In many books published in the past a distinction was made between migration and other forms of movements. This statement perhaps best describes the problem with an exact definition of migration. Dynamic migration is directed movement controlled by tides or wind, with navigation abilities not essential. The majority of migratory insects fall into this category. Homeostatic migrations are two-way movements with migrants or offspring returning to breeding areas, hence the need for navigational abilities.
Weather appears to be an important factor for the majority of insect migrations.
They then fly down to ground when they encounter suitable habitats. Scopoli also disperses with local winds. After several hours of flight and often many kilometers from their takeoff site, the aphids begin to descend, now attracted to yellow or green colors. Some insects can rise above lower air turbulence by wind currents or powered flight. Migratory flights at these altitudes can allow insects to disperse against wind directions found at lower altitudes.