Project Highlights:


  • International—collaborate with an international research network with opportunities to spend time at other universities.
  • High impact—contribute to the development of carnivorous pitcher plants as models for understanding fundamental ecological processes.
  • Cross disciplinary—collaborate with researchers from a range of ecological disciplines to provide insight into this complex system.

The carnivorous pitcher plant Sarracenia purpurea captures insect prey in pitchers formed from modified leaves. Prey are digested by a simple detritus-based food web that lives inside the pitchers. The nutrients from digested prey are then absorbed into the plant’s tissues and used for growth and reproduction. Sarracenia purpurea has a native distribution across the Eastern seaboard of N America, and NE USA and Canada, and has also been introduced into peat bogs across NW Europe, where it has become naturalised.

The aquatic communities which live in Sarracenia purpurea pitchers are model ‘micro-ecosystems’. For example, they have been used to understand trophic interactions in food webs and ecosystem tipping points. In particular, comparison of how the plant and the pitcher community function in their native vs introduced European range is potentially a powerful approach for understanding how ecosystems function. This is the focus of the newly created Sarracenia Purpurea International Network (SPIN), which links together researchers from a range of disciplines in North America and Europe, to investigate the S. purpurea system.

Prey capture and the nutrients this provides is fundamental to the ecological success of S. purpurea. Surprisingly little, however, is known about prey capture, digestion and nutrient uptake, and the controls over and ecological significance of this. Dr Millett has worked extensively investigating the nutritional ecology a different carnivorous plant (sundew Drosera spp.), using stable isotope approaches and trait measurements. This PhD will use similar approaches to provide key information for understanding the function of the S. purpurea model system by investigating the nutritional ecology of this species. This will build on ongoing work, including a current PhD student, focussed on understanding S. purpurea distribution and microbial ecology in Europe and N America.

Key questions this PhD project will address are:

What and how much prey do Sarracenia purpurea in Europe catch?

How reliant are Sarracenia purpurea in Europe on prey derived nutrients?

How and why do these vary within and between populations in Europe?

What is the role of the microbial community vs extrinsic factors in this variability?

Do these patterns differ in European populations compared to North American populations?


Sarracenia purpurea naturalised on a small bog in South West Sweden. Here, as in many European populations the plants grow at densities far higher than in their native range.


Study design, approaches and methods will be finalised in discussion with the student. Sites will be selected from the range of c.100 sites across Europe where Sarracenia purpurea is naturalised, and selected sites in North America. Sites may cover environmental ranges—e.g. temperature, nutrient pollution, precipitation—or time since introduction. Study plants will be selected to encompass within-site environmental gradients of hydrology, shade and ‘age’ (to encompass the original ‘starter’ population and the invasion front).

Prey capture will be measured by collecting pitcher contents and comparing to background prey availability. The contribution of prey to plant nutrition will be measured using natural abundance stable isotope approaches. Tracing of prey nutrient uptake will also be undertaken using isotopically labelled prey addition in-situ. Use of a collection of plants at Loughborough University will enable focussed studies of prey digestion and nutrient uptake. There is also the potential to investigate the microbial ecology of pitchers and impacts on prey nutrient uptake using DNA metabarcoding approaches.

Training and Skills

Training will include plant ecophysiolgical measurements, field techniques, statistical analyses and species distribution modelling. The project will develop some key skills identified by NERC as ‘most wanted’ for jobs in the environment sector such as, fieldwork, sampling techniques, field observation and modelling.


Year 1: Literature review and focussing of research questions and methods/approaches to be taken. Identification of European study sites. Initiation of European study, comparing key sites across Europe. Laboratory work to identify pitcher contents and measure stable isotopes within plant and prey tissues.

Year 2: Continuation of European study to make detailed measurements of a sub-set of sites. Visit to USA to replicate European study on populations in native range. Set up of ex-situ study at Loughborough University. UK-based conference.

Year 3: continuation and completion of ex-situ study. Data analysis, thesis writing. International conference.

Partners and collaboration (including CASE)

The PhD includes two international Co-investigators—Dr Erica Young and Dr Leonora Bittlestone— who will provide access to sites in the native range of Sarracenia purpurea and approaches for investigating the aquatic communities within the pitchers. The student will also have the opportunity to engage with the Sarracenia Purpurea International Network (SPIN) which includes researchers across the native range of S. purpurea and also in Europe. There is considerable potential to work with researchers from a wide range of geographic locations and academic disciplines within environmental sciences.

Further Details

 Contact Dr Jon Millett (j.millett@lboro.ac.uk) for further details.