IAP-26-088

Stress Testing the Future: Assessing the Impact of Heatwaves on Insect Biology

Insects play wide-ranging and crucial roles in ecosystems and pollinate most crops, while also representing major pests and disease vectors. Insects are ectothermic and consequently highly sensitive to temperature extremes. It is therefore essential to predict how future climate change will affect these animals. While many studies have explored how temperature affects insects, few have directly assayed the impact of predicted future extremes. This project aims to characterise how predicted future high temperature extremes affect insect development, life history and behaviour.

The project will focus on Drosophila suzukii and D. melanogaster, which provide a powerful comparative framework to decipher general and species-specific resilience and vulnerability to climate extremes between pest and non-pests. D. suzukii is a major pest of soft fruit that recently spread across the world from Asia causing severe annual economic damage. D. melanogaster is a harmless widespread, generalist. Drosophila represent an excellent study-system because they can easily be reared in the laboratory mimicking environmental conditions.

The aim of the project will be delivered through the following Objectives:
O1. Predicting future spring-time high temperature extremes in Northern and Southern Europe.
O2. Characterising how high temperature extremes affect gene expression and morphology?
O3. Determining how high temperature extremes affect life history traits and behaviour?
O4. Modelling the impact of a wider range of temperature extremes and identifying vulnerable locations.

O1. To inform O2–4, we will first analyse current and future climatic conditions.
(i) ERA5-Land/CHELSA reanalysis data will be used to understand the geographical distribution and magnitude of climate extremes across Europe under contemporary conditions.
(ii) High-resolution Regional Climate Model simulations from the EURO-CORDEX project will be employed under CMIP6 scenarios to characterize future climate for Southern and Northern Europe. Subsequently, we will assess how spring-time high temperature extremes are anticipated to change relative to current conditions to determine future acute and chronic high temperature extremes.

For O2 and O3, populations of D. suzukii and D. melanogaster from Southern and Northern Europe will then be raised under control conditions mimicking normal Spring-time at their origins and projected acute and chronic high temperature extremes from O1.

O2. RNA-sequencing will be used to identify differentially expressed genes after treatments. Measurements of the size of body parts will be made to determine overall body size and whether individual organs respond differently in a species- or population-specific manner.

O3. Viability will be measured by comparing eclosed fly numbers among treatments. Fertility will be assessed by counting fertilised eggs from experimental males crossed to control females and vice versa. Immunity will be assessed by exposing flies to bacteria and plotting survival. Memory will be tested by ability to remember association between olfactory cues and rewards.

O4. The data from O1-O3 will be used to model how each trait is likely to respond to exposure to even more extreme temperatures and for longer times. By applying this framework to projected temperature extremes across climatic gradients from Southern to Northern Europe, the student will identify locations where levels of vulnerability or resilience to extreme temperatures are most likely to occur over forthcoming decades.

Year 1

Months 1-6: Computational prediction of future high temperature extremes (O1)
Months 4-12: Analysis of gene expression and morphology of flies raised at these temperatures compared to controls (O2).

Year 2

Months 13-16: Analysis of gene expression and morphology of flies raised at these temperatures compared to controls (O2).
Months 16-24: Assaying the effects of treatment temperatures on life history traits and behaviour (O3).

Year 3

Months 25-33: Assaying the effects of treatment temperatures on life history traits and behaviour (O3).
Months 34-36: Modelling the impact of wider extremes and identifying vulnerable regions (O4).

Year 3.5

Months 37- 39: Modelling the impact of wider extremes and identifying vulnerable regions (O4).
Months 38- 42: Thesis writing.

The student will employ the professional development planner from the Vitae Researcher Development Framework (VDRF) to align their training and career development with the four domains of this framework. This will allow reflection and flexibility to dynamically respond to the student’s progress and needs during the project.

The student will be trained by four supervisors, whose expertise span the required disciplinary backgrounds, with complementary experience and skills in different areas of wet lab biology, bioinformatics, life history and behaviour as well as eco-geography and climate modelling.

The student will be trained in computational approaches used in physical geography to predict future high temperature extremes to determine the experimental conditions in the laboratory with LTL (O1). They will then use approaches from a range of biology disciplines, including genetics, development, bioinformatics, genomics, behaviour, immunity and evolution to assess the impact of treatments on focal traits and explore the mechanistic basis (O2 and O3). AM will provide training for fly husbandry, developmental biology, RNA-seq data collection and bioinformatic analysis for O2 with MK delivering training in microscopy and morphological analysis. The second supervisor MR will provide training in approaches to analyse life history traits under different treatments for O3. Training in the design and application of statistical approaches and mathematical models of climate change to predict broader patterns and extremes, and pinpoint regions of particular vulnerability will then also be provided by LTL (O4).

To deliver this training the student will be based in AM’s research group but will also be associated with LTL’s group, allowing interactions with other PhDs in an interdisciplinary supportive, cosmopolitan and vibrant environments, where EDI principles are promoted and that operate flexible working hours and holidays. The student will participate in lab meetings supplemented by individually meeting their primary supervisor fortnightly and with all supervisors every trimester. The student will be enrolled in Biosciences’ PGR programme and meet their progress committee biannually. While the student will be based in the primary supervisor’s lab and work with LTL at Durham, placements in the labs of the other two supervisors will form essential elements of the student’s training and skills development. To deliver this, the student will visit the second supervisor MR in St Andrews in years 2 and 3 for O2 and O3, and well as visit MK’s lab in Oxford for O2.

The student will also practice communication skills through disseminating their findings at conferences and prepare manuscripts for publication. They will also have opportunities to supervise undergraduate projects and practicals to develop teaching and mentoring skills.
This project and training programme will facilitate the student’s development to conduct independent, impactful research and prepare them for diverse future career options at the nexus of biology and geography with lab and computational skills much sought after by employers in academia and beyond. The supervisory team will collectively support the student in further career development training and opportunities.