Scientists investigate how size matters for parasitic wasps
Posted on 18 January 2006
Scientists in the University's Department of Biology, who have been studying the development of parasitic wasps, have discovered that smaller females go on a breeding fast-track as soon as they emerge from the pupa.
But the team, led by Dr Peter Mayhew, has found that though smaller females reproduce more quickly, their lifespans are correspondingly shorter.
Though his work is mainly with insects, Dr Mayhew believes the research published in the Proceedings of the Royal Society B may eventually provide important lessons in agriculture and medicine, including a better understanding of how to treat low birth-weight human embryos.
The female parasitic wasps used in the research vary in body size between 2mm and 4mm and each had their egg load measured on emergence from the pupa. The scientists found that small individuals emerge with about 70 per cent of their lifetime egg load ready to lay, but for a larger individual it was only about 30 per cent.
[This research] could improve our understanding of a range of phenomena from population biology to child health
Dr Peter Mayhew
Dr Mayhew said: "This provides a reproductive fast track for small females to exploit opportunities early in life, though at the cost of a shorter lifespan. If body size commonly alters animal development in this way, it could improve our understanding of a range of phenomena from population biology to child health.
"Across animal species development mechanisms are sometimes very similar, so these findings will help to focus people's minds on how animals change their development according to the circumstances of early life."
The parasitic wasps used in the research lay their eggs in fruit fly larvae. They are only found in New York State in the USA - the wasps used in the York project originated in New York City.
Notes to editors:
- Pictures of the parasitic wasps are available from David Garner on 01904 432153
- The full paper Small body size in an insect shifts development, prior to adult eclosion, towards early reproduction can be seen at www.pubs.royalsoc.ac.uk/index.cfm?page=1087
- The University of York's Department of Biology is one of the leading centres for biological teaching and research in the UK with a top ranking of 5 for research quality. The Department both teaches degree courses and undertakes research across the whole spectrum of modern Biology, from molecular genetics and biochemistry to ecology. Its biomedical research includes an Immmunology and Infection Unit, work on infertility and three separate research teams studying cancer.