Insect study shows mothers know best
Posted on 29 January 2010
Scientists at the University of York with colleagues at Oxford University and the University of Helsinki have reviewed the evidence of whether or not insect mothers do their best for their offspring.
Previously, insects that lay their eggs on plants had been viewed as poor mothers, since many studies had shown a poor fit between the egg-laying preference of the mother and the performance of their offspring on those plants
Dr Peter Mayhew
Their findings reported in the March issue of Ecology Letters confirmed the ‘preference-performance hypothesis’ (PPH), which states that female plant-eating insects have evolved to lay eggs on hosts on which their offspring fare best.
The study showed that offspring survive better on preferred plant types, and females lay more eggs on plants that helped offspring to develop more vigorously. It also found that the tendency of mothers to opt for more favourable plant types was more marked where insects only have to choose between a few types of plant, as opposed to many.
The results suggest that 'good motherhood' is a result of fine-tuned natural selection.
Many previous studies have focused on factors preventing evolution towards good motherhood, but the new work shows that the combined evidence shows the picture of insect mothers make good life choices for their offspring.
Dr Peter Mayhew, of the Department of Biology at the University of York, said:
“Previously, insects that lay their eggs on plants had been viewed as poor mothers, since many studies had shown a poor fit between the egg-laying preference of the mother and the performance of their offspring on those plants. Our work shows that, when all the evidence is gathered together, mother insects do prefer to lay eggs on plants where their offspring perform well, although some insects are better at this than others.
“Insect species that feed on many different kinds of plant make worse egg-laying decisions than those that feed on only a few. This supports one previous suggestion, that having too many choices makes it harder for insect mothers to make the best decision for their offspring.”
ENDS
Notes to editors:
- The full paper A meta-analysis of preference–performance relationships in phytophagous insects is available at www3.interscience.wiley.com/journal/123249031/abstract?CRETRY=1&SRETRY=0
- The University of York’s Department of Biology is one of the leading centres for biological teaching and research in the UK. In the 2008 Research Assessment Exercise, it was ranked equal first among broad spectrum bioscience departments in the UK for quality that was judged to be world-leading. 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 Immunology and Infection Unit (jointly with the Hull York Medical School), work on infertility and three research professors funded by Yorkshire Cancer Research and York Against Cancer.
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