Dr. Diana Robson, our curator of botany, has been studying pollination ecology of native plants for several years. Recently she documented the insects that pollinate the nationally rare Western Silvery Aster (Symphyotrichum sericeum) plant that grows in sandy, tall-grass prairies. One of the things she discovered was how this rare plant, and other tall-grass prairie species, is connected to both crop plant pollinators and predators of crop pests. Before and after crop plants flower, their pollinators rely on native plants to survive. Although Western Silvery Aster is rare, it produces flowers at a time when most crop plants are going to seed, potentially providing much needed nectar to pollinating insects. Canadian crop plants that benefit from wild pollinators like bumblebees and leaf-cutter bees include alfalfa, canola, flax and sunflower, to name a few.

Native plants may also help increase populations of insect predators of crop pests. Bee fly larvae parasitize grasshopper eggs, Tachinid fly larvae parasitize the caterpillars of Fall Armyworms (Spodoptera frugiperda) and Corn Earworms (Helicoverpa zea), and Toxomerus larvae eat aphids. The adults of these insects have been observed feeding on the nectar and pollen of native plants, including Western Silvery Aster.

So just how important might these beneficial insects be for crop production? The annual economic value of ecological services, such as pollination and pest control, provided by wild insects was estimated to be $57 billion in the U.S. alone. We know that these beneficial insects need wild prairies, hedgerows, shelterbelts and forests to live in, and yet, the pressure to cultivate these areas continues to grow. Ironically, more food can be probably be produced by cultivating less land, and even replanting some areas with native vegetation. Recent research from Simon Fraser University suggests that leaving 30% of all land in an agroecosystem uncultivated to provide habitat for wild pollinators will maximize crop yields and profit for farmers.

"By pointing out the connections between beneficial insects and wild plants I’m hoping to encourage farmers and rural landowners to conserve those little patches of prairie and forest remaining on their property," says Dr. Robson. It turns out that what was once considered to be "waste land" may be very valuable.

Dr. Robson is involved in the Canadian Pollinator Initiative, which was started by scientists to increase pollinator research in Canada. The Museum gratefully acknowledges the financial support of WWF-Canada, the Government of Canada, Manitoba Conservation and The Manitoba Museum Foundation.