When you think of bees, you probably think of two different kinds – I know I used to! The big fat fuzzy ones – Bumblebees, and the skinnier ones which look similar in shape to wasps – Honeybees.
It wasn’t until a couple of years ago that I realised that there seemed to be other bees visiting the flowers in the garden. I knew they weren’t Honeybees – I’ve been a beekeeper for 5 years so that’s one species I can comfortably identify! And they were way too small for Bumblebees – so what were they?
A little research told me that they were solitary bees. And to my surprise, my reading told me that there are about 270 different species of bee in the UK, and around 250 of those are solitary bee species. So Honeybees and Bumblebees are actually the minority.
Honeybees and Bumblebees are social bees – they live together in a colony comprising of workers (females), males and a queen. Solitary bees, as the name suggests, live alone, though they can sometimes nest in close proximity to others of their own species, giving the impression that they are part of a large colony – as seen in the photo below. This is a large group of nest tunnels used by Mining Bees.
While in social bee colonies young bees are born and raised by their siblings and live as part of a community headed up by a Queen, Solitary Bees go it alone from day one. During the chill of Autumn and Winter, an egg is forming into a baby bee. It was laid the Summer before in a nest chamber by a mother bee who will never meet her offspring, and sealed in with a stockpile of pollen left as food. It will become a larvae, then slowly undergo the metamorphosis needed to turn into a bee. One Spring day it will hatch out – and spend the Summer following repeating the cycle, and so laying the foundations for the next generation of it’s species.
While this aspect of the lifecycle are common to most species of Solitary Bee, in most other ways they are a staggeringly diverse group of species in terms of their appearance, living conditions and behaviour. Some nest aerially, in holes in wood or plant stems, others choose to site their nest underground or even in old snail shells! Nesting chambers can be sealed with mud, leaves, plant fibres or resin. They will collect pollen and nectar from almost any plant or from a single species. This they will carry on their legs, on their abdomen or some will ingest it as they lack any apparatus to store the pollen they collect externally. They can range in size from a few mm long to 15mm. They can be all black or red and black, be yellow and black like social bees, and seemingly any colour inbetween. Some species are a metallic green or bronze, and some have beautifully multicoloured eyes. Most only fly for a few weeks, but the different species flight seasons are spread across the year so there are usually Solitary Bees on the wing from March to November.
There are even ‘cuckoo bees’, who (and the clue’s in the name here) don’t fashion their own nests but lay their own eggs inside nest chambers carefully prepared by an unsuspecting mother bee for her own offspring. Different species of Cuckoo Bee will parasitize each species of Solitary Bee, to ensure that the larvae will develop at a similar rate and that the pollen stores in the host bee nest chamber are suitable for the cuckoo.
The more I read, the more I wanted to know! Before I knew it, I’d fallen head over heels for the tiny creatures, and I’ve tried to focus a lot of my efforts in developing the garden on making a suitable environment for them. Here I’ll cover some of the species of Solitary Bee that I’ve come across over the past 18 months in my garden and elsewhere.
Mining Bees (species Andrena) are one of the first species of Solitary Bee to emerge in the Spring and the last to fly in the Autumn with some species emerging in March and the Ivy Bee in September. As the name suggests they nest in the ground, and a suitable spot will often see many nest tunnels in use, giving the impression that the bees are in a colony. I was lucky enough to see this male hatching from his nest tunnel on the bank of a lake in a local nature reserve. The entrance to his tunnel had actually been partially blocked by a large stone which we carefully removed to help him emerge from his nest tunnel for the first time.
Different species of Mining Bees nest in different environments, from bare soil to lawns to golf courses to sand dunes. They collect pollen on their legs, a build up of which can make them look like they are wearing pollen pants –
Mason Bees (Osmia species) nest in various places, such as holes in wood, plant stems and old snail shells. They can often be seen in garden bee hotels, where they plug up holes with mud, behind each cap will be several chambers containing developing bees.
These cappings were made by a Red Mason Bee, we’ve had these large bees in the garden for the past couple of years but this is the first year that we’ve had more than one chamber in the bee house filled – I’m hoping this means we have lots more next year. These are normally one of the first Solitary Bees that I see in the garden and that’s when I know that Summer is on the way!
This year we’ve also had Blue Mason Bees, the females of which are dark, glittery blue. The males are really striking – a bronze and gold colour with multi coloured eyes. They seem to enjoy sunbathing on the roof of the bee hotels on Sunny days.
Mason Bees are remarkably efficient pollinators, and are said to be more effective than Honeybees or Bumblebees especially for fruit trees. Their value as pollinators is now being recognised and they are sometimes used for commercial pollination in orchards.
Species Lasioglossum and Halictus, these are small bees that most often nest in the ground. They collect pollen on the legs or abdomen. Males are easily identifiable due to their long antennae and slender abdomens. They are also called ‘Sweat Bees’ as they are said to be attracted to sweat. They seem to be attracted to a range of different flowers but they adore Ragwort – we have a clump in the garden and if I wait by it on a sunny day in the Summer it won’t be long before a Furrow Bee turns up.
Species Megachile, these bees cut small holes out of the edges of leaves to seal off their nest chambers using their fearsome looking mandibles.
If you notice crescent shaped holes in the edges of the leaves on rose bushes, Leafcutter Bees are probably the culprit! They fly to the nest site with pieces of leaf which they will cut up further and mix with saliva to make a sticky paste to seal the entrance with.
They collect pollen on their abdomen which then takes on the colour of the pollen they have collected as seen here.
Leafcutter Bees often nest in holes in wood, and so are the other species often seen in garden bee hotels. I often see them collecting pollen in the garden, but have not known them to nest here yet. I planted a rose bush this year in the hope that ready access to both pollen and nesting materials would tempt them to stick around! We’ll see how well this works next summer.
Yellow Faced Bees
Hylaeus species, these tiny black bees take their name from the yellow or white markings on their faces. They move like lightning and seem quite shy – other species don’t seem to mind me sticking a camera in their faces, these – not so much.
Yellow Faced Bees collect pollen and nectar in an unusual way – they lack any apparatus to store this on their outsides, so collect it in their crop – a muscular pouch near their gullet used to store food temporarily.
I found this one standing uncharacteristically still one day last year, and I noticed that it seemed to be ‘blowing a bubble’. It is regurgitating the pollen/nectar mix that it has collected – the sun warms the bubble and concentrates the mixture. Quite a unique space saving technique – IKEA eat your heart out!
I’ll write in more depth about some of these bees in further posts, and the things I’ve done to try to encourage them to call the garden ‘home’.