| In superb fairy-wrens (Malurus cyaneus), helper males can assi... In superb fairy-wrens (Malurus cyaneus), helper males can assist females by providing extra food to their chicks. When this is the case, females lay smaller eggs that give rise to lighter chicks. Females benefit from increased survival. Photo: BIOS Ruoso Cyril/Peter Arnold Inc. |
Wollongong link to cover of Science journal
29 Aug 2007 | Bernie Goldie
Research involving the University of Wollongong’s Acting Deputy Vice-Chancellor (Research) Professor Lee Astheimer is featured on the cover of the prestigious journal, Science, published by the American Association for the Advancement of Science (AAAS).
Professor Astheimer has co-authored a paper entitled “Reduced Egg Investment Can Conceal Helper Effects in Cooperatively Breeding Birds”. Professor Astheimer conducts research in the broad area of comparative physiology and endocrinology.
In humans, the concept of family-living and cooperation are well known -- helpful offspring can reduce the work-load of parents.
One might expect that producing helpful offspring will allow mothers to invest more in current offspring.
However, Professor Astheimer and her co-researchers from the Universities of Sheffield and Cambridge in the UK and the Australian National University and Macquarie University suggest that this might not be the case.
By studying the cooperative breeding system of superb fairy-wrens, the researchers showed that mothers breeding in the presence of helpers at the nest actually reduced their investment in eggs. Fairy wrens and many other Australian endemic cooperatively breeding birds are often assisted in raising their young by related helpers at the nest.
In this study, mothers nesting in the presence of helpers laid smaller eggs of lower nutritional content that gave rise to lighter chicks at hatching than mothers breeding without helpers. However, these smaller chicks did not suffer because the helpers compensated for maternal reductions in investment by increasing the amount of food that the chicks received during development.
The researchers found that mothers benefited by reducing their energy investment in egg production and thus were more likely to survive for longer, enabling them to reproduce later in their lifetimes.
The reported reduction in maternal investment and the resulting contribution to female survival identifies a previously unrecognised benefit of cooperative breeding strategies.
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