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.