Wild bees are an increasingly important part of the “pollinator portfolio” for modern agriculture. We have ongoing studies on the role of wild bees as apple pollinators in New York state apple orchards.
To date we have documented a surprising diversity of wild bees contributing to apple pollination in NY – over 120 species of wild, native bees have been collected visiting apple flowers in surveys of NY apple orchards over the past ten years. We have found that wild bees are more effective pollinators, on a per-bee basis, than honey bees and that wild bee abundance and species richness is impacted by both pesticides and loss of natural habitat. We recently developed a smartphone app that allows apple growers to collect data on wild bee abundances in their orchards and to share these data with us so that we can provide them with how best to manage their pollination needs.
My laboratory is currently working on a long-term project on the role of native bees in apple pollination. This project was started in 2009 with a small grant from the USDA-Hatch program and has now grown to a much larger project encompassing:
1. Effectiveness of native bees in apple pollination
2. Drivers of native bee diversity in the apple orchard ecosystem
3. Impact of native bee species richness and abundance on apple fruit and seed set
4. Host plant preferences of wild bees in apple orchard habitats
5. Exposure and impact of pesticides on solitary bees
6. Diversity and frequency of pathogens in wild solitary bees
Thanks to funding from the Atkinson Center for a Sustainable Future, we have been able to extend our studies into the impacts of pathogens on wild bees in apple orchards. Using sophisticated methods for pathogen detection, we have been screening focal bee species for the presence of viral, bacterial, fungal, and microsporidian pathogens. We initially developed our screening methods based on pathogens known from honey bees, but have recently expanded our survey to include all potential viral and bacterial pathogens. Research Associate Shannon Hedtke has taken the lead on developing methods for pathogen detection.
7. The changing view of orchard managers to the importance of native bees for apple pollination
In 2009 (and again in 2012) we conducted a survey of the approximately 690 commercial apple growers in NY with the help of the National Agricultural Statistics Service, New York Field Office. Our survey included 24 questions related to grower practices and perceptions about native bees as pollinators. The majority of growers surveyed (85%) viewed native bees a significant pollinators in their orchards and many growers (68%) expressed willingness to adopt low-cost management practices for enhancing native bee diversity and abundance in their orchards. Overall, the view from orchard managers was extremely positive toward the contribution of native bees to apple pollination. For more information on our survey data, see the New York Fruit Quarterly, Spring 2010.
These various projects were funded by a USDA-AFRI grant and a grant from the Atkinson Center for a Sustainable Future. These projects involved an army of undergraduates and temporary technicians, three graduate students (Mia Park: mgp27[at]cornell.edu, Mary Centrella: mlc344[at]cornell.edu and Katherine Urban-Mead (kru4[at]cornell.edu) and two former post-docs (EJ Blitzer; ejb278[at]cornell.edu and Laura Russo; lr382[at]cornell.edu).
In collaboration with colleagues at Rutgers University (Ignasio Bartomeus and Rachael Winfree) and the New York State Agricultural Experiment Station (Alan Lakso), we examined the impact of climate change on the temporal synchrony of bees and apple flowering in central New York over a 46 year timeframe. When the most important apple pollinators were considered together, we found extensive synchrony between bee activity and the peak of apple bloom. Bee species showed different responses to shifting peak apple flowering times, with some species emerging earlier, some later, and some in synchrony with apple over time. However, the number of bee species in synchrony with apple remained stable over the 46 year timeframe of our study, indicating that biodiversity can buffer the impacts of climate change on agriculturally important plant-pollinator interactions. Our study was highlighted in the November, 2013 cover of Ecology Letters (figure above).