Tropilaelaps

 

Causal agent

Tropilaelaps clareae and T. koenigerum - Parasitic mites

Mites are 1 long x 0.6mm wide.  T. koenigerum is slightly smaller.

Age group

Egg

Larvae

Pupae

Adult - worker

Drone

Queen

No

No

Yes (Drone+)

Yes

Yes

Yes

Clinical signs

 

The mites natural host is Apis dorsata (Asian honey bee)

  Note the different shape to Varroa

Infestation of the hive may lead to collapse and absconding.

Infectivity

 

The adult female mite infests a larvae as the larvae is about to be capped.

The larvae pupates and the mite feeds off the pupae haemolymph.  The mite lays eggs.  The first egg hatches is a male and the subsequent mites are female.  The male mates with his sisters.  The life cycle is must faster than in Varroa rate of 25:1.  The adult female mite cannot feed off the host.  Female mites die within 2 days without brood.

Transmission

 

Horizontal - Drifting and robbing.  Concentration of hives in an area.  Can live on other bees.

Vertical –through the brood

The mite can live on a number of Apis species – A. dorsata (Asian Honey Bee); and also A. laboriosa, A. ceranae and A. florea (other Asian species)


 

Post-mortem Lesions

 

Presence of mite. 

Diagnosis

Mite seen on the bee

Note the difference between Tropilaelaps and Varroa – Tropilaelaps is smaller and elongated.

Monitoring mites with a screened bottom board with a sticky surface – spray on cooking oil for example.

Take 500ml of car windscreen washer fluid (alcohol).  Shake around 500 bees into the solution (one frame).  Shake the fluid and bees.  The bees are killed in the fluid.  Count the mites which appear.   The mites will generally float to the top.

Ether roll – Collect 200-300 bees into a jar and anaesthetise with ether – from an car store used in air to start engines.  Use 1-2 second blast.  Roll jar for 10 seconds, mites dislodge and adhere to side of jar.  Remaining bees can be spread on a white paper to see additional mites if required.

Treatment

 

None of the treatments achieve elimination only control

Mite can be controlled without brood – cold climates may limit spread of mite.

Chemical

Tau-Fluvalinate (Apistan) or Flumethrin (Bayvoral) both synthetic pyrethroids Start treatment when sticky boards reveal over 200 mites after 3 days exposure. 

The strips are normally applied for up to 6 weeks

Note these chemicals can build up in the honey and eventually will affect the bees.  2 years of application has affected queen bee fertility.

These products may be more useful in the Autumn.

Apiguard – Thymol.  Once the temperature is above 15°C Thymol products can be used. Use two applications 10 to 15 days apart.

Api Life Var – Thymol, eucalyptus oil, menthol and camphor.    This is used two 14 days apart.

 

Organophosphates - Coumaphos (Checkmite+).The checkmite+ strip hangs down between frames in the broodnest so bees can walk on it and pick up minute amounts of the active ingredient.  Do not put the strip on the bottom board, tops of frames.

 

Be careful when medicating with products that may affect honey quality

Organic acids treatments are being developed

Oxalic acid – This is not authorised in the UK.  Oxalic acid can kill brood and therefore has to be used in brood-less colonies – in the wintertime.

Mix 6% of oxalic acid with 30% sugar solution and apply by the trickling method.  Note the products have to be used fresh and breakdown products can be toxic to the bees –hydroxymethylfurfuraldehyde.  

Sucrose octanoaten – a sugar and soap solution. Need to repeat 3 times to kill mite eggs.

Formic acid can be used on the bottom boards.  This can be useful to control tracheal mite.  Administer 30 mls every week for 3 to 5 applications in the spring.   Then again in June.   Air temperature needs to be above 22°C but below 30°C

Mechanical

Eliminate brood for more than 3 days will eliminate mites

Drone brood sacrifice – drone trapping

Queen trapping

Artificial swarm technique

Shook swarm technique

Screening bottom boards – sticky boards.  With a moderate to heavy mite infestation the sticky board will have 150 to 500 mites stuck to it.

Others

Reducing drifting

Common differentials

 

Varroa –much bigger

Zoonosis

None

 

 


Life cycle of Tropilaelaps

From this a generation time can be calculated:

Time

Event

Time

Event

7.5 days queen would emerge

2 days

Male laid

8 days

Male matures

 

3 days

Female laid

9 days

Females matures

 

4 days

Female laid

10 days

Females matures

 

5 days

Female laid

11 days

Females matures

 

6 days

Female laid

12 days

Females matures

12 days worker would emerge

7 days

Female laid

13 days

Females matures

 

8 days

Female laid

14 days

Females matures

 

9 days

Female laid

15 days

Females matures

14.5 days drone would emerge

10 days

Female laid

Female not mature in time to be mated

 

This explains why the queen larvae are rarely infested with Tropilaelap mites, but the longer pupation of the drone allows for large number of mites to reach maturity and fertility, but the effect is less than noticed with Varroa.

On average, the female mite produces 4 new female (as well as herself) for each worker larvae infested and 7 female mites for each drone larvae infested.

There can be many different female mites infesting the same larvae at the same time- 14 have been recorded.

It is even possible for new females to produce a mated female offspring before drone mature.