Nesting Habitat Enhancements and Native Bee Population Measurements in Apple Orchards in Georgia

View the project final report

Commodities

• Fruits: apples

Practices

• Crop Production: beekeeping

Honeybees contribute $15 billion in pollination services annually. Reliance on a single insect species, the honeybee, for the pollination of over 1/3 of the human food supply can be dangerous. Alternative pollination strategies that are less dependent on the honeybee must be developed in order to ensure long-term sustainably of insect pollinated crops.

The best alternative to honeybees is the native bees already present in the local environment. Therefore, research is needed to determine which native bees are present in a given region and how best to enrich the habitat (e.g. nesting areas) to increase target native bee populations.

Our studies have identified the mining bee, Andrena crataegi, and its close relatives, the Melandrena, as being the ideal native bee species for Georgia Apple production. It is time to expand the study to the next step: (1) to estimate the native population sizes in the orchards, and (2) to develop habitat enrichments and other strategies to increase the abundance of these target native bees in the apple orchards.

By establishing a strong network of native bees in Georgia agriculture, we can make Georgia agriculture more secure and sustainable. In addition, an increase in reliance on native bees means that farmers will spend less money on pollination services, which will result in greater farmer profits and potentially reduce food costs for the general public.

Introduction

Honeybees contribute $14.6 billion in pollination services to U.S. commercial agriculture annually [1]. The yields of some crops decrease by more than 90% when honeybees are not present [2]. Reliance on a single insect species, the honeybee, for the pollination of over 1/3 of the human food supply can be dangerous [3]. Indeed, this is especially true considering that honeybees are in decline from Colony Collapse Disorder (CCD), thus putting the global food supply at risk. Today, honeybee colonies are down by 40% compared to colonies available in the 1970’s [4,5]. In 2007, CCD resulted in sharp declines in honeybees in at least 35 states, including Georgia. In the affected areas, 50% of beekeepers reported significant colony losses [6].

The reduced availability of honeybee colonies has increased food production costs and reduced potential crop yields. Most farmers are dependent on rented honeybee hives in order to ensure their crops are fully pollinated. The shortage of honeybee colonies has resulted in a rapid increase in the cost of renting honeybee hives. For example, the cost of renting a single honey bee colony used in almond pollination in California increased from $35 in the early 1990’s to $150 per colony in 2007 [6]. The potential loss or reduction of the honeybee can have a devastating effect on agricultural production. Alternative pollination strategies that are less dependent on the honeybee must be developed in order to ensure long-term sustainably of insect pollinated crops.

The best alternative to honeybees is the native bees already present in the local environment [7-11]. With nearly 3500 species in North America alone, the diversity of different forms, pollen-strategies, and behaviors of native bees provide a wide range of use for agricultural operations. It is estimated that native bees already annually contribute $3 billion to U.S. agriculture [12].

In addition, native bees may exhibit much greater pollination efficiency compared to honeybees [13]. For example in apple pollination, one female Osmia cornifrons is estimated to pollinate 2450 apple per day, compared to 80 apples per day by a honeybee [14].

Every region, even every crop, has its own characteristic group of native bee pollinators. Data concerning regional make-ups of these native pollinator-guilds are severely lacking, which has led to our reliance on the European honeybee. In fact, across the continent, available information on native bees is spotty at best [15]. Therefore, research is needed to determine which native bees are present in a given region and how best to enrich the habitat (e.g. nesting areas) to increase target native bee populations.

Our studies have identified the mining bee, Andrena Crataegi, and its close relatives, the Melandrena, as being the ideal native bee species for Georgia Apple production. Other excellent apple pollinating native bees indentified were carpenter bees (Xylocopa virginica) and mason bees (Osmia species). It is time to expand the study to the next step: (1) to estimate the native population sizes in the orchards, and (2) to develop habitat enrichments and other strategies to increase the abundance of these target native bees in the apple orchards.

As mentioned previously, each geographic region has its own unique native bee species make-up. The mining bees (Family Andrenidae) are likely to be the main native bee group useful in pollinating early flowering fruits and vegetables in the Southeastern United States. The high clay content in the soils of the Southeastern United States has created ideal nesting sites for mining bees, resulting in large abundances of mining bees. In other areas of the U.S., such as the west coast, native bee research has focused on mason bees (Osmia species).   In order to provide farmers with the most reliable scientific and agricultural information, field studies must be performed regionally.

By establishing a strong network of native bees in Georgia agriculture, we can make Georgia agriculture more secure and sustainable. In addition, an increase in reliance on native bees means that farmers will spend less money on pollination services (e.g. renting honey bee hives), which will result in greater farmer profits and potentially reduce food costs for the general public.

Literature Cited

1. Morse R.A. and N.W. Calderone. The Value of Honey Bees as Pollinators of U.S. Crops in 2000. Bee Culture 128:1-15.

2.Watanabe, M. 1994. Pollination Worries Rise as Honey Bees Decline. Science 265 (5176): 1170.

3. Klein A.M., B.E. Vaissiere, J.H. Cane, I. Steffan-Dewenter, S.A.Cunningham, and C. Kreman. 2007. Importance of Pollinators in Changing Landscapes for World Crops. Proceedings of the Royal Society B: Biological Sciences 274: 303–313.

4. USDA National Agricultural Statistics Service. 1977. 1976 Honey production report. United States Department of Agriculture, Washington DC.

5. USDA National Agricultural Statistics Service. 2006. 2005 Honey production report. United States Department of Agriculture, Washington DC.

6. Johnson, R. 2007. Recent honeybee colony declines. CRS Report to Congress.

7. Kremen, C., N.M. Williams, and R.W. Thorp. 2002. Crop Pollination from Native Bees at Risk from Agricultural Intensification. Proceedings of the National Academy of Sciences of the United States of America 99 (26): 16812-16816.

8. Chagnon M., J. Gingras and D. de Oliveira. 1993. Complementary Aspects of Strawberry Pollination by Honey Ad Indigenous Bees (Hymenoptra). Journal of Economic Entomology 86:416-420.

9. DeGrandi-Hoffman, G. and J.C. Watkins. 2000. The Foraging Activity of Honey Bees (Apis mellifera L.) and Non-Apis Bees on Hybrid Sunflowers (Helianthus annuus L.) and its Influence on Cross-Pollination and Seed Set. Journal of Apic Research 39:37-45.

10. Greenleaf, S.S. and C. Kreman. 2006. Wild Bees Enhance Honey Bees’ Pollination of Hybrid Sunflower. Proceedings of the National Academy of Sciences USA 103(37): 13890-13895.

11. Kremen C., R.L. Bugg, J.P. Fay, and R.W. Thorp. 2004. The Area Requirements of an Ecosystem Service: Crop Pollination by Native Bee Communities in California. Ecology Letters 7:1109-1119.

12. Losey J.E., and M. Vaughan. 2006. The Economic Value of Ecological Services Provided By Insects. Bioscience 56:311-323.

13. Sampson, B.J., S.J. Stringer, J.H. Cane, and J.M. Spiers. 2004. Screenhouse evaluations of a mason bee Osmia ribifloris (Hymenoptera: Megachilidae) as a pollinator for blueberries in the southeastern United States. Small Fruits Review 3:381-392.

14. Parker, F.D., S.W.T. Batra, and V.J. Tependino. 1987. New pollinators for our crops. Agricultural Zoology Reviews 2: 279-304.

15. National Academy of Science. 2007. Status of pollinators in North America. National Academies Press, Washington, DC.

For the 2014 field season, we have 3 main objectives.

The first objective is to gain a better understanding of native bee population sizes and their distribution in the orchards.

The second objective is to develop habitat enrichments to boost the abundance of specific native bee species.

The third objective is to survey native bee abundance and diversity in the apple orchards. Native bee diversity and abundance shift during the apple bloom and can vary depending if very early or late apple bloom periods occur.