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Sustaining and Enhancing Genetic Variation in Honey Bee Pollinators
Robert DankaUSDA, ARSHoney Bee Breeding, Genetics & Physiology Lab1157 Ben Hur Rd., Baton Rouge, LA [email protected]
From Status of Pollinators in North America (NRC 2007):
Varroa destructor has caused dramatic declines in honey bee abundance in North America and throughout the world. Twenty years after its introduction to the United States, V. destructor continues to devastate honey bee populations.
The sustainability of the honey bee, the principal managed pollinator in North America, could be buttressed through the development and adoption of parasite- and pathogen-resistant stocks of bees.
Varroa resistant honey bees:
• Minnesota hygienic• Bees with VSH (varroa sensitive hygiene)• Russian
Minnesota hygienic
• developed from a commercial Italian stock• moderate varroa resistance• presumably excellent pollination ability
VSH (previously SMR)
• a trait (not a stock) for breeding• excellent varroa resistance• pollination traits unknown
Russian
• imported from Russia then intensively selected• very good varroa resistance
general flight activity
pollen vs. nectar collection
single-visit pollen deposition
flight activity during almond pollination
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Combs of bees
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Combs of bees
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Russian
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Temperature (ºC)
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large coloniessmall colonies
colony populations
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flight activity during lowbush blueberry pollination
electronic counters (ApiScan Plus®)
manual counts with a “flight cone”
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Temperature (ºC)
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large colonies small colonies
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Populations of Russian and Italiancolonies are similar in late spring
nectar vs. pollen foraging
This has been measured in almonds and upland cotton, and during an autumn wildflower flow
There are insignificant differences in the proportions of pollencollectors in Russian and Italian foraging populations
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% P
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single-visit pollen deposition
Russian and Italian foragers deposit similar numbers of pollen grainsduring one foraging visit
This has been measured in rabbiteyeblueberries and upland cotton
Russian and Italian colonies forage at the same rates:- when colony populations are of equal size- throughout the range of temperatures studied (~10-30 °C)
Other aspects of foraging are similar for Russian and Italian bees
Russian colonies tend to be less populous early in the season→ Can breeding or management boost Russian populations?
summary
Russian
Italian
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ees
Germplasm diversity in the USA appears not to be declining dramatically
Enhancements to diversity:• recent imports – Australia, Austria, Russia, UK
and Yugoslavia. Others proposed.• Africanized honey bees
Australian package bees
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Temperature, CO
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overwintered colonies
package colonies
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Polle
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Recent findings of genetic variation for foraging:
• apples – extant & selectable (Dag et al 2005 J. Apic Res.)
• avocados – extant (Dag et al. 2003 Apidologie)
• sunflowers – Africanized honey bees (Balsuado et al. 2000 J. Econ. Entomol.)
