Tropilaelaps: how to spot and report the pest

Tropilaelaps is a notifiable bee pest. These bee mites are native to Asia and have been spread from their original host the giant honey bee to the European honey bee. They are serious parasitic mites affecting both developing brood and adult honey bees.

Clinical signs

Tropilaelaps causes damage similar to varroa, resulting in irregular brood patterns and stunted adults with deformed wings and shrunken abdomens.

The mites are thought to be unable to survive in broodless colonies. Parasitisation by these mites can cause abnormal brood development, death of both brood and bees, leading to colony decline and collapse, and can cause the bees to abscond from the hive.

Colonies heavily infested with either Tropilaelaps or varroa show similar damage. The infestation and feeding activities of the mites causes brood mortality and a reduction in the lifespan of any adult bees that survive the parasitized brood stage. Individual bees infested during their development that survive to emergence may show signs of physical or physiological damage as adults. These include a shorter lifespan, lower body weight, with shrunken and deformed wings and legs. These bees may be seen crawling at the entrance to the hive.

Other signs include: irregular and poor brood patterns with patches of neglected brood and perforated cappings (due to worker bees attempting to clean out sick or dead larvae); in severe infestations up to 50% of the developing brood may be killed (in some infested colonies there may be so much dead brood that you will notice the smell of decaying pupal and larval remains). At this stage colonies may abscond and so aid the spread of the mite.

How tropilaelaps mite are spread

Tropilaelaps is spread by the importation of bees. The mites are mobile and can readily move between bees and within the hive. However, to move between colonies they depend upon adult bees for transport through the natural processes of drifting, robbing, and swarming. Mites can spread slowly over long distances in this way. They are also spread within apiaries through distribution of infested combs and bees through beekeeping management. However, movement of infested colonies of Apis mellifera to new areas by the beekeeper is the principal and most rapid means of spread.

Human health implications

There are no human health implications because the disease is not zoonotic.

Legislation

The Bee Diseases and Pests Control (Scotland) Order 2007

Biosecurity

Beekeepers are encouraged to undertake heightened vigilance, good biosecurity measures and hygiene procedures, as these are two key actions that beekeepers can take to help control this disease. Useful information is available to beekeepers on the SBA website and BeeBase.