Marsden News

Attack by Cuckoos and Cowbirds Inherited from Mothers

Female Cowbird. Source: M. Hauber

30th October 2007

The impact of brood parasitic birds, which place their eggs in a nest for other birds to care for, can act like an inherited disease - affecting future generations of the birds they victimise.

Brood parasitic birds, such as cuckoos and cowbirds, often remove some eggs of the host and replace them with their own eggs, sometimes forcing the foster parents to accept the substitution through violent behaviour. New Marsden research by Dr Mark Hauber of The University of Auckland in collaboration with Dr Jeff Hoover of the Illinois Natural History Survey, has shown that daughters of parasitised warbler mothers are even more prone to the actions of parasitic birds, although these females use different nest boxes across years.

“Brood parasitic birds are much like other parasites and pathogens, reducing the reproductive success of the birds they victimise,” says Dr Hauber. “However, this study suggests a longer term consequence on affected individuals, infecting subsequent generations with the same problem. This creates lineages of warbler families unable to escape the cost of parasitism whilst other families are not affected.”

The research, co-funded by the US Fish and Wildlife Service, the Marsden Fund, and the National Geographic Society, and conducted in collaboration with the Illinois Natural History Survey, studied prothonotary warblers Protonotaria citrea and brown-headed cowbirds Molothrus ater in Southern Illinois over a period of twelve years. See Journal of Animal Ecology 2007, 76: 1208-1214.

$44 million for New Zealand Researchers

6th September 2007

The Marsden Fund has announced its investment of NZ$44 million (incl. GST) in a wide range of leading-edge research projects. A total of 93 new projects have been given the go-ahead, advancing New Zealand research excellence in the sciences, engineering, maths and information sciences, social sciences and the humanities. Just under a third of the awards (28) are Marsden Fast-Starts, designed to support outstanding researchers early in their careers.

Dr Garth Carnaby, Chair of the Marsden Fund Council, was delighted with the outcome, saying, “All of the projects funded are in the top five percent of research activity internationally. Marsden invests in New Zealand's brightest and best, enabling them to explore their ideas, and contribute to innovation and development in our society, and in the research community globally.”

A recent $2.25 million (incl. GST) budget boost from the Government has enabled the Marsden Fund Council to increase its investment in New Zealand’s early career researchers, and seed fund a number of projects it would have been impossible to support otherwise.

“This investment by the Government is crucial – it enables New Zealand based researchers and scientists to engage with the international discovery frontier. It is also particularly pleasing that we were able to fund such a good cross-section of our most promising young researchers this year,” said Dr Carnaby.

Applications to the Fund are extremely competitive. Of the 910 preliminary proposals received (693 Standard proposals and 217 Fast-Start proposals), 232 were asked to submit a full proposal with 93 ultimately being funded.

Click here to see a full list of the projects funded.

New Caledonian Crows Outsmart Apes

19th August 2007

Marsden-funded research, published in this month’s Current Biology, suggests that New Caledonian crows are capable of using tools in an indirect way to obtain food. The findings provide evidence the birds have a reasoning ability rivalling that of the great apes.

Researchers at The University of Auckland placed New Caledonian crows in a situation where they were required to carry out a sequence of tool tasks to access food. The crows had to use a short stick to extract a longer stick from a barred box, which could in turn be used to extract out-of-reach food from a hole. The study suggested that the birds solved the task by reasoning rather than using trial and error or previous learning.

“Tool use is a major turning point in species evolution,” says Professor Russell Gray who led the study. “Evidence suggests that, from the earliest human stone tools, analogical reasoning has been at the core of human innovation. Through this study, New Caledonian crows have, quite surprisingly, exhibited intelligence at the same level as the best performances by great apes on such a difficult problem. Crows in folklore have often been portrayed as crafty, cunning creatures. In the last few years there has been a growing appreciation in the scientific community that there may be a basis to these tales, Our results suggest crows’ abilities might reflect a mix of learning appropriate procedures and more complex cognition.”

Controlling the Kids with Chemicals

25th July 2007

Professor Alison Mercer and her research team in the Department of Zoology at the University of Otago have discovered that exposing young worker bees to queen pheromone alters the chemistry of the honey bee brain. The study, supported by the Marsden Fund and published in the journal Science,  demonstrates a direct link between changes in brain biochemistry and complex behaviour.

Queen honey bees exude an aromatic chemical, homovanillyl alcohol, which acts on the young workers as they groom and feed her. The researchers have found that the chemical blocks "aversive learning" - the acquisition of negative memories which would normally trigger an aggressive sting reflex in the bees.

In tests, young bees were taught to associate a particular odour with an electric shock. Thereafter, when they were exposed to the odour, they unsheathed their stings - but not if they had been exposed to the queen bee's pheromone. Bees given a sniff of the pheromone remained docile, and kept their stings unextended.

Young worker bees perform many essential tasks in the hive. They feed and groom the queen, and distribute her pheromones throughout the colony. By blocking aversive learning in young workers, it seems that the queen may be making her life, and that of the colony, more secure. Exposure to their mother’s pheromone will prevent young workers from developing an aversion to odours within the hive; including those produced by the queen herself. With increasing age, worker bees begin to leave the colony in search of food. Professor Mercer’s team have found that by the time bees begin foraging, their ability to learn and recall information about noxious stimuli is no longer affected by the queen’s pheromone bouquet. For more information see: Vergoz et al., Science 20 July 2007: 384-386.

Silkworm Sequencing Success

A keen sense of smell plays a vital role in the life history of most insects. Locating a mate - or finding the right place to lay eggs can depend upon it. Odour detection in insects is controlled by odourant receptors, usually found on the antennae. To date, few gene sequences encoding these receptors have been identified from the insect order Lepidoptera. Some of the most important pest species worldwide fall into this group, and cause substantial economic losses each year to crop production worldwide.

An international collaboration including Dr Richard Newcomb of HortResearch and supported by the Marsden Fund, has recently reported the sequence of 41 odourant receptor or Or genes from the silkworm (Bombyx mori), the first lepidopteran to have its genome sequenced.  Because of its domestication, the silkworm has become an important model in insect genetics and olfaction research.  The team found that several of the Or genes were not expressed equally in male and female antennae.  Some that are involved in sex pheromone reception, were more highly expressed in males, while others were more highly expressed in females suggesting that these receptors might be involved in recognising aphrodisiac pheromones produced by males or egg-laying cues.   Most Or genes, however, were equally expressed in both sexes and may be involved in detecting plant volatiles including those of their host plant mulberry.

Identifying and characterising these sequences will facilitate the discovery of similar receptors from other insects. In addition, by understanding more about the ways that moths detect and locate potential mates and host plants, the team have provided a possible route for researchers to develop new insect control technologies. For more information see: Wanner et al., Insect Molecular Biology (2007) 16(1), 107-119

Bugging Beech Trees

Herbivores can have a considerable impact on the plants they feed upon. They can be tolerated or resisted, but their actions can regulate forest diversity and ecosystem productivity.

Using the interaction between phloem-feeding scale insects and the southern beech tree, Associate Professor Dave Kelly, Professor Matthew Turnbull, and Dr Roger Dungan of the University of Canterbury, have recently published their assessment of the costs of herbivory to a native forest tree species. Scale insects infest beech bark, and feed on the sugar-rich sap, secreting any excess sugar as honeydew. By measuring photosynthesis and simultaneously harvesting honeydew over a two-year period, the team have estimated the amount of carbon fixed through photosynthesis and the fraction of this that is lost by the host tree as a result of insect feeding.

The results showed some remarkably similar numbers: annual honeydew production was equal to 8% of net photosynthesis, and infested trees had a level of net photosynthesis 8% greater than non-infested trees, suggesting a strong link between herbivory and productivity. So, although scale insects harvest relatively high amounts of carbohydrate from their host trees, the consequences of this for tree growth and reproduction may be small. This is important to the functioning of 1 million hectares of beech forest in the South Island, and also to global theories of the impact of herbivores on vegetation.  For more information see:  Journal of Ecology (2007) 95, 603-613

New Weapon in Norovirus Research

23rd July 2007

Research into ways of combating norovirus, a major cause of gastrointestinal illness worldwide, has taken a significant step forward thanks to a project funded by Marsden and the Wellcome Trust. University of Otago microbiologist, Associate Professor Vernon Ward, has discovered how to manipulate the genome of the recently discovered mouse norovirus, making it much easier to study.

Norovirus is a major source of gastrointestinal disease, causing acute vomiting and diarrhoea in 53,000 people per year in New Zealand. The virus has caused a number of well-publicised temporary closures of hospital wards, and outbreaks are being increasingly recognised in hotels, elderly and child care facilities. Currently, there are no antiviral drugs or vaccines available to treat the disease.

Human noroviruses are extremely difficult to study because they can’t be grown or cultured in the laboratory - and that this is what spurred the research team to take a different approach. “Much effort has been expended trying to discover a mechanism for manipulating the genetic material of these viruses. The mouse norovirus is the first that can be cultivated in the lab. But, until now, attempts to manipulate the mouse norovirus genome have been thwarted”, says Associate Professor Ward. “Our breakthrough uses a simple system of reverse genetics, and will allow dissection of what is important in the virus, how these viruses replicate, and the identification of key elements involved in how the virus manipulates host defences to cause disease.”

Associate Professor Ward says that this success will facilitate new discoveries in norovirus biology, and help in the development of antiviral drugs that can be used to stem future outbreaks. For further information see Proc. Natl. Acad. Sci. USA: vol. 104; no. 26; 11050-11055.

Increase in the Marsden Fund Announced

21st May 2007

The Budget statement included an additional $2 million per year (excl. GST) for the Marsden Fund. The Fund, which supports fundamental research in the sciences, social sciences and humanities, will now receive a minimum of $35.9 million per year.

Dr Garth Carnaby, Chair of the Marsden Fund Council, was delighted with the announcement. “Marsden is widely regarded as a hallmark of excellence, freeing up New Zealand's brightest and best to explore their ideas. This welcome increase to the Fund means that the Marsden Fund Council can extend its support to more of New Zealand ’s highest calibre researchers – and contribute yet further to the ideas that underpin innovation and the development of our society.”

The Marsden Fund currently has 372 active research contracts, spanning world class basic research in the humanities, social sciences, sciences, mathematics and engineering. In recent months, Marsden-funded researchers have participated in decoding the honeybee genome; ANDRILL - the record-breaking international Antarctic collaboration; unpicking the brain’s role in human fertility; monitoring the Mount Ruapehu lahar and investigating young people’s attitudes to alcohol.

Marsden Fund, The Royal Society of New Zealand, 9 Turnbull Street, Thorndon, PO Box 598, Wellington, New Zealand. Ph: +64 4 470-5799          Fax:+64 4 473-1409          Email: marsden@royalsociety.org.nz          Web: http://marsden.royalsociety.org.nz