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The Fauna Of Tunbridge Wells And Rusthall Commons - Part 6

Female mining bees often make great efforts to conceal their nests from predators, carefully opening and sealing them as they travel to and fro with supplies. However, this does not protect them from the cuckoo bees whose females are highly skilled in detecting other bees’ burrows so that they can lay their own eggs inside and save themselves the trouble of gathering their own stores of food. Every species of mining bee has a particular specialist cuckoo species which is attached to it, roaming around its nesting sites in search of opportunities. The smaller mining bees have associated cuckoos of the genus Sphecodes, which are red and black in colour, but the larger varieties are parasitised by the more conspicuous nomad bees. The nomad bees, which can often be seen in spring exploring the areas where mining bees congregate, have a close resemblance to wasps. One of the commonest, the Red-horned Nomad (Nomada flava), has yellow, black and brown bands, and three vertical red stripes on the thorax. The body of the larger Six-banded Nomad (N. fulvicornis), one of the Commons’ rarities, is pattterned entirely in yellow and black.

Nomad Bee

Later in the year, the mining bees are joined by various smaller groups, some of which make their nests in rotten wood. The Red Carpenter Bee (Osmia rufa) has light orange fur on its abdomen, while the Blue Carpenter Bee (O. coerulescens) is of a dark metallic colour. The females of the Commons’ three species of leaf-cutter bees (Megachile spp.) use their powerful jaws to cut semicircular pieces out of leaves. They use these to make a series of individual cells in their burrows, filling them with honey and pollen for their young. The pieces of leaf are folded into a cylinder, with smaller round portions serving as a base and lid. Female leaf-cutters have a rather flattened body with a brush of coloured hairs underneath for carrying pollen. The scarce flower bee Anthophora quadrimaculata, which resembles a small brown bumblebee with a swift darting flight, is exclusively devoted to flowers of the labiate family, which it visits in company with the larger orange-tailed A. furcata and the yellow-spotted Wool-carder Bee (Anthidium manicatum).

Solitary wasps do not generally become active until June or later. Many species nest in similar locations to those favoured by mining bees, while others burrow into dead wood and can be found exploring sunlit timber. In contrast to the bees, these wasps provide live food for their young. The largest group, the digger wasps, show a wide range of size and colour pattern, some having the typical wasp pattern of yellow and black stripes, while other species are red and black, or all black. The nesting females capture flies, beetles, caterpillars or other insects, according to the preference of each species. They prepare their captures for use by the expedient of paralysing them with their sting, so that the victims remain fresh but unable to escape from the burrow while the wasp larva hatches from its egg and begins to devour them. Among the more conspicuous ground-nesting species, with substantial colonies around Wellington Rocks and Toad Rock, are the yellow and black Cerceris arenaria, which hunts for weevils, and the red and black Astata boops, whose prey is shield-bug nymphs. The spider-hunting wasps, red and black or all black in colour, have similar habits to the digger wasps, but specialise in the capture of spiders. They are agile and fast-moving insects which run rather than fly as they seek out their prey.

As with solitary bees, the digger wasps and spider-hunting wasps have their associated cuckoo species which intrude into their stocked nests and lay their eggs there. These parasites include several species of ruby wasps, which are among the most attractive and exotic-looking of British insects. They are active only in bright sunshine and are brilliantly metallic, coloured in various combinations of green, ruby red and deep blue. The most beautiful of all, Chrysis viridula, is most often seen on Rusthall Common, exploring the nesting sites of its host the Spiny Mason Wasp (Odynerus spinipes), which is distinctive in its own right by reason of the curious curved mud chimneys which it constructs over the entrance to its burrows in bare vertical sandy surfaces.

Although numerically abundant, social bees and wasps are much fewer in number of species than their solitary cousins. On the Commons, the most widespread are six species of bumblebees, whose furry coat enables them to fly in cold, dull or rainy weather when most other insects are immobilised. Like all insects that live in colonies, each species is divided into three castes: queens, males and workers. The queens are the fertile females and founders of the colony, surviving the winter by hibernation and emerging as early as possible in the new year to establish their nests, either in holes in the ground or in dense vegetation. The nest consists of a ball of dried grass or moss, in the centre of which the female builds wax cells for her eggs.

Page last updated: 22/01/07