Understanding Varroa Mite Spread

The parasitic Varroa destructor is now established in parts of Australia and represents one of the greatest challenges to beekeepers in recent memory. Once a hive becomes infested, these tiny parasites are adept at moving both within and between colonies — and, in the absence of strict controls, they can travel across landscapes through multiple pathways. (Agriculture Victoria)

Recognising how Varroa spreads is essential for Australian beekeepers who want to safeguard their apiaries and limit the pest’s impact.

---

1. Bee-to-Bee Transmission

Varroa mites don’t hop around on their own in the environment — instead, they rely on bees to carry them. These mites are mobile and will attach themselves to honey bees’ bodies, especially during their phoretic stage, when adult female mites cling to bees to travel. (Agriculture Victoria)

When bees from an infested hive interact with other bees — either through foraging, drifting between colonies, or robbing weakened hives — the mites easily transfer hosts. Worker bees that evening return from flowers or neighbouring hives can unwittingly bring mites with them. (National Varroa Mite Management Program)

---

2. Drifting and Swarming Bees

Honey bees do not always return exactly to the hive they originated from. Bees occasionally drift into nearby colonies — especially when apiaries are close together — which allows mites to move naturally between apiaries. (National Varroa Mite Management Program)

During swarming, a colony splits and a group of bees establishes a new nest location. If the parent hive is infested, mites will be carried directly into the new colony via the bees that swarm. This is a highly effective natural transmission method across landscapes. (Agriculture Victoria)

---

3. Human Activity and Beekeeping Practices

One of the most significant contributors to long-distance spread is human movement of bees and equipment. Transporting:

• Infested brood frames
• Registered or unregistered hives
• Used hive boxes or bee equipment
• Queens for introduction into new colonies

can all quickly move mites hundreds of kilometres in a short period. Aussie beekeepers frequently transport hives for pollination and honey flows, and this mobility can inadvertently accelerate Varroa’s range expansion. (Agriculture Victoria)

Because mites can survive several days without a honey bee host, they may also be carried on equipment, tools, vehicles, or even clothing between apiaries. (National Varroa Mite Management Program)

---

4. Robbing and Colony Collapse

When a hive becomes heavily infested and weakened, it may collapse or have reduced defences. Nearby colonies may then rob the honey from that hive — a behaviour where bees invade a weakened colony to steal its stores. This direct contact makes it easy for mites to transfer from one colony to another during the robbing event. (National Varroa Mite Management Program)

---

5. Long-Distance Spread Across States

In Australia, the movement of Varroa mites across regions has occurred both through natural bee behaviour and human-assisted movement. Since the pest was first detected in New South Wales in 2022, cases have been detected in South Australia, Victoria, Queensland, and the Australian Capital Territory. (outbreak.gov.au)

Although biosecurity measures have tried to restrict the movement of hives and monitor at borders, the reality is that Varroa spread can be fast across large distances due to the migratory nature of commercial beekeeping and the natural behaviours of bees. (Agriculture Victoria)

---

Why Spread Prevention Matters

Varroa mites not only weaken bees through parasitism but also act as vectors for debilitating viruses like deformed wing virus. Once mites are established in a colony, these viruses can spread rapidly and undermine colony health. (Encyclopedia Britannica)

Understanding how Varroa moves — and taking steps to slow that movement — is a core part of responsible hive management and long-term resilience for the Australian honey bee industry.

---

Practical Takeaways for Beekeepers

• Inspect hives frequently to catch early infestations.
• Avoid sharing contaminated equipment between apiaries unless thoroughly cleaned.
• Be cautious when transporting hives or bees long distances.
• Report any suspected Varroa detection immediately to your state or territory authority.

Staying informed and proactive in monitoring will give you a better chance of limiting the spread of these mites and protecting your colonies.