Dr Daniel Leybourne

Research Fellow

Curriculum vitae

Evolution, Ecology and Behaviour. Institute of Infection, Veterinary and Ecological Sciences

The University of Liverpool

Landscape effects on endosymbionts of the cabbage stem flea beetle (British Ecological Society; Large Research Grant; 2021-2023; PI; Hannover University)

Project Overview: 
In many herbivorous insect species, including aphids and weevils, insect endosymbionts can have far-reaching effects on insect biology. Insect endosymbionts confer numerous traits, including protection against natural biocontrol agents, which can reduce their effectiveness as sustainable pest management solutions. However, little is known about intra-specific variation of the cabbage stem flea beetle, and less is known about how these might influence insect biology. The cabbage stem flea beetle is a significant herbivorous insect of agricultural importance throughout Europe and herbivorous insect management is impeded by high incidence of insecticide-resistant populations across Europe. Therefore, successful management of cabbage stem flea beetle is becoming increasingly reliant on sustainable non-chemical practices and an agro-ecological approach.

Characterising the endosymbiotic diversity of the cabbage stem flea beetle will be the first step in determining whether sustainable management of cabbage stem flea beetle might be influenced by herbivorous insect intra-specific variation, as is the case for other important herbivorous insects (e.g. aphids). This project will characterise the endosymbiont community of cabbage stem flea beetles and investigate whether landscape diversity influences the endosymbiotic profile found in cabbage stem flea beetle populations collected from fields that have contrasting landscape structures.
Sequencing data:
We just received the sequencing data from our samples! So there will be a lot of analysis to do over the coming weeks and months. An overview of where we are with the project: 72 Beetles were sampled from multiple winter rapeseed fields in summer and autumn 2021. We extracted DNA from the hind legs (for genetic diversity analysis) and from the "remaining beetle" tissue (for microbiome analysis).

Leg DNA was analysed using the Mig-Seq method (https://www.nature.com/articles/srep16963) and the microbiome (16S for bacteria + ITS for fungi) was sequenced using a MiSeq platform.  We will be looking to see how genetically and microbially diverse the different populations are, and examining whether this is influenced by the landscape surrounding each sampling site. 
Student success:
This project was supported by an MSc student, Antonia Pahl, who played a fundamental role in helping to source our autumn 2021 study sites. Antonia carried out the fieldwork for her MSc project on these field sites, and the sites were also used to support a BSc project student, Alexander Manentzos. Alex successfully presented his BSc project in winter 2022, and Antonia successfully passed her MSc viva in early 2023!

Antonia's MSc project was entitled: "Population dynamics of Psylliodes chrysocephala (L.): Do winter oilseed rape crops benefit from increased protection in more complex landscapes?".  In her project Antonia identified some local ecological and landscape drivers behind beetle pressure and associated crop damage.

Alex's BSc project focussed on characterising the endosymbiont profile of cabbage aphid (Brevicoryne brassicae) and peach-potato aphid (Myzus persicae) populations sampled across our field sites. Surprisingly, Alex rarely found any endosymbionts in these aphid populations.


Sharing the burden: Cabbage stem flea beetle pest pressure and crop damage are lower in rapeseed fields surrounded by other rapeseed crops

D.J. Leybourne, A.M.C. Pahl, P. Melloh, E.A. Martin

Agriculture, Ecosystems & Environment, vol. 366, 2024, p. 108965


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