Blue-grey Worm

The blue-grey colour of the Blue-grey Worm is distinctive, sometimes with yellow on the end of the tail.

Species introduction

At a glance
Latin name: 
Octolasion cyaneum
Family: 
Earthworms
Family Latin name: 
LUMBRICIDAE
Category: 
Invertebrates

Species description

Species description

The blue-grey colouration of this endogeic species is distinctive, sometimes with yellow on the end of the tail. Often found in waterlogged soil but it has a wide tolerance of soil conditions.

Species photographs

Larger photograph(s) (click to magnify)

Details

Species family information

Nearly all British earthworms belong to this large northern hemisphere family. Having retractile body structures helps them while burrowing. Species of this family have four pairs of setae per segment, which have diagnostic usefulness.

Category information

Centipedes, millipedes, and their kin are collectively called myriapods. Centipedes are carnivores, and have one pair of jointed legs per body segment, which never have 100 segments, but vary from 30 to 354. Millipedes have two pairs of jointed legs per body segment, up to 333 in number, and mostly feed on decaying plant material. Myriapods are arthropods and share a common ancestor with the crustacea, that includes insects, which in turn share a common ancestor with the arachnids. Arthropods have an exoskeleton, a segmented body, and paired, jointed appendages. They have highly developed sense organs. 84% of all species on the Earth are arthropods. Crustacea generally have two pairs of appendages (antennules and antennae) in front of the mouth and paired appendages near the mouth that function as jaws. They occupy a wide range of habitats, and many are aquatic, although the largest group in terms of number of species, the insects, are mainly terrestrial. Woodlice are common crustaceans in gardens.

Earthworms are annelids, evolving on a separate lineage to the arthropods, but they share a common ancestor with the molluscs. The Annelida is a large group of segmented worms, also called ring worms. Molluscs are a large, diverse group of invertebrates, which have unsegmented bodies enclosed within calcareous shells, and are represented in gardens mainly by terrestrial gastropods such as snails and slugs. Other molluscs, particularly the bivalves and cephalopods, are aquatic. Representatives of all these groups are found in the cemetery.

Further information

Our local representatives of the huge group of Annelid worms are easily distinguished and among the most recognisable of our invertebrates. Earthworm bodies are constructed of many ridged segments (called annuli) covered in minute hairs (setae) like small bristles, with which they burrow and move. They have no lungs, but breathe through the skin. To keep the skin moist they secrete mucus. Earthworms are hermaphrodite, but two worms are needed for mating as they are not self-fertilising. Along the body is the clitellum, or saddle, which contains both male and female sex organs. A linear area of the clitellum is called the Tubercula pubertatis (TP), and this indicates that the individual is a sub-adult. If there is no clitellum, and therefore no TP, the individual is a juvenile. About half-way between the head and the TP will be the ‘male pore’, if there is one. Earthworms are omnivores, eating plant material and small invertebrates. They occur in most soils, unless they are extremely acidic or waterlogged, and need to maintain moisture levels, so tend to lie dormant if conditions are very cold or dry. They are active at night, consuming soil and extracting food from it. The mouth is in the first segment, and the unwanted soil debris is passed through the body. Their burrowing aerates the soil, and their feeding helps distribute minerals and organic matter, so they are vital to soil health. In the UK we have one species in the family Acanthodrilidae, one species in the family Sparganophilidae, and 28 species in the family Lumbricidae. Four common lifestyles are recognised amongst British earthworms. Compost earthworms seek warm, moist rotting vegetation, such as garden compost heaps. They are often bright red in colour and have striped markings. Anecic earthworms make permanent vertical burrows in soil, and drag leaves down into them to feed on. They make casts on the surface, and some make piles of casts (middens) round the burrow entrance. They are usually darkly coloured at the head end, red or brown, with paler tails. Endogeic earthworms live in and feed on soil, and make horizontal burrows. They are often pale coloured, grey, pink, green or blue. Epigeic earthworms live on the surface in leaf litter, and are often bright red but do not have striped markings.