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School of Biological and Behavioural Sciences

Defensive symbiont dynamics in the biological control of agricultural pests

Project Overview

Insects are attacked by diverse natural enemies, driving the evolution of defence mechanisms. Beyond endogenous defences, many insects recruit symbiont bacteria for protection. This is particularly evident in heritable facultative symbionts, which are common in globally important agricultural and medical pests. However, the dynamics of defensive symbionts in natural insect populations is poorly understood. In particular, it is unclear whether insects recruit different microbes to defend against specific enemies. If true, this would indicate that insect symbionts form a "horizontal gene pool," a reservoir of adaptive traits that insects can exchange to rapidly respond to changing pressures from antagonists.

This project will rigorously test this hypothesis using aphid defensive symbionts as a model system. It builds on pilot data showing that each aphid species typically carries its own ‘parasitoid-specialized’ genotype of the symbiont Hamiltonella defensa that exclusively protects against its primary parasitoid species, the main enemy of aphids. A key unresolve question is how do symbionts resist specific parasitoid species and do aphids share symbionts to defend against common enemies? By employing advanced molecular and experimental techniques, the student will uncover mechanisms of target specificity in defensive symbiont and investigate the ecology of symbiont transmission in insects. Given the presence of defensive symbionts in globally important pests, understanding the factors shaping their microbial communities—and the adaptations they carry—is vital for improving sustainable pest management.

Research Environment

The successful applicant will join a vibrant research environment under the supervision of Prof. Lee Henry. His lab offers world-class facilities in genomics, synthetic microbiology, and molecular biology, providing the student with comprehensive training and professional development. The student will have access to ample funds to facilitate the research through Prof. Henry's external funding. He currently supervises 4 PhD students, 1 PDRA, and a technician, with an outstanding track record of guiding students toward high-impact first-author publications (e.g., Wu et al. 2022, Proc Soc B; Jackson et al. 2022, ISME Journal).

For more research details, visit: https://www.henry-lab.co.uk

Find out more about the School of Biological and Behavioural Sciences on our website.

Keywords: microbiome, symbiont, pest, agriculture, evolutionary ecology, genomics.

Entry Requirements

We are looking for candidates to have or expecting to receive a first or upper-second class honours degree and a Master’s degree in an area relevant to the project such as agriculture, biology, microbiology, etc.

Knowledge of molecular biology, microbiology, or computational biology is desirable, but not essential.

You must meet the IELTS requirements for your course and upload evidence before CSC’s application deadline, ideally by 1st March 2025. You are therefore strongly advised to sit an approved English Language test as soon as possible, where your IELTS test must still be valid when you enrol for the programme.

Please find further details on our English Language requirements page.

How to Apply

Formal applications must be submitted through our form by 29th January 2025 for consideration. Please identify yourself as a ‘CSC Scholar’ in the funding section of the application.

Applicants are required to submit the following documents:

  • Your CV
  • Personal Statement
  • Evidence of English Language e.g.) IELTS Certificate
  • Copies of academic transcripts and degree certificates
  • References

Find out more about our application process on our SBBS website.

Informal enquiries about the project can be sent to Dr Lee Henry AT l.henry@qmul.ac.uk Admissions-related queries can be sent to sbbs-pgadmissions@qmul.ac.uk

Shortlisted applicants will be invited for a formal interview by the supervisor. If you are successful in your QMUL application, then you will be issued an QMUL Offer Letter, conditional on securing a CSC scholarship along with academic conditions still required to meet our entry requirements.

Once applicants have obtained their QMUL Offer Letter, they should then apply to CSC for the scholarship with the support of the supervisor.

For further information, please go to the QMUL China Scholarship Council webpage.

Apply Online

References

  1. Wu T, Monnin D, Lee RAR, Henry LM (2022) Local adaptation to hosts and parasitoids shape Hamiltonella defensa genotypes across aphid species. Proceedings of the Royal Society B 289, 20221269. https://doi.org/10.1098/rspb.2022.1269
  2. Wu T, Rodrigues AA, Fayle T, Henry LM (In review) Defensive symbiont genotype distributions are linked to parasitoid attack networks. BioRxiv 07. 24.604610 doi: https://doi.org/10.1101/2024.07.24.604610
  3. Cornwallis C, van’t Padge A, Ellers J, Jackson R, Kiers T, West S, Henry LM (2023) Symbioses shape feeding niches and diversification across insects. Nature Ecology and Evolution 1-23. doi: https://doi.org/10.1038/s41559-023-02058-0
  4. Monnin D, Jackson R, Kiers ET, Bunker M, Ellers J, Henry LM (2020) Parallel evolution in the integration of a co-obligate aphid symbiosis. Current Biology 30, 1949-1957. doi: https://doi.org/10.1016/j.cub.2020.03.011
  5. Henry LM, Peccoud J, Simon J-C, Hadfield JD, Maiden M, Ferrari J, Godfray, HCJ (2013) Horizontally transmitted symbionts and host colonization of ecological niches. Current Biology 23, 1713-1717. https://doi.org/10.1016/j.cub.2013.07.029
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