Researchers studying data from 600 fields in 20 countries have concluded that managed honey bees are not as successful at pollinating crops as wild insects. Their findings raise serious questions over government policy in light of findings that certain pesticides are threatening the health of bees and other wild pollinators.

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The team found that wild bees play the greatest role in pollination activities and suggested that the continued loss of a range of wild insects from many agricultural landscapes is already having negative consequences for crop harvests. Although their study focused on habitat loss, not the effect of pesticides, the researchers suggest may well be contributing to declines.  

The study was published in respected journal Science; upon its release, the study's authors issued an urgent call to maintain and manage pollinator diversity to protect agricultural production in the long term. The 50 international researchers analysed 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.

Professor Lawrence Harder of the University of Calgary, Canada is one of the report's authors. On Thursday, he stated unambiguously, "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. We also show that adding more honey bees often does not fix this problem, but that increased service by wild insects would help."

Insect pollinators, including bees, flies, butterflies and beetles, usually live in natural or semi-natural habitats, such as the edges of forests, hedgerows or grasslands. As these habitats are lost, primarily owing to conversion to agriculture, the abundance and diversity of pollinators decline and crops receive fewer visits from wild insects.

The study 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 on both natural heritage and agricultural harvest.

Professor Harder added, "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. Our study highlights the benefits of considering this paradox in designing and implementing agricultural systems."

The study suggests that new practices for integrated management of both honey bees and wild insects will enhance global yields of animal-pollinated crops and promote long-term agricultural production. These 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.