1. Causes and costs of colony losses
Gloria DeGrandi-Hoffman, Fabiana Ahumada*, Richard Henry Graham
Carl Hayden Bee Research Center, USDA-ARS, Tucson, AZ
*AgScience Consulting, Tucson, AZ

2. This study was funded by a grant from USDA-APHIS and in with the collaboration of Randy Verhoek and Harvest Honey Inc. Thank you!!!

3. Overview of the study
2016
April : Split 95 colonies coming out of almonds to make 190 colonies
June: Moved colonies to North Dakota
August: Removed honey from colonies
November: Moved half of the colonies into cold storage, sent other half back to Texas to overwinter
2017
February: move colonies to almonds
Compare cost, survival and colony grade of the two overwintering strategies

4. Colony splits – 95 hives were split to make 190
Splitting colonies: labor + travel = $412
Installing queens: labor + travel + cost of queens + sugar syrup = $5827
Total cost of splits: $6239 or $33 per colony

5. Colony states – mid - April
Frames of bees: 7 ± 0.1
Frames of brood: 4 ± 0.1
Mites per 100 bees: 1 ± 0.1

6. Late April colony check – 158 colonies
Feed syrup, add brood chamber and super: labor + travel + syrup = $648
32 colonies were dead - $33 * 32 = $1056
Total expenditure of splits: $6887

7. Move colonies to North Dakota in June
State of colonies:
- frames of bees: 15 ± 0.7
- mites per 100 bees: 1.3 ± 0.1
Task
Cost
Move colonies to holding yards
Load trucks and transport colonies
labor + travel = $177
labor + transport to ND yards = $2060

8. June mite treatment
labor + transportation + miticide = $1505 ($9.50 / colony – 158 cols.)
mite drop:
Pre-treatment – 3.6 ± 0.4
Post-treatment – 48.4 ± 3.5
mites / 100 bees:
Pre-treatment – 1.3 ± 0.1
Post treatment – 0.2 ± 0.02

9. June, July and August colony checks
Labor + transportation = $216 per check
Total for colony checks = $648

10. Harvest honey in late August
12,160lbs of honey was removed from 158 colonies
Labor + transportation + extraction fee = $3542
Total expenditures to date: $13,346
Honey price per pound (Dakotas): $1.65-$1.70*
Value of honey crop: $20,064 - $20,672
Profit: $ $7326
* USDA-AMS Specialty Crops Program Market News Division, Dec. 23, 2016

11. September mite treatment and colony measurements - 133 colonies remain
Cost of mite treatment: labor + transportation + miticide = $1279
Frames of bees: 15.5 ± 0.1
Frames of brood: 8.2 ± 0.1
Mite drop
pre-treatment: 74.4 ± 8.4
post-treatment: 529 ± 29
Mites per 100 bees
pre-treatment: 4.6 ± 0.3
post-treatment: 1.4 ± 0.1
June mite drop:
Pre-treatment – 3.6 ± 0.4
Post-treatment – 48.4 ± 3.5
June mites / 100 bees:
Pre-treatment – 1.3 ± 0.1
Post treatment – 0.2 ± 0.02

12. Colony preparation for overwintering September and October feeding, October mite treatment (120 colonies)
Cost of feeding: labor + transportation + sugar syrup + fumagillin+ protein patty = $ 4868
Frames of bees: 14.4 ± 0.2
Mite treatment: labor + transportation + miticide = $1459
Mite drop:
pre-treatment: 10.8 ± 0.7
post-treatment: 61.7 ± 3.7
Total expenditure: $6327

13. What’s behind the numbers
Mite population growth

14. Why are there so many mites?
Mites per forager Mites per 100 bees % of brood cells with mites
DeGrandi-Hoffman et al. 2014, 2016

15. What’s behind the numbers

16. Overwintering strategies active in Texas apiaries vs cold storage
Texas colonies: labor + transportation = $878
Cold storage in Idaho: labor + sugar syrup + transportation = $1075

17. Projected overwintering costs
Cold storage: cold storage fee + transportation + feeding = $2800
Cost per colony in cold storage: $8.00
Active in Texas apiary: feeding + transportation = $8165
- assuming 6 feedings at $1112 per feeding
Total investment in colonies:
Active in Texas: $25,588 ($135 / col)
Cold storage: $20,223 ($106 / col)

18. Cost of colony losses prior to almond pollination
Active in Texas: ($135 + $185) = $320
Cold storage: ($106 + $185) = $291

19. Cost of colony shortages to almond growers

20. Accuracy of model predictions
Pounds per acre

21. Estimated loss in yield with 30% reduction in bees
Lbs of nuts per acre
Difference = $1170 / acre
Difference = $943 / acre
Bloom period weather conditions

22. Expanded economic analysis
Predicted revenue per acre with price adjustments and service fee cost savings
Frames per colony 6 7 8
Hives per acre
Revenue in good weather ($ / acre)
Revenue in poor weather ($ /acre)
1.4
5615
5836
6054
4449
4753
5009
1.5
5703
5912
6103
4556
4863
5114
1.6
5783
5979
6143
4659
4967
5213
1.7
5855
6036
6174
4757
5066
5305
1.8
5918
6084
6197
4852
5160
5392
1.9
5973
6122
6212
4942
5249
5473
2.0
6020
6150
6217
5027
5332
5549
From: Bond et al (2016) Honey Bee Health Challenges: What are the Implications of Fluctuating Pollinator
Availability on Almond Production and Profitability? J. of Agric. and Appl. Econ. In review.

23. Conclusions
Colony losses are the sum of the investment and lost rental fees.
Mite control and colony losses
Great disparity in costs and risk of overwintering strategies.
Overwintering losses also affect almond yields and grower revenue.