The Tree Bumblebee Moves North, and Education Online.

Introduction.

This week two of my friends contribute to our further knowledge and understanding of bees. Gelda tells us about bumble bee behaviour and development, and Tony Harris shares his wide knowledge of beekeeping in his recently-set up YouTube channel. Thank you, Gelda and Tony, for supporting the Beelistener and taking the time to share your expertise. I also want to thank both of you for helping me develop my own beekeeping skills. My handling skills, knowledge, and confidence increased markedly during the years Tony and I worked together on delivering the Healthy BEES Courses in Scotland, and I am indebted to him for egging me on and supporting me. Gelda has kept me on my toes in my mentor role as she is curious and keen to learn the “whys”, and delve into detail. Her questions often get me hauling down a textbook from the shelf. It is a real priviledge to teach others and we are lucky if we get the chance.

Gelda.

Gelda MacGregor has had a career in community education, social work, and private therapy, including becoming the first full time Scottish Adult Literacy Co-ordinator in Lothian Region from 1975-80. Gelda moved north to Forres Morayshire in summer 1999 and became a volunteer with the Bumblebee Conservation Trust in 2010. Later Gelda started giving talks on bees to various charitable and church groups. She is now retired and in 2019 decided to try becoming a beekeeper, and has been privileged to have had Ann Chilcott as a mentor since 2021.

The Tree Bumblebee.

The Tree Bumblebee, Bombus hypnorum, has a fascinating story within the British Isles, as it is a recent migrant from Europe who entered quietly and found a very welcoming environment! This has enabled it to prosper extremely well as a formerly unknown, non native species. In fact it has now become one one of the “Big 8”, the most populous bumblebees in England. I will explain why, later in my tale. Currently it can be found in mainland Europe up to the Arctic Circle, but not in the Mediterranean below Tuscany.

The Tree Bumblebee is one of the easiest species to identify (1) as it is a ginger bumblebee, so there is no confusion with the number and location of black and yellow stripes. It has a bright ginger thorax, a black abdomen, and always a white tail. Later in the season some bees can lose the light ginger colouring if they have been bleached by the sun or lose fur, or with occasional melanistic darker forms, but the tail and abdominal colouring are always the same. Like all social bumblebees it has 2 female castes which are queens and workers. Drones are male and are not a caste because their only role is to mate outside the nest and castes are assigned to social bees that have age related tasks and roles within the nest. The tree bumblebee is a social bee, and builds a nest for between 150-400 bees, from March to the end of July. Some queens can go on to create a late summer colony as well. For more information on physiology and thermoregulation check out this page. https://www.beelistener.co.uk/uncategorized/bumble-bees-social-life-thermoregulation/

Features.

The queens, female workers, and drones all look exactly the same, the only difference being that the queen is bigger and the males will have blunter tails. The drones are approximately twice the size of a honeybee worker. It has a short proboscis (tongue) , unlike many other bumblebees, eg. the garden bee. Unusually for bumblebees, the queen is polyandrous and can mate up to 6 times, so bee sisters in a nest may have different fathers (ref. Wikipedia). There are also 2 work divisions of workers: house bees and foragers. House bees will not leave the nest, and as inferiors, are sometimes even bitten by foragers.

Key to Breeding Success.

The key difference is that this species prefers to choose nesting sites off the ground, in trees, shrubs, loft spaces, old mouse nests in garden sheds, or, in many cases, in tit nesting boxes, which offer a wonderfully dry and safe habitat. It is this choice which has lead to its extraordinary breeding success in the British Isles, owing to our human behaviour of providing many bird boxes for our feathered friends. This is a less popular habit in continental Europe, apparently! Tree bumblebees have been known to evict Blue Tits, but they would not face competition from wild honey bees as the nest site would be too small for them. The emerging queen in spring also has a nest search pattern that searches vertically, rather than like other bumblebees zig zagging horizontally just above ground. The Tree Bumblebee now has 3 evolutionary advantages: they nest off the ground ,which prevents any nest failure from sudden flooding caused by climate change; they have no predating cuckoo bumblebee species; the only competition they have for their preferred nest sites is from Blue or Great Tits, and they are likely to get in there first.

Arrival and Dispersion.

The Tree Bumblebee has only been in the British Isles since 2001, when it was first identified on 17 July in Landford, Wiltshire. Since then it has managed a remarkably rapid colonisation, and is now widespread throughout England and Wales. It was first seen in Scotland in Lennoxlove, East Lothian in 2013, and it reached Eire in 2014 (4). In 2017 it was first recorded in Aberdeenshire (2), and by 2020 it had reached Forres, where a Bumblebee Conservation Trust volunteer found a nest in an old Great Tit box. As far as we know, in 2017 there were none in the west Highlands or the Cairngorms. As the species spreads both north and west and into the islands, it is still worth recording a sighting of it, as its progress north is still very much underway in the Highlands. Please send a photo record to BWARS, the Bees Wasp and Ants Recording Society (3), or to the Bumblebee Conservation Trust, via I-Record. Your record is very much worth sending, as its remarkable spread in Scotland is still in progress.

Relevance to Beekeepers.

Where this species is of particular interest to beekeepers, is that swarm collectors or bee keeping associations may be called out by members of the public who believe they have a “swarm” of honey bees either in a tit box, shed or in a roof space. This is because the drones muster in what looks like a swarm outside the colony, and swoop on virgin queens as they fly out from the nest, which again does not occur in other bumblebee species. This is called Nest Surveillance, and may be the first indicator that a nest is there in your garden! As they rarely use the same nest site twice, they are harmless, will not grow into a huge colony, and should be left to breed if possible. Sometimes an occupied bird box will have bee faeces or nesting material messily stuffed on the front, which shows the bees have taken it over.

Forage.

The Tree Bumblebee will forage on a variety of flowers and trees but apparently prefers small pendulous flowers. In March of 2023 I saw a queen Tree Bumblebee, Early Bumblebee Bombus pratorum and Buff Tailed Bumblebee Bombus terrestris feeding with inches of each other on spring-blossoming heather Calluna vulgaris. They also like foraging on raspberries, comfrey, gooseberries, brambles, all heathers, open roses, and cotoneaster. They have been noted foraging on 100 flower species.

References.

1. Bumblebees, an Introduction pub. Bumblebee ConservationTrust, 2018 by Dr Nikki Gamans, Dr Richard Comont, SC Morgan and Gill Perkins.

2. Highland Biological Recording Group

3. Bees, Wasps, and Ants Recording Society website http://bwars.com/identification guides

4.“Tracking 2 bumblebees” from the All-Ireland Pollinator Plan, November 2022

Next Bumblebee Event in the Highlands.

On Sunday 16^th July the Bumblebee Conservation Trust will have a stall as part of “Under Canvas-Eco edition” at Eden Court Theatre, Inverness from 12-2pm. I will be there to chat and answer questions and look forward to meeting you if you can attend.

Tony Harris.

Scottish Expert Beemaster, Ann Chilcott, has been a friend of mine for many years and we have worked together running beekeeping courses throughout Scotland. She is a most fine writer evidenced by her popular Beelistener blog and the many articles she has had published in the beekeeping journals, both at home and abroad.

I turned my beekeeping hobby into a business and the original 3 hives of bees I acquired in 2006 had increased to 150 by 2012. I ran these for honey production on the Moray coast in Scotland and operated a queen rearing programme, also selling nucleus colonies until I retired as a bee farmer in 2020. After a brief hiatus in France, I now live in Spain with my wife Pat, and our 3 dogs. It is far too hot over here to keep bees so I now prefer to talk and write about them with the hope that I can pass on some of my knowledge and help you enjoy your bees more.

I am a Scottish Expert Beemaster and I hold the National Diploma in Beekeeping qualification. I have taught beekeeping at the highest level and given presentations and lectures to community and beekeeping groups, including the UK national events, on all matters relating to bees, beekeeping, and the environment.

After 3 years of retirement, (I know, you don’t think I am old enough to be retired) I am posting instructional videos for potential, improver and advanced beekeepers on my YouTube channel, ‘All About Bees with Tony Harris NDB’. These videos are free so please enjoy with my pleasure. Here’s the link All About Bees with Tony Harris NDB – YouTube

I am also writing beekeeping articles which again you can read for free following this link Tony Harris NDB is posting videos for potential, improver and advanced beekeepers (buymeacoffee.com) If you would like to buy me a virtual beer as a thank you for my time you can follow the link above. It will be very much appreciated and will help me keep both channels going and increase their content.

I would be delighted to hear from you and encourage comments. I promise to reply to any questions you have on any matter to do with bees and beekeeping, and if I don’t know the answer, I will find it out for you. Happy beekeeping, Tony. Adios Amigos.

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