I am interested in population biology (population dynamics, community ecology, evolutionary ecology). Research in the group focuses on a wide range of questions such as the population and evolutionary dynamics of life history strategies (e.g. the evolution of longevity), the role of spatial structure on shared enemy and competing enemy interactions, the effects of enrichment on the diversity of ecological communities, the interplay between noise and dynamics in multispecies interactions and the evolution of resistance to microbes.
Many of these projects involve the development of theoretical models in conjunction with experiments or observations in the field or laboratory. To this end, we aim to test different ecological and evolutionary ecology theories by fitting relevant mathematical models to appropriate ecological experimental (or observational) data. Further details of my research interests can be found here.
I have a strong interest in science policy. From 2007 - 2016 I was a member of DEFRA's Advisory Committee on Releases to the Environment (ACRE) and more recently involved in science policy work with the European Food Safety Authority (EFSA). As part of science policy work with WHO (TDR) and FNIH, I was involved in producing a report on the efficacy, biosafety and regulations of GM Mosquitoes. In June 2014, this report, as a Guidance Framwork for testing GM Mosquitoes, was published. Through July to December 2015, I served as science advisor to the House of Lords Science and Technology committee - a report was published on GM insects.
I am involved with the academic management teams on several Doctoral Training Programmes and more information on these is available here.
Publications
Combining refuges with transgenic insect releases for the management of an insect pest with non-recessive resistance to Bt-crops in agricultural landscapes
January 2021
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Journal article
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Journal of Theoretical Biology
Reinforcing the high-dose/refuge strategy with releases of transgenic insects has been posited as a method for simultaneously managing agricultural pest populations and resistance to transgenic crops. Theoretical and empirical studies have shown that these approaches can work when deployed against closed populations and the assumptions of the HDR strategy are met. However, field-evolved resistance is often linked to non-recessive resistance or refuge non-compliance, and pest management regimes are likely to take place at the landscape-level. It is therefore important to understand how effective such strategies are when resistance is non-recessive, and how they could be employed in agricultural landscapes. We developed a spatially-explicit model to investigate the efficacy of strategies combining refuges with transgenic insect releases to manage a pest with non-recessive resistance in agricultural landscapes. We compared two release strategies, area-wide releases and localised releases targeted at population hotspots, and analysed the effects of refuge and release parameters on population and resistance dynamics. Area-wide releases reliably achieved landscape-level pest eradication. Localised releases also eradicated the pest when low release thresholds were combined with high release ratios, and maintained the pest at low densities when insufficient to achieve extinction. Reinforcing refuges with localised releases also greatly enhanced the probability of resistance extinction. However, when resistance remained in the population, localised releases prevented resistance from reaching fixation rather than greatly delaying or reversing resistance evolution. Our work indicates that combining refuges with simple release policies is effective for landscape level pest suppression when the HDR assumptions are violated, but more nuanced release strategies may be required to enhance the benefits to resistance management.
Temporary ‘circuit breaker’ lockdowns couldeffectively delay a COVID-19 second wave infectionpeak to early spring.
December 2020
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Journal article
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Frontiers in Public Health
Multiple countries are assessing or already implementing short-term “circuit-breaker" lockdowns to suppress recent second- wave surges in COVID-19 cases. We present modelling simulations to quantify the impact and effectiveness of circuit-breaker lockdowns of varying effectiveness. Using UK case data, and assuming a four-week lockdown starting on October 1st, we show that these short-term lockdowns prove effective at postponing a peak in infection numbers to the spring of 2021, allowing an uncoupling from other health pressures that predominantly occur in winter. However, in the absence of any other intervention, such as a vaccination program, the lockdown will not affect the magnitude of the eventual subsequent peak. As such, circuit-breaker lockdowns are a suitable measure to help prevent strain on health services during the winter months, on the understanding that new measures may also be required after such a lockdown to suppress any re-emerging high case numbers.
The timing of evolutionary transitions suggests intelligent life is rare
November 2020
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Journal article
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Astrobiology
A mathematical modelling approach to uncover factors influencing the spread of Campylobacter in a flock of broiler-breeder chickens.
October 2020
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Journal article
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Frontiers in Microbiology
Despite continued efforts to improve biosecurity protocols, Campylobacter continues to be detected in the majority of commercial chicken flocks across Europe. Using an extensive data set of Campylobacter prevalence within a chicken breeder flock for over a year, multiple Bayesian models are presented to explore the dynamics of the spread of Campylobacter in response to seasonal variation, species-specificity, bird health, and total colonisation prevalence. These models indicated that birds within the flock varied greatly in their response to bacterial challenge, and that this phenomena had a large impact in the overall prevalence of different species of Campylobacter. Campylobacter jejuni appeared more frequently in the summer, while Campylobacter coli persisted for a longer duration, amplified by the most susceptible birds in the flock. Our study suggests that strains of Campylobacter that appear most frequently likely possess no demographic advantage, but are instead amplified due to the health of the birds that ingest it.
A mathematical modelling approach to uncover factors influencing the spread of Campylobacter in a flock of chickens
October 2020
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Journal article
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Frontiers in Microbiology
Despite continued efforts to improve biosecurity protocols, Campylobacter continues to be detected in the majority of commercial chicken flocks across Europe. Using an extensive data set of Campylobacter prevalence within a chicken breeder flock for over a year, multiple Bayesian models are presented to explore the dynamics of the spread of Campylobacter in response to seasonal variation, species-specificity, bird health, and total colonization prevalence. These models indicated that birds within the flock varied greatly in their response to bacterial challenge, and that this phenomenon had a large impact on the overall prevalence of different species of Campylobacter. Campylobacter jejuni appeared more frequently in the summer, while Campylobacter coli persisted for a longer duration, amplified by the most susceptible birds in the flock. Our study suggests that strains of Campylobacter that appear most frequently likely possess no demographic advantage, but are instead amplified due to the health of the birds that ingest it.
Sleep duration on the first night following a traumatic event and subsequent intrusive memories
September 2020
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Conference paper
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JOURNAL OF SLEEP RESEARCH
Sleep and intrusive memories immediately after a traumatic event in emergency department patients.
August 2020
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Conference paper
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Sleep
STUDY OBJECTIVES: Intrusive memories of psychological trauma are a core clinical feature of posttraumatic stress disorder (PTSD), and in the early period post-trauma may be a potential target for early intervention. Disrupted sleep in the weeks post-trauma is associated with later PTSD. The impact of sleep and intrusive memories immediately post-trauma, and their relation to later PTSD, is unknown. This study assessed the relationship between sleep duration on the first night following a real-life traumatic event and intrusive memories in the subsequent week, and how these might relate to PTSD symptoms at 2 months. METHODS: Patients (n = 87) recruited in the emergency department completed a sleep and intrusive memory diary from the day of their trauma and for the subsequent week, with optional actigraphy. PTSD, anxiety, and depression symptoms were assessed at 1 week and 2 months. RESULTS: A U-shaped relationship was observed between sleep duration on the first night and intrusive memories over the subsequent week: sleeping "too little" or "too much" was associated with more intrusive memories. Individuals who met Clinician-Administered PTSD Scale (CAPS) criteria for PTSD at 2 months had three times more intrusive memories in the first week immediately post-trauma than those who did not (M = 28.20 vs 9.96). Post hoc analysis showed that the absence of intrusive memories in the first week post-trauma was only observed in those who did not meet CAPS criteria for PTSD at 2 months. CONCLUSIONS: Monitoring intrusive memories and sleep in the first week post-trauma, using a simple diary, may help identify individuals more vulnerable to later psychopathology.
