Both are external mites that reproduce in sealed brood, and both damage colonies severely. Telling them apart matters because Tropilaelaps is notifiable in many countries and requires a different response.

Appearance

• Varroa: Broader than long, flattened, reddish-brown, comparatively large — visible on an adult bee
• Tropilaelaps: Longer than broad, smaller, reddish-brown, and noticeably faster moving

The shape is the clearest distinction: Varroa is crab-like and wide; Tropilaelaps is elongated.

Behaviour

This difference is more useful in the field than shape.

• Varroa stays on adult bees between reproductive cycles and feeds on them
• Tropilaelaps cannot feed properly on adult bees. It must return to brood quickly and moves rapidly across the comb

Mites running quickly over the comb surface when a frame is lifted point to Tropilaelaps.

Why the difference is decisive

Because Tropilaelaps depends on brood, its population grows faster than Varroa's and it can overwhelm a colony more quickly.

But the same dependence is its weakness: a brood-free period of sufficient length kills it, because it cannot survive on adult bees. That makes brood interruption a more powerful tool against Tropilaelaps than against Varroa.

Monitoring

• Opening sealed brood is the most reliable method for Tropilaelaps
• Alcohol wash and sugar roll are designed for Varroa and detect Tropilaelaps less reliably, precisely because it does not stay on adults
• Floor tray: Both fall onto it; the shape distinguishes them

A beekeeper who monitors only by washing adult bees may miss Tropilaelaps entirely.

What to do on suspicion

• Photograph and record the date and location
• Report it to the competent authority — it is notifiable in many countries
• Do not move colonies or equipment
• Do not treat before reporting

Why it matters now

Tropilaelaps has been expanding its range. Information about how to recognise and monitor it travels through beekeeping networks ahead of the mite itself — which is an advantage beekeepers did not have when Varroa arrived.