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.
Memory Champions- The methods and characteristics of memory athletes
People with superior memories fascinate us. Memory artists perform on
TV and books on memory training often hit bestseller lists. Still,
the mnemonic techniques remain rather unknown even though amazing
performances like memorizing a number with 500 digits in five minutes
or to learn the names of more than 100 people in five minutes are
based upon them. In the scientific literature one finds a lot of
single-case studies and few group studies proving that the techniques
work and can be learned by a wide range of people. In the last years
Neuroimaging studies looked further into the neuronal background of
superior memory performance. The upcoming of memory as a competitive
sport generated a number of memory athletes, who push the World
records for memory performances further year by year and build an
interesting group of people to be studied. Our speaker, Boris Nikolai
Konrad, will talk about the state of affairs of research in superior
memory. He will also demonstrate what a trained memory is capable of
and teach you basic mnemonic techniques that enable immediate success in
My interest in the neuroscience of memory was first sparked by an
unusual hobby. After hearing about mnemonic techniques for the first
time at the age of 18, I discovered the sport of memory. To make a
long story short, between 2005 and 2018 I have won the World Memory
Championships team division eight times with my times, entered the
Guinness Book of World Records four times and was invited to appear on
large TV shows all around the world. To my surprise, when I try to
find research on this topic as a student over a decade ago, there was
not very much to be found. So I was happy when I got the chance to
enter this field myself. After studying physics and computer science
in Dortmund and Reading, I did my PhD research at the Max Planck
Institute of Psychiatry in Munich, where I earned my PhD in Psychology
investigating neural correlated of superior memory. In 2014 I moved to
Nijmegen to join the Donders Institute for Brain, Cognition and
Behaviour as a PostDoc where till today I continue my research in the
fields of superior memory, memory training and plasticity in parallel
with a career in public speaking and science communication. In the
latter field my book “De geheimen van ons geheugen” reached the
national besteller list of the Netherlands in October 2018.
Maladaptive learning of mate preference in a butterfly facing climate change
Over the last decade, it has become clear that most animals learn including short lived and non-social ones. Although learning is expected to increase adaptation to rapidly changing environments, this remains poorly documented. Our experimental work focus on one type of rapid environmental change, the climate crisis, because it is the human-induced environmental change best documented for its negative effects on biodiversity.
Learning is well studied in the context of sexual selection, which is an important evolutionary force to consider for quantifying adaptation of organisms to changing environments because it can work against natural selection. Maladaptation may occur when individuals prefer one resource (e.g., one type of mates) that reduces the fitness compared to other available resources. So far, how learning affects animal responses to the climate crisis by producing adaptive or maladaptive, learned sexual behaviours remains virtually unexplored.
We used as a model the tropical butterfly Bicyclus anynana displaying wet (warm) and dry (colder) season forms that match the alternation of African seasons. We found that a learned mate preference produces maladaptation at three levels under climate change, each of which may be enough to put populations at risk of rapid extinction by 2100 after climate has warmed. Worryingly, learned sexual behaviours were reversed compared to those displayed by naïve individuals; hence ignoring learning in adaptation to climate change may lead to seriously erroneous conclusions. We discuss how general our results may be for other insects and other animals. Altogether, we argue that we need to take a more integrative account of animal responses to human-induced, environmental threats, to predict their extinction risk.
The making and keeping of memory
Inspired by the discovery of ‘place cells’ in the hippocampus by O’Keefe, my research began with thinking of new ways to investigate spatial memory beyond the usual confines of the operant chambers and simple mazes that then populated many behavioural neuroscience laboratories. Place cells have receptive fields determined by an animal’s location in a familiar environment, with distal cues dominating over local cues. Accordingly, I sought to develop a task that would require navigation to a place unmarked by local cues – and from that came the open-field ‘watermaze’ developed in St. Andrews. I and my colleagues soon established that the integrity of the hippocampal formation is required for successful learning, and later that interference with local N-methyl-D-aspartate receptor function is deleterious for learning but not for retrieval. Over time, however, I became frustrated by studying only allocentric spatial memory and navigation. What of the memory for events and the place where they happen – a conjunction that tends always to be remembered together? At the time, I also found myself reading Dutch ethological research, for which the country is justly famous, which was hinting at the existence of such associative ‘episodic- like’ memory in animals gated in a chronobiological manner (work of Serge Daan in Groningen). This led me to ponder new paradigms to study such memory within both the watermaze and new tasks in the ‘event arena’, all set within a programme of research focusing on the synaptic plasticity and memory hypothesis. These studies are now delivering intriguing challenges to classical ideas about memory encoding and memory consolidation.
Information Storage in Memory Engrams
A great deal of experimental investment is directed towards investigating the biological mechanisms of long-term memory storage. Such studies have traditionally been restricted to the investigation of the anatomical structures, physiological processes, and molecular pathways necessary for memory function, and have avoided the question of how individual memories are stored as information in the brain. Moreover the behavioral and physiological aspects of memorystorage are usually investigated in distinct experimental paradigms, with behavioral studies being conducted in whole animals, while plasticity studies mainly relying on in vitro preparations.
Over the past five years, memory engram technology has provided an unprecedented tool for the labelling and experimental manipulation of specific memory representations in the mouse. Memory engram technology integrates immediate early gene (IEG) labelling techniques with optogenetics to facilitate the activity-dependent tagging and reversible manipulation of components of specific memory engrams. Using engram technology we can ask how learning effects the plasticity of engram cells, and conversely, how manipulation of engram cells alters memory function. Thus it is now possible to study the causal relationship between the isomorphic behavioral and physiological properties of memory in a unitary experimental preparation.
In my talk, I will describe the early development of engram technology and how it enables us to label sparse populations of hippocampal cells that are both sufficient and necessary for the recall of specific contextual memories (Liu et al., 2012; Ramirez et al., 2013). I will then present our more recent research on engram cell plasticity, in order to demonstrate how engram technology can be applied as an effective tool for progressive investigation into the neurobiology of long-term memory consolidation and amnesia (Ryan et al., 2015). Our findings indicate that memory engrams survive various forms of retrograde amnesia, but have compromised accessibility due to retrieval deficits. Furthermore, while learning-induced potentiation of engram cell-specific synaptic inputs is necessary for the efficient retrieval of a memory, it is dispensable for the storage of information itself. However we also identified a novel form of engram circuit plasticity characterized by an “all or none” engram-to-engram cell transynaptic connectivity, which survives retrograde amnesia. Based on this research I will discuss a working model of how learned information may be persistently stored in a distributed and hierarchical memory circuit through stable engram cell connectivity patterns (Ryan and Tonegawa, 2016; Tonegawa et al., 2015). I will describe unpublished data produced in my research group which extend these findings. Finally, I will outline my future research program that will directly investigate the role of engram cell connectivity in memory information storage.