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The Fauna Of Tunbridge Wells And Rusthall Commons - Part 5

Common Darter, which is the last to emerge and continues to be active well into November, long after most other insects have ceased to appear. In contrast, the larger dragonflies, of which the commonest are the Emperor, the Broad-bodied Chaser, the Southern Hawker and the Brown Hawker, live a mostly solitary existence. They are fiercely territorial, with individuals commanding a small pond or part of a larger one and driving off any potential rivals. In total, seventeen species of dragonflies have been recorded from the Commons to date, although a number of these are only occasional residents or strays from richer localities on the Sussex border. Such visitors include the Downy Emerald and the magnificent Gold-ringed Dragonfly, the largest British species.

Azure Damselfly

Grasshoppers and crickets form a prominent part of the Commons’ insect fauna, particularly in high summer when the distinctive songs of a number of species can be heard throughout the areas of open grass and heathland. These songs are a means of communication between the sexes, and can be recognized in the same way as bird song. Most of the sound to be heard in summer grassland emanates from the Commons’ three grasshopper species: the Common Field Grasshopper and Common Green Grasshopper, both of which are fully winged, and the short-winged Meadow Grasshopper. Of the bush-crickets, the only one with an audible song is the Long-winged Conehead, a former rarity which has only recently colonized the Tunbridge Wells area. The Dark Bush-cricket and Speckled Bush-cricket live in dense vegetation such as bramble thickets and may be spotted sitting on leaves. The delicate pale green Oak Bush-cricket spends its time high in the trees and is only occasionally seen at ground level, when for example it is blown down by the wind. The Common and Slender Ground-hopper are generally inconspicuous creatures that can sometimes be spotted in numbers on sparsely vegetated ground, often near water.

Walkers on the Commons in high summer will undoubtedly have seen clusters of small holes in the sandy ground of footpaths and around rocks, and may well have spotted insects of various sizes and colours, looking vaguely like bees and wasps, going in and out of them. The more observant may have noticed similar burrows in south-facing drainage ditches, root plates or banks with sparse vegetation from early spring onwards. These small tunnels are the nests of solitary bees and wasps, an often overlooked but important element of the Commons’ fauna. The sandy soil and rock outcrops of the Commons are ideal for these creatures, and many otherwise rare varieties find a refuge here. Over a hundred and thirty species have so far been recorded, including eighteen on the official national list of scarce and endangered species.

Solitary bees and wasps are so called to distinguish them from their ‘social’ relatives which live in communities with a breeding queen and sterile workers. Although solitary species often nest in close proximity, congregating in particularly favoured spots, each female digs its own individual burrow and stocks it with suitable food for its offspring. The earliest species to appear are the mining bees, some of which can be active even in late February while most are at their peak in March and April. The females dig burrows in bare or sparsely vegetated ground, which they stock with honey and pollen before laying their eggs. They are especially fond of south-facing areas such as Pope’s Terrace Walk, the back of Brighton Lake, and Happy Valley. Wellington Rocks and the rocks at Denny Bottom are also favoured sites. Laying in a store of food for their offspring entails numerous visits to and from nearby flowers, so the females can often be seen entering their tunnels carrying clumps of brightly coloured pollen in the baskets of hairs on their hind legs. Mining bees are very diverse in size and colour, the largest being about the size of a honey bee, while the smallest are not much bigger than a large ant. The most spectacular, the Tawny Mining Bee (Andrena fulva), has bright orange fur on its hind body, while the thorax is deep scarlet. Other species frequently observed in spring include the Early Mining Bee (A. haemorrhoa), which has a golden tip to its body, the Yellow-legged Mining Bee (A. flavipes), which has a golden pollen basket and pale brown bands, and the very early flying Andrena clarkella, with black fur behind and red in front. Among the few which fly in summer is the white-banded Colletes succinctus, always seen visiting heather. Female mining bees are generally more distinctive than males, but the light grey males of Andrena barbilabris often make themselves conspicuous by flying low over areas of bare sand.

Page last updated: 22/01/07