Wax moth in the hive.

A talk by Zoë Mack, Beekeeper and Research Technician at University of Exeter, and Dr James Pearce of the Galleria mellonella Research Centre.

Held at Kilmington Village Hall, 3rd April 2025. 38 attendees.

The title of the talk was IPM – bees, moths and science. Zoë would explain the What, How and Why of integrated pest management and James would introduce the work of the Galleria mellonella research centre with special reference to potential disease transmission in the hive.

The University of Exeter use the COLOSS honeybee research standard practice so that results are comparable with other research using the same protocol. COLOSS (Prevention of honey bee COlony LOSSes) is an international, non-profit association based in Bern, Switzerland that is focussed on improving the well-being of bees at a global level. These scientists are working towards a better understanding of the reasons why bee populations are threatened in today’s world.

In order to effectively use IPM we must first scientifically define the pests, pathogens, parasites and control methods, as well as features such as any resistance to control measures that may occur. This may sound rather daunting but, for hobbyist beekeepers, all the information you require is available on BeeBase, the National Bee Unit website. Just to remind you of the notifiable pests and diseases:

• The foulbroods EFB and AFB (bacteria).
• Predators – Vespa velutina nigrithorax (Yellow-legged Asian hornet).
• Pests – Varroa destructor (mite).
• Exotic pests – small hive beetle Aethina tumida and Tropilaelaps mites.

Overall, honeybee problems include:

• Viruses (e.g. deformed wing virus, chronic bee paralysis virus)
• Pests (e.g. greater and lesser wax moth, Varroa destructor)
• Fungi (e.g. chalk brood)
• Bacteria (e.g. AFB, EFB)
• Predators (e.g. Yellow-legged Asian hornet)
• Parasites (e.g. Nosema / Vairimorpha)

* Images courtesy The Animal and Plant Health Agency (APHA), Crown Copyright

How we quantify these invasive organisms depends on the species characteristics. For example, Varroa mites can be counted as natural mite drop per day and compared with standards, but, as hobbyist beekeepers, pathogens may only be detected by observing the physical signs of their presence.

Control is also species dependent. Using Varroa again, mites may be removed by physical means (mesh floors or drone brood removal), but pathogens may require removal of infected brood (e.g. shook swarm) or in the worst-case scenario, removal of the whole colony (e.g. destruction of AFB).

Understanding the essentials of IPM requires the beekeeper to be conversant with the various pests and the legal means of dealing with each of them. As a general principal, “Make it easy for the bees”. Try to use control methods that do not stress the colony.

IPM Methods ethos

Honey bees are generally well adapted to coping with pests and diseases, within reason, but are limited by their physiology. Beekeepers are limited by legislation and experience. Ideally, treatments and interventions should be minimised, consistent with achieving the desired result. To do this, it is essential to monitor and record interventions. As the name suggests, the basic principle is to use several different methods over time to achieve the desired outcome, thereby minimising resistance build-up.

Cleanliness

Cleanliness was a topic that Zoë spent some time on. Regular comb replacement was high on the agenda. For a brood frame, two to three years should be considered the maximum life. Wax and frames can be recycled. Hive tools, smoker and clothing need regular washing/cleaning. 20% solution of washing soda is the usual means of removing wax and propolis which harbour pathogens. Bleach is another commonly used sterilant. Read the article on preparation and use of bleach solutions on the Apiary page.

Beekeepers also need to be aware of hive conditions. Successful IPM may hinge on factors such as temperature during treatment, for example. Treatments should be carried out according to the manufacturer’s instructions.

The science of EFB and wax moth

European foul brood (EFB) is one of the notifiable honeybee diseases, caused by a bacterium called Melissococcus plutonius. The bacteria invade the bee gut and multiply by many millions. Contaminated bees will pass on the infection to other bees via cleaning and trophallaxis activity. There is a suggestion that it may not just be honeybees that contribute to the spread of EFB, (see later).

Greater wax moth

Galleria mellonella, the greater wax moth, is a pest that lays large numbers of very small eggs in any crevices within the hive, making it difficult for bees to find and remove them. The larvae prefer the dark comb that contains the remains of pupal casing and can reduce the comb to a pile of debris, wax moth frass and webbing. They will even make shallow grooves in the wooden parts of hives before pupating. The lesser wax moth, Achroia grisella, also live in UK bee hives.

James described the life cycle of Galleria mellonella. Eggs hatch in about 1 week. Larvae feed, first on honey, then on comb, pupating in 4 to 7 weeks. They then hatch after another week into male and female moths. Mating and egg laying complete the cycle.
These organisms are used in bee and medical research in a variety of ways at the Galleria mellonella Research Centre (GMRC).

GMRC is dedicated to promoting the use of Galleria mellonella as an alternative to using rodents and other mammals for scientific experimentation. They are developing a comprehensive biological toolkit to facilitate wider uptake of this novel model system. As an example, they are working to validate an alternative method of assessing snakebite pathologies using Galleria mellonella larvae. It has also been demonstrated that Galleria mellonella larvae can break down plastics, an ability that may find uses in environmental clean-up operations.

Waxmoth behaviour

Our speakers showed some fascinating video clips of wax moth and bee behaviour. The first was a group of bees struggling to remove a dead moth from the hive. Wax moth larvae are large compared to a honeybee worker. Despite the obstacles, they eventually succeeded. Another clip showed just how fast the larvae can move across the comb, making it difficult for the bees to control them.

EFB and wax moth

Honeybee-associated pathogens can be found in over 50% of all native bees and wasps. We must also remember that beekeepers keep honeybees in an unnatural environment and make unnatural demands on them, which in turn, increases stress levels.

University of Exeter research project

The proposal: Collaboration of beekeepers’ experiences and scientific research will hopefully improve IPM methods through better understanding.

M. plutonius has been found to be carried by adult bees, but whether or not the bacterium has other hosts that may propagate infection is yet to be established – though evidence of M. plutonius has been found at the site of Varroa mite wounds in adult drones.”
Q – Where does EFB come from?
Q – Is Galleria mellonella a pathogen host?
Note – AFB has been found in the gut of galleria.
You are invited to take part in the project. We would like your wax moth larvae, please. Help us gain more understanding so that beekeepers can better manage honeybee health.

Those members who attended the talk have now been sent an email from Val detailing how to take part in the collection of samples for this project. If you have any questions, please get in touch with Nick Silver, education@edbk.co.uk.

Links

Galleria Mellonella Research Centre – Home
National Bee Unit – BeeBase – https://www.nationalbeeunit.com
COLOSS – honey bee research association – https://coloss.org/
Home page – International Bee Research Association (IBRA) – https://ibra.org.uk/