Rapid Adaptation and Sex Bias in Crickets: a Genomic and Behavioural Approach

This PhD project focuses on unresolved ideas about the genomic architecture and fitness consequences of novel mutations using a compelling, well-resourced field cricket system. Adaptive evolution can occur very rapidly, but in natural systems it is challenging to characterise its early stages, during and directly after new genotypes arise. How big are the effects of new adaptations, what are their genomic features, and can we predict evolutionary “paths of least resistance” for future bouts of adaptation?

This PhD capitalizes on Hawaiian crickets (Teleogryllus oceanicus) that have recently lost the ability to sing. Some males carry a morphological mutation which erases male-specific, sound-producing structures on their wings, partially feminising them. Silent ‘flatwing’ males are protected from an acoustically-orienting parasitoid fly, but cannot attract and court females using song.

The abrupt spread of flatwing males represents one of the fastest evolutionary rates documented in a wild system, but poses many questions about the genomic basis of rapid adaptation, the behavioural impacts of signal loss, and the role of sex-biased gene expression in facilitating future evolutionary change. Convergent forms of silent flatwing male cricket on different Hawaiian islands – one with more feminised wings than the other – tantalizingly hint that genomic pathways involved in sex differentiation may represent a particularly evolvable substrate for adaptive evolution through natural selection.

Genomics of adaptation, sex-biased gene expression, and behavioural evolution will be central themes of the project, but there is an opportunity and expectation that the student will develop research goals to suit their own interests. The Bailey lab uses genetic and NGS-based genomic approaches in combination with behavioural assays and bioinformatics analysis. The student may also engage with other techniques used in the group, including geometric morphometrics, quantitative modelling, behavioural tracking and meta-analysis.

The School of Biology at St Andrews has an outstanding PhD programme in Evolutionary Biology, and hosts a diverse and engaged postgraduate community. The Bailey lab has also instigated collaborative projects outwith the university, for example on genome browser development for singing insects, and neurobiology of acoustic signalling. Bailey is a core contributor to the St Andrews Bioinformatics Unit, and encourages and fosters training opportunities for PhD students including reading groups, seminars, outreach, in-house bioinformatics training, and external workshops.

Further details about the group and our research interests are available at www.flexiblephenotype.org