Certain species of invertebrate are specific to the coast, others are also found inland but find sand dunes in particular suit their requirements. More are shown in the Purbeck pages in this section, but here are a few photographed elsewhere.
Glanville Fritillary butterflies (Melitaea cinxia, wingspan 45mm) are a Biodiversity Action Plan priority species, principally because their breeding requirements are so precise, leading to their being restricted to the Isle of Wight.
Essentially they need unstable cliffs or coastal slopes where the caterpillars’ foodplant, Ribwort Plantain (Plantago lanceolata), can thrive. The Isle of Wight offers this in abundance, and in June there is usually a plentiful supply of adults. However, given the necessarily temporary nature of any breeding habitat based on erosion, there may be problems for the Glanville Fritillary in the long-term.
The solitary wasp Oxybelus argentatus (6mm) is a nationally scarce sand specialist. They are found in south-east England in a few pockets on the coast and in Norfolk, as well as in a handful of inland heaths. Their behaviour is similar to Oxybelus uniglumis, dealt with under Sandpits in the Lowland Heathland section of this website.
Ancistrocerus scoticus (12mm long) is one of the potter/mason wasps and is found mainly on the coast. They prey on small Lepidoptera caterpillars or beetle larvae to stock the nest, which is usually constructed in hollow places such as crevices in rocks or in dead plant stems.
In July and August coastal dunes are a classic setting for one of the most attractive of the mining bees, the nationally scarce Dasypoda hirtipes (12mm), though they are also found in inland heaths.
The female has the largest scopae (pollen brushes) of any British bee and can carry formidable quantities of pollen collected from Composites. Using the hind legs almost like paddles to remove the spoil, she swiftly digs a burrow up to 60cm in depth. This contains several cells, each stocked with around 300mg of pollen rolled into a ball and supported on three plinths of sand to allow air to circulate and maintain quality while the larva in the cell develops. The larvae pupate the following year.
Among leaf-cutter Megachilid bees, Megachile leachella (12mm), formerly Megachile dorsalis, is dealt with in the Purbeck pages of this website, but another member of the genus found mainly though not exclusively on the coast is Megachile maritima (14mm), which is locally common. This species is preyed on by the physically impressive cuckoo bee Coelioxys conoidea (13mm). From the same genus, Megachile circumcincta is becoming scarce and local. They used to be found inland but now are pretty well restricted to coastal dunes.
On a slightly larger scale, the coast, particularly Kent and Essex, now provides one of the last strongholds for several species of bumblebee. Considering their status as one of Britain's most obvious, best-known and best-loved invertebrates, the bumblebee family is in a pretty parlous state, to some extent due to modern agricultural practices resulting in the removal of flower-rich grasslands. All but one of the species shown here, three of which are the subject of Biodiversity Action Plans, were seen in Kent on one day in July 2008.
Bombus humilis (14mm) has small nests with fewer than 100 workers and is associated with grasslands holding legumes, especially clover. Bombus sylvarum (12mm), or the Shrill Carder Bee, is a small species and one under severe pressure, being found in only five areas of the UK. They, too, use legumes and also labiates. Bombus muscorum (15mm) needs similar flowers and although more widespread is also declining. The same comment applies to Bombus ruderarius, (16mm), which closely resembles the Red-tailed Bumblebee. They use old mouse or vole burrows for their nests. Bombus ruderatus (18mm) is a large species found only in south-east England, and not often there. It may be associated with wetland areas and nests are quite large, reportedly holding at least 150 workers. More research about, and assistance for, all these species is certainly required.
Bombus subterraneus, the Short-haired Bumblebee (15mm), was not photographed along with these other bumblebees in 2008 for a good reason. The species had been declared extinct in Britain 20 years earlier but, backed by various conservation groups, the campaign to try and reintroduce the species resulted in dozens of queens being taken in Sweden and released at the Dungeness RSPB reserve in Kent in May 2012 then again in June 2013. This was the last place where the bee had been seen in the 1980s. It took a huge amount of effort to get the habitat in prime condition, full of appropriate flowers such as Red Clover, for the release. One can only hope that the reintroduction proves successful but the bad summer of 2012 did not help in that regard. Equally, all the excellent foraging areas in Kent that have been developed over the last few years to help this bumblebee will undoubtedly assist other bees too.
Glow Worms (Lampyris noctiluca) are fairly large beetles which have suffered from the so-called improvement of grassland in the modern era and are at least as common inland as on the coast. However, my first sighting of any for many years was at Sandwich in Kent in 2008, hence their inclusion on this page. The winged male is 10-12mm and the wingless female 15-20mm. They are active mostly after dark and so need good cover to conceal themselves from predators. Grassland vegetation, logs, cracks and crevices with humid conditions are ideal habitats. In addition, the female needs a prominent position such as a bank, hummock, tussock or similar feature, to attract a passing male.
The green light females use is produced by a series of chemical reactions within the cells of the light organ. Oxidation of an active chemical, luciferin, in the presence of a catalyst, luciferase, causes the shedding of atoms and a release of energy in the form of light. The reaction is remarkably efficient since only 2% of the energy is lost as heat. As a consequence a brilliantly glowing female remains cold to the touch. Adult Glow Worms are active between June and August in a short summer breeding period. Snails are among the food taken.
Among other invertebrates, the Dune Tiger Beetle (Cicindela maritima, 13mm) looks very like the Heath Tiger Beetle (Cicindela sylvatica) shown in the Heathland pages of this website but as the name suggests, it is a coastal species occurring on dunes and sandy beaches. Within the area covered by this website that is in Kent and Norfolk, though Hampshire also used to host the species. Classified as Nationally Scarce, like all the others in the genus they run and fly readily in search of invertebrate prey. Breeding occurs in spring and summer, with larvae in burrows in hard-packed sand.
The Dune Robber-fly (Philnocus albiceps, 12mm) lives up to its name by foraging for varied prey around sand dunes, using the proboscis to suck victims dry. Other invertebrates which are particularly at home in dunes are the Black Marram Weevil (Otiorhynchus atroapterus, 6mm) and the Dune Chafer (Anomala dubia, 9mm).
Similarly, the Dune Wolf Spider (Xerolycosa miniata, 7mm) can be seen scurrying across the sand from May to August and the Six-spot Burnet moth (Zygaena filipendulae, wingspan 45mm), the commonest of seven Burnet moths in Britain, is often found on sandhills. Much rarer, and now virtually limited to eastern coastal counties, is the Ground Lackey moth (Malocosoma castrensis, wingspan 35mm). The larvae feed on saltmarsh plants including sea-lavender.
The handsome hoverfly Helophilus trivittatus (16mm) is the largest of the five-strong genus in Britain and though not common it is widely distributed, with coastal areas leading the way. The species visits flowers to take nectar, including thistles and umbellifers such as Hemlock Water-dropwort as in the image. The resident population is probably increased by migrants each summer.
Images © Jeremy Early. All rights reserved.
My latest book, My Side of the Fence – the Natural History of a Surrey Garden, was published in spring 2013. Details may be found, and orders placed, via this hyperlink My Side of the Fence.