The Physiology of Migration

Abstract

Abstract There are two major aspects to the physiology of migration. The first is the central nervous system (CNS) control of migratory behavior by means of interactions between migration and “settling” responses. This aspect was discussed in Chapter 2, where migration is defined. The nervous control of migratory behavior by the CNS was analyzed for the aphid, Aphisfabae,by J. S. Kennedy, as we have seen, and it involves not only the enhancement of locomotory behavior but also the reciprocal inhibition of “vegetative” responses such as feeding and reproduction, even in the face of stimuli that would usually trigger those responses. Although there is strong suggestion of reciprocal interaction between migratory and vegetative behaviors in other animals, many songbirds, for example, migrate at night when they would otherwise be sleeping (a vegetative response) and other examples occur throughout this book, Kennedy’s aphid study is virtually the only one in which the action of the CNS has been explicitly considered. Analagous reciprocal mechanisms occur in the migratory physiology of plants, but they, too, have been little studied from a perspective of promoting migration (see Chapter 2). Even though CNS control is so fundamental to migratory and indeed all behavior in animals, the lack of understanding of the CNS function and role in migration, and the almost total lack of studies investigating that role, is undoubtedly the single biggest lacuna in our entire conception of the migration phenomenon. Unfortunately there is little one can do at this point except plead that the conceptual foundation established by Kennedy for aphids be followed up in studies of migratory behavior in other organisms.