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One of the three types of locust that
forms swarm's in Africa is the desert Locust. This locust usually lives like a
grasshopper in what is called a solitary phase. Some times, however, all the
solitary locusts from a wide area drive3n together, perhaps by the weather, and
they may find the conditions just right for feeding and mating. As locusts mate
and lay eggs many times in a short period. enormous numbers of young locusts
hatch and become stimulated by each other to form a swarm. They change color and
when all the available plants have been eaten they migrate in search of more.
The King crab, or
horseshoe crab, is not really a crab at all. In fact it is not even a crustacean
but a y primitive arthropod which belongs to a group of its one. From fossil
evidence we know that king crabs were abundant in seas about 175 million years
ago. The few species that survive today are virtually unchanged from those early
ancestors and for this reason they are sometimes called "living fossils".
King crabs have
some unusual features. They are about a foot across, have a heavy domed shell
divided by a joint across the middle, four pairs of walking legs and a long
spiky tail. The bony mouth extends between the bases of the legs which help in
chewing up the food. These characteristics, together with their gills and
mouthparts, tell us that the king crab is actually descended from the
forerunners of another group of arthropods adapted for life on land the
arachnids. These include the scorpions, spiders, mites and ticks, and daddy long
legs or harvestmen.
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