Scent of Survival: Chemical Communication and the Threat of Pesticides to Insect Societies.

Insects are declining at an unprecedented rate globally and in the UK, driven by habitat loss, climate change, and pesticide use. These losses threaten food security, biodiversity, and ecosystem resilience.

Much research to date has focused on the managed honeybee (Apis mellifera), which is the world’s most important pollinator, and is therefore critical for agriculture and food security. However, this focus has neglected other key groups of insects including bumblebees, solitary bees, and ants despite their critical ecological roles in pollination, soil health, and ecosystem function.

At the heart of insect reproduction and social organisation are pheromones: chemical signals that regulate mating, reproduction, social cohesion, and many other behaviours. In bumblebees, pheromones mediate queen–worker interactions and reproductive division of labour, but the precise compounds and mechanisms remain poorly understood. Solitary bees, such as Osmia species, use pheromones for mating and reproduction, yet little is known about the molecular and behavioural basis of these cues. Ants, meanwhile, rely on some of the most complex pheromone systems in the animal kingdom, coordinating everything from foraging to nestmate recognition.

We know that sub-lethal pesticide exposure can disrupt many behaviours that are also regulated by pheromones, including foraging, sucrose sensitivity, and reproduction. This raises the possibility that pesticides act in part by directly interfering with pheromone signalling, compounding their effects on insect health. Almost nothing is known about how pesticides might interact with pheromone systems across the spectrum of insect sociality, from solitary bees to advanced ant societies.

This PhD project will take a comparative approach that combines chemical, behavioural and population ecology to explore the pheromone “landscape” of bumblebees, solitary bees, and ants, and to test how these systems respond to pesticide exposure. The results will provide both fundamental understanding about the evolution of communication and eusociality and reveal new insights about the risks that biodiversity faces from pesticide use.

 

Research questions

1. What are the key pheromone compounds in important insect species?
2. How do these pheromones regulate reproduction, mating and social cohesion?
3. Do field-realistic levels of pesticides interfere with normal pheromone functioning?

 

Experimental Approach

This project will use a comparative chemical ecology framework to study pheromone communication in bumblebees, solitary bees, and ants. We will combine chemical analyses (e.g. GC–MS) to identify pheromones in target species. Behavioural assays will test how these pheromones regulate reproduction, mating, and social organisation. Molecular tools (RNA-seq, RT-qPCR) will assess how pheromone signalling pathways, and their interaction with pesticides, are regulated at the genetic level. Laboratory and semi-field experiments will be used to test how pheromones mediate life history traits and ecology of affected species, and whether pesticide exposure disrupts these processes. Together, these approaches will generate new knowledge on the evolution of eusociality and provide a mechanistic understanding of how pesticides affect insect communication.

 

Skills and Training

The student will have a background in biological sciences (e.g. Biology, Ecology, Genetics, Zoology) and will have an appetite for applying molecular techniques to ecological problems.

The student will join a vibrant research environment and will receive multidisciplinary training in chemical ecology, behavioural ecology, and molecular biology.  There will be opportunities for laboratory-based studies and some field work (likely UK focussed) and will benefit from broader training in transferable skills.

 

Further Reading

Bartling, M.-T.; Brandt, A.; Hollert, H.; Vilcinskas, A. Current Insights into Sublethal Effects of Pesticides on Insects. Int. J. Mol. Sci. 2024, 25, 6007. https://doi.org/10.3390/ijms25116007

R.A. Knapp, V. C. Norman, J. L. Rouse, E. J. Duncan, Environmentally Responsive Reproduction: Neuroendocrine Signalling and the Evolution of Eusociality. Current Opinion in Insect Science, (2022) https://doi.org/10.1016/j.cois.2022.100951