IAP-25-026

What drives aggression? Linking Ecology, Evolution, and Genes

Social interactions are some of the most dramatic, complex, and varied behaviours on Earth. From colourful courtship displays to brutal dominance disputes, behaviours between individuals of the same species have captured the public and scientific imagination. Social behaviours can shape the survival and reproductive success of individuals, as well as determine group size, habitat selection, and predator avoidance. Unlike many morphological traits, behaviours are flexible and context-dependent, allowing organisms to respond rapidly to changing environments, yet their expression and potential for change are also shaped by deep evolutionary constraints—such as phylogenetic history, genetic architecture, and trade-offs with other fitness-related traits. Studying behavioural diversity therefore allows us to investigate how ecological pressures can generate adaptive plastic traits over evolutionary time.

Aggressive behaviour is a fundamental component of animal interactions, shaping access to food, mates, and territories. However, the ecological and evolutionary drivers of aggression, and the molecular mechanisms underlying its variation across species, remain poorly understood. This project will use Drosophila (fruit flies) as a powerful comparative system to investigate how ecological factors and evolutionary history shape the expression and regulation of aggression.

The student will examine aggression across ~20 Drosophila species that vary in their natural history, including differences in mating systems, reproductive strategies, resource use, and oviposition ecology. By combining comparative analyses with controlled behavioural experiments, the project will test how ecological drivers influence the evolution of aggressive behaviour.
To complement behavioural and ecological data, the student will apply transcriptomic approaches across species, and within selected species under experimental conditions, to identify patterns of gene expression associated with aggression. Candidate genes revealed by these analyses may then be functionally tested using established molecular genetic tools. This integrative approach will link ecological drivers, behavioural expression, and molecular mechanisms to provide a comprehensive picture of the evolution of aggression.

This project will use a variety of lab-based methods. First, there will be insect husbandry techniques – acquiring and maintaining stock lines of multiple Drosophila species. Next, there will be behavioural assays (e.g. mating and aggression assays), which will be recorded and stored on a computer. The student will then learn machine learning skills to train the computer to automatically track and score behaviour on these videos. They will also learn key transcriptomic skills – extracting RNA, performing techniques to prepare samples for sequencing and bioinformatics for analysing transcriptomic data. Other skills include reproductive assays, taking morphological measurements (using microscopes, microbalances), and data analysis of behavioural and morphological data using R.

Year 1

Perform behavioural assays on 20 species. These will be aggression assays on males, unmated and mated females from each species. These assays involve 15-minute recordings of 20 pairs of flies at once, followed by video tracking and automated scoring. The student will learn insect husbandry and handling techniques, behavioural experimental design, machine learning, and data analysis.

Year 2

Transcriptomic experiments on some selected species (based on outcome of experiments from year 1). Collection and processing of material for RNA-seq, sequencing, data cleaning and analysis. Functional experiments to validate candidate genes/follow on from transcriptomic results. Writing up results from year 1. The student will learn transcriptomic and genetic methods, as well as bioinformatics.

Year 3

Targeted experiments manipulating resource availability in selected species – e.g. changing food or mate availability. Follow-on (if necessary) and writing up results from year 2.

Year 3.5

Writing up year 3 and final thesis.

Training in key skills in behavioural ecology, evolutionary biology, and bioinformatics. The student will learn insect husbandry and handling skills, behavioural assaying, machine learning to track animals and score complex social behaviours. They will also learn transcriptomic lab-based skills and desk-based bioinformatics and data analysis skills. They will also acquire comparative analysis skills, and general lab skills (such as microscope use). The student will be encouraged to go to relevant workshops to acquire such skills (e.g. transcriptomics workshop).