Endangered Insects - Ants

Black Backed Meadow Ant | Black Bog Ant | Narrow Headed Ant | Red Barbed Ant

Black-backed meadow ant - the Black-backed meadow ant (Formica pratensis) is a large ‘wood ant’ that resembles the more common southern wood ant (Formica rufa). Its thorax displays some red colouration, however, generally this species is much darker than its related species. Its abdomen is dark brown to black and the whole of its body is covered in many fine hairs.

The Black-backed meadow ant has been rare since it was first recorded in the UK. It was confined to a few sites around the Bournemouth and Wareham areas of Dorset however, despite a number of informal searches, there have been no sightings of this species since the 1980's, when two last known colonies in the Morden area disappeared. A population still exists on cliff top sites on the Channel Islands. The black-backed meadow ant is widespread in Europe but is declining. The Black-backed meadow ant is listed as Vulnerable by the IUCN/WCMC and as Endangered in the GB Red List. The Black-backed meadow ant is possibly now extinct in the UK.

One of the reasons for this ants decline is urban development on cliff tops, particularly in Bournemouth.

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Black bog ant - the Black Bog ant (Formica candida) is very rare. It is a medium-sized ant that is black and shiny. In the UK the black bog ant is known from only a small number of bogs, wet heaths and mossy stream sides in Dorset and Hampshire and from an isolated site near Carmarthen in Dyfed, Wales.

The Black Bog ant seems to have disappeared from a number of its former territories in the New Forest and has been recorded in only nine one km squares there since 1975. The Black Bog ant is listed as Endangered in the GB Red List.

There are many factors leading to the decline of the Black Bog ant including loss of habitat, trampling of nests through excessive grazing and drought.

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Narrow-headed ant - the Narrow-headed ant (Formica exsecta) is native to the British Isles. The Narrow-headed ant is a rare formicine ant with a deeply excised head and forms small mounds up to one foot in height consisting of much finer material than that used by 'true' wood ants. In Britain, the Narrow-headed ant can be found only in a few scattered heathland locations in South West England mainly Chudleigh Knighton heath and nearby Bovey Heath which both are managed by the Devon Wildlife Trust and in the central Scottish Highlands.

The Narrow-headed ant is listed as Endangered on the GB red List.

The reasons for this ants decline are loss of suitable heathland due to destruction and inappropriate management including untimely and extensive fires and encroachment by scrub, trees and bracken leading to shading out of nests and subsequent encouragement of competitive species of ant at sites in England.

Other reasons include loss of natural habitats in Scotland. Motorcycle scrambling at Bovey Heathfield in England. Excessive grazing and inadequate browsing by inappropriate species of ponies in the New Forest. Nutrient enrichment of soils and development of grass swath. Habitat fragmentation leading to potential inbreeding and loss of genetic fitness in isolated populations.

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Red-barbed Ant - the Red-barbed ant (Formica rufibarbis) is most distinguishable by the large amounts of red colouration on the head and alitrunk. In Britain, the red-barbed ant is possibly the rarest resident animal in mainland Britain confined to Surrey heathland and the Isles of Scilly, where it is known as the 'St Martin's ant'. There is only one colony now known on Chobham Common and it is all one gender, lacking a queen, putting the species at high risk of being lost in mainland Britain.

The Red-barbed ants nests are completely within the ground, usually in sandy banks and nest chambers situated about a foot beneath the surface and are accessible only from a single entrance. This makes the locating of colonies very difficult, so it is possible that the tiny numbers of recorded colonies constitute an under-representation.

Worker ants possess a remarkable sense of sight and will proceed to their nest entrance in a very straight line even if major obstacles are placed to disrupt their path. Foraging red-barbed ants will also challenge other ant species for food, gripping on and tussling until it can decamp with the prey.

Colonies usually contain one to three queens. Eggs are first laid early in the new year and colonies reach a maximum size of around 500 worker ants. Alates (reproductions of a social insect) emerge in late June to early July.

Like other Servifusca, this species is subject to raids by dulotic species such as Formica sanguinea and Polyergus rufescens where their ranges coalesce. In Britain this only takes place at Chobham in the case of the former (the latter does not occur in the country).

The Red-barbed ant is on the red list in Britain, although it is not considered at risk in continental Europe.


 
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