The impact of artificial light at night on optimal foraging, trophic networks and ecosystem services

Background: Artificial light at night (ALAN) affects invertebrate abundance and function1 with downstream impacts on ecological processes and ecosystem services2 including trophic interactions3 and nutrient cycling4. Nutrition and foraging are inherently linked5 and, as these change, animals will seek optimal resources and patches6, likely driving observed community structure changes under ALAN.

This will, in turn, impact local provision of ecosystem services such as pollination and predation, thereby effecting both natural and semi-natural systems. The drivers of these changes are, however, poorly understood.

Objectives: Determine how nutrient availability changes under ALAN, how this drives changes in trophic network structure and function, and how this impacts ecosystem services (ESs) such as pollination and biocontrol.

Methodology: This project will use equipment and expertise from Newcastle University's Molecular Diagnostics Facility to identify and compare ecological interactions at paired lit and unlit sites. Using techniques such as floral eDNA and dietary metabarcoding, and nutrient analysis, this project will compare trophic interactions and nutrient contents between paired lit and unlit sites.

These data will be used to construct networks5 to determine how interactions are structured by ALAN and the consequences for ESs.

Training and development: The successful student will be embedded within Newcastle University's Ecology Group, a thriving research community, and will receive training in molecular analysis of interactions via metabarcoding, field entomology and nutritional analysis in Newcastle University's Molecular Diagnostics Facility and experimental farms. Training in ecological informatics skills including multivariate and network analyses, and bioinformatics will also be provided with opportunity to attend additional external training.

Key research gaps and questions: 1) How does nutrient availability for predators and pollinators change under artificial lighting?

2) Are community structure changes under artificial light driven by foragers seeking nutritionally optimal resources or patches? 3) What is the impact of these changes on ecosystem service provision? References: 1. Boyes et al. 2021, Science Advances. 2. Macgregor et al. 2019, Ecosphere.

3. Grubisic & Van Grunsven 2021, Current Opinion in Insect Science. 4. Li et al. 2023, Geoderma. 5. Cuff et al. 2022, Authorea. 6. MacArthur 1966, American Naturalist.