April Flowers for redOrbit.com – Your Universe Online
An international study of wild insects finds that managed honeybees are not as successful at pollinating crops as wild insects, especially wild bees. Collected from 600 fields in 20 countries, the data suggest the continuing loss of wild insects in many agricultural landscapes is having negative consequences for crop harvests.
The study, published in a recent issue of Science, is an urgent call to maintain and manage pollinator diversity for long-term agricultural production.
The research team was comprised of 50 international scientists, including Dr. Lawrence Harder, professor in the Department of Biological Sciences (Bio) at the University of Calgary. They 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 agricultural crops.
“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 Harder. “We also show that adding more honey bees often does not fix this problem, but that increased service by wild insects would help.”
Before making fruits and seeds, the flowers of most crops need to receive pollen. Insects that visit the flowers enhance this process. Bees, flies, butterflies and other pollinators usually live in natural or semi-natural habitats, such as the edges of forests, hedgerows or grasslands.
As the abundance and diversity of pollinators decline, typically as a result of habitat loss, crops receive fewer visits from wild insects. This habitat loss is primarily due to land conversion for agricultural use.
The proportion of flowers producing fruits is considerably lower at sites with fewer numbers of wild insects visiting crop flowers. Our national heritage and agricultural harvest will likely be impacted by the reduction of wild insects in agricultural landscapes.
“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 study findings suggest that new integrated management practices of both honeybees and wild insects will increase global yields of animal-pollinated crops. This, in turn, will promote long-term agricultural production. Such practices should include 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.