Photo: Daniel Cariveau
Wild insects are better at pollinating crops than captive honeybees trucked into fields by humans, new research suggests. Crashing populations of wild insects could spell disaster for our food supply, the researchers suggest.The new study, published online in the journal Science Thursday, Feb. 28.
Flowering plants produce “male” and “female” varieties. Male plants produce pollen, and female grow flowers, which when pollinated, become fruit. Since plants can’t move, insects or other animals are needed to carry pollen from the male plant to the female.
(Some plants use wind, but they have specialised pollen.)
Without insects to pollinate them, crops can’t make food. To see which were the most important and efficient pollinators, scientists collected and analysed data from 600 fields of 41 crops, which included fruit, nuts, seeds, and coffee.
They counted the number of times different insect species visited different flowers, and how much pollen each insect left on the plant.
They also measured how many flowers on each plant eventually turned into fruit (which happens when pollination is successful).
Insects to the rescue
They found that pollination by wild insects (instead of those trucked into the fields, like bees in hives) produces a greater variety and abundance of crops.
Specifically, wild insects increased productivity in every crop system studied. Farmed bees only increased fruit production in 14 per cent of crops.
Photo: Saul Cunningham
People seem to think that we can rely on farmed insects to pollinate our crops, but the data indicates that wild insects are badly needed for continued crop productivity.That’s bad news for farmers, because habitat loss and pesticides — mostly from agriculture — have led to declines in wild insect populations.
Some species are undergoing local extinctions — for example parts of Illinois have lost some of their wild bee species.
“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,” study researcher Lawrence Harder, of University of Calgary, said in a press release.
Future of food
Three quarters of the world’s food comes from pollinated crops like those in the study, and these insect declines will likely lead to worldwide crop shortages and future food instability.
In the Sichuan region of China, pollinator decline has grown so severe that farmers now pollinate apple flowers with “pollinator sticks” made from cigarette filters and chicken feathers, according to information published online by the European Commission, the central government for the European Union.
Some popular crops might be hit particularly hard, the scientists said.
Photo: Rufus Isaacs
“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,” said Harder. “We also show that adding more [captive] honey bees often does not fix this problem, but that increased service by wild insects would help.”The researchers recommended preserving patches of wild area among farmland, adding places for insects to nest, and rethink how farmers use pesticides. These changes would have “financial and opportunity costs”, but are in the end well worth it.
Without such changes the scientists said, “the on-going loss of wild insects is destined to compromise agricultural yields worldwide.”
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