Endangered beetle faces ‘unholy alliance’ of rabbits and redbacks

An “unholy alliance” between rabbits and Australian redback spiders is threatening the existence of an endangered New Zealand species, a study led by AgResearch has shown.

Carried out with the Department of Conservation (DOC) and University of Otago, the study has illustrated the struggle for the ongoing survival of the Cromwell chafer beetle – a nationally endangered native species that can now be found only in the 81 hectare Cromwell Chafer Beetle Nature Reserve between Cromwell and Bannockburn, in Central Otago.

The study found numerous rabbit holes that provided shelter for the rabbits were also proving ideal spaces for the redback spiders to establish their webs. Investigation of those webs in the rabbit holes found the Cromwell chafer beetle was the second-most commonly found prey of the spiders.

These findings “give a fascinating insight into the almost accidental relationships that can develop between species in the natural world, and how that can impact on other species,” says AgResearch Principal Scientist Dr Barbara Barratt.

As a result of the research, DOC has carried out a programme to break down old rabbit holes and hummocks in the reserve to destroy spider nests, and does regular rabbit control. An annual survey for beetle larvae with AgResearch will show whether these actions are having an effect.

Beetle larvae will be surveyed next summer to see what effect reducing redback spider nests is having on the Cromwell chafer beetle.

The Cromwell chafer beetle (Prodontria lewisi) is a large flightless beetle that lives underground in the sandy soils of the Cromwell river terrace. In spring and summer adult beetles emerge from the ground at night to feed on plants and to breed.

The smell of success: insect pests avoid boosted pasture grasses

A  study from the Bio-Protection Research Centre has shown for the first time that pasture grasses containing beneficial microorganisms are less attractive to soil-dwelling insect pests.

Most New Zealand ryegrass and fescue pastures contain beneficial microorganisms that live within the grass shoots. These fungal endophytes are key to the country’s healthy grasslands. In return for food and shelter the endophyte can help its host grass resist insect attack, survive droughts, and even protect against overgrazing.

Insect pests are attracted to plants by odour as they can smell minute amounts of chemical compounds that tell them if a plant is damaged or healthy.

Food-for-health Challenge scientists will aim to boost NZ exports

The University of Auckland, Massey University and University of Otago, along with Crown Research Institutes AgResearch and Plant & Food Research, are being teamed up for the Government’s High-Value Nutrition National Science Challenge.

The task for the scientists from the five institutions – with other collaborators – is to produce cutting-edge, multi-disciplinary research to help New Zealand companies take advantage of global demand for foods with health benefits.

The ten year challenge is approved with $30.6 million subject to finalisation of contract conditions.

A review at the end of five years means another $53.2 million becomes available for a second five-year period.

Total funding for the High-Value Nutrition Challenge is up to $180.8 million over ten years.

Genome researchers discover how onions recognise when to bulb

Research findings from Plant & Food Research and the University of Otago will help to breed new onions tailored to grow in specific conditions.

Onions, the third largest vegetable crop in the world, form a bulb in response to lengthening days, but the molecular mechanisms controlling this response were not previously known.

The research has identified the gene controlling bulb development, the first step in discovering genetic markers that can be used as tools to screen conventional breeding programmes for new onion varieties with the right genetic profile.

The research is published in the online journal Nature Communications with related research published in Theoretical and Applied Genetics.

“This research is an excellent example of how new genome technologies can enable major discoveries that, in the past, have been difficult,” says Associate Professor Richard Macknight.

“By understanding how these plants control development of the bulb, we can support the breeding of new cultivars that have the right genetic profile to respond to specific growing conditions, ensuring each plant produces a bulb for sale on the market.”

“Commercial production of onions relies on cultivars tailored to the environment they are grow in, responding to the right combination of day length and temperature to form a bulb,” says John McCallum of Plant & Food Research.

“Around 90 million tonnes of onions are produced globally each year, but genetic studies of onions have been limited. Our research is now beginning to link genetics and physiology of onions, allowing industry to tap into more diverse genetic resources and breed products adapted to different and changing environments.”

Onion is the second largest vegetable crop in New Zealand, with 586,000 tonnes produced each year and generating $62 million in export revenues.

The research was funded by the Ministry of Business, Innovation and Employment and supported by FruitFed Supplies, Allium Solutions and Enza Zaden Ltd.