Moths and Migration

[gordon.ramel]

Hi everyone,
            Moths certainly do migrate, about 172 species in the UK.  For a discussion of the nature of migration and its definitions see "Migration the Biology of Life on the Move" by H. Dingle ISBN = Pbk 0 19 509723 8, Hbk 0 19 508962 6.

But some comments.
Generally speaking mass movements of insects in a single direction for a unit of time during which they are unresponsive to sigles which normally generate a known response is considered to be migration.

Migration is an adaptation to temporary of fluctuating resources or environmental factors.
Migration is characterised by a persistant movement in one direction.
Migration may be obligatory or facultative.
The use of a directional wind does not stop something being migration, the animal chooses when to fly, when not to and when to come down. The air movemnet is just energy efficiency. Insects that wait on the French coast for a favourable wind before flying to England are just being sensible.  Ofcourse 'just drifting' occurs as well it is called dispersal the difference is discussed in Dingle's book.
Migration often involves physiological changes (i.e. larger wings in migratory forms).
Females often migrate as newly emerged adults, before reaching sexual maturity or developing an eggload.
The stimulation that initiates migration are varied and differ particularly between obligatory and facultative migrators.

Just for the wonder of it 
Aphids migrate, across the English Channel as do Hoverflies and Ladybirds.
Simulid flies migrate in West Africa and Plsnt Hoppers Migrate in various countries.