PMC

Forty-colony apiary profit with gradual adoption of MAS colonies replacing weakest (highest Varroa loads) existing non-MAS colonies. Untreated colonies with high Varroa loads do not survive the season and are replaced.

(a,b) Colony profit for MAS and non-MAS focused honey-producing colonies and commercial pollinating colonies with variable honey prices and treatment decisions as well as low and high Varroa-infestation levels.

Honey and pollinating colony average profits for treated and untreated Varroa infestations of 2% and 20% with non-MAS and MAS colonies. *Untreated colonies with 20% Varroa loads do not survive and are replaced.

Percent Varroa infestation per colony (mean ± SEM) by sampling period and stock type (MAS or BEN). MAS colonies n = 147 (July), 133 (September), 95 (October); BEN colonies n = 127 (July), 109 (September), 64 (October). Unpaired t-test assuming unequal variances, July: 166 df, P = 0.086; September: 207 df, P = 0.084; October: 86 df, P = 0.0699.

A 40-colony apiary (half honey producers and half commercial pollinators) with gradual MAS colony adoption when treatment resistance develops in the Varroa mite population at 50%. In this simulation with 50% treatment resistance, all treated and untreated non-MAS colonies with 2% and 20% Varroa loads are replaced. Marker-assisted selection colonies are replaced at 20% Varroa loads. *Untreated colonies with 20% Varroa loads do not survive and are replaced.

Honey production by producer (mean ± SEM) for MAS and benchmark stocks. Unpaired t-test assuming unequal variances: df and P values by producer reported as: Producer 1: df 14; p= 0.277, Producer 2: df: 14, p=0.329, Producer 3: df: 20, p= 0.419, Producer 4: df: 11, p= 0.021, Producer 5: df: 6, p= 0.375, Producer 6: df: 15, p= 0.495, Producer 7: df: 16, p= 0.247, Producer 8: df: 14, p= 0.345, Producer 9: df: 15, p= 0.123, Producer 10: df: 18,p=0.426 and Producer 11: df: 15,p= 0.028.

Average honey and pollinating colony profit for treated and untreated Varroa infestations of 2% and 20%, with varying levels of treatment resistance within the Varroa mite population for MAS and non-MAS colonies. Non-MAS colonies are now unable to survive when treatment resistance reaches 50% when faced with a 2% Varroa load, and when treatment resistance reaches 25% with a higher 20% Varroa load. For MAS colonies, as no treatment is necessary at lower Varroa levels, MAS colonies survive regardless of treatment resistance, and with higher Varroa levels, treated MAS colonies are considered unable to survive when treatment resistance reaches 75%.