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The evolution of tolerance in feral honey bees

Sara Bryant�Australian National University

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SaraBee�Beekeepers are superhero's in the fight against Varroa!

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Varroa: A deadly parasite

Individual: Weakens bees, shortens lifespan, causes deformities
Colony: Reduces brood, weak foraging, queen failure, collapse
Viral Spread: Amplifies DWV and other viruses, increases virulence
Spillover: Viruses spread to wild pollinators (ants, wasps, bumblebees)

Varroa’s Impact

1. Individual Level

Parasitizes developing and adult bees (feeds on fat body tissue)

Causes reduced body weight, shortened lifespan

Impaired immunity and detoxification pathways

Visible deformities (e.g., deformed wings)

2. Colony Level

Brood damage reduces worker replacement rate

Lower foraging efficiency → reduced food stores

Increased stress → queen failure, colony collapse

Loss of genetic diversity in feral populations

3. Viral Spread

Varroa is a vector for multiple honey bee viruses

Most significant: Deformed Wing Virus (DWV)

Increases viral load and shifts virus strains toward more virulent types

4. Viral Spillover

Viruses carried by Varroa-infected bees can transmit to non-Apis species (e.g., bumblebees, ants, wasps)

Potential ecosystem-wide impacts beyond honey bees

Risk of destabilizing pollinator communities

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The future under Varroa

Feral bees: Most will die without intervention

Managed bees: Can survive with beekeeper support

Problem: Pesticide resistance in Varroa is increasing

Question: What can we do?

Silver bullet: Develop and support Varroa-tolerant honey bee strains

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The Australian Solution

Last continent invaded → rare advantage
Global data shows some feral bees evolve resistance
Only chance to capture pre-Varroa baseline
Chance to observe resistance evolution in real time
Unlock genetic basis of resistance → protect bees & biodiversity

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Citizen Science Initiative

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If you would like to get involved in citizen science

Please contact me:

email: sarabrant@anu.edu.au
mobile: 0435 247 137