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Definition for Insect Migration

Mere movement does not mean to be migration. Vegetative behaviours like feeding

and reproduction process in insects will be suppressed temporarily during the course

of migration [5].

The migration of insects can be classified based on specific behaviour phases as

follows [6]:

• Insects migrate with a determined mission to move from one place to other

favorable place.

• Some insects will move consistently in a straight movement.

• Some insects focus on moving to one targeted area without halting at suitable host

plants.

• In the process of preparation a few insects will undergo with distinctive changes

in behavior for reproduction. Insects like locusts initially are solitary will become

gregarious during migration. They also store lot of fat content as a fuel for migra-

tory flight. Insect body fat plays a major role in migration for releasing energy by

using triglycerides.

Kennedy [7] explains a limited criterion for defining migration as for a behaviour

persistent.

Evidence for Insect Migration

Some of the important observations are listed below [8].

• Large numbers of insects from different insect orders flying in one direction with

steady air flow were observed by field naturalists.

• Sudden appearance/disappearance of insects with wings in large numbers which

were not observed previously is interesting.

• Many insects were usually seen flying at far off oceanic islands and at high

altitudes.

The first insect mass migration of over 10,000 moths was reported to be monitored

by radars oriented directly with downwind [5].

Reasons for Migration

There are many reasons for insect migration, and these may include physiological

and ecological as well. Some of the critical reasons for migration are listed below

[9]: