Photoperiodism The Biological Calendar

This book examines the role of photoperiod in timing seasonal adaptations, and is divided into three sections. Each of the three sections begins with an introductory chapter by the section editor. The first section examines the role of photoperiod in plants. The second section comprises chapters detailing the role of photoperiod in invertebrate biology. The third section consists of chapters about vertebrate photoperiodism. At the end of the third section, the three editors attempt synthesis and emphasize common themes in photoperiod time measurement across taxa, common and dissimilar approaches to the study of photoperiodism, and propose future directions in research on photoperiodic time measurement. Although studies of photoperiodic time measurement originally included both plants and animals, the current literature is distinctly separated among investigators studying plants, invertebrates, and vertebrates. This separation has meant that researchers are often re-inventing the wheel so to speak. For example, understanding that there are genetically-distinct morphs among species that responded to different critical photoperiods depending upon latitude was discovered separately in plants, invertebrates and vertebrates over the course of 22 years. Remarkable progress has been made over the past decade in understanding the phenomenology, as well as the molecular and genetic mechanisms underlying circadian rhythms and clocks. Part of this success was the rapid communication among researchers working on circadian rhythms in Drosophila (fruit flies), Arabidopsis (mustard plant), and Mesocricetus and mutant Mus and (hamsters and mice). The field is poised to make rapid progress in the understanding of seasonal clocks at all levels of analysis and we hope that this book will stimulate cross-talk among investigators from all related disciplines.

Randy J. Nelson is a Distinguished University Professor of Social and Behavioral Sciences at Ohio State University.
David L. Denlinger is a Distinguished University Professor in the Department of Entomology at the Ohio State University.
David E. Somers is an Associate Professor in the Department of Plant Cellular and Molecular Biology at the Ohio State University.