The 256 acres of Tunbridge Wells and Rusthall Commons provide an important and most unusual refuge for wildlife within the urban area. Unlike most public open spaces, they have never been landscaped or cultivated. This is not to suggest that they are pristine wild countryside, something which in any case does not exist in present day England. They owe much of their present appearance to human activity, and active management is required to maintain them in a fashion beneficial to their natural inhabitants. But the Commons nonetheless represent a genuinely ancient landscape, which long ago achieved a state of equilibrium between the needs of humanity and nature.
At the end of the last Ice Age, as temperate conditions reasserted themselves, the vast expanse of the primeval Wealden forest gradually came into existence. Within the forest, open heathy areas would have become established on thin soils, quite probably around the rock outcrops which brought the present Commons to the attention of their prehistoric inhabitants. Deliberate clearance of the forest cover, for hunting purposes, very probably took place as early as the Mesolithic, some 7000 years ago. This would have transformed the Commons into a mixture of open grassland and heathland, with heather and gorse the most conspicuous vegetation, as they remained until the early twentieth century.
Deliberate planting of commemorative and ornamental trees, mainly between 1860 and 1940, led unintentionally to the reestablishment of woodland, as the traditional practice of grazing declined and finally ceased altogether in the inter-war period of the twentieth century. The Commons today consist of a mosaic of habitats, in which surviving areas of heath and grassland, along with the open sandy areas around the major rock formations, coexist with tracts of secondary woodland. Further diversity is provided by a series of semi-natural ponds. Current management aims to preserve this diversity, and a reasonable balance of the different elements, by containing the spread of woodland and expanding the open areas.
The present conservation management programme on the two Commons continues to improve them as a habitat for wildlife, and the long-established resident butterflies and dragonflies are flourishing in consequence. In addition, new species continue to appear. Some of these may have been present all along, but previously in such small numbers as to escape detection, but others are evidently new visitors or colonists for which conditions have now become suitable. It is fortunate for the Commons that the development of Tunbridge Wells has never cut them off completely from access to the open countryside. If they had become isolated islands in an urban landscape, it would have been much more difficult for wildlife from outside to reach them. Tunbridge Wells Common is open on its western boundary to the woodlands and meadows of the county border, and these same extensive habitats are adjacent to the southern edge of Rusthall Common.
The Commons have been noted for many years as a good spot for bird watching, bearing in mind their urban location and relatively small size. In the early 1960s local ornithologist Harold Betteridge listed 36 species nesting on the Commons, and made a photographic record of their nests. Nowadays, around 40 resident species can be found, along with about 15 summer or winter visitors. Familiar garden birds such as the Robin, Chaffinch, Blue Tit, Great Tit and Wren may readily be seen, and there are also records of more elusive relatives like the Bullfinch, Hawfinch, Goldcrest, Linnet and Redpoll. The large numbers of Magpies cannot fail to be observed, and their relatives the Carrion Crow, Jackdaw and Jay are also to be found. One of the most characteristic of the resident species is the Long-tailed Tit, often seen in small flocks moving from tree to tree; its elaborate nests of moss, spider webs and hair, covered with lichen, are constructed in gorse bushes. Groups of the colourful Goldfinch may be observed on occasions feeding at thistle seeds in large stands such as that beneath Mount Edgcumbe Rocks. The Song Thrush finds abundant snails of various species on the Commons, and its characteristic ‘anvils’, stones arising from bare ground and surrounded by shell fragments, can often be spotted along footpaths. The Mistle Thrush is also resident. The Nuthatch and Treecreeper inhabit the various wooded areas, where the occasional Pheasant has also been seen. Nightingales have been confirmed as nesting on Tunbridge Wells Common in the past, and adult birds continue to be reported.
The three British species of woodpecker are all to be found on the Commons, although the Great Spotted and Lesser Spotted are much less conspicuous than the Green. The latter has been noted feeding at anthills in the grassland near Wellington Rocks. Among the birds of prey, examples of the Kestrel and Sparrowhawk have been observed actively hunting in recent times, the former in open spots and the latter in more wooded areas. The Little Owl, Tawny Owl, and Long-eared Owl also have recent records. Few water birds occur on the Commons, but Mallard and Moorhen may be seen at Brighton Lake, and a Kingfisher has been seen there recently. Summer visitors include the ubiquitous Cuckoo, generally heard rather than seen, as well as the Spotted Flycatcher, Chiffchaff, Willow Warbler, Wood Warbler, Garden Warbler and Blackcap. Swallows and House Martins are to be seen hunting insects over open ground such as that between Victoria Grove and Wellington Rocks. Winter visitors include the Fieldfare and the Redwing.
A full list of mammals has yet to be compiled, but several species occur in addition to the substantial populations of grey squirrels and rabbits. Foxes are often to be seen, even in daylight, while badgers forage on the Commons at night from sets situated around the perimeter. Small deer undoubtedly occur on both Commons, although it is unclear whether they are a permanent feature or occasional visitors from the contiguous open countryside. Roe Deer have been seen on Rusthall Common, and there is some evidence for the introduced Muntjac. Mole hills are a familiar feature of some grassy areas such as that near Brighton Lake, and hedgehogs are also resident. Weasels have been recorded on Tunbridge Wells Common, and a Common Dormouse near Toad Rock. The areas of acid grassland with their tussocks and anthills are ideal for small rodents to feed while keeping themselves hidden from predators: voles, mice and shrews all occur, although particular species have not been identified. In the evening bats may be seen, mostly the Pipistrelle, a small and very common species, although the larger Noctule has also been reported.
The heathland environment of the Commons, along with their various ponds, have historically supported a variety of reptiles and amphibians. Despite the more recent decline of heathland, species such as the Common Lizard have managed to survive in more open areas. Lizards are seen quite regularly sunning themselves on anthills or similar exposed situations, although they are easily disturbed and rapidly vanish out of sight among the grass. They are most likely to be spotted in the grassland near Highbury or along Mount Ephraim. The Slow worm, a legless lizard, has also been recorded, but is much more elusive. Another conspicuous reptile is the Grass Snake, which is most often seen near water. It can swim very effectively, and is regularly seen doing so in Brighton Lake. The Adder, a characteristic heathland species, is much less likely to be observed. The most widespread and abundant amphibians are the Common Frog and Common Toad, which breed prolifically in all the ponds on both Commons. The adults may be seen quite some distance from water. The three British species of newts are also found breeding in ponds on the Commons, although the rarer Great Crested in more restricted than the Smooth and Palmate.
Fish occur only in Brighton Lake, where they must originally have been introduced, as this pond was only created in 1858. However, they undoubtedly flourish there, and some surprisingly large specimens are in evidence. The population of sizable Carp is the most conspicuous, but Perch, Tench, Roach and Rudd are also present. A small Pike was recorded recently. Sticklebacks are also to be found.
The most prominent and widespread members of the Commons’ insect fauna are the butterflies, of which twenty-five species have been recorded to date. Some are permanent residents, sedentary species with old established colonies breeding on site generation after generation, while other more mobile species are regular or occasional visitors. The majority of the permanent residents are species characteristic of open grassland and heathland, and at their appropriate season most of them can be seen in areas such as (on Tunbridge Wells Common) the acid grassland along Mount Ephraim and overlooking London Road, the vicinity of Gibraltar Cottage, the north-west corner, and the space between Wellington Rocks and Victoria Grove; and (on Rusthall Common) Denny Bottom, and the grassland at the north-west corner, around the Marl Pits and in front of Rusthall Church. Such butterflies avoid dense woodland, but can be quite numerous along the open fringes of the wider footpaths like Pope’s Terrace Walk.
The earliest of the grassland species to appear is the Small Copper, with its distinctive metallic orange colouration. Emerging in May, it is also one of the latest butterflies to remain on the wing in autumn. The Common Blue also has an early generation, and it too can appear remarkably late in the year. The period from June to August exhibits the greatest diversity of grassland butterflies, with the appearance of five warmth-loving species that produce only a single generation of adults each year, and whose caterpillars feed on grasses. The Small Skipper and Essex Skipper are the most difficult of British butterflies to distinguish, but can be reliably told apart by the tips of their antennae which are orange underneath in the former and black in the latter. The Large Skipper differs in size, as its name suggests, and has an orange patch on the forewing against a darker background. The Meadow Brown and the smaller Hedge Brown or Gatekeeper are characterized by small eye-spots and light forewing patches on a darker brown background. Currently much scarcer than any of these is the Small Heath, a light orange-brown butterfly related to the two Browns but considerably smaller. The recently discovered Brown Argus, recorded only twice, is perhaps best interpreted as an elusive resident. A small brown butterfly with orange spots along the edges of its wings, it is easily mistaken for the female of the Common Blue, but the latter always has at least some blue scales, if only towards the base of its wings.
A common resident with somewhat different habitat preferences is the Speckled Wood, a distinctive butterfly with cream-white patches on a dark brown background which can be found from as early as April to as late as October. Although it breeds in open spots, its larvae feeding on grasses, the adults tend to frequent shady paths through woodland where the males defend territories consisting of a shifting patch of sunlight. The Purple Hairstreak is a much more elusive woodland resident, as the adult spends most of its life high in the branches of oak trees, where it feeds on honey-dew. Its whole history centres around oaks, the eggs being laid on the leaf buds and the caterpillars feeding on the young foliage in spring. This butterfly is characterized by its metallic purple forewing patches, but it is rarely seen at close quarters. The Ringlet, a blackish brown butterfly with distinctive cream-coloured rings on its underside, was first recorded on the Commons in the mid-1990s and may well become a permanent resident. It is most likely to be seen in summer at brambles along rides and woodland edges.
There are a number of more mobile butterflies which regularly breed on the Commons and can be counted as residents, although they are active over a wider area, and individuals move in and out from urban parks and gardens and the adjacent countryside. One familiar group of three species whose larvae feed on nettles are among the first butterflies to appear in spring, as they hibernate as adults on site, concealing themselves in hollow trees and other sheltered spots, from which they emerge on the first warm sunny day of the year. The bright orange Small Tortoiseshell and the Peacock with its multi-coloured eye spots are familiar garden butterflies, but they are equally at home in such wild habitats as are found on the Commons, particularly in more open areas. The Comma, an orange-brown butterfly with irregular outlines to its wings, has a preference for more sheltered spots, favouring wide rides and woodland edges and in the autumn often feeding at ripe fruits like blackberries.
Late April sees the emergence of the distinctive Orange-tip, whose bright orange eggs are surprisingly easy to spot on their main foodplant, garlic mustard. Only the males have orange-tipped forewings, the females being mainly white, but sharing the same mottled green hindwing underside pattern. In flight, female Orange-tips closely resemble the Green-veined White, but when settled the latter’s grey-green veins on the light yellowish hindwing underside are distinctive enough. Unlike the Orange-tip, which has only a single spring generation, the Green-veined White can be found throughout the year. Also present from spring to autumn is the Holly Blue, whose plain silver-white underside with a few black specks is the most obvious feature distinguishing it from the Common Blue. Its larvae feed on holly and ivy, and examples are generally seen along rides and woodland edges where its foodplants grow, rather than in the open areas frequented by its relative.
The lemon yellow males of the Brimstone are a familiar sight on the Commons in early spring. They hibernate as adults and generally appear at the same time as the Small Tortoiseshell, Peacock and Comma, ranging over a wide area. The Large White and Small White are also highly mobile species, their British populations regularly augmented by migration across the Channel. Both are frequently seen on the Commons, and the latter may sometimes breed there on wild members of the cabbage family. The familiar Red Admiral, patterned in white and scarlet on black, is similar to the Small Tortoiseshell and Peacock in its habits and also breeds on nettles, but as it rarely survives the English winter it is not a permanent resident. Its population too is reinforced each year by migrants. The salmon pink Painted Lady is a much less regular migrant, although in favourable summers it has been recorded on the Commons in considerable numbers.
Day-flying moths can often be confused with butterflies, and some are surprisingly brightly coloured. A characteristically early species is the Orange Underwing, which flies in March and April, sunning itself with outspread wings on the ground in the wider footpaths or feeding at sallow catkins. May sees the appearance of the Small Yellow Underwing, a grassland species. The brilliant red and black Cinnabar moth is occasionally seen on the Commons, as is its distinctive orange and black striped caterpillar feeding on ragwort. In high summer, the Six-spot Burnet can sometimes be found flying in open grassland on both Commons, together with various butterflies. This moth has a similar colour scheme to the Cinnabar, but it is distinguished by the array of red spots on a forewing that is black with metallic reflections. These patterns are examples of warning colouration, which vertebrate predators learn to associate with creatures that are distasteful. The Silver Y is a much duller coloured insect, although its intricate pattern incorporating the metallic mark from which it takes its name is attractive on close inspection. Although sharing the nocturnal flight pattern of the majority of moths, the Silver Y is often active during the day as well, feeding at heather and other flowers. The metallic Green Longhorn and its relatives are much smaller insects, but the males with their astonishingly long antennae make themselves conspicuous in spring by flying in dancing swarms around sunlit trees and bushes.
The majority of the moths which live and breed on the Commons are purely nocturnal, and are therefore rarely or never seen by the general public. However, the use of a light trap at a number of locations, mainly on Tunbridge Wells Common, on several nights through 1992 produced a list of over one hundred and fifty species. It is certain that further and more regular trapping would increase the list considerably, and it is likely that most of the six hundred or so moth species recorded from Tunbridge Wells in modern times could be found on the Commons. Although moths have a reputation for being drab and nondescript insects, they are actually extremely diverse in colour and pattern, and a number of those recorded from the Commons are visually impressive creatures. Among the largest are the hawk moths, including the delicately patterned green Lime Hawk, the Poplar Hawk, and the brilliantly coloured pink and green Elephant Hawk. The latter takes its name from the resemblance of its caterpillar, found on willowherb, to an elephant’s trunk. As its name suggests, the White Ermine is pure white with scattered black spots, while its relative, the Buff Ermine, has a similar pattern but different ground colour. The Buff-tip has a remarkable resemblance to a broken silver birch twig when its wings are folded, while the related Swallow Prominent and Lesser Swallow Prominent have streamlined wings with an elegant white and brown pattern. The Brimstone moth, with bright yellow wings, shares its name with a butterfly, as does the Swallow-tailed, a large broad-winged insect of a delicate yellowish shade. Other strikingly coloured species include the Peach Blossom, the Light Emerald, and the bright metallic Burnished Brass.
Brighton Lake, Fir Tree Pond and Bracken Cottage Pond (on Tunbridge Wells Common) and the Marl Pits (on Rusthall Common) all support breeding colonies of dragonflies, although the larger spring-fed Brighton Lake is the most productive. The early stages or nymphs of these insects live as predators underwater, and adult females can often be seen laying their eggs by dipping the tip of their abdomen into the water. Regular breeding species include a number of damselflies, the smaller members of the dragonfly order, of which the most numerous are the distinctive Large Red, first to appear in spring, the Blue-tailed, and the Common Blue and Azure, which resemble each other very closely. The scarce White-legged Damselfly, creamy white in colour, is less often seen. Damselflies fly together, often in large numbers, as does the medium-sized 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.
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.
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.
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, along with containers for storing food. Her first offspring are workers, sterile females which assist in the development of the colony and take over the work of gathering nectar and pollen. The Buff-tailed (Bombus terrestris), White-tailed (B. lucorum), Garden (B. hortorum), Early (B. pratorum) and Red-tailed (B. lapidarius) Bumblebee are all familiar visitors to flowers on the Commons, as is the distinctive brown Common Carder Bee (B. pascuorum). Lone queens seen flying low in the early months of the year are engaged in their search for suitable nest sites. Honey-bees are regularly seen on the Commons too, but these are visitors from domestic hives. Social wasps recorded on the Commons comprise the two familiar urban species Vespula vulgaris and V. germanica, along with the Tree Wasp (Dolichovespula sylvestris) and two related species which have recently colonized southern Britain from the Continent (D. media and D. saxonica).
The other social insects found on the Commons are the ants, one of which contributes a major feature to the landscape in the form of the prominent earthen mounds to be seen in areas of acid grassland such as that around Highbury. These are constructed by the Yellow Meadow Ant (Lasius flavus), and may be many decades old. The ants themselves remain below the surface and are unlikely to be seen unless one of their nests is disturbed. Sections of these old nest mounds are sometimes occupied by colonies of the brown ant Myrmica scabrinodis. Unlike the meadow ant, this and its relative M. ruginodis are commonly seen actively foraging, often high up on grassland vegetation. Most widespread of all, found both in open spots and in woodland, are the subterranean nesting Lasius niger, the familiar garden black ant, and the larger long-legged Formica fusca. It is the latter two species whose winged females are most likely to be noticed by the general public as swarms of ‘flying ants’ on hot days in high summer. These are newly emerged queens engaged, along with the much smaller males, in their annual synchronised courtship flight, after which they shed their wings to retreat underground as founders of new colonies.
Numerous as they are, bees, wasps and ants form only part of Britain’s largest order of insects, the Hymenoptera. The other members of the order are also well represented on the Commons, but most are small and inconspicuous. Several species of sawflies, however, are quite large and brightly coloured, and may be seen visiting flowers. Their name derives from the females’ saw-like ovipositor, used to insert their eggs within plant tissues. Many sawflies have larvae which feed openly on leaves and resemble the caterpillars of moths and butterflies, but others develop inside galls which their foodplant produces in response to the larva’s presence. Galls, which take distinctive forms according to the insect species that causes them, are also produced by the Cynipidae or gall wasps, and in this case they are much easier to identify than the minute insects themselves. Many cynipid galls can be found on the Commons, including the familiar oak-apple, the marble and spangle galls, also on oak, and the robin’s pincushion on rose. Another important group of Hymenoptera are the ichneumon flies, whose larvae feed as parasites inside caterpillars or other insects. The females are generally armed with a conspicuous ovipositor, and some of the larger species are brightly patterned in yellow and black or red and black. They are most often seen running about on sunlit foliage, or flying around bushes and low vegetation in search of suitable hosts.
Among the most prominent of the two-winged flies or Diptera are the hoverflies, named for their aerial skills which allow them to hang motionless in mid-air. They are also effective mimics of bees and wasps. Young birds soon learn that insects patterned in yellow and black or red and black are either distasteful or capable of stinging, and many harmless insects gain protection by having a similar appearance. Around sixty species of hoverflies are to be found on the Commons, most of them visiting flowers along with their models. The largest British species belong to the genus Volucella, and the impressive V. zonaria, a migrant species, has occasionally been recorded on the Commons. More likely to be seen is V. pellucens, which regularly hovers along woodland paths; its black and white colouration, unusual among hoverflies, is shared by the smaller spring-flying Leucozona lucorum. The slender-bodied members of the genus Xylota are to be seen on sunlit leaves rather than flowers: they include the red-banded X. segnis and the beautiful gold-banded X. sylvarum. The droneflies, of which six species are found on the Commons, are bee mimics, and include the very common Eristalis tenax, which is notable for hibernating as an adult and appearing on sunny days all through the year. This species and the similar E. pertinax resemble honey-bees, while E. intricarius is a furry bumblebee mimic. Many of the Commons’ hoverflies have variations on the standard wasp pattern of yellow and black stripes. These include the common Syrphus ribesii, the distinctive Helophilus pendulus with vertical stripes on the thorax as well as the usual horizontal ones on the abdomen, and the latter’s larger and scarcer relative H. trivittatus.
Robber flies are a group of fierce predators which capture smaller insects with their spiny fore-legs. A number, like the widespread Machimus atricapillus, are characteristic of open areas where they perch on bare sand, rocks or low vegetation, waiting for suitable victims. Other forms, such as the shiny black Laphria marginata and Neoitamus cyanurus with its metallic blue tail, are found in woodland areas and may be spotted on sunlit foliage beside footpaths. Much smaller predators are the long-headed flies, often metallic green or silvery in colour, many of which are also to be seen on sunlit foliage or around the edges of ponds. The males of the most conspicuous, Poecilobothrus nobilitatus, have white-tipped wings which are waved in its courtship display as large numbers of both sexes swarm over damp mud. Soldier flies are brightly coloured sun-loving insects, of which those found on the Commons include the metallic green Chloromyia formosa and the three-coloured Sargus bipunctatus. The bee-fly Bombylius major, as its name suggests, resembles a brown bumblebee, and is frequently seen in spring exploring the nest sites of solitary bees, in which its larvae live as parasites, or hovering in front of flowers and probing them with its long rigid proboscis.
The largest member of the Diptera found on the Commons is the impressive marbled-winged cranefly Tipula maxima. Craneflies, with their enormously long legs, are an easily recognized group of insects, and the familiar medium-sized forms, some patterned with yellow and black, are widespread in the grassy areas of the Commons, as is the shiny black St Mark’s Fly ( Bibio marci), named after its characteristic swarming flight in spring. The flies of the family Tachinidae spend their larval stage as internal parasites of other insects, usually caterpillars, but the bristly adults often feed conspicuously at flowers, and some are brightly coloured. One of the most numerous species on the Commons is the red-spotted Eriothrix rufomaculatus which can be found visiting ragwort. The beautifully metallic greenbottles ( Lucilia spp.) are among the most abundant of many Diptera species which rest in open view on sunlit foliage and tree trunks; others include the shiny black Mesembrina meridiana with its bright yellow wing bases. Numerous species of beetles occur on the Commons. Although the majority are inconspicuous creatures, there are some which by reason of their size or colour may bring themselves to the attention of the non-specialist. The majority of the fast-moving predatory ground beetles are nocturnal, but a number of metallic brassy species make themselves conspicuous by running across sunlit paths. The related Green Tiger Beetle ( Cicindela campestris), a brightly coloured species which flies readily in hot weather, is sometimes seen in similar situations. The ladybirds, whose bright colours advertise them as distasteful to birds, are also predators, feeding on aphids. Such species as the very common Seven-spot ( Coccinella septempunctata) and smaller Two-spot ( Adalia bipunctata) Ladybird hibernate as adults and may be in evidence on sunny days in winter. Aquatic predators include the impressive Great Diving Beetle ( Dytiscus marginalis), found with many related forms in the various ponds on both Commons.
Many beetles feed on plant foliage, keeping themselves well hidden, but some of the Chrysomelidae or leaf beetles are brightly coloured, as are the metallic green leaf weevils ( Phyllobius spp.) found on various trees and low-growing plants. The Variable Reed Beetle ( Plateumaris sericea), found on emergent vegetation at the fringes of ponds, may be bronze, copper, deep blue or purple in colour. Of the beetles which feed actively at flowers, the most abundant is the soldier beetle Rhagonycha fulva, orange with black tips, a characteristic insect of high summer. Several related species occur in smaller numbers, all being particularly fond of the tall flower heads of umbellifers, thistles and ragwort. The red-tipped Malachius bipustulatus and the slender Oedemera nobilis, both metallic green, are more characteristic of low-growing flowers such as buttercups. The brilliant reflective scarlet of the Commons’ two species of cardinal beetle ( Pyrochroa coccinea and P. serraticornis) render them instantly noticeable, whether they are visiting flowers, sitting on foliage or in flight. Many of the longhorn beetles, noted for their conspicuous antennae, are strikingly coloured or patterned, flying on sunny days and feeding at brambles and other flowers. They include the yellow and black Wasp Beetle ( Clytus arietis) and Spotted Longhorn ( Strangalia maculata), and two larger orange and black species, S. quadrifasciata and the rare and impressive S. aurulenta.
Rove beetles, characterized by their short wing cases exposing most of the abdomen, are abundant inhabitants of the Commons, although most species are small and do not attract attention. Only the large black Staphylinus olens, the so-called Devil’s Coach-horse, is likely to be noticed by the general public running over sunlit footpaths. Click beetles, slender insects so called because of their ability to flip themselves into the correct position after falling on their back, are also numerous, and the common Athous haemorrhoidalis actively flies by day. The large mottled Agrypnus murinus is another notable member of the same family. Members of the scarab group found on the Commons include the familiar Cockchafer or May-bug (Melolontha melolontha), which is nocturnal and attracted to light, the Minotaur Beetle (Typhaeus typhoeus), a dung-beetle with three horns in the male, and the Lesser Stag Beetle (Dorcus parallelipipedus).
The extensive order Hemiptera is divided into two sections, the true bugs or Heteroptera and the aphids, leafhoppers, froghoppers and related forms of the sub-order Homoptera. An often overlooked group of insects, many species are found in grassland and woodland on the Commons. The Homoptera are mostly small insects which attract little attention, although the nymphs of froghoppers make themselves conspicuous by producing protective ‘cuckoo spit’, and some aphids feed in large clusters which are attended by ants in search of honeydew. Some of the larger and more colourful leafhoppers may also be noticed by the non-specialist, for example the bright green Cicadella viridis which frequents the damp grassland around ponds. Among the largest of the true bugs found on the Commons are the shieldbugs, including the common Green Shieldbug (Palomena prasina), often seen on bramble foliage, and the attractive green and purple Hawthorn (Acanthosoma haemorrhoidale) and Birch (Elasmostethus interstinctus) Shieldbug. The large brown squashbug Coreus marginatus is also easy to spot, as it sits openly on dock leaves. Aquatic members of the Heteroptera include the backswimmer Notonecta glauca and the familiar pond-skaters (Gerris spp.), which live on the surface film of ponds.
The ponds on the Commons also support various species of mayflies, stoneflies and caddis-flies. The larvae of the latter are well-known for the protective cases they construct out of plant material or other debris gathered from their watery habitat, but the adults, if noticed at all, are likely to be mistaken for moths. These three groups are among the smaller insect orders, as are the lacewings, which are predatory on aphids in both adult and larval stages. Those most likely to be noted on the Commons are the delicate green species of the genus Chrysopa. A related group are the scorpion-flies, often seen fluttering among brambles or nettles. Despite the curious scorpion-like tail of the male, they are harmless scavengers.
In conclusion, brief mention should be made of invertebrate groups other than insects. On the Commons, the spiders are the most conspicuous of these, representing a variety of lifestyles. Spiders are most popularly associated with the building of webs, the most elaborate being those constructed by the orb weavers such as the large and familiar Araneus diadematus or the smaller bright green Araniella cucurbitina. Many species, however, actively hunt their prey. These include the jumping spiders (Salticidae), often seen on sunlit rocks, the fast running wolf spiders (Lycosidae) which may be seen in large numbers on open ground, the females carrying their silken egg-sacks, and impressive white-banded Pisaura mirabilis, which is generally seen perched conspicuously on foliage. The white or yellow crab spider Misumena vatia sits on flowers waiting to pounce on visiting insects. Centipedes, millipedes and woodlice generally keep themselves out of sight under stones or fallen timber, although the shiny black cylindrical millipede Tachypodoiulus niger sometimes makes its presence more obvious by climbing the trunks of trees. The Pill Millipede (Glomeris marginata) defends itself by rolling into a ball, as does the superficially similar Pill Woodlouse (Armadillidium vulgare). Unlike the slower millipedes, centipedes are fast moving predators, the most distinctive species on the Commons being Lithobius variegatus with purple bands on its legs and similarly coloured marks on its body. Molluscs too are a significant element in the Commons’ fauna, both in the various ponds and on land. The most attractive of the terrestrial snails is the highly variable Cepaea hortensis, whose brightly coloured or banded shells are often seen in fragmentary form around the ‘anvils’ of the Song Thrush.