Long-distance navigation in birds: lessons learned from cage experiments and individual tracking
Spectacular long-distance migration has evolved repeatedly in animals enabling individuals to explore resources separated in time and space on a global scale. Young solo-migrating avian migrants rely on an endogenous migration program, encoding time, distance and direction of migration to reach their non-breeding sites of residency. To select an inherited migration direction during migration birds may rely on information from three different biological compasses, based on the sun, stars and the geomagnetic field. Birds may cover several thousands of kilometers on one seasonal migration path, but still the compass mechanism used during migration flights is not yet completely understood. How birds explore the geomagnetic field for compass orientation and navigation during long migrations, and how they may use magnetic information to detect their position in space is something I have explored by experiments and individual tracking. In this lecture, I will present my recent work and discuss some of the open questions that still needs to be addressed in order to understand the adaptations to long-distance migration in birds.
In my current research, I study movement ecology and especially the phenotypic characteristics of the endogenous migration program in birds, and how animals have adapted to cope with long migrations. Part of this work is dedicated to study the migration phenotype of young birds, and especially the variation and functional characteristics of the endogenous migration program guiding solo-migrating birds on their first migration. I am interested in how different internal and external factors may lead to variation between individuals and species in how the program is expressed. I also have a strong interest in research questions connecting biology and physics, more precisely in sensory ecology, involving studies of how animals use skylight polarization and the earth’s magnetic field for orientation. Some of these studies have been performed during expeditions in the high Arctic. I find common swifts (Apus apus) and their mobile lifestyle most fascinating and I study their non-breeding movements in a continental-wide tracking project since 2009, including populations from different parts of the European and Asian breeding range. I am currently a professor in animal ecology at Lund University and a director of the Center for Animal Movement Research (CAnMove) at Lund University. I am a fellow of the Royal Institute for Navigation in London, a fellow of the Royal Physiographical Society in Lund and a Fellow of the Royal Academy of Sciences in Stockholm.
The role of individual heterogeneity in the collective behaviour of animal groups
Sociality plays a fundamental role in the lives of most animals. An essential goal in biology is therefore to establish how collective behaviour emerges, and how animal social systems form and function. There exists considerable variation among individuals within animal groups and communities across a broad range of levels. Such individual heterogeneity may play a fundamental role in how animals behave and interact within animal collectives, and thereby could affect and drive their structure, collective dynamics, and functioning. My research is focused on unravelling this role of individual heterogeneity in collective behaviour and predict their consequences across social scales. In my work I combine the strong mechanistic approach of Collective Behaviour Research with fundamental concepts from Behavioural Ecology to unravel the link between phenotypic variation, the emergence of collective properties and group functioning, and in turn individual fitness and between-group dynamics. In my talk I will discuss my recent experimental and modelling work and present a unified framework I have been developing for the study of individual heterogeneity in animal groups.
Fascinated how individual animals live and move together in groups, my long-term research goal is to better understand the role individuals play in animal social systems and how phenotypic variation may arise and persist in animal groups. I was born and raised in the Netherlands, and got my Bachelors in Biology at the University of Groningen, and my Masters in Neuroscience and Cognition at the University of Utrecht. I then moved to the UK where I did my PhD at the University of Cambridge. With my doctorate work I showed that individual differences in boldness and sociability play an important role in collective behaviour and drive the spatial positioning, leadership, social dynamics, and group performance of schooling sticklebacks. I then moved to the Collective Behaviour Department at the Max Planck Institute of Ornithology, Konstanz, first as a postdoc and currently as an independent postdoctoral research fellow, where I have been pushing a mechanistic approach for the study of animal behaviour, combining controlled laboratory experiments, field observations, and computers simulations, and build my own fish lab. Recently I have been focused on developing a unified, interdisciplinary framework to help properly explain and predict the role of individual differences in collective behaviour and their consequences across social and ecological scales.
The Social Clock of the Bee
Circadian clocks enable organisms to anticipate predicted changes in their environment and coordinate endogenous processes with external day-night cycles. In spite of the evidence for the importance of circadian rhythms for survival and health, recent studies in an ecologically-relevant context show that in nature many animal species show extended periods of activity around-the-clock with attenuated circadian rhythms and no ill effects. For example, social insects such as honey bees, bumble bees, and several species of ants show remarkable socially-regulated plasticity in circadian rhythms. Forager bees typically have strong circadian rhythms that are needed for time-compensated sun-compass navigation and for timing visits to flowers (“time memory”). “Nurse” workers on the other hand, tend brood around-the-clock which is thought to improve the quality of brood care. We discovered that some clocks in the brain of nurse bees continue to tick in the constantly dark and thermoregulated environment of the hive, and are synchronized (“entrained”) by social time-givers in the nest. These findings raise many questions including: How does circadian plasticity manifest at the molecular level? Which are the endogenous processes for which circadian regulation is essential? Why do nurses need a clock? Do around-the-clock active nurse bees sleep? And what are the social signals that entrain the circadian clocks of nest bees? To answer these questions we use an integrative, multi-level approach, combining sociobiology, animal behaviour, physiology, neuroanatomy, and functional genomics. In my talk I will answer some of these questions and present the state of the art of our research.
My research interests are the evolution and mechanisms underlying sociality and social behavior, I study bees as a model. The notable ecological success of social insects such as bees is largely attributed to advantages associated with sociality. Bee social organization is astonishing; thousands of individuals coordinate their activities to achieve efficient division of labor, food gathering, and complex migratory (swarming) ventures. In spite of their relatively small and simple nervous system, bees show complex social behavior, elaborated learning and memory capacities, sophisticated navigation skills, and in the case of the honey bee, also a symbolic dance (language) communication. The availability of the genome sequences of several bee species sets the stage for studying the intricate behavior of bees in molecular terms. Sociality is not only a puzzling proximate enigma, but also an ongoing evolutionary mystery. I am specifically interested in understanding how an insect with a solitary life style evolved to live in complex societies with social modulation of almost every aspect of its behavior and physiology. To study these fascinating and intricate phenomena we integrate analyses at different levels, from genomic and molecular processes that regulate behavior to sociobiology. We study plasticity and social regulation of behaviors such as division of labor, dominance, phototaxis (directional response to light), and sleep. The major line of inquiry in my group however, has been the interactions between social factors and the biological clock (“Sociochronobiology”). Additional major lines of research include hormones (mainly juvenile hormone and ecdysteroids) and social behavior and the social and molecular regulation of body size in bumble bees.