SWD oviposition deterrents project
In collaboration with researchers at the Natural Resources Institute (NRI) and industrial partners Berry Garden Growers, NIAB EMR are leading a BBSRC-IPA grant to protect fruit crops from spotted-wing drosophila (SWD, Drosophila suzukii). The project builds on previous research conducted at NIAB EMR, which shows that SWD avoid laying their eggs in or around fruit previously exposed to another fly species, Drosophila melanogaster. New experiments are being carried out to identify the chemical signals responsible for this avoidance behaviour, with the aim of producing a novel, naturally-derived product which can be applied to fruit for crop protection.
In this three-year research project (2019-2022), we are investigating the strong natural interspecific interactions between SWD and its sister species within the Drosophila melanogaster species group with the aim of developing a novel approach to control of the pest. The project aims to identify new chemical oviposition deterrents that can be applied within the cropping area to deter fruit damage by SWD as a new component of IPM strategies.
In this research programme, we are investigating which stage of D. melanogaster (adults or eggs) releases the chemical signals that are responsible for reducing egg-laying by SWD. We plan to:
- Extract the active chemicals from melanogaster (and other Drosophila species if these prove to be more effective) and apply the signals (without D. melanogaster individuals present) to egg-laying substrates to demonstrate that the chemical alone is responsible for deterring SWD.
- Investigate how SWD detect the active chemical(s) and show whether this is via olfaction (detection of relatively volatile chemicals) or gustation (involving relatively non-volatile signals), by investigating responses of flies that have sense organs missing (removed surgically) or not functional (due to genetic modification). This will identify the sense organs responsible for the detection of chemical deterrents (e.g. parts of the antennae or the mouthparts).
- Record electrical responses of SWD sense organs to components of extracts that have been separated out using appropriate techniques such as chromatography. In combination with other methods in analytical chemistry, we will identify the chemical structure of the active chemical signal for synthesis in the laboratory.
- Carry out further behavioural and electrophysiological experiments to demonstrate effects of individual chemical components and blends on SWD egg laying activity, initially in small-scale laboratory studies and then in the field on raspberry and strawberry crops.
- In consultation with growers, representatives from industry and economists, we plant to design new approaches to pest management that include deploying oviposition deterrents.
This research programme will therefore lead to the discovery of new scientifically valuable information on insect signalling and the implementation of new approaches to crop protection.
The project is led by Dr Michelle Fountain (PI) and Dr Glen Powell (Co-I) at NIAB EMR and also benefits from the expertise of Dr Bethan Shaw, building on the results of her PhD thesis (Shaw et al., 2018). Dr Trisna Tungadi has been employed as the NIAB EMR-based postdoctoral research scientist dedicated to the project. Professor David Hall and Dr Daniel Bray, together with their colleagues at NRI, are responsible for identifying the chemicals which deter SWD from egg laying, and the mechanisms through which they are detected. In addition to funding from the BBSRC, the work is supported by industrial partners Berry Garden Growers and the AHDB, who will ensure that the research findings have maximum impact for fruit growers.
This project is part of a long running collaboration between NIAB and NRI. The two institutions have worked together for over 25 years, conducting a portfolio of applied research in support of the UK horticultural industry.
Harris A, Shaw B (2014) First record of Drosophila suzukii (Matsumura) (Diptera, Drosophilidae) in Great Britain. Dipterists’ Digest 21.
Shaw B, Brain P, Wijnen H, Fountain MT (2018) Reducing Drosphila suzukii emergence through inter-species competition. Pest Management Science 74: 1466-1471 (doi:10.1002/ps4836).