How eco-evolutionary dynamics shape natural enemies in complex landscapes

"Producing more food while preserving the environment is a major societal aim and sustainable development goal. This implies harnessing and conserving benefits from nature, such as pollination of crops by wild pollinators, and natural control of crop pests by beneficial predatory insects. A current paradigm is that such ecosystem services are supported by increasing the density of landscape elements in agricultural landscapes through providing shelter and alternative food resources for beneficial organisms. While there have been major advances on harnessing pollination services from wild pollinators, recent syntheses suggest the response of natural enemies to agricultural management is not well understood, which may in part reflect differences among functional groups in their dispersal ability and response to pesticide use (1).
Spiders are important biocontrol agents of pest species in agricultural landscapes, and can help farmers reduce their reliance on insecticides and have a net benefit on yield (2). As pests evolve resistance to pesticides they are expected to play an increasingly important role. The most widespread and abundant spiders in temperate agricultural systems belong to the Family Linyphiidae. These small ‘money’ spiders are shown to be effective in preventing pest populations, such as aphids, from escaping predator control, in part because their unique ‘ballooning’ dispersal strategy enables them to quickly recolonise agricultural fields subject to pesticide application (3). These ecological dynamics raise a number of important questions around how to best manage the landscape to maximise the benefits of natural enemies - including the timing and spatial spread of pesticide application, the role of refugia in landscapes e.g. trees and field margins, the impacts of mismatches in life-history between predator and prey under climate change, and the potential for evolutionary responses in dispersal strategy and pesticide resistance in complex landscapes.
The aim of this project is to develop a modelling framework to investigate these questions. The student will develop an agent-based model for money spiders, one that incorporates full life-history, realistic spatial landscapes and biological interactions, providing a tool to better inform decisions on how to promote these beneficial species through better habitat management and landscape design in a changing climate (4). It also provides a framework that can be extended to other natural enemies and different crop types within agricultural landscapes, contributing to our wider understanding of biodiversity attributes and ecosystem services.
Main project objectives
1) Develop an agent-based model of Linyphiidae spiders parameterised with data from the literature and laboratory.
2) Validate predictions of ballooning events using citizen science data from Nottingham’s Open Air Laboratories (OPAL)
3) Extend the model to include predator prey interactions with aphids to explore the potential for phenological mismatch under climate warming
4) Investigate various scenarios of habitat management on the effectiveness of spiders to control pest populations.
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