record, and for which good genomic resources are available (Arnqvist et al. unpublished). We are currently maintaining several experimental lines of this species in the laboratory, which have been evolved to express various degrees of dietary generalism. Using these existing lines, the student will:
1) Run several range expansion experiments where generalist and specialist lineages of C. maculatus will be allowed to expand along different gradients of novel resources over multiple generations. Parallel lines will be run without the spatial component or without the novel resource, in order to tease apart additive and interactive effects of these factors on evolutionary change.
2) Conduct common garden experiments at regular time intervals to test for genetically-based differences in dispersal propensity and dietary adaptation under spatial and non-spatial evolutionary scenarios, and under different novel resource scenarios.
3) Run the same experiment as in 1 & 2, but in the presence of one of several competitor species of seed beetles. The data can be used to discern how inter-and intra-specific competition differ in how their pressures affect evolution of dispersal or adoption novel or sub-optimal resources.
4) The student will also have the opportunity to develop theoretical predictions using process-based modelling, leveraging the expertise in our group.

Results of this study will provide data with the potential to support the discovery of how superpests evolve, with potential application to pest detection and management strategies. Theoretical models can be applied to predict the spread of pest species considering these evolved responses during the invasion. This study will also provide new, general insight into the evolutionary process. The student will gain valuable and transferrable skills in experimental evolution and statistical and process-based modelling.

Application Procedure:

Please send your completed EASTBIO application form, along with academic transcripts and CV to Alison McLeod at . Two references should be provided by the deadline using the EASTBIO reference form. Please advise your referees to return the reference form to .

Funding Notes

This 4 year PhD project is part of a competition funded by EASTBIO BBSRC Doctoral Training Partnership. This opportunity is only open to UK nationals (or EU students who have been resident in the UK for 3+ years immediately prior to the programme start date) due to restrictions imposed by the funding body. Queries on eligibility? Email Alison McLeod ().

Candidates should have (or expect to achieve) a minimum of a First Class Honours degree in a relevant subject. Applicants with a minimum of a 2:1 Honours degree may be considered provided they have a Distinction at Masters level.

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