Wild provide sufficient pollination services to pumpkin

January 20, 2016

Jessica D. Petersen & Brian A. Nault

Department of Entomology Cornell University, New York State Agricultural Experiment Station, Geneva, NY

QuickTime™ and a TIFF (Uncompressed) decompressor are needed to see this picture. Honey (Apis mellifera)

Value attributed to honey bees for crop pollination in the U.S. estimated to be $15 billion (Morse & Calderone 2000) Honey Bee Populations are in Decline

Data compiled from USDA-NASS Honey Bee Populations are in Decline

• Pests and Parasites (e.g., Varroa mite, small hive beetle, Nosema apis) • Pathogens (e.g., American foulbrood, Chalk brood, Israel acute paralysis virus, others)

• (Death and perhaps sub-lethal effects) • Colony Collapse Disorder (Likely a combination of stress, sub-lethal effects of pesticides, viruses and pathogens) • What are the Alternatives to Honey Bees?

• Wild bees • Provide about $3 billion in crop pollination services (Losey & Vaughan 2006) • In NJ and PA, native bees were estimated to provide sufficient pollination for watermelon in 21 of 23 small fields (<2 acres) • Alternative managed pollinators • Commercial bumble bees provide equally sufficient pollination compared to rented honey bees in blueberry systems What Bees Pollinate Pumpkins in NY? Common Eastern Honey Bee Bumble Bee (Apis mellifera) ( pruinosa) () What Bees Pollinate Pumpkins in NY? Common Eastern Honey Bee Squash Bee Bumble Bee (Apis mellifera) (Peponapis pruinosa) (Bombus impatiens)

• Managed and feral • Social • Generalist • Forages less in cool, cloudy weather • Prone to disease and pests What Bees Pollinate Pumpkins in NY? Common Eastern Honey Bee Squash Bee Bumble Bee (Apis mellifera) (Peponapis pruinosa) (Bombus impatiens)

• Managed and feral • Wild bee • Social • Solitary • Generalist pollinator • Cucurbit specialist • Forages less in cool, • Nests on bare, cloudy weather undisturbed soil • Prone to disease and pests What Bees Pollinate Pumpkins in NY? Common Eastern Honey Bee Squash Bee Bumble Bee (Apis mellifera) (Peponapis pruinosa) (Bombus impatiens)

• Managed and feral • Wild bee • Wild bee • Social • Solitary • Social • Generalist pollinator • Cucurbit specialist • Generalist pollinator • Forages less in cool, • Nests on bare, • Nests in rodent cloudy weather undisturbed soil burrows and other • Prone to disease and cavities in woods pests • Perhaps more active on cool cloudy days How are Pumpkins Pollinated? How are Pumpkins Pollinated?

Male Female flower flower Pumpkin Pollination

Female flower Male flower

Nectar and Pollen

Nectar only • Monoecious = Separate female and male flowers on the same plant (range: 1:9 to 1:30 ratio ) • Flowers open at dawn and wilt by late morning; flowers last one day Pumpkin Pollination

?

Does pollination affect fruit size?

Pumpkin Pollination

✔ ?

Seed set is a direct result of pollination, but does greater seed set result in greater fruit weight?

Seed Set and Fruit Weight Relationship

16 14 R² = 0.56 YES! P < 0.0001 12 n = 288 10 8 6 4

Fruit Weight (kg) Weight Fruit 2 0 0 200 400 600 800 1000 Number of Viable Seeds Which Species is More Efficient?

Female flower pollen Male flower

Nectar and Pollen

Nectar only Bumble Bees are the Best

• Bumble bees are efficient pumpkin pollinators – Deposit 3X more pollen per visit than honey bees – Contact the stigma more often than honey bees – Fewer visits to flowers required for pollination – Bumble bees are active on cool, cloudy days • Available commercially from Koppert and Biobest

QUAD = 4 colonies

Artz, Hsu & Nault (2011) Environ. Entomol. Artz & Nault (2011) J. Econ. Entomol. Objectives 1. Determine effects of supplementing pumpkin fields with bumble bees, honey bees or none on… • Bee visits to pumpkin flowers, and • Fruit yield Bumble bee Honey bee None

Supplementation Methods

• Commercial pumpkin fields in NY in 2011 & 2012 • Fields randomly assigned for supplementation with bumble bees, honey bees or none (total of 43 fields) • No managed bees within 1 km • Jack-o-lantern variety planted in 3 locations per field • Bee visits recorded 3 times during bloom (3 x 40m transects) • Marketable fruit harvested and weighed

Bumble bee Honey bee None

n=12 fields n=17 fields n=14 fields Mean Marketable Pumpkin Yield Petersen et al. 2013 PLOS

7

6

5

4 N=12 N=17 3 N=14

2

1

Average fruit weight per plant (kg) perplant weight fruit Average 0 Bumble bee Honey bee Non- supplemented supplemented supplemented Bee Visits to Flowers Petersen et al. 2013 PLOS

12

10

8

6

4

2

Bumble beevisitsper100Bumble flowers 0 Bumble bee Non- supplemented supplemented Bee Visits to Flowers Petersen et al. 2013 PLOS

12 12

10 10

8 8

6 6

4 4

2 2 Honeybeevisitsper100 flowers Bumble beevisitsper100Bumble flowers 0 0 Bumble bee Non- Honey bee Non- supplemented supplemented supplemented supplemented Objectives 1. Determine effects of supplementing pumpkin fields with bumble bees, honey bees or none • Pumpkin yield – NO differences • Bee visits to pumpkin flowers – NO differences

Objectives 1. Determine effects of supplementing pumpkin fields with bumble bees, honey bees or none • Pumpkin yield – NO differences • Bee visits to pumpkin flowers – NO differences Was the stocking density was not high enough?

Objectives 1. Determine effects of supplementing pumpkin fields with bumble bees, honey bees or none • Pumpkin yield – NO differences • Bee visits to pumpkin flowers – NO differences Was the stocking density was not high enough? 2. Determine effects of increasing the stocking density of bumble bees QUAD Density Methods

• Commercial pumpkin fields in NY in 2012 & 2013 • Fields randomly assigned for supplementation with bumble bees at: • low density – 1 QUAD per 2 acres • high density – 3 QUADs per 2 acres • none • Jack-o-lantern variety planted in 3 locations per field • Bee visits recorded 3 times during bloom (3 x 40m transects) • Marketable fruit harvested and weighed QUAD Density Yield Results 2012 & 2013 7

6

5

4 N=10 N=10 3 N=10

2

1 Average fruit weight per plant (kg) perplant weight fruit Average 0 Low density High density Non- supplementationsupplementationsupplemented QUAD Density Bee Visits Results 2012 & 2013 40

35

30

25

20

15

10

5 Bumble beevisitsper100Bumble flowers 0 Low density High density Non- supplementation supplementation supplemented Objectives 1. Determine effects of supplementing pumpkin fields with bumble bees, honey bees or none • Pumpkin yield – NO differences • Bee visits to pumpkin flowers – NO differences 2. Determine effects of increasing the stocking density of bumble bees • High density of commercial bumble bees did not increase yield or bee visits Bumble Bee Visitation and Yield

2011 & 2012 14 12 10 8 6

plant (kg) plant 4 y = 0.14x + 5.16 2 R² = 0.24 P<0.001 Average fruit weight per weight fruit Average 0 0 10 20 30 40 Bumble bee visits per 100 flowers Wild Bees in the Landscape Are there certain types of landscapes that support more wild bees and produce greater yield? Objectives 1. Determine effects of supplementing pumpkin fields with bumble bees, honey bees or none • Pumpkin yield – NO differences • Bee visits to pumpkin flowers – NO differences 2. Determine effects of increasing the stocking density of bumble bees • High density of commercial bumble bees did not increase yield or bee visits Could landscape features affect wild bees and the pollination services they provide? Objectives 1. Determine effects of supplementing pumpkin fields with bumble bees, honey bees or none • Pumpkin yield – NO differences • Bee visits to pumpkin flowers – NO differences 2. Determine effects of increasing the stocking density of bumble bees • High density of commercial bumble bees did not increase yield or bee visits Could landscape features affect wild bees and the pollination services they provide? 3. Determine effects of landscape features on bee visitation rate and yield Landscape Methods

• Ground-truthed and digitized the landuse features within 2km of each pumpkin field

• Typical foraging distance of bees 1-2km

• Landuse features that might be important: 2km Ø % Grassland pumpkin (7-40%) Ø % Forest (9-42%) Ø Landscape diversity/ heterogeneity Landscape Results 2011 & 2012 8 High % 7 grassland

6

5 Low % 4 grassland

3 yieldFruit per plant (kg)

2 Low honey bee High honey bee visitation frequency visitation frequency Landscape Results 2011 & 2012 8 High % 7 grassland

6

5 Low % 4 grassland

3 yieldFruit per plant (kg)

2 Low honey bee High honey bee visitation frequency visitation frequency Landscape Results 2011 & 2012 8 8 High % High 7 grassland 7 diversity

6 6

5 5 Low % 4 4 grassland Low Fruit yieldFruit per plant (kg) 3 yieldFruit per plant (kg) 3 diversity

2 2 Low honey bee High honey bee Low bumble bee High bumble bee visitation frequency visitation frequency visitation frequency visitation frequency Landscape Results 2011 & 2012 8 8 High % High 7 grassland 7 diversity

6 6

5 5 Low % 4 4 grassland Low Fruit yieldFruit per plant (kg) 3 yieldFruit per plant (kg) 3 diversity

2 2 Low honey bee High honey bee Low bumble bee High bumble bee visitation frequency visitation frequency visitation frequency visitation frequency Landscape Conclusions

Honey bee density % High Low Grassland High Supplementing Consider not necessary supplementing Low Supplementing Consider recommended supplementing Landscape Conclusions

Honey bee density % High Low Grassland High Supplementing Consider not necessary supplementing Low Supplementing Consider recommended supplementing

Bumble bee density Landscape High Low diversity High Supplementing Consider not necessary supplementing Low Supplementing Consider recommended supplementing http://www.nysipm.cornell.edu/factsheets/vegetables/ Objectives 1. Determine effects of supplementing pumpkin fields with bumble bees, honey bees or none • Pumpkin yield – NO differences • Bee visits to pumpkin flowers – NO differences 2. Determine effects of increasing the stocking density of bumble bees • High density of commercial bumble bees did not increase yield or bee visits 3. Determine effects of landscape features on bee visitation rate and yield • High bumble bee flower visitation rate and high landscape diversity offers the highest yield Conclusions

• Supplementing pumpkin fields with either bumble bees or honey bees

– did NOT increase fruit yield

– did NOT increase visits to flowers

• Increasing the stocking density of bumble bee hives did NOT increase fruit yield or visits to flowers

• Pumpkin yield and bee visits are influenced by features of the landscape Acknowledgments

Collaborators S. Reiners, Dept. of Horticulture (Cornell University)

Field Assistance R. Austin, M. Campo, K. Cappiello, T. Castle, J. Colon, A. DaSilva, M. Garlick, A. Gresov, M.L. Hessney, M. Holdrege, A. Huseth, E. Maloney, E. Miller, J. Nichols, M. Petersen, J. Petzoldt & A. Yost

Bee Identification J. Gibbs

Beekeeper S. Hall

Pumpkin Growers K. Burnap, R. Chase, B. & D. Eastman, L. Fish, E. Hansen, Jr., A. Heizmann (Meade), D. Hemminger, S. Holdraker, H. Hoover, T. Leubner, G. Lilyea, D. Mason, C. McFetridge, G. Moore, D. Nielsen, R. & L. Pedersen, S. Roe, B. Tomion, and A. Wickham.

Support NYS Agric. & Markets Specialty Crops Block Grant K. Skyrm (Koppert Biological Systems)

QUESTIONS?