Pollinator-friendly practices to enhance sustainability and crop production in apples and pears

BENOÎT GESLIN; MARCELO AIZEN; NANCY GARCIA; PEREIRA ANA JULIA ; BERNARD VAISSIÈRE; LUCAS GARIBALDI

Montpellier

Congreso; 27th International Congress for Conservation Biology; 2015

Society for Conservation Biology

Facing the global challenge of agricultural sustainability, an ecological intensification of agriculture through optimization of ecosystem services has been proposed. Yet, insect pollination management in practice remains poorly known beyond the widely used practice to supply crops with colonies of honey bees (Apis mellifera) at the onset of flowering. Yet their contribution to pollination quantity (amount of pollen deposited) and quality (percentage of pollen tubes per pollen grains) and then to crop yield and quality often remains unknown. In the main fruit producing area of Argentina, we studied apple and pear pollination and analyzed the pollinator friendly practices that might make it more sustainable. Concretely, we studied the effects of crop management and colony management on the a) pollinator visitation rate, b) pollinator behavior, c) stigmatic pollen load, d) ratio of pollen tube/pollen grain, e) quantity of fruits, and f) quality of fruits. Surprisingly, we did not record a single wild pollinator during our 45 days of survey and so the whole pollination process relied solely on introduced honey bees, of which we observed 1300 visits on the two crops. We found that visitation rate and fruit set were positively influenced by bee abundance and organic farming. High bee abundance also affected bee behavior with higher effectiveness of single visits. Since this pollination system rests totally on just one introduced species, developing management practices that could sustain bee populations appears crucial. We suggest management practices to improve colony performance in regards to their development and health. This work has important general applications because it depicts a situation that might regrettably be widespread in the future, if wild bee populations continue to decline, with the service of pollination relying only on honey bees. We will also discuss these results with regards to the economic costs and benefits of pollinators friendly practices.