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Insect Migration

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• The locomotory functions are enhanced, and vegetative functions (like feeding

and reproduction) are suppressed.

• Migration takes place before reproduction in the life of an adult insect.

• The insects with migration ability tend to have temporary habits and have high

potential to increase their population.

• Physiological and ecological parameters of migration are bound to change.

Desert Locust completely depends on seasonal rains for breeding. However, based

on climatic conditions they migrate to different areas. Considering the availability

of food, these insects will migrate and the rate of migration increases to a particular

area in the process of searching for food [10]. The female insects prefer to migrate

from breeding area to feeding area. These insects develop mature ovaries and will

return to the place from where they came or to a similar region for laying eggs. Such

migration involves longer distances with unusual long life spans including diapause

[11]. Migration itself is a highly complex problem due to diapause.

This climate during hibernation will not be suitable for breeding and hence the

insects return to the same place for laying eggs. Such migration process involves

longer distances. During spring again they return to breeding areas. A ladybug

(Hippodamia convergens) lives in California to hatch eggs and adults develop in

spring. During summer they migrate to suitable mountains for laying eggs [11].

Cardé [5] reported a special mechanism in moths in order to determine the direc-

tion of displacement during airborne flight. They presumably descend to the ground

levels if the wind direction is wrong during night times and stop migration.

Monarch butterfly (Danausplexippus) is known to be the best example for return

migration. In autumn, these butterflies migrate to southward (see Fig. 10.2) for hiber-

nating by travelling 3,600 km and migrate back towards north for breeding during

Fig. 10.2 Migration cycle of Monarch butterfly in North America. Source Guerra and Reppert [12]

(Modified Diagram)