March 3rd, 2013 by James Ayre
Wild pollinating-insect numbers have been on the decline over the past century, primarily as a result of wide-scale habitat-loss and pesticide use. This loss has very important implications for the agricultural industry, as many crops are entirely dependent upon pollinators, without them crop yields would fall drastically. And now, new research from the University of Calgary has revealed that the managed honeybees typically brought in to help pollinate crops are considerably less successful doing so than wild insects are.
The new research was done using data taken from over 600 different fields in 20 different countries. The data clearly showed that wild pollinators, primarily wild bees, were much more effective pollinators and that their continuing decline will have very negative effects on crop yields.
The researchers involved state that it is very important that something be done to limit the decline of these important wild pollinators, or agricultural productivity will drop as a result.
The study analyzed data “from 41 crop systems around the world including fruits, seeds, nuts, and coffee to examine the consequences of having abundant wild pollinators for crop pollination.”
“Our study demonstrates that production of many fruit and seed crops that make diets interesting, such as tomatoes, coffee and watermelon, is limited because their flowers are not adequately pollinated,” says Lawrence Harder, professor in the Department of Biological Sciences in the Faculty of Science at the University of Calgary. “We also show that adding more honey bees often does not fix this problem, but that increased service by wild insects would help.”
For many crops to create seeds and fruits it’s first necessary for their flowers to exchange pollen with other individuals of the same species, which occurs via the help of insect pollinators. These insect pollinators are primarily (for crops used by humans) bees, beetles, flies, and butterflies. These insects live almost entirely in “natural or semi-natural habitats, such as the edges of forests, hedgerows or grasslands.” Not in agricultural fields. But these habitats have been disappearing at an increasing rate in recent years, primarily because of they are being converted to agriculture. This has resulted in the previous abundance and diversity of pollinators declining considerably, and crops having fewer and fewer interactions with wild insects. Deforestation, and it’s accompanying processes of soil erosion, and in some regions, desertification, has contributed to this loss.
The new research found “that the proportion of flowers producing fruits was considerably lower in sites with fewer wild insects visiting crop flowers. Therefore, the reduction of wild insects in agricultural landscapes will likely impact both our natural heritage and agricultural harvest.”
“Paradoxically, most common approaches to increase agricultural efficiency, such as cultivation of all available land and the use of pesticides, reduce the abundance and variety of wild insects that could increase production of these crops,” says Harder. “Our study highlights the benefits of considering this paradox in designing and implementing agricultural systems.”
The researchers have suggested that new methods for the management and support of wild pollinators, and also honey bees, need to be adopted to ensure crop yields remain similar to those we currently experience. The methods that the researchers single out, include: “the conservation or restoration of natural or semi-natural areas within croplands, promotion of a variety of land use, addition of diverse floral and nesting resources, and more prudent use of insecticides that can kill pollinators.”
The significant uptick in the use of powerful insecticides in recent years is likely a very difficult problem to solve though. These insecticides have been clearly shown in several studies to be extremely toxic to bees, but they still remain in use for reasons that appear to be mostly about lobbying and the fact that they make some people money. While it appears that the European Union may ban at least some of these insecticides in the near future, the US is as of now unlikely to do so.
The new research was just published in the journal Science.
Source: University of Calgary
Image Credits: Dale Hensley, Bee via Wikimedia Commons
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