Honey bees accelerate tree disease spread in Australia, study finds

Created at 11 Jun · 8:35 AM1 source↑ Market-relevant

IN SHORT

New research indicates that honey bees, introduced to Australia by Europeans, may be unintentionally spreading myrtle rust, a destructive plant disease. The bees collect nutritious fungal spores, which remain viable in hives and can be transported across vast distances, potentially exacerbating the disease's spread beyond wind dispersal.

Key Numbers

200+years honey bees have been in Australia

2010year myrtle rust was first detected in Australia

22%protein content in myrtle rust spores

9days myrtle rust spores remained viable in hives

17%of Australia's endemic vegetation potentially at risk from myrtle rust

Who's Involved

European settlers

introduced honey bees to Australia in the early 19th century

Austropuccinia psidii

fungus causing the myrtle rust plant disease

Western honey bees

observed collecting fungal spores as a potential food source

Researchers

published findings in NeoBiota on honey bee and myrtle rust interaction

↳ Why This Matters

This research challenges the long-held view of honey bees as purely beneficial agricultural allies by revealing their potential role in spreading a destructive plant disease, highlighting the complex and often unpredictable consequences of introducing non-native species into new ecosystems.

Key facts

Honey bees, introduced to Australia over 200 years ago, may be unintentionally spreading myrtle rust.
Researchers observed bees collecting nutritious fungal spores from infected plants, potentially as a food source.
Myrtle rust spores remained viable inside bee hives for at least nine days.
The movement of commercial honey bee colonies could spread the disease farther than wind alone.
This interaction may represent an 'invasional mutualism' with implications for forest regeneration and biosecurity.

Honey bees, long considered agricultural allies since their introduction to Australia by European settlers over 200 years ago, may be inadvertently contributing to the spread of myrtle rust, a destructive plant disease. New research published in NeoBiota reveals that western honey bees are actively collecting fungal spores from infected plants, not just accidentally, but potentially as a highly nutritious food source.

The study found that these rust fungi contain over 22% protein and all ten essential amino acids, supporting normal development in bee larvae. This behaviour is thought to be an alternative feeding strategy during periods of scarce traditional pollen. Crucially, the myrtle rust spores remain viable inside bee colonies for at least nine days, raising concerns about disease transmission.

Given that commercial honey bee colonies are frequently transported across Australia for crop pollination, scientists fear this movement could significantly accelerate the spread of myrtle rust beyond natural wind dispersal. This interaction has been termed 'invasional mutualism', where two introduced species benefit each other, potentially disrupting native plant-pollinator relationships and hindering forest regeneration.

The findings have broader implications beyond Australia, as the western honey bee is a globally distributed pollinator. The research suggests that the role of pollinators in spreading plant diseases may be underestimated, prompting a need to reconsider biosecurity strategies to include the movement of animals, not just plants and environmental conditions.

Frequently asked questions

Myrtle rust is a plant disease caused by the fungus Austropuccinia psidii, which attacks plants in the Myrtaceae family, including eucalyptus trees and other native Australian species.

Honey bees collect myrtle rust spores as a nutritious food source. These spores remain viable in their hives and can be transported to new locations when bee colonies are moved for pollination.

The bees' transport of viable spores could spread myrtle rust much farther and faster than wind alone, potentially impacting native biodiversity and forest regeneration, and is an example of 'invasional mutualism'.

Invasional mutualism occurs when two introduced species benefit each other in a way that amplifies their impact on the environment, such as honey bees benefiting from fungal spores while helping the fungus spread.

What Happens Next

01Future biosecurity policies may need to consider the movement of pollinators as a factor in disease spread.

02Further investigation into the relationship between honey bees and myrtle rust is ongoing.

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How It Developed

Honey bees were introduced to Australia by European settlers over 200 years ago.

Myrtle rust, a plant disease caused by the fungus Austropuccinia psidii, was first detected in Australia in 2010.

Researchers observed honey bees collecting myrtle rust spores from infected plants.

The fungal spores were found to be highly nutritious, containing over 22% protein.

Bee larvae fed fungal spores developed normally, comparable to those fed high-quality pollen.

Myrtle rust spores remained viable inside bee hives for at least nine days.

Commercial honey bee colonies are frequently moved across Australia for crop pollination.

Scientists suggest bees may act as additional carriers of myrtle rust, alongside wind.

Sources

In 1822, Europeans brought honey bees to Australia as agricultural heroes; 200 years later, researchers found they were helping tree death spread faster than windThe Economic Times