Air pollution significantly reduces pollination by confusing butterflies and bees

A new study finds pollination reduced by almost a third when diesel fumes and ozone were present – the negative impact of these common air pollutants on pollination were observed in the natural environment.

Common air pollutants from both urban and rural environments may be reducing the pollinating abilities of insects by preventing them from sniffing out the crops and wildflowers that depend on them, new research has shown.

Scientists from the University of Reading, the UK Centre for Ecology & Hydrology, and the University of Birmingham found that there were up to 70% fewer pollinators, up to 90% fewer flower visits and an overall pollination reduction of up to 31% in test plants when common ground-level air pollutants, including diesel exhaust pollutants and ozone, were present.

The study, published in the journal Environmental Pollution, is the first to observe a negative impact of common air pollutants on pollination in the natural environment. The theory is that the pollutants react with and change the scents of flowers, making them harder to find. Continue reading

Designing plantings to boost pollination in kiwifruit

New native plantings have been established in the Bay of Plenty to support kiwifruit pollination and encourage bio-diversity.

The plantings of 600 trees and shrubs on previously low-productivity land include a carefully selected mix of plants that support insects known to pollinate kiwifruit, while reducing the risks of harbouring pest species, mainly passion vine hopper.

Based on Plant & Food Research science, the project is funded by Operation Pollinator®, a Syngenta global initiative to boost the number of pollinating insects on commercial farms. It is expected that the effect of the new plants will increase as the plants establish, grow, and start to produce flowers.

The research team hopes to monitor changes in insect populations and kiwifruit yields during this period.

While restoring natives to production landscapes has become an increasingly common practice in New Zealand, this is the first project of its kind to take a prescriptive approach to enhancing pollination and avoiding creating a reservoir for pests in kiwifruit.

“If you want to stabilise a streambank, or return nitrogen to the soil, we know certain native plants can do that”, says project leader Dr Brad Howlett from Plant & Food Research. “We want to take the same approach for enhancing crop pollination by managing the landscape.”

Dr Howlett’s team worked for several years to get a clear picture of which insects, including native bees, flies, and beetles are the most important for kiwifruit pollination. To be good pollinators, the insects must visit kiwifruit flowers and  transfer sufficient amounts of pollen between male and female flowers.

Once researchers identified the most important pollinators, they surveyed native plants to learn which of these were important for the best pollinators.

“The plantings that were established this year include plant species which we know kiwifruit pollinators use during their life cycle and, importantly, these plants flower at different times to kiwifruit. This will support large populations of pollinating insects ready to move onto the crop during flowering,” says Dr Howlett.

The kiwifruit industry is entirely dependent on pollination, and relies heavily on managed honey bees and manual pollination to ensure that flowers set fruit. Human pollination (either by hand or vehicle-based) can be expensive, and access to honey bee hives can be limited because of overlap with Mānuka honey collection and concerns about the effects of crop-protecting nets on colony health.

Increased support for native insects should help to reduce concerns about pollination in this high-value crop.

Source:  Plant & Food Research

Designing diverse plantings to support non-bee and bee pollinators

Ecological intensification of agriculture is viewed as a means of managing natural biodiversity and ecology to support agriculture. Supporting insect pollinator abundance and diversity is integral to this goal.

One strategy to achieve this is to establish, manage and protect biodiverse semi-natural habitats.

To design biodiverse semi-natural plantings it’s essential to account for the variation in species-level relationships between insects crops and non-crop plants within regions. Otherwise designed habitats might not only fail to improve crop pollination but create pest reservoirs.

Research on global crop pollination has mostly focused on bees, despite the fact that numerous non-bee insect species contribute to crop pollination. There is currently a lack of research about how to optimally manage habitats to promote broader diversity in crop pollination.

In this study, scientists from Plant & Food Research demonstrated the concept of designing mixed species native plantings to optimise bee and non-bee crop pollinators in an intensively managed agricultural landscape. The plantings on three farms were designed using existing literature to identify and anticipate interactions between native plants and crops with pests and pollinators.

The scientists found that five years post planting 20 pollinating species were supported by the designed plantings (out of the 21 anticipated).

While the expected bee-plant species interactions were confirmed by the study, the networks of non-bee pollinators were bigger and more complex than predicted. This indicates that the plantings were highly effective in supporting these interactions. Immature life stages of non-bee pollinators, however, were not supported by plantings suggesting that alternative strategies should be sought for larval requirements.

The findings are being shared with industry to support the development of designed habitats on farms.

Journal Reference
B.G. Howlett, J.H. Todd, B.K. Willcox, R. Rader, W.R. Nelson, M. Gee, F.G. Schmidlin, S.F.J. Read, M.K. Walker, D. Gibson, and M.M. Davidson. Using non-bee and bee pollinator-plant species interactions to design diverse plantings benefiting crop pollination services.  Advances in Ecological Research. DOI: 10.1016/bs.aecr.2020.11.002

Source:  Plant and Food Research

Keeping abreast with the buzz about research on bees

We returned from the summer holiday break to find things have been quiet on the ag-hort science front in this country but ScienceDaily has been abuzz – so to speak – with news of research related to bees.

Among recent research findings are –

Shedding Light on the Secret Reproductive Lives of Honey Bees

Honey bee health has been on the decline for two decades, with US and Canadian beekeepers now losing about 25 to 40% of their colonies annually. And queen bees are failing faster than they have in the past in their ability to reproduce.

The reason has been a mystery, but researchers at North Carolina State University and the University of British Columbia are finding answers. Continue reading

Ecologically friendly agriculture doesn’t compromise crop yields

Increasing diversity in crop production benefits biodiversity without compromising crop yields, according to an international study comparing 42,000 examples of diversified and simplified agricultural practices.

Diversification includes practices such as growing multiple crops in rotation, planting flower strips, reducing tillage, adding organic amendments that enrich soil life, and establishing or restoring species-rich habitat in the landscape surrounding the crop field.

“The trend is that we’re simplifying major cropping systems worldwide,” says Giovanni Tamburini at the Swedish University of Agricultural Sciences and lead author of the study.

“We grow monoculture on enlarged fields in homogenized landscapes. According to our study diversification can reverse the negative impacts that we observe in simplified forms of cropping on the environment and on production itself.”

Continue reading

Scientists are cracking the code to kiwifruit pollination success using a “digital twin”

Plant & Food Research scientists and collaborators from the USA have compiled more than 30 years of field-based data from kiwifruit research to create “digital twins” of pollination processes in kiwifruit orchards, and have used these to predict how growers can optimise their fruit set.

Digital twins are virtual replicas of physical systems – in this case mathematical models of the biology of the plants and the behaviour of pollinating bees.

These digital twins give researchers the ability to examine complex scenarios which examine multiple, intertwined factors at once. These types of trials are difficult or impossible to test in field – running a full combination of even six variables would require more kiwifruit orchards than exist in New Zealand. Continue reading

Pesticides and food scarcity dramatically reduce wild bee population

American researchers have found that the combined threats from a loss of flowering plants and the widespread use of pesticides have reduced blue orchard bee reproduction by 57 per cent and resulted in fewer female offspring.

Just like humans, bees don’t face one single stress or threat, said lead author Clara Stuligross, a Ph.D. candidate in ecology at University of California – Davis.

“Understanding how multiple stressors interplay is really important, especially for bee populations in agricultural systems, where wild bees are commonly exposed to pesticides and food can be scarce.” Continue reading

Study finds insects are as effective as bees for pollination

Research has found that “non-bee” insects are as important as honey bees in pollinating flowers, a service vital for crop production.

A global research team, including scientists from Plant & Food Research, analysed honey bee, other bee and non-bee insect visits to 480 fields of 17 different crop types on five continents.

The findings of the study have been published in the Proceedings of the National Academy of Sciences.

The research found that total pollination services provided – based on visitation frequency and pollen deposition per visit – was the same for honey bees and non-bee insects (38%), with around a quarter of services (23%) provided by other bees. In addition, fruit and seed set of crops was enhanced by increased visitation by non-bees and other bees, but not honey bees.

“Honey bees are well-documented as effective pollinators of many crops, but this research shows that other insects, such as flies, wasps, beetles, butterflies and moths, are just as important,” says Brad Howlett of Plant & Food Research.

“Whilst these non-bee insects carry less pollen than honey bees, they tend to visit flowers more frequently, which balances out the equation. The non-bee insects are also seen to be more adaptable to changes in environment and landscape than bees, so are even more important as pollinators in some situations where land use is changing. It’s vital that when we consider pollination services for our commercial crops we don’t forget about these other insects as effective pollinators.”

The research project included scientists from more than 35 organisations in 18 countries, including three scientists from Plant & Food Research in New Zealand. The study was led by the University of New England, Australia.


EU to vote again on pesticide ban to save honeybees

Scientific support is growing for a proposed ban of pesticides called neonicotinoids to reverse a massive die-off of honeybees but some experts are calling for more field studies. Hives are dying off around the globe in a phenomenon known as colony collapse disorder, says a report (here) in Scientific American. Pesticides called neonicotinoids are among the proposed culprits. These are supposed to be less harmful to beneficial insects and mammals than the previous generation of chemicals.

Debate over neonicotinoids has become fierce. Conservation groups and politicians in the United Kingdom and Europe have called for a ban on their use, but agricultural organizations have said that farmers will face hardship if that happens. Next Monday, European governments will take a crucial vote on whether to severely restrict or ban three neonicotinoids.

Scientific American says neonicotinoids, which poison insects by binding to receptors in their nervous systems, have been in use since the late 1990s. They are applied to crop seeds such as maize (corn) and soya beans, and permeate the plants, protecting them from insect pests.


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