Diel Vertical Migration

Abstract

This article provides an overview of the variation in diel vertical migration (DVM) behavior observed in zooplankton in inland water bodies. We view DVM as a habitat selection behavior, which provides a good starting point to link physiological responses (proximate factors) with adaptive significance (ultimate factors) in explaining (variation in) diel vertical migration behavior in natural populations. Relative changes in light intensity are identified as the most important proximate stimuli driving DVM, including the amplitude of the migration as well the timing of the up and downward movement. The presence of predator kairomones and hunger are important modifying factors of the response to light stimuli. Predator avoidance and the avoidance of damage associated with UV light are viewed as key factors explaining DVM. DVM should be considered part of a predator avoidance strategy that also involves other traits such as body size and pigmentation, and that may interact with UV-tolerance and competition avoidance. Finally, we discuss DVM briefly in invertebrate predators such as the phantom midge larvae Chaoborus, in phytoplankton and in fish.