About Chilopoda
CHILOPODA, or centipedes, are a class of terrestrial predators
belonging to the phylum Arthropoda.
Morphology
The body of centipedes is elongated to worm-like and frequently
flattened. A distinct head, covered by a flat head shield, is
followed by a multi-articulated trunk with one pair of legs on each
segment.
The head bears a pair of frontal sensory appendages (antennae) and
three pairs of ventral mouth parts (mandibles, first maxillae, and
second maxillae). A pair of simple or (scutigeromorphs only)
multifaceted eyes are commonly present, but these sensory structures
are completely lacking in the geophilomorphs, in the cryptopid
scolopendromorphs and in many subterranean lithobiomorphs.
The trunk appendages of the first pair are developed as strong,
conspicuous, stinging fangs, used to poison the prey and for defence.
Most of the other segments and their appendages are quite uniform,
but for the last pair of legs, which are often specialised in shape
and function, as either handling or sensory appendages. The terminal
part of the trunk bears a pair of small appendages (gonopods), which
are close to the genital opening and are often involved in handling
spermatophores.
Life cycle
Centipedes are oviparous. The female lays a small number of fairly
large eggs. In scolopendromorph and geophilomorph centipedes the eggs
are guarded continuously by the mother which remains coiled around
them even after eclosion. Newly hatched individuals are poorly active
and abandon the brood only after moulting to a more mobile instar.
In some centipedes (Epimorpha, i.e. scolopendromorphs and
geophilomorphs) all body segments are formed at the end of the
embryonic phase, in the others (Anamorpha, i.e. scutigeromorphs,
lithobiomorphs and craterostigmomorphs) the final segment number is
achieved after a series of moults. Maturity is generally reached
after one year or more. Egg fertilization relies on the indirect
transfer of sperm by spermatophores.
Ecology
Centipedes are a major component of terrestrial ecosystems throughout
the temperate and tropical regions. Most of them move in the upper
soil levels, among leaf litter and rock debris, others live deeper in
the soil; the scutigeromorphs are surface-runner or cave-dwellers.
Centipede diversity is highest in forest soils, but representatives
of this arthropod group can be found from littoral shingle to cold
montane prairies, from dump soil to arid ground.
All centipedes are active predators, feeding on small invertebrates,
sometimes even larger than them. The largest invertebrate carnivores
in many terrestrial ecosystems are indeed centipedes.
Diversity
More than three thousand species have been described to date, but
many other are waiting description. Five main lineages are
recognisable among extant centipedes. The geophilomorphs are the most
diverse and widespread. Of the other larger groups, the
scolopendromorphs are well represented and diverse in the tropical
regions, whereas the lithobiomorphs dominate in temperate areas. The
very distinctive scutigeromorphs (‘house centipedes’) are much
less diverse, and mainly tropical, while the craterostigmomorphs are
represented by one species only..
General References
- Lewis, J.G.E., 1981. The biology of centipedes. Cambridge: Cambridge
University Press.
- Minelli A., 1993. Chilopoda, in F.W. Harrison (ed.) Microscopic Anatomy of Invertebrates. New York: Wiley-Liss, 12: 57-114.
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