Earthworm - Lampito mauritii
is a terrestrial invertebrate that inhabits the upper layers of the moist soil,
rich in decaying organic matter. It is nocturnal and during the day it lives in
burrows made by burrowing and swallowing the soil. In gardens, they can be
traced by their faecal deposits known as worm castings on the soil surface.
Earthworms are considered as “Friends of Farmers”. The common Indian earthworms
are Lampito mauritii (Syn. Megascolex mauritii),
Perioynx excavatus and Metaphire
posthuma (Syn. Pheretima posthuma). Earthworms are also conveniently
classified based on their ecological strategies as epigeics, anecics and
endogeics (Figure 4.1). Epigeics (Greek for “up on the earth”) are surface
dwellers, eg. Perionyx excavatus and Eudrilus eugeniae. Anecics (Greek for “out
of the earth”) are found in upper layers of the soil, eg. Lampito mauritii,
Lumbricus terrestris. Endogeics (Greek for “within the earth”) are found in
deeper layers of the soil eg. Octochaetona thurstoni.
Lampito mauritii is commonly found in Tamil Nadu.
It has a long and cylindrical narrow
body which is bilaterally symmetrical. L. mauritii is 80 to 210 mm in length
with a diameter of 3.5 – 5 mm, and is light brown in colour, with purplish
tinge at the anterior end. This colour of the earthworm is mainly due to the
presence of porphyrin pigment. The body of the earthworm is encircled by a
large number of grooves which divides it into a number of compartments called
segments or metameres (Figure 4.2). L. mauritii consists of about 165 – 190
segments. The dorsal surface of the body is marked by a dark mid dorsal line
(dorsal blood vessel) along the longitudinal axis of the
body. The ventral surface is distinguished by the presence of genital openings.
The mouth is found in the centre of the first segment
Overhanging the mouth is a small flap called the
upper lip or prostomium. The last segment has the anus called the pygidium. In
mature worms, segments 14 to 17 may be found swollen with a glandular
thickening of the skin called the clitellum. Thishelps in the formation of the
cocoon. Due to the presence of clitellum, the body of an earthworm is divided
into pre clitellar region (1st – 13th segments), clitellar region
(14th – 17th segments) and the post – clitellar region (after the 17th
segment). In all the segments of the body except the first, last and clitellum,
there is a ring of chitinous body setae. This body setae arises from a
setigerous sac of the skin and it is curved as S – shaped. Setae can be
protruded or retracted and their principal role is in locomotion.
external apertures are the mouth, anus, dorsal pores, spermathecal openings,
genital openings and nephridiopores. The dorsal pores are present from the 10th
segment onwards. The coelomic fluid communicates to the exterior through these
pores and keeps the body surface moist and free from harmful microorganisms.
Spermathecal openings are three pairs of small ventrolateral apertures lying
intersegmentally between the grooves of the segments 6/7, 7/8 and 8/9. The
female genital aperture lies on the ventral side in the 14th segment
and a pair of male genital apertures are situated latero-ventrally in the 18th
segment. Nephridiopores are numerous and found throughout the body of the
earthworm except a few anterior segments, through which the metabolic wastes
The body wall of the earthworm is very moist, thin, soft, skinny, elastic and consists of the cuticle, epidermis, muscles and coelomic epithelium. The epidermis consists of supporting cells, gland cells, basal cells and sensory cells. A spacious body cavity called the coelom is seen between the alimentary canal and the body wall. The coelom contains the coelomic fluid and serves as a hydrostatic skeleton, in which the coelomocytes are known to play a major role in regeneration, immunity and wound healing. The coelomic fluid of the earthworm is milky and alkaline, which consists of granulocytes or eleocytes, amoebocytes, mucocytes and leucocytes.
digestive system of the earthworm consists of the alimentary canal and the
digestive glands. The alimentary canal runs as a straight tube throughout the
length of the body from the mouth to anus (Figure 4. 3). The mouth opens into
the buccal cavity which occupies the 1st and 2nd segments. The buccal cavity
leads into a thick muscular pharynx, which occupies the 3rd and 4th segments
and is surrounded by the pharyngeal glands.
narrow tube, oesophagus lies in the 5th segment and continues into a muscular
gizzard in the 6th segment. The gizzard helps in the grinding of soil particles
and decaying leaves. Intestine starts from the 7th segment and continues till
the last segment. The dorsal wall of the intestine is folded into the cavity as
the typhlosole. This fold contains blood vessels and increases the absorptive
area of the intestine. The inner epithelium consists of columnar cells and
glandular cells. The alimentary canal opens to the exterior through the anus.
ingested organic rich soil passes through the digestive tract where digestive
enzymes breakdown complex food into smaller absorbable units. The simpler
molecules are absorbed through the intestinal membrane and are utilized. The
undigested particles along with earth are passed out through the anus, as worm
castings or vermicasts. The pharyngeal or salivary gland cells and the
glandular cells of the intestine are supposed to be the digestive glands which
secrete digestive enzymes for digestion of food.
earthworm has no special respiratory organs like lungs or gills. Respiration
takes place through the body wall. The outer surface of the skin is richly
supplied with blood capillaries which aid in the diffusion of gases. Oxygen
diffuses through the skin into the blood while carbon dioxide from the blood
diffuses out. The skin is kept moist by mucous and coelomic fluid and
facilitates exchange of gases.
mauritii exhibits a closed type of blood vascular system consisting of blood
vessels, capillaries and lateral hearts (Figure 4.4). Two median longitudinal
vessels run above and below the alimentary canal as dorsal and ventral vessels
of the earthworm. There are paired valves in the dorsal vessels which prevent
the backward flow of the blood. The ventral vessel has no valves and is non
contractile, allowing the backward flow of blood. In the anterior part of the
body the dorsal vessel is connected with the ventral vessel by eight pairs of
commissural vessels or the lateral hearts lying in the 6th
to 13th segments. These vessels run on either side of the alimentary canal and
pump blood from the dorsal vessel to the ventral
The dorsal vessel receives blood from various organs in the body. The ventral
vessel supplies blood to the various organs. Blood glands are present in the
anterior segments of the earthworm. They produce blood cells and haemoglobin
which is dissolved in the plasma and gives red colour to the blood.
bilobed mass of nervous tissue called supra - pharyngeal ganglia, lies on the
dorsal wall of the pharynx in the 3rd segment, is referred as the “brain”. The
ganglion found below the pharynx in the 4th segment is called the
sub-pharyngeal ganglion (Figure. 4.4). The brain and the sub - pharyngeal
ganglia are connected by a pair of circum-pharyngeal connectives. They run one
on each side of the pharynx. Thus a nerve ring is formed around the anterior
region of the alimentary canal. The double ventral nerve cord runs backward
from the sub - pharyngeal ganglion. The brain along with other nerves in the
ring integrates sensory inputs and command muscular responses of the body.
earthworm’s receptors are stimulated by a group of slender columnar cells
connected with nerves. The Photoreceptors (sense of light) are found on the
dorsal surface of the body. Gustatory (sense of taste) and olfactory receptors
(sense of smell) are
found in the buccal cavity. Tactile
receptors (sense of touch), chemoreceptors
(detect chemical changes) and thermoreceptors
(changes in temperature) are present in the prostomium and the body wall.
is the process of elimination of metabolic waste products from the body. In
earthworm, excretion is effected by segmentally arranged, minute coiled, paired
tubules called nephridia. There are three types of nephridia; (i) pharyngeal or
tufted nephridia – present as paired tufts in the 5th - 9th segments (ii)
Micronephridia or Integumentary nephridia – attached to the lining of the body
wall from the14th segment to the last which open on the body surface (iii)
Meganephridia or septal nephridia – present as pair on both sides of
intersegmental septa of the 19th segment to the last and open into intestine
(Figure 5). The meganephridium has an internal funnel like opening called the
nephrostome, which is fully ciliated. The nephrostome is in the preceding
segment and the rest of the tube is in the succeeding segment. This tube
consists of three distinct divisions, the ciliated, the glandular and the
muscular region. The waste material collected through the ciliated funnel is
pushed into the muscular part of nephridium by the ciliated
region. The glandular part extracts the waste from the blood and finally the
wastes exit out through the nephridiopore.
nephridia, special cells on the coelomic wall of the intestine, called
chloragogen cells are present. They extract the nitrogenous waste from the
blood of the intestinal wall, into the body cavity to be sent out through the
are hermaphrodites or monoecious i.e. male and female reproductive organs are
found in the same individual (Figure 4. 6). Self fertilization is avoided
because two sex organs mature at different times, which means the sperm
develops earlier than the production of ova (Protandrous). Thus cross fertilization takes place.
male reproductive system, two pairs of testes are present in the 10th and 11th
segments. The testes give rise to the germ
cells or spermatogonia, which
develops into spermatozoa in the two pairs of seminal vesicles. Two pairs of
seminal funnels called ciliary rosettes are situated in the same segments as
the testes. The ciliated funnels of the same side are connected to a long tube
s deferens. The vasa deferentia run upto the 18th segment where they open to
the exterior through the male genital
aperture. The male genital aperture contains two pairs of penial setae for copulation. A pair of prostate glands lies in the 18th – 19th
segments. The secretion of the prostate gland serves to cement the spermatozoa
into bundles known as spermatophores.
female reproductive system consists of a pair of ovaries lying in the 13th segment. Each ovary has finger like
projections which contain ova in linear series. Ovarian funnels are present
beneath the ovaries which continue into the oviducts. They join together and
open on the ventral side as a single median female genital pore in the 14th
segment. Spermathecae or seminal receptacles are three pairs lying in segments
7th, 8th and 9th, opening to the exterior on the ventral side between 6th &
7th, 7th & 8th and 8th & 9th segments. They receive spermatozoa from
the partner and store during copulation.
A mutual exchange of sperms occurs between two worms during mating. One worm has to find another worm and they mate juxtaposing opposite gonadal openings, exchanging the sperms. Mature egg cells in the nutritive fluid are deposited in the cocoons produced by the gland cells of the clitellum which also collects the partner’s sperms from the spermthecae. Fertilization and development occurs within the cocoons, which are deposited in the soil. After about 2 – 3 weeks, each cocoon produces baby earthworms. Development is direct and no larva is formed during development.
Lampito mauritii begins its life cycle, from the
fertilized eggs. The eggs are held in a protective
cocoon. These cocoons have an incubation period of about 14- 18 days after
which they hatch to release juveniles
(Figure 4.7). The juveniles undergo changes into non-clitellate forms in phase
– I after about 15 days, which
then develops a clitellum, called
the clitellate at the end of the
growth phase – II taking 15 - 17 days to complete. During the reproductive
stage, earthworms copulate, and later shed their cocoons in the soil after
about 10 days. The life cycle of Lampito
mauritii takes about 60 days to complete.
are known as “friends of farmer” because they make burrows in the soil and make
it porous which helps in respiration and penetration of developing plant roots.
Vermiculture, vermicomposting, vermiwash and wormery are inter-linked and
interdependent processes, collectively referred as Vermitech. Lampito mauritti
helps in recycling of dead and decayed plant material by feeding on them.
Artificial rearing or cultivation of earthworms involves new technology for the
betterment of human beings. This process is known as Vermiculture. The process of producing compost using earthworms is
called Vermicomposting. Vermiwash is
a liquid manure or plant tonic obtained from earthworm. It is used as a foliar
spray and helps to induce plant growth. It is a collection of excretory
products and mucus secretion of earthworms along with micronutrients from the
soil organic molecules. Earthworms can be used for recycling of waste food,
leaf, litter and biomass to prepare a good fertilizer in container known as wormery or wormbin. It makes superior compost than conventional composting
methods. Earthworms are also used as bait in fishing.