Introduction

Another exciting week has flown past and the good weather has given way to a day of steady rain. The weeds will love it! The bees don’t mind it much today either and are pollen- collecting would you believe.

My small grandson Leo (17 months) has discovered the magic of bees and when he takes my hand saying ‘sh sh’ and leads me to the side of the house, I know that he wants to visit the observation hive– again– and put his hand on the glass to feel the warmth and see the bees moving. There are so many bees now that I think that they will swarm soon so I watch for queen cell development. We stop at the hive of wild bees first to watch them fly in. Louise brought over a tiny bee suit that is too small for Charlotte but will keep Leo safe though still very big for him. I guess nobody makes bee suits for toddlers.

Native Dark Honey Bees

Matthew Richardson from BeeBytes in Edinburgh emailed with the results of the genetic testing of the drone pupae I collected from the wild colony rescued from the church roof near Loch Ness. They are 96% M lineage meaning that they are as near native Apis mellifera mellifera as you can get in the wild I think. At the moment they are thriving and want to swarm having started off a couple of months ago as a tiny colony on new comb. They were rescued by a professional bee remover after 40 years of colonies inhabiting the church roof space and sending honey dripping down onto the congregation. To reduce disease risks, Mac gives rescue bees new foundation and syrup feeds right away. This colony has never been treated for varroa and, so far, the total mite count for June is 13. They are also chewing out some pupae which is a sign of hygienic behaviour. They are easy to handle and I love having them in the garden.

I asked Matthew about the dilution of this great lineage over time since I don’t plan to buy in pure Amm queens or do anything different in my apiary apart from requeening a couple of colonies with this stock. He reassures me that they will probably remain fairly high, in the 90-96%, region for some years, but of course nobody can predict and I will need to have them tested again in a few years.

M/C Lineage Admixture Assay

This assay analyses a number of variations in the bee’s DNA, known as SNPs (single-nucleotide polymorphisms). These SNPs have been shown to differentiate the two main honey bee lineages present in Northern Europe: M – mellifera, and C – carnica/ligustica.

The collective result of the allele frequencies measured across the assay is provided as a “global ancestry estimate”, indicated in the top figure. For reference, the stacked bar chart shows the M (black)/C (yellow) lineage allele frequencies at each SNP that passed a certainty threshold. SNPs with allele frequencies that do not pass this threshold are low-confidence, coloured grey and light yellow, and do not contribute to the global ancestry estimate. The y axis ranges from 0 (100% C lineage) to 1 (100% M lineage), providing an indication of admixture levels at discrete regions within the genome. Where a bar is empty that SNP either failed to call for the sample in question, or was excluded from the assay.

Honey Bee Lineages

The Western Honey Bee – Apis mellifera – is native to Africa, Europe and western Asia. It can be subdivided into 5 main evolutionary lineages:

• A – subspecies from central and southern Africa.
• C – subspecies from east and south of the Alps.
• M – subspecies from northern and western Europe.
• O – subspecies from western Asia.
• Y – subspecies from Ethiopia.

Throughout much of Europe the M and C lineages predominate. Rare occurrences of the other lineages can be found where they have been introduced by beekeepers.

Map showing the estimated natural ranges of the M and C lineages prior to human intervention.

Adapted from A revision of subspecies structure of western honey bee Apis mellifera.Ilyasov et al. 2020.

Over the last century, high levels of colony movement by beekeepers seeking to develop strains with desired characteristics has resulted in high levels of genetic admixture. Consequently, many colonies are now composed of, or exposed to bees of admixed ancestry. In some areas of the UK and elsewhere reduced levels of admixture can be observed, either through isolation due to landscape topography, reduced beekeeping activity in the area, or through a conscious effort of beekeepers in the area to conserve a particular lineage – such as the dark honey bee on Colonsay (Scotland) and Ouessant (France). The extent of admixture throughout the UK is poorly documented, and through this assay your bees are contributing towards improving our understanding in this area.

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Varroa

I continue with the daily recording of both mature and immature varroa drops on the floor boards. Louise set me up with a spreadsheet and you can see the neat graph. The bar chart is based on BeeBase’s calculations of daily (mature) varroa drop x 30 this month for estimation of live varroa in the hive. BeeBase suggests 1,000 varroa is the threshold above which the bees are harmed, but, of course, there are many other influencing factors including pesticides, malnutrition, infection and other diseases which can mean even lower varroa levels may be very bad for some colonies. Two colonies have yet to make swarm plans, and hive 7 is going to have a brood break soon ( instigated by me) if there are no queen cells on the next inspection and I have to remove the queen to a nuc box. Hive 7 has the largest number of estimated varroa shown in green on the left. The colours in the two charts do not correlate, and that will be sorted soon, but you can get the general idea of what I am trying to achieve and how I can tell at a glance what the colonies are doing varroa-wise.