Swedish University of Agricultural Sciences/Sveriges Lantbruksuniversitet
Department of Plant Protection Biology
Division of Chemical Ecology
We investigate and develop chemical messenger compounds, pheromones and other semiochemicals, for control and monitoring of insects in agriculture, horticulture and forestry, and for insects that transmit diseases. A changing climate with higher summer temperatures and altered rainfall patterns makes insect control an increasingly urgent challenge.
In addition to application-oriented work, our research interests include sensory physiology, evolutionary processes underlying odour communication systems, molecular mechanisms of odour perception, and behavioural modulation by learning and multisensorial stimuli.
(Translated from SLUs website)
1. Chemoecology of insect, fruit and yeast: from the model to the pests
The importance of yeast for the ecology of fruit-living insects, including pests, had for a long time not been recognized. Yeast links the fruit fly Drosophila melanogaster(Dm) to fruit. We studied the role of yeast in fruit-living insects.
The main focus of this project was on the cherry vinegar fly Drosophila suzukii(Ds), which is a serious invasive pest in Europe. A quick dispersal in the US together with its recent appearance in Italy, France and Spain was a call for instant action also in Sweden. In fact Ds came to Sweden during the project time in 2014, most likely through import of infested fruit. Afterwards Ds has established populations in fruit growing areas all over Scania.
The goal of this project was to study the ecological importance of yeast for fruit-living insects, and to apply this know-how in pest control. Fermenting baits have traditionally been used to attract insects but their power has neither been sufficiently studied nor exploited.
Wild yeasts associated with fruit and insects had been isolated, identified and fermented under controlled conditions. Fermentation products were chemically analysed and behaviourally and physiologically studied in Dm and Ds. We started to decipher the chemical signals from yeasts that mediate attraction in fruit-living insects, foremost Ds. This research contributed to the development of a yeast-based attract-and-kill technique and might lead to new methods for an integrated pest management of horticultural insect pests.
Project leader and participants: Paul G. Becher, Peter Witzgall (SLU Alnarp), Jure Piskur (LU)
Project period: 2012-2016
Funding: The Swedish Research Council Formas
2. Behavioural manipulation by microbial semiochemicals: a foundation to manage Drosophila suzukii and other pest
The spotted wing Drosophila (SWD), D. suzukiiis a disastrous pest insect of soft fruit and berries. Since 2008, SWD has spread over North America and Europe and was found in Sweden in 2014. Basic understanding of SWD ecology and behaviour is essential to develop sorely needed control tools. Yeasts and other microbes live in close relation to drosophilids. SWD-associated yeast Hanseniaspora uvarumand entomopathogens are able to manipulate SWD behaviour. To understand why SWD is strongly attracted by the smell of H. uvarumwe will correlate wind tunnel attraction behaviour with responses from a feeding assay, a mating assay and an egg-laying assay. Responses of male and female flies that are starved or fed and virgin or mated will be analysed separately to clarify sex-specific responses and physiological modulation. Larval yeast attraction will be tested for implementation of a new control method. Furthermore, we will study how insect pathogens attract flies and transmit infection. Manipulation of insect behaviour is an established strategy in pest management but application has focused on pheromones and plant volatiles. Microbial volatiles complement the range of semiochemicals applied in pest control and allow a comprehensive manipulation of insect behaviours. We will test the concept of new strategies to control SWD in the field.
Projektstart: Januari 2016 – ongoing
Projectleader and participants: Paul G. Becher, Teun Dekker, Peter Witzgall (SLU Alnarp), Sebastian Håkansson (SLU Uppsala); Henrik Hjarvard de Fine Licht (University of Copenhagen)
Funding: The Swedish Research Council Formas
3. Novel techniques to control the invasive Drosophila suzukii fly
Originally restricted to Asia, the fly Drosophila suzukii became a widespread insect pest on fruit. Introduced to Europe and North America in 2008, D. suzukii has spread over both continents. In 2014 D. suzukiiwas found in Sweden, and likely will impact cultivated crops, including blueberries and strawberries, but also wild berries and consequently forest ecosystems, similar as in the US. A general aim of this project is to understand the ecological interactions between insects and associated microbes to apply this knowledge for development of new control strategies. The fly lives in close association with yeasts and is strongly attracted to fermentation compounds. By applying specific yeasts, we want to improve attract-and-kill strategies and furthermore increase trap efficiency to monitor the fly. We want to physiologically characterize D. suzukii-associated yeasts, which will help us to understand the metabolic requirements of the yeast, and facilitate yeast production in bioreactors, for field use. By combining a killing agent with a yeast formulation targeting D. suzukii, we aim at an efficient and sustainable control method reducing non-target effects of currently applied insecticide spray applications.
Project start: October 2015 – ongoing
Project leader and participants: Paul G. Becher (SLU Alnarp), Sebastian Håkansson (SLU Uppsala)
Funding: SLU – Plattform Plant Protection
4. The microbiome of the invasive pest Drosophila suzukii and its impact on the fly’s sexual communication, behavior and reproduction
Insects are closely associated with microbes. Microbes help insects for example to digest food, resist infections or to detoxify plant compounds and insecticides. Moreover, microbes modulate insect behaviour. We plan to elucidate the consequences of different host fruits (larval diet) on SWDs microbial associates and their effects on fly development, sexual communication, behaviour and reproduction.
Revealing the influence of fruit and microbes on sexual behavior and reproductive output will help us to understand the ecology and evolution of complex interactions among host plants, insects and microorganisms and may provide novel strategies for pest control in future.
Project start: September 2016 – ongoing
Project leader and participants: Paul G. Becher, Amrita Chakraborty, Sandeep K. Kushwaha (SLU Alnarp)
Funding: The Crafoord Foundation
We thank our funding agencies for their generous support of our research.