Solitary bees and wasps

“Some of the smallest we may see in the UK may be just 3mm in length,” said Ivan Wright, who is a recorder in Oxfordshire for wasps, bees and their relatives the ants.

Mr Wright is also chairman of Shotover Wildlife, the volunteer organisation which was founded to research and communicate the importance of Shotover Hill for wildlife. There, he has an ideal series of habitats in which to study aspects of insect life — which for him has become a source of great pleasure.

“I am very pleased that the insects found me,” he said, referring to the fact that when he first became involved in the conservation work at Shotover it was mentioned to him by fellow entomologist Steve Gregory that somebody should be looking at its wasps and bees, as they are part of its history.

“I said I would give it a try,” he recalled, “and I just got drawn in. It is very satisfying to have done that work on Shotover, for it is a nationally important site.

“I enjoy these creatures, they are a fascinating group of insects. People do not recognise the smaller wasps and bees as such, so do not fear their sting. In colouring they may be black, some are metallic green, some red and black and they may be hairy or not hairy.

“These are solitary wasps and bees, without the social structures of others such as honey bees and bumblebees, those with that wonderful ability to build a colony from scratch, colonies which eventually become very large.”

Among the solitary bees, the female digs a hole for a nest in which she lays her eggs. She fills the hole with a supply of pollen as food for the larvae when they hatch, and she will continue digging and filling further holes.

After hatching, the young may over-winter as larvae or may pupate and over-winter as adults.

Among the wasps, only nine species in Britain are of the yellow and black colouring. Of the solitary wasps, there are very many more species, in colours such as red and white, black and white, and all black.

Like ladybirds, they should be given a welcome in the garden, for their larvae, being carnivorous, will help to control aphids and weevils.

“They are one of the checks and balances among the insects,” said Mr Wright.

While the wasp larvae are carnivorous, bee larvae feed on vegetable matter.

“Apart from that, they are very closely related, and it is difficult to tell whether something red and black and only about 5mm long is a bee or a wasp,” said Mr Wright.

“It is not very easy to see any differences apart from the fact that the bees are much more hairy.”

Where recording is concerned, there are both the historic species on Shotover and new arrivals to observe. Among the newest arrivals is the bee wolf wasp.

In the 1990s it was known only on the south coast of Britain, and specifically on the Isle of Wight. By the early years of the 21st century however, it was being seen in two locations in Oxfordshire, one at Abingdon and the other, in 2002, at Shotover.

“Its northward migration might be due to climate change — or there could be some other reasons,” said Mr Wright.

Like other solitary bees and wasps, it is a burrowing insect, and Shotover can provide it with suitable habitats — and ones more reliable that those it would have found on the coast, which would be subject to erosion.

“The bee wolf wasp is one which likes to burrow horizontally,” said Mr Wright. “As part of its coastline strategy it may have to burrow as far into the sand as one metre, for only about 5cm of its home may be left when it emerges after hibernation.”

Small solitary wasps and bees can look quite like ants — and these are another source of infinite interest. There is much more to be known about them than their habit of gathering in large numbers around household doorsteps.

“Fifty species of ant can be found in Britain, but only nine have been recorded on Shotover Hill,” said Mr Wright.

“Quite a few species are quite rare, and most people are only likely to see a few of the ant species. Quite a lot are very specialised as regards their habitats, and you have to know where to look for them. Some are hosts for other ants and you can only see these by looking in the nests.”

Those in the nests are the females: the flying ants are the males.

Those we most usually see in our houses and gardens are the black ants (which are actually brown). “They are the ones most commonly seen at Shotover,” said Mr Wright. “They nest underground, and will use other insects, seeds and honeydew for food.”

The worker ants of this species are about 4mm long and can live for up to seven years. They move into houses in their search for food.

Hedges and tree stumps are where the jet black ants are mostly found, in south-east England. These shiny black insects, with yellow legs and heart-shaped heads, may be seen running backwards and forwards on trails that they have made.

The yellow meadow ants, of a pale yellow colour, nest in grassy areas and create the well-known ant-hills.

“They are skilled nest-builders and can control the temperature of the nest and ‘farm’ aphids for honeydew,” said Mr Wright.

“Foraging is done underground, and so the ants are seen above ground only at mating time, or if disturbed.”

Whereas these are one of the smallest ants, only about 3mm long, the negro ants are more than twice this size, and their workers are the largest found at Shotover. They are also numerous, with as many as 1,000 in one colony.

Three species of red ants may be found in this country; they have smaller colonies, about one-third the size of those of the negro ants.

Ants belong to the same order of insects as the wasps and bees, but they have a different structure, which places them in a family of their own — the Formicidae. Like the wasps and bees, they have two pairs of wings which are held together by tiny hooks and which work as a single wing on each side but they differ in their bodies having either one or two extra segments, depending on the individual species.

This ‘petiole’ is placed between the thorax and the abdomen.

Mr Wright added: “I am trying to paste together a picture of the local populations of bees and wasps.

“I would like to hear of any locations where solitary bees and wasps are known to be nesting.”

Mr Wright can be contacted by e-mail at irwright@shotover-wildlife.org.uk or via the website www.shotover-wildlife.org.uk