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By: Ikedi Ani-okoye

Arthropod Behaviour

Brains of Arthropods are relatively small. An adult locust, for example, has approximately one million nerve cells to serve all its sensory and motor needs. Smaller insects have far fewer nerve cells. Nevertheless, insects are capable of surprisingly sophisticated behaviour, which is evident in the way that they move, avoid predators, feed, mate, and care for their offspring.

Courtship and mating

In most species of arthropod, the male and female need to mate Before the female can lay her eggs. The sexes may simply meet at good feeding or egg-laying sites, or they may take a more active parr in finding a suitable crate, attracting each other with songs, odours, and even light displays.

At close range, courtship can be a complicated process. Insects may move their wings, legs, and antennae in move their wings, legs, and antennae in terrain ways, secrete pheromones, and give and receive nuptial gifts (usually pieces of food). Not all species have to mate, however. The females of many archropod species are able to lay viable eggs without the need for males.

Light attraction

In some beetles, such as the Glowworm, Lampyris noctiluca , females attract males of the same species by emiitingflasAes of light. In a few cases, females lure males of other species them.

Getting together

In many arthropods, sperm is Transferred to the female indirectly. However, is insects , copulation always takes place.

Care of the young

Parenal care of eggs and young is fairly common in centipedes, arachnids, and insects. female spiders wrap their eggs in silk and
carry them around, or stay close by until they hatch. Scorpions and related groups brood their eggs and later carry their young on their backs; Among insects, it is usually the female who takes fesponnliry for "child-carew, but the males may so play a part in some families.

Standing guard

Several species of bugs guards their young nymphs, and even guide them to goodfeeding sites.

Methods of self-defence

An arthropod's first line of defence is its cuticle, which may be very tough or Ieathery. Sharp, cuticular spines and profusions, such as warts and bumps, or the ability to roll up into a ball, may further increase the protection that the exoskeleton provides. Mandibles and limbs are effective wlson used to strike out at enemies - the kick from a locust's hind leg can draw blood in most predators.

Physical defences are enhanced by producing unpleasant sounds, or repellent chemicals or odours. Many bugs, for instance, produce strong-smelling compotid~ from thoracic stink glands. Sap-sucking bugs, such as aphids, often surround themselves with "bodyguards" in the form of ants: the ants are attracted to the sugar-rich honeydew ~excrement) that the bugs produce, and in turn help to protect the aphids from predators. Some arthropods are brightly coloured, which may serve to warn predators of their toxicity; sometimes eyespots and other bright patches are flashed at predators to startle them.

Camouflage

Many insects have evolved to blend into their surroundings, or to mimic dead leaves, sticks, thorns, bird droppings, stones, or even other, more dangerous, species.

Warning colours

Bight, contrasting warning colours advertise the presence of chemical defences. Some species "cheat", and are not actually poisonous. 

Poisonous prickles

Toxic chemicals may be made . inside the body or obtained from poisonous Food plant. These chemicals are ofien scored in outer parts of the body.