Turn a stone over
and you may see tens of bugs crawling, running and leaping around. Although
many of them are too small for people to notice, bugs live everywhere around us
and are animals just like fish, birds, frogs, lizards and mammals. Bugs with
legs belong to a large group of animals called the Arthropods. This group
includes insects, arachnids, centipedes, millipedes and crustaceans. It is easy
to tell each group apart just by counting their legs and looking at the shape
of their body. Insects always have six legs and a body divided in three main
parts. Arachnids always have eight legs and a body in one part (daddy long
legs) or two parts (spiders). Centipedes
have a long segmented body with 15 to 191 pairs of legs, as one pair of legs
for each body segment. Millipedes have two pairs of legs per body segment and
may have between 6 and 175 segments; that means that a single millipede can
have up to 700 legs!
Crustaceans usually live in fresh water and in the sea but some of them
live on land. Crustaceans can be recognised by their segmented body and their
many mouthparts. Arthropods never have a skeleton inside their body like we do;
instead, they have a strong carapace called an exoskeleton. When an arthropod
grows too large for its exoskeleton, it will just shed it and grow a new,
larger one.
Devil’s
Coach Horse
Dara daol Ocypus olens
Dara daol Ocypus olens
The Devil’s
Coach Horse is one of the largest beetles in Ireland, measuring 25 to 30mm long.
It can be found between April and October, usually under stones and in the leaf
litter of humid grasslands and forests. When disturbed, the Devil’s Coach Horse
tries to scare its opponent by raising the rear end of its bluish-black body, in
a position similar to a scorpion ready to sting. Devil’s Coach Horses are mainly
predators: they use their large mandibles to catch and devour bugs, worms and
slugs. In Ireland it was believed that the Devil could take the shape of a
Devil’s Coach Horse to travel unnoticed through the country, and seeing this
beetle was considered to be a very bad omen!
Stone Centiped
Céadchosach Lithobius forficatus
Céadchosach Lithobius forficatus
The Stone Centipede
has a long reddish-brown body, and 15 pairs of legs when adult. Stone Centipedes
do not like direct sunlight and they spend most of their life under stones and
logs where they hunt small bugs and worms. To catch their prey, centipedes use a
pair of legs which are modified into two large venom claws located under the
head. While Stone Centipedes can’t hurt you with their claws, their cousins
from the tropics can reach 30cm long and are well-known for inflicting very
painful or even life-threatening stings. In parts of Asia people have erected
temples to honour these fierce predators and to ask centipedes for good fortune
through the year.
The Common
Darter is one of the most abundant dragonflies in Ireland. It is about 40mm
long, with four large wings and a dark grey, green or red body. The Common
Darter can be seen between May and November, flying rapidly in search of small
prey usually over rivers, lakes and ponds. Dragonflies spend most of their
lifetime in the form of aquatic larvae called naiads. Naiads do not have wings,
but they do have six legs like adult dragonflies and have gills to be able to
breath under water. After three to five years in the water, naiads climb on
plants to get above the surface of the water and metamorphose into adult
dragonflies.