Insect Defense
Above the countless number of species on our planet, insects stand among the most successful animals on Earth in regards to sheer variety and abundance. About one million species of insects have been identified so far (some estimates reach three million), which is about half of all the animals known to the scientific world. Insects inhabit nearly every nook on Earth. Rock crawlers survive in the peaks of the Himalayas by producing a kind of antifreeze, and worker ants forage for food in the Sahara Desert at temperatures above 47oC. Insects can be aquatic, air-borne, land-dwelling, tree-dwelling and anything in between. Some insects, such as the silverfish have even adapted to living indoors and surviving on a diet of paper and glue. Because insects are nutritious, abundant, diverse, and found everywhere, they are eaten by humans, animals and plants alike. So how is it that these tiny creatures have managed to subsist so successfully for millions of years in the face of such adversity? Evolution has endowed them with a remarkable ability to adapt and defend. A great variety of moths spend their days resting safely upon tree trunks, so perfectly matching the mottled bark that their very invisibility forms their defense.
There are two classes of compounds that have emerged from the study of chemical secretions in insects; Class I and Class II. Collective defence everywhere in nature serves to fulfill two theories: the dilution effect and the selfish herd. Spraying is frequently accomplished with a high degree of accuracy and over considerable distances. Insects do not strictly stick with the imitation of environmental objects; they have also taken a liking to copying each other, either in colour, pattern, form, or behaviour. However, if the caterpillar's eyes are cauterized before the chrysalis is formed it loses this adaptive ability (Wigglesworth, 1964). Chemically defended insects often signal their chemical capacity by warning signals known as aposematic signals. All of the insects in the group gain mutual benefit from having others in the group spend time watching for predators. Some insects, such as the puss moth caterpillar, can be so elaborate in their defenses that an attack is almost impossible. One benefit to this highly effective method of defence is that the defending insect inevitably contaminates itself with the sprayed chemical and therefore enjoys a period of invulnerability to attack. A wide array of insects responds by regurgitating or defecating, when disturbed. When an entire limb is shed for escape, the process is known as autotomy. In addition to using these body parts for defensive attacks, some insects may shed body structures for escape purposes. Social insects also incur methods of collective group defences to ward off attacks. Clearly there are countless specializations of the more common methods discussed here; one could indeed make a life's work from this field of study. Obviously, which of these methods is chosen depends on the species of insect.
Common topics in this essay:
CRYPSIS Undoubtedly,
DEFENCES Chemical,
Class II,
Sahara Desert,
DEFENCE Adaptations,
Henry Bates,
CHEMICAL DEFENCE,
Mimicry Mimicry,
CONCLUDING REMARKS,
,
eye spots,
puss moth caterpillar,
batesian mimicry,
moth caterpillar,
puss moth,
passive defence,
species insects,
mechanical defence,
class ii,
line defence,
insects evade,
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Acceptance Essays
