It is the last week of October, as I watch a “Common Carder Bee” gathering nectar and pollen for her winter store. She is a young queen. The “Carder Bee” is usually the last Bumblebee that we see in the UK, before temperatures drop.
The ginger hairs on her thorax serve as a woolly waistcoat. She will need that as she prepares to survive winter. The black hairs on her abdomen give her a striped appearance.
Her hibernation spot is usually in tussocks of grass, or mossy mats.
This bee would have hatched within the past 4 weeks. She will already have mated with a male, who will die before winter. He only lives a few weeks as an adult. Usually a queen mates with only one male, who inserts a plug to prevent another male fertilising “his queen”. The sperm is stored in her spermatheca, where it remains viable for many months.
“Carder Bees” have long tongues, and enjoy plants with tubular florets. Her metabolism will slow as temperatures drop, and she will depend on her fat stores to survive through to Spring.
When the weather warms, she will awaken, and find a suitable nesting place. This could be underground, in an old mouse run, above ground level in an old bird’s nest, or, more commonly, amongst moss on the ground.
She will collect moss and dry grass and comb it with her legs, to form an outer nest layer. This is known as ‘carding’. Liquid wax is produced from glands on her abdomen. From this, she creates thimble shaped wax cells, which harden to protect her first eggs. These are all fertilised with sperm stored since the previous autumn. There are about 15 cells in number. She also makes wax cups to store pollen and nectar, as food reserves.
The queen does not leave the nest, as she incubates the eggs. She feeds from the cups of stored food. After 4-6 days, the eggs hatch into small larvae. These are fed by the queen, who is now busy flying from the nest, and finding more pollen and nectar. The larvae moult several times as they grow, before pupating after 12-14 days. Within the pupa, an astonishing transformation takes place. After two weeks, the first adult bees emerge. These are sterile female worker bees, which are small in size due to limited food supplies. Some of them remain to clean and guard the nest. They take over from the queen in construction duties, as she lays more eggs. Others workers fly off to get more food, to feed the growing number of larvae. From this moment, the queen does not leave the nest again, until she dies in the autumn.
By August, there will be 60-150 bees in the nest, which will have a diameter of 15 to 20 centimetres. At this time, the queen stops producing female workers. These female worker bees have been infertile all summer. This is due to two things. The queen produces a pheromone, which affects the larvae, making them infertile. Secondly, their diet is poorer in early summer.
By late summer, the queen is getting weaker. She produces smaller amounts of ‘infertility pheromone’ than before, and food supplies for larvae have improved. The result is that some female bees now hatch with ovaries, and can produce eggs. The queen’s store of sperm runs out, and she starts to produce unfertilised eggs.
She is now competing with young healthy worker bees, who are producing some eggs as well. The eggs are now all unfertilised and these develop into fertile males. A battle between the girls takes place, with the queen eating some of the worker eggs, and vice versa. The queen head butts the workers, and pulls their legs, trying to remain dominant. She also produces a fresh pheromone, which affects some of the workers, by preventing their ovaries maturing, leaving them infertile. They continue to maintain the nest. The result is that the queen produces the majority of the males, but 10% of the males in fact develop from worker eggs. Some of these fertile female workers leave the nest and mate with males from other nests. These are the new queen bees.
To summarise this difficult concept, an egg fertilised by sperm stored by the queen will contain two sets of chromosomes. These are ‘diploid’ and develop into females (workers, and later, queens).
An unfertilised egg, contains only the mother’s chromosomes. These are called ‘haploid’, and these develop into fertile males, sometimes called ‘drones’.
This means that male bumblebees have no father.
The genus name ‘Bombus” comes from the Latin word for ‘buzzing’.
‘pascuorum’ is from Latin ‘of the pastures’.
‘Carder’ is from the nest making process of combing moss and grass. A ‘comb for wool’ was called a ‘card’, and a cleaning process in the textile industry is known as carding.
In Charles Darwin’s “Origin of Species” (1859) this insect was called the “Humblebee”.
The name shifted to ‘Bumblebee’ in the 20th century, partly influenced by Beatrix Potter’s “The Tale of Mrs Tittlemouse”.
Simon Papworth NOV 2025
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