Scientists at Rothamsted Research, working with UK scientific colleagues at the Universities of Exeter, Greenwich, York and Oxford, the Lund University in Sweden and the Met Office, combined data from entomological radars and ground-based light-traps to show that annual migrations are highly adaptive in the noctuid moth Autographa gamma (silver Y), a major agricultural pest that migrates northward every spring from its winter breeding-grounds in North Africa and the Middle East to its temporary summer breeding grounds in Northern Europe.

Lead author, Dr. Jason Chapman, of the Department of AgroEcology at Rothamsted Research, which receives strategic funding from the BBSRC noted that "billions of insects immigrate annually to, or within, the temperate zone, providing major ecosystem services as well as, in some cases, causing serious crop damage and spreading diseases of humans and their livestock."

Previous to this work, it was believed billions of insects migrate to exploit temperate zones, but their offspring seldom return, the 'Pied Piper' effect. But this work shows that after a period of intense northward flight in the spring, when 10-240 million immigrants reach the United Kingdom, summer breeding leads to a four-fold increase in the abundance of adults, most of which return southward in the autumn.

Thus, the authors suggest, the moth's poleward movement not only results in population growth but also contributes to its survival as a species by facilitating summer breeding. Dr Chapman said that "these findings may require a fundamental change in our understanding of insect migration."

Professor Keith Goulding, leader of the Delivering Sustainable Systems research programme at the world renowned Rothamsted Research said "This is tremendously exciting research that is opening up new ways of tracking and understanding the movement and development of agricultural pests. A better understanding of their lifecycles will enable us to develop sustainable control methods."

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