Evolution of Natural Mite Resistant Honeybee Colonies on Hawaii�

Stephen J Martin¹, Scott Nikaido² & Ethel M. Villalobos²

1-Environment and Life Sciences, The University of Salford, Manchester M5 4WT, UK

2-Environmental Protection Science, University of Hawaii at Manoa, Honolulu, HI, USA 2-School of

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Varroa mite

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Varroa and Deformed Wing Virus

• Varroa destructor is a vector for the virus
• High viral loads have obvious phenotypes
• Low viral loads (covert) still have detrimental impacts
• Reduced life span
• Impaired immune systems
• Learning deficiencies

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Deformed wing virus in Hawaii

• Varroa mite arrived in Oahu in 2007
• In 2008 Varroa was detected in the Big Island of Hawaii
• These are the only 2 islands in the archipelago that have mites

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Oahu

Big Island of Hawaii

Deformed wing virus in Hawaii

• Dramatic change in viral environment
• Great losses of managed and feral colonies
• Closed system
• Genetic bottleneck

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Martin et al.,2012

Varroa life cycle

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Bald brood

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How some bees become resistant to the mite

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Mondet et al. 2021

1-Recognition of chemicals (ketones and acetates) associated with mite infestation

How some bees become resistant to the mite

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Mondet et al. 2021

2-Decision by another group of bees whether to the keep or remove the pupa.

The process of recapping

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Mother mite has roughly 20+ eggs��Each cycle she may lose 3 or 4

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Recapping and mite fertility

Common traits of resistant bees

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Colonies that can survive without treatment

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1-Phoretic mite levels are low (but not always below 3%)

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2-Recapping rates are above 40%

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3-Colonies efficiently remove infested worker brood

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4-Mite fertility if low

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Colony survey: recapping as a proxy of mite detection and removal

• Survey of capped brood
• Only those with dark pink eyes or older
• 100-150 cells per colony
• Size of the recapping
• Age of the pupa
• Presence of the mite (Varroa reproductive success)

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Oahu’s colonies

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Solid brood patterns are common in Africanized bees

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Mite resistance and recapping are not limited to a particular type of honeybee

Cuba with >200,000 colonies

European honeybees

Largest population of EHB not treating for Varroa

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Infested cells recapped

Not infested cells recapped

Mite introductions

Insertion of reproductive female mites into recently capped cells

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Manipulation of cells to imitate physical damage as a control

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Allowed to continue to develop and then check

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P<0.001

Queen swap

Evidence that queen genes matter a lot

Colonies led by daughters of a resistant queen seem to be resistant

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Colonies with poor Varroa performance improve when a resistant queen is introduced

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Resistant traits are linked

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Thanks! Gracias!

Thanks to the Oahu beekeepers

Thanks to Scott Nikaido, Kevin Sander and Zhening Zhang

Research supported by

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