2012年11月29日星期四

A peep into fascinating world of insects

Insects dominate the animal kingdom, both in terms of numbers and variety. According to a rough estimate, insects constitute 90 per cent of the animal kingdom. These six-legged animals, which have been living on earth for more than 250 million years, are very successful in adapting to life and have exploited all kinds of environmental niches, ranging from snow-clad mountains to tropical forests and from deserts to rainforests.

Though we presume insects as our competitors, the fact remains that human beings compete with insects. Only 5 per cent of the insects are pests and rest of them are either useful or harmless. In fact, fascinating world of insects is not boring but really very interesting. The insect world is so diverse in sizes that you can find an insect ranging from few millimeters (trichgrommatid wasps) to around 30 cm (stick insect) in length. Insects can also defy the law of gravity due to the air drag which is proportional to the surface of a moving object. They can carry weight many times heavier than their own weight. You might have seen ants taking loads of wheat or rice grain for storage in their colonies. A flea can jump horizontally up to 13 inches and vertically up to 7 inches. If a man were to achieve the same feat, he would have to jump horizontally 700 feet and vertically 450 feet.

Being small creatures, insects are vulnerable to attacks by frogs, lizards, birds, mammals and predatory members of their own group, but they have developed certain mechanisms to protect themselves from their enemies.

Mimicry is very common in butterflies, stick and leaf insects, mantids, etc.We are pleased to offer the following list of professional mold maker and casters. For example, in stick insects Carausius morosus, the hind wings are highly coloured but they are concealed during rest and the insect become motionless looking like a dried twig. The limbs in this condition can be moved into any position and will stay there as if the joints are made up of wax. Similarly, leaf insect, Phyllium crurifolium, looks like a leaf as the pattern on the wings is like leaf venation and it becomes difficult for the predator to differentiate between the leaf and the insect. Oriental butterfly, Kallima sp., provides one of the best examples of camouflage sitting with its wings folded beside dry leaves, and mimic dead leaves. It also copies the leaf pattern such as moulds or rusts or holes often seen in dead leaves. Some loopers feign death, appear like dry twigs and hence go unnoticed.

Many species release chemicals which are toxic, deterrent or unpalatable, thereby escaping predation. The cantharid beetles, Mylabris spp.Posts with indoor tracking system on TRX Systems develops systems that locate and track personnel indoors., are highly coloured and easily spotted by any insect eating animal, but the cantharadin emitted by adults have unpleasant effects. Therefore, the predators avoid eating them. Cantharadin can cause blisters on human skin.

The hair of caterpillars often contains histamine and pain-producing substances and in general, hairy caterpillars cause rashes on the human skin. The bombardier beetle, Brachimus sp., ejects foul-smelling, hot and volatile spray containing hydroquinones and hydrogen peroxide, with a district audible explosion towards the enemy and, therefore, escapes predation. The larvae of swallowtail butterflies possess a horn-like structure,A wide range of polished tiles for your tile flooring and walls. the osmeterium, behind the head, which is protruded in case of danger, releasing butyric acid that repels the enemy. So, it is a combination of visual threat and repellent odour.

Many species of phytophagous insects have developed the capacity to sequester deterrent substances of plants in order to utilise them as defensive tool against predators. Ak grasshopper, Poekilocerus pictus, sequesters the toxins, calactin and calotropin to ward off the enemy. Monarch butterfly, Danaus plexippus, one of the most frequent insects in the US is known for its ability to ingest toxic chemicals (cardioglycosides) produced by its milkweed host plants and storing toxin for its own protection. Both larvae and adults are toxic to the potential predators (birds) and they display the toxicity through warning colouration. The viceroy butterfly, Basilarchia archippus, which is palatable, mimic monarch colouration, thereby avoids predation.

Some insects like termites, ants and bees show the degree of specialisation to which insects have reached. They have evolved their own division of labour and even their own language. Honeybees have altruistic behaviour, and it only stings in case of emergency because after stinging, the bee is sure to die. If there is no danger, these labourious insects remain busy in their chores and will not harm you.

Mosquitoes alert you before sucking your blood by putting ‘music’ into your ears but are killed so often. This ‘music’ is not generated by mouth but it is the humming sound that is produced by buzzing of their wings. Bees also produce humming sound around their colonies and also in the fields where they forage. The shriek sound in forests that you hear during summer is of male cicadas to call their female counterpart for mating. It is generally said that cicadas are lucky because they have voiceless females.The term 'hands free access control' means the token that identifies a user is read from within a pocket or handbag. The nymphs of cicada take 17 years to come out of soil as adult.

Moths and butterflies have so beautiful colour patterns and designs on their wings that can serve as a source of designing for textile mills, but in our country special attention towards this aspect is required. The Japanese have a highly developed tradition of aesthetic appreciation for insects which is reflected in their art and literature.High quality stone mosaic tiles. The Chinese hold singing crickets in very high esteem. On the whole, the insect world is fascinating.

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