Integrating ecology and genetics for insect pest control

Pest insects do enormous damage to human health (through transmission of diseases such as dengue fever and malaria) and to agriculture (through damage to crops or livestock). Insecticide resistance has been reported in many important insects and against every chemical class of insecticide and some insecticidal crops. The public and consumers increasingly want to see more sustainable methods used to control pests. The recent development of genetic transformation techniques for pest insects has opened up the possibility of employing new genetic methods to reduce the harm done by insects. The Sterile Insect Technique (SIT) is a species-specific and non-polluting method of insect control that relies on the release of large numbers of sterile insects. Native females that mate with released sterile males have no or fewer progeny. If enough sterile males are released for a sufficient period of time, this can lead to the local elimination or suppression of the pest population. Highly successful, very large scale area-wide SIT programmes have eliminated several species, mainly of agricultural pest insects, and on very large geographical scales. New genetic technology is being developed which improves on this technique, using genetically sterile insects. This is more precise than using radiation for sterilisation, so the released insects are generally less unfit. It also allows for some useful variations, such as choosing the insect life stage at which death of the non-viable individuals occurs - it can be better to have them survive for a while through some harmless stages rather than simply not hatch from eggs. The potential release of transgenic insects has great potential benefit for crop protection, and human and animal health, by reducing or eliminating populations of harmful crop pest insects or insects that transmit human or livestock diseases. However, inevitably with any new technology, questions arise to which regulators and policy decision-makers would like answers before implementing any large plans. As well as the obvious 'will it work?' and 'will it be too expensive?' we could ask 'what will this mean for other species in the environment?' and 'what if insects evolve resistance to this new technology too?' Our project aims to find scientific answer to such questions. We will use mathematical models developed at the University of Oxford, alongside laboratory experiments and trials conducted by our project partner Oxitec Ltd, a small British biotech company that is at the leading edge of producing transgenic insects. We are both working with various regulatory and policy-making bodies around the world, and aim to produce a policy document that we hope will form a key part of the information that such stakeholders need to assess the risks and benefits of this new technology. It is important that decisions and regulations are underpinned by a good understanding of insect biology and ecology, and of relevant interactions between different elements of the complex ecological systems in which we, our livestock and crops, and those insects currently coexist.

Our research programme is a cross-disciplinary collaborative LINK project (with Oxitec Ltd) to explore ecological and genetic aspects of insect pest control. We will combine mathematical models, genetic technological development with laboratory and field trials to develop an integrated research approach for novel methods of insect pest management. While the SIT (Sterile Insect Technique) has potential advantages (e.g., species specificity) as a method of insect control, several recent genetic improvements have been proposed. Oxitec has pioneered the development of one of these: RIDL (Release of Insects carrying a Dominant Lethal). Although the benefits of RIDL are well-established, our knowledge on the underlying population ecological and population genetic aspects of these control methods less well-developed. For example, the likelihood of alterations in ecological interactions and the evolution of resistance to the genetic constructs require thorough and careful consideration. Our LINK project aims to address these objectives. We divide our research into four work packages (Modelling pest interaction dynamics, Strategies for managing biochemical resistance, New strains for Olive Fly, Impact of RIDL control). Our mathematical models will provide specific predictions on how ecological interactions (patterns of coexistence and exclusion) and genetics (evolution of resistance to control) are affected by different SIT and/or genetic-based (RIDL) control strategies. With the LINK partner novel sexing strains for Olive fly for conditional female lethality will be developed and test in the laboratory and field trials. To understanding the economic impact of this sort of genetic control we will develop a series of bio-economic models. We will use information from the LINK partner to explore the cost-effectiveness of different genetic control methods for pest insects.

Who will benefit: Direct beneficiaries from this research will be academics with similar research interests and those interested in developing novel approaches for insect pest management. Our LINK project has direct benefits to those in the commercial sector in understanding the ecology and genetics of transgenic insects. Indirect beneficiaries of the collaborative research projects include groups and organisations within DEFRA and HSE such as the Agriculture and Horticulture Levy Board, ACRE (Advisory Committee on Releases to the Environment) and SACGM (Scientific Advisory Committee on Genetic Modification) and, more broadly EFSA (European Food Safety Authority). As our research project is focused on the empirical and theoretical aspects of pest control, this research will also be relevant to those with an interest in transgenic manipulations using gene-based and microbial-based biological control methods. The general public will benefit from this research by gaining an increased understanding of the transgenic biology of insects and the modern methods for the management of pest insects. How will they benefit: Our research has clear benefit to those interested in the control of pest insects. Any method of pest management (whether based on genetic or conventional techniques) requires an understanding of the potential issues associated with the evolution of resistance. Our research has the potential to foster greater awareness amongst all direct and indirect beneficiaries (and consequently has economic implications) of the effects of resistance on undermining the use and release of novel pest control strategies. What will be done: We will use the standard routes of dissemination (e.g conferences, seminars and publishing scientific papers) for informing our academic colleagues of the progress in our project. As outlined in our impact plan we have an established track record (e.g. our involvement with STEMNET, ACRE and the Royal Society) in disseminating our research findings more broadly amongst different stakeholder groups. In particular, we will use STEMNET to engage with the wider public (particularly schools) to present our research findings in a non-technical and engaging way. Contacts within DEFRA (and particularly ACRE) will be used to ensure that this group of beneficiaries are fully informed our progress throughout the project and made aware of publications arising from the research after the lifetime of the grant. The collaborative LINK project (with Oxitec Ltd) will allow us to ensure that the economic benefits of our work on insect pest management are fully realised.