Bee health and varroa

Cliffe Castle Bee Blog #21 2023

Today’s inspection by Steve and myself clearly demonstrated the relationship between food availability and the queen’s rate of lay. We now have five frames containing eggs, larvae, and sealed brood, with traces of nectar glistening on most combs.

Our valiant red queen was keen to show off her agility, balancing precariously on the woodwork of the last but one frame to be returned to the hive after the inspection. She has started to lay on one of the outer frames now, so if you are visiting the museum this week, you may well spot her.

This week our Beekeeper by the Hive really is Andy (with apologies to Mike who I failed to name check last time!). Just one more Tuesday session to go (29th August) before we need to return the Cliffe Castle bees to our ABKA apiary for the winter.

A bit about varroa

One of the reasons we remove the bees at the end of summer is to allow us to check their health - specifically to check the number of varroa mites in the colony and apply treatment if needed.

The varroa mite (a non-native species that arrived in the UK in the early 1990s) has entirely changed the practice of beekeeping. It is now endemic throughout the UK and most of the world, with very few exceptions.

Varroa mites breed very rapidly within a honeybee colony, feeding off an organ in the larvae and adult bees called the fat body. This acts as a food store and also filters toxic waste from the bee’s equivalent of blood. It helps adult bees that survive the winter to act as nurse bees in the spring and feed the new season's young until they are ready to assume nursing duties in their own right.

So, the varroa mite weakens a honeybee colony because of its diet and because mites pierce the inner tissue of the bees to feed. This means they can transmit various viruses that affect honeybees directly into the bee’s body, rather like giving the bee a concentrated injection of a virus. For this reason, the varroa mite has amplified the effect of some conditions that honeybees were able to tolerate before varroa arrived in the UK.

Linda

Some pictures of varroa below... (with apologies to anyone who doesn't like creepy crawlies...!)

This is a picture of an adult female mite ready to enter a cell on the comb and lay her eggs. She is about 1.5mm long. © Crown Copyright

Here mites are clearly visible on the body of an adult bee and the comb. The bee’s wings have been affected by a virus transmitted by the mites when she was still growing. This colony is suffering a very heavy mite load and is most probably going to die out. © Crown Copyright