Join us!

Potential PhD projects:

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Animal-microbe symbioses in pest insects

Supervisors: Tracey Chapman, Philip Leftwich

Sequencing technologies have fuelled a rapid rise in descriptions of microbial communities associated with hosts, but what is often harder to ascertain is the evolutionary significance of these symbioses. In recent research we found that mixed modes of microbial transmission play an underappreciated role in the establishment of animal host-microbe relationships. The goal of this project is to test this idea empirically and thus define fundamental rules governing such associations.

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The project uses the Mediterranean fruit fly (medfly, Ceratitis capitata) and its putative stable gut symbiont Klebsiella oxytoca. This represents a powerful system in which the composition of the symbiotic microbiome can be experimentally manipulated in multiple ways. The project applies a combination of metagenomics, transmission studies, forward genetics and modelling, to test the mechanisms which promote host-symbiont associations.

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The project aims to (i) test the transmission mechanisms that facilitate gut colonisation by symbionts, (ii) determine the extent of, and mechanisms underlying, host fitness benefits, and (iii) conduct genome-wide screens to identify essential genes of symbiotic bacteria required for colonisation and mutualism in medfly.

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References:

Leftwich PT, Edgington MP & Chapman T. (2020) Transmission efficiency drives host-microbe associations. Proc Roy Soc B accepted. bioRxiv 2020.07.23.216366; doi: https://doi.org/10.1101/2020.07.23.216366

Leftwich PT*, Nash, WJ*, Friend LA, & Chapman T. (2019) Contribution of maternal effects to dietary selection in the medfly. Evolution, 73: 278-292.

Leftwich PT, Hutchings MI & Chapman T. (2018) Diet, gut microbes and mate choice: understanding the significance of microbiome effects on host mate choice requires a case by case evaluation. BioEssays, 40: 1800053.

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Please contact me if you are interested in discussing further!

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tracey.chapman@uea.ac.uk

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Sex, diet and lifespan

Supervisors: Tracey Chapman, Alex Maklakov and Wilfried Haerty

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The key question addressed in this project is to determine why each sex typically has a different length of life.

Males and females possess distinct morphological, physiological and behavioural characteristics, of which differences in lifespan are among the most striking, but perhaps the least well understood. Length of life can also be extraordinarily plastic – varying significantly with reproductive status and nutrient availability. However, the extent to which lifespan is plastic in each sex also differs markedly. For example, sex differences in male vs female lifespan in fruitflies can be completely reversed by manipulations of diet and mating status via dramatic effects on females.

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The main aim of the project is to test the idea that differences in male and female lifespan arise because each sex chooses and require different nutrients to maximise their lifespan and fitness. The student will test this using the latest experimental and bioinformatic tools in the fruitfly system.

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The core idea is to test the effects of different experimental diets separately on male and female fitness, in the presence and absence of dietary choice. The student will profile ageing phenotypes and physiological measures of health and fitness throughout life and identify the loci and regulatory mechanisms contributing to sex-specific lifespan.

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References:

Rostant WG, Mason JS, deCoriolis J-C & Chapman T. (2020) Resource-dependent evolution of female resistance responses to sexual conflict. Evolution Letters, 4, 54-64.

Duxbury EML & Chapman T. (2020) Sex-specific responses of lifespan and fitness to variation in developmental versus adult diets in D. melanogaster. Journals of Gerontology: Biological Sciences. 75, 1431-1438.

Leftwich PT*, Nash, WJ*, Friend LA, & Chapman T. (2019) Contribution of maternal effects to dietary selection in the medfly. Evolution, 73: 278-292.

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Please contact me if you are interested in discussing further!

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tracey.chapman@uea.ac.uk