PhD Studentship: Cloaks and Daggers: Fitness Effects of Ceratotoxin Antimicrobials in a Global Fruit fly Pest

Strong interdisciplinary training, within the ARIES Ecology and Biodiversity theme, to equip you with high-in-demand analytical skills in phenotypic and molecular genetic engineering. Suiting an individual interested in tackling fundamentally important questions with applied potential for control of insects that threaten food security.

In all species that lay eggs externally - in nests, ponds, mudpiles, food or other substrates - eggs and young may face unpredictable exposure to harmful or beneficial microbes. Mothers may manipulate the immediate microbial environment by provisioning eggs with protective antimicrobial compounds. One enigmatic example - the focus here - occurs in a global agricultural pest, the medfly (Ceratitis capitata). Medfly mothers 'cloak' their eggs with potent, broad-spectrum antimicrobial peptides comprising four 'Ceratotoxins' encoded by 7 genes. These kill microbes by punching holes in them. Offspring from eggs lacking protective antimicrobials are slower to develop, giving the first insight into potential benefits and providing a springboard for you to use phenotype engineering, sequencing and gene-editing tools to determine:

(i)Overall fitness benefits of Ceratotoxin egg cloaks under natural conditions

(ii) Functional significance of Ceratotoxin redundancy

(iii) Potential of Ceratotoxins for insect control

Methodology

(i) Fitness benefits

Test major hypotheses for protective egg cloaks:

• Protecting eggs and larvae from harmful microbes
• Protecting the female reproductive tract from sexually transmitted infections
• Creating a beneficial microbial community for larvae and eggs
• Facilitating vertical transmission of beneficial microbes

Assays of key fitness measures (survival, fertility, semi-natural conditions) using phenotypic manipulations (egg cloak removal, microbial add-backs), sequencing (16S rDNA of microbial communities) and molecular genetics (CRISPR-Cas9 knock-outs of Ceratotoxin gene combinations).

(ii)Functional redundancy

To determine if Ceratotoxin redundancy is adaptive: (i) test antimicrobial spectrum and potency of synthetic Ceratotoxin peptide mixtures, (ii) assay key fitness measures of gene-edited medflies lacking Ceratotoxins.

(iii) Insect control

Depending upon interests, explore (via experimentation, modelling, or quantitative literature synthesis) different possibilities for Ceratotoxin use in control, including via female-specific lethality, fertility loss, X-chromosome shredding, probiotics.

Training

High-in-demand technical (bioinformatics, molecular genetics, microbiology, phenotype engineering) and transferrable (critical thinking, ethics, Open Research) skills. Embedded in thriving, respectful and inclusive research environment.

ARIES studentships are subject to UKRI terms and conditions. Successful candidates who meet UKRIs eligibility criteria will be awarded a fully-funded studentship, which covers fees, maintenance stipend (21,805 p.a. for 2026/27) and a research training and support grant (RTSG). A limited number of studentships are available for international applicants, with the difference between 'home' and 'international' fees being waived by the registering university. Please note, however, that ARIES funding does not cover additional costs associated with relocation to, and living in, the UK, such as visa costs or the health surcharge.

ARIES is committed to equality, diversity, widening participation and inclusion in all areas of its operation. We encourage applications from all sections of the community regardless of gender, ethnicity, disability, age, sexual orientation and transgender status. Projects have been developed with consideration of a safe, inclusive and appropriate research and fieldwork environment. Academic qualifications are considered alongside non-academic experience, with equal weighting given to experience and potential.

After submitting their application for the relevant ARIES project(s), applicants are expected to complete the ARIES Equality and Diversity Form Applicants - 2027 Entry  Fill in form. One form is required per application, so applicants applying to more than one project must complete a separate form for each.