I am happy to say that today I start my new job as an independent postdoctoral researcher at the Center for Ecological Research and Forestry Applications (CREAF)! CREAF is a research institute in Barcelona, Spain, focused on biodiversity and global change and has been accredited as an Severo Ochoa Center of Excellence. I am excited to continue my work on individual heterogeneity here in Catalunya to understand how animal groups and communities deal with environmental change. Watch this space!
My latest paper has just been published in the Journal of Open Source Software! It is the paper that accompanies my Python package pirecorder, which facilitates controlled and automated image and video recordings with optimal settings for the raspberry pi, specifically developed for biological research.
So far, researchers have often relied on writing their own recordings scripts to take still photographs and videos from the command line.
Although some specific software solutions exist, what was missing is a complete solution that helps researchers, especially those with limited coding skills, to easily set up and configure their raspberry pi to run large numbers of controlled and automated image and video recordings.
pirecorder was developed to overcome this need. You can get a quick overview of the package and what it is capable of in the video below:
Pirecorder is open source via GitHub, https://github.com/JolleJolles/pirecorder, easy to install using pip (
pip install pirecorder), and comes with its own dedicated documentation website: https://jollejolles.github.io/pirecorder/.
The accompanying paper is published in the Journal of Open Source Software:
Jolles, J.W. (2020). pirecorder: controlled and automated image and video recording with the raspberry pi. Journal of Open Source Software 5(54), 2584. doi: 10.21105/joss.02584.
Today my latest paper came out in Biology Letters! You can find it here.
The spectacular and complex visual patterns created by animal groups moving together have fascinated humans since the beginning of time. Think of the highly synchronized movements of a flock of starlings, or the circular motion of a school of barracudas. Using state-of-the-art robotics, a research team from the University of Konstanz, Science of Intelligence, and the Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB) shows that animals’ speed is fundamental for collective behavioral patterns, and that ultimately it is the faster individuals that have the strongest influence on group-level behavior. The study, published in Biology Letters of the Royal Society, gives new insights on complex collective behavioral patterns in nature, and provides knowledge that could help develop robotic systems that move collectively, such as robot swarms, driverless cars, and drones.
Researchers have long focused on identifying the emergence of collective patterns. Thanks to a combination of behavioral experiments, computer simulations, and field observations, it is clear that many seemingly complex patterns can actually be explained by relatively simple rules: move away from others if they get too near, speed up towards others if they get too far away, and otherwise move at the same speed and align with your group mates.
“Besides understanding the rules that individuals follow when interacting with others, we need to consider the behaviors and characteristics of those individuals that make up the group and determine their influence for collective outcomes” says Dr. Jolle Jolles, a scientist at the Zukunftskolleg, University of Konstanz, and lead author of the study. “Across the animal kingdom, it has been found again and again that animals tend to differ considerably from one another in their behavior such as in terms of their activity, risk-taking, and social behavior“. What are the consequences of this behavioral heterogeneity when it comes to collective behavior? And how can one test for its social consequences?
To disentangle the role of individual differences in collective behavior and the mechanisms underlying this type of behavior, the research team built “Robofish”, a robotic fish that not only realistically looks and behaves like a guppy – a small tropical freshwater fish – , but also interacts with the live fish in a natural way. The experimenters paired the robotic fish with a guppy and programmed it to always follow its partner and copy its movements, lacking however any movement preferences of its own. The team then used high-definition video tracking and a closed-loop feedback system to let the robotic fish respond to the live fish’s actions in real-time.
“One of Robofish’s simple interaction rules was to keep a constant distance to its shoal mate” explains Dr. David Bierbach, who works within the Berlin-based Excellence Cluster ‘Science of Intelligence’ at the HU Berlin and the IGB, and is senior author on the paper. “Using this rule, our Robofish tried to keep the same distance to the live fish by accelerating and decelerating whenever the live fish did. Also, programming the robotic fish without any own movement preferences gave us the unique opportunity to investigate how individual differences in the behavior of the live fish led to group-level differences. In short, with our unique approach, we could isolate the effect of the fish’s movement speed on the pair’s collective behavior“.
The researchers first quantified the guppies’ natural movement speed by observing their movements when alone in an open environment, and found that there were large individual differences in how fast guppies tended to move. When the fish were subsequently tested with Robofish, the fish and Robofish tended to swim naturally together as a pair. However, the researchers observed that there were large differences in the social behaviors between the pairs: pairs in which the guppy had a faster movement speed tended to be much more aligned, more coordinated, and less cohesive, and the guppy emerged as a clearer leader. As Robofish behaved according to the same identical rules with each and every guppy, it is the individual speed of the guppies that must have led to these differences in group-level properties.
By involving state-of-the-art robotics, this research shows that individual speed is a fundamental factor in the emergence of collective behavioral patterns. As individual differences in speed are associated with a broad range of phenotypic traits among grouping animals, such as their size, age, and hunger level, the results of this study may help understand the role of such heterogeneity in animal groups.
Future studies using the interactive Robofish will focus on other aspects of collective behavior: For example, how can animals act in synchrony if they just respond to the actions of their neighbors? “We want to improve Robofish’s software so that it can predict and anticipate the live fish’s next steps, which is assumed to be how animals do it.” says David Bierbach.
Understanding these mechanisms is not only fundamentally important as it reveals information about the mechanisms that underlie collective behavior and decisions, but also because this knowledge can be applied to artificial systems and used to develop machines that move collectively, such as robot swarms, driverless cars, and drones.
I have been awarded a €3.900 grant from the Young Scholar Fund for a pilot project in the Spanish Pyrenees to assess the effects of severe drought on fish persistence. Specifically, I want to understand how individuals and groups of fish deal with severe droughts and how phenotypic variation may impact population structure and persistence. This project will hopefully provide the basis for a long-term project whereby I will use an individual-based approach to understand how individuals and groups of fish cope with environmental change.
Today my latest paper Schistocephalus parasite infection alters sticklebacks’ movement ability and thereby shapes social interactionshas been published in Scientific Reports! Although many fundamental aspects of host-parasite relationships have been unravelled, few studies have systematically investigated how parasites affect organismal movement. In this study we combine behavioural experiments of Schistocephalus solidus infected sticklebacks with individual-based simulations to understand how parasitism affects individual movement ability and how this in turn influences social interaction patterns.
By detailed tracking of the movements of the fish, we found that infected fish swam slower, accelerated slower, turned more slowly, and tended to be more predictable in their movements than did non-infected fish. Importantly, the strength of these effects increased with increasing parasite load (% of body weight), with the behaviour of more heavily infected fish being more impaired.
When grouped, pairs of infected fish moved more slowly, were less cohesive, less aligned, and less coordinated than healthy pairs. Mixed pairs exhibited intermediate behaviours and were primarily led by the non-infected fish. These social patterns emerged naturally in model simulations of self-organised groups composed of individuals with different speeds and turning tendency, consistent with changes in mobility and manoeuvrability due to infection.
Together, our results demonstrate how infection with a complex life cycle parasite affects the movement ability of individuals and how this in turn shapes social interactions, providing important mechanistic insights into the effects of parasites on host movement dynamics. Download our open access paper here!
Today I gave a talk at the 2020 ASAB Summer meeting about my recent work about the effects of Schistocephalus parasite infection on individual and social behaviour (paper here). It was my first talk at a virtual meeting, which took a bit more time to prepare, but despite being completely virtual due to the covid-19 pandemic, the conference turned out really well. Many people “attended” my talk, which was followed by a live Q&A with the other speakers in my session. All other conferences I was planning to attend this year (at least 4) have been cancelled this year, so it was great to that this conference was made possible in the virtual realm at least!
I am excited to hereby release this 3 min short about my work. With support from the Zukunftskolleg, I teamed up with Berlin filmmaker Nicolas Buenaventura to create this video to provide a visual overview of my research. It also gives some nice insights about the various aspects of my work, from catching fish, setting-up experimental systems, writing my own recording and tracking software, to analysing data.
Today I released a new preprint on bioRxiv, Group-level patterns emerge from individual speed as revealed by an extremely social robotic fish, which is the result of a great collaboration with David Bierbach and colleagues at the Humboldt Universität zu Berlin.
In this paper we present results of an experiment to investigate how the speed of individual group members leads to group-level patterns. We paired guppies with a biomimetic robot that was programmed to always follow and lack any individual preferences of its own. We used a state-of-the art closed-loop tracking and feedback system to be able to properly control for the influence of individual heterogeneity of the individual’s group members.
We show that individual differences in guppies’ movement speed were highly repeatable and shaped key collective patterns: higher individual speeds resulted in stronger leadership, lower cohesion, higher alignment, and better temporal coordination in the pairs. By combining the strengths of individual-based models and observational work with state-of-the-art robotics, we provide novel evidence that individual speed is a key, fundamental process in the emergence of collective behaviour.
I am excited to say that our review in Trends in Ecology and Evolution, after already being available online, is out now in print and is shining on the front cover! I took this photo of this stunning stickleback school while snorkelling in the Bodensee to study their collective behaviour. Read our open access paper here.
Today my latest paper came out in Animal Behaviour, one of my favourite journals. It is titled “Personality, plasticity and predictability in sticklebacks: bold fish are less plastic and more predictable than shy fish“. In this paper, which is a result of a collaboration with Neeltje Boogert and Yimen Araj-Ayoy and a MSc project of Helen Briggs, we present an extensive experimental study focused on better understanding the sources of behavioural variation among individual animals.
In short, we tested 80 three-spined sticklebacks repeatedly on their boldness across a 10-week testing period and automatically tracked their movements. We then employed advanced statistical model techniques (GLMMs and DHGLMs) to use this large behavioural dataset to investigate the potential links between the personality (consistent differences in average behaviour), the plasticity (how individuals change their behaviour over time/contexts), and predictability (the remaining intra-individual variation after accounting for personality and plasticity differences) in behaviour.
Besides detecting large consistent individual differences in boldness and the extent to which fish changed this behaviour over time (temporal plasticity), we found that boldness personality and plasticity were negatively linked, with bold fish changing little in their behaviour over time. Interestingly, there were still large individual differences in the remaining behavioural variation, with bold fish showing much less behavioural variation and thus behaving more predictable than shy fish. Importantly, these results suggest that boldness, plasticity and predictability may be fundamentally linked and form part of the same behavioural syndrome.
Jolles, J. W., Briggs, H. D., Araya-Ajoy, Y. G., & Boogert, N. J. (2019). Personality, plasticity and predictability in sticklebacks: bold fish are less plastic and more predictable than shy fish. Animal Behaviour, 154, 193–202.
From swarm to school, stickleback groups differ repeatedly in their collective performance
among schooling fish, groups can have different collective personalities, with some shoals sticking closer together, being better coordinated, and showing clearer leadership than others.
For centuries, scientists and non-scientists alike have been fascinated by the beautiful and often complex collective behaviour of animal groups, such as the highly synchronised movements of flocks of birds and schools of fish. Often, those spectacular collective patterns emerge from individual group members using simple rules in their interactions, without requiring global knowledge of their group.
In recent years it has also become apparent that, across the animal kingdom, individual animals often differ considerably and consistently in their behaviour, with some individuals being bolder, more active, or more social than others.
New research conducted at the University of Cambridge’s Department of Zoology suggests that observations of different groups of schooling fish could provide important insights into how the make-up of groups can drive collective behaviour and performance.
In the study, published today in the journal Proceedings of the Royal Society B, the researchers created random groups of wild-caught stickleback fish and subjected them repeatedly to a range of environments that included open spaces, plant cover, and patches of food.
My latest paper on the collective behaviour of stickleback shoals is out today in the journal Current Biology!
Jolles, JW, Boogert, NJ, Sridhar, VH, Couzin, ID, Manica, A. (2017) Consistent individual differences drive collective behaviour and group functioning of schooling fish. Current Biology 27: 1-7. doi: 10.1016/j.cub.2017.08.004 (link).
New research sheds light on how “animal personalities” – inter-individual differences in animal behaviour – can drive the collective behaviour and functioning of animal groups such as schools of fish, including their cohesion, leadership, movement dynamics, and group performance. These research findings from the University of Konstanz, the Max Planck Institute of Ornithology and the University of Cambridge provide important new insights that could help explain and predict the emergence of complex collective behavioural patterns across social and ecological scales, with implications for conservation and fisheries and potentially creating bio-inspired robot swarms. It may even help us understand human society and team performance. The study is published in the 7 September 2017 issue of Current Biology.
Observations of schooling Mediterranean barbel
Last week I was in Catalunya visiting friends and family and some undistracted paper writing. Catalunya, where my wife grew up, is an amazing place and feels like a second home to me. With the Mediterranean sea and the Pyrenean mountains within half an hour’s drive, there is always a lot to explore.
During some recent trips, I went hiking in the Pyrenean foothills and discovered schools of Mediterranean barbel (Barbus meridionalis). They seemed to be separate populations living in semi-isolated pools of a small mountain river. This species of Barbus is only native to a small area in and around the Eastern Pyrenees. Sadly, in recent years its numbers have plummeted with 30% (source: IUCN), highlighting an urgent need to better understand their ecology and vulnerabilities.
The last few months I have been working hard on the sophisticated new experimental set-ups in the lab with which we will be able to get high spatial and temporal resolution tracking of large schools of fish, in tanks that are up to 3x3m in size!
To get highly accurate spatial data of the fish we need to correct for the distortion of the camera lens, which almost all lenses have to some extent. I just finished the script (in Python) that enables us to undistort the image from a camera using functions in opencv based on a video of a moving checkerboard.
It works pretty well already, even with non-optimal videos. Next step will be to stitch the videos of multiple linked camera’s.
Recently I started a couple experiments related to parasite infection of Sticklebacks with Schistocephalus, a tapeworm with a fascinating life cycle that requires three separate host species. Our experiments focus on how the parasite affect the fish’s movements, its social interactions and positioning, collective behaviour, and survival in the context of predation.
Today, when moving fish around for experiments, I noticed one particularly bulged individual that, instead of a the smooth elongated body had the body shape of a brick! A clear sign of Schistocephalus infection. We put it down and measured its body weight, both before and after opening up its stomach cavity. What we found was not one, not two, not three, but four individual flatworms with a total weight of 55% of that of the fish! Incredibly how the fish could actually survive with such an immense parasite load.
Went out again with the boat yesterday to catch sticklebacks. A cold but beautiful day. At first we couldn’t find them where I saw them last week, but soon enough it was clear they were still there but just very well camouflaged against the pebbled background!
With the three of us we managed to catch about 300 of them in half an hour by wading through the shallow waters. Most of the fish are likely 1st-years, but we also caught a couple older individuals that were huge, close to 10 cm!
After mooring the boat, we moved all fish to a large social housing tank at the Limnological institute where they will undergo a anti-parasite treatment for a couple weeks. After that I will move them to our fish lab at the University of Konstanz as well as to outside mesocosms. There they will ‘participate’ in a range of my behavioural experiments focused on individual differences in collective behaviour.
The past summer, I successfully completed a motorboat course to enable me to drive a motorboat on the Bodensee, required for my ongoing research on fish collective behaviour. I got my “Sportbootführershein” in the post a couple weeks ago, and finally this weekend was able to ‘take the boat out’.
In the cold rainy weather of early November, I set-off with with a good friend on one of the motorboots from the Limnological Institute. The water was considerably clearer than during the summer, providing a visibility of just over 5 meters. It was beautiful being out on the water. However, in the first hour almost being out, we still hadn’t seen our first fish!
We navigated around the island of Mainau, and started exploring the very shallow areas near the mainland. I was a bit annoyed I hadn’t seen any fish yet, let alone any sticklebacks, but when we decided to cross under the bridge leading to Mainau we suddenly found thousands of them!
The water was so shallow that it was necessary to take the motor out, and continue by oars. But this also meant we could observe the swarming fish from very close. Despite sticklebacks being very abundant in the Bodensee, in the autumn and early winter most of them move to deeper waters, likely following the movements of their invertebrate prey. These remaining fish were apparently some of the last ones remaining in the shallows, likely seeking shelter in the shadow of bridge, and I was therefore very happy to have found them.
We spent about half an hour observing their movements and behaviour and I got some good ideas to come back for some more quantitative field measures of their group sizes and compositions. After that we decided to go for a quick snorkel before going back to the harbour.
With my freediving wetsuit, the 11 degrees C actually still felt very comfortable, and I was enjoying the relatively clear waters of the lake. The Bodensee has a very interesting geology, with relatively shallow water on its edges that can suddenly drop almost vertically tens and tens of meters into the deep.
We only snorkeled a bit above a drop-off near the harbour to check our wetsuits and the visisbility, which both passed our expectations. I therefore can’t wait to go back again and take the boat out the lake to catch wild individuals for my experiments, get some more quantitative observations of the sticklebacks and their predators, and explore underwater.
Last weekend I went exploring the streams and lakes in the countryside near Konstanz to search for Moderlischen and determine the possibilities for doing fieldwork to investigate group movement dynamics and composition in the wild.
I was able to find them in some tiny streams leading to a small lake, showcasing some nice examples of collective shelter use and leadership and exploration of the stream, see the video below. Looking forward to starting exploring possibilities to start some actual field work on these populations.
For my new research projects on the role of individuality in collective movements and decision making at the University of Konstanz, I have been getting new sticklebacks from the Bodensee. Last weekend I went to see them together with my 10mo son! I think it was the first time he actually ever saw moving fish. Although I showed him fish in aquaria before, he was too young to react to them, but this time he was amazed by the large school of fish swimming back and forth. The sticklebacks from the lake were absolutely huge, I estimate up to about 9cm, much bigger than the ones I ever saw in Cambridge and the ones in the ponds near the University here. I hope to go on a trip soon to observe the collective behaviour of the sticklebacks in lake Konstanz, the ponds, and streams in the area to set-up some exciting experiments on the population-specific differences of this amazing species.
My research is currently centred around understanding the role of consistent behavioural differences in the collective movements and functioning of animal groups. In particular, I assay large numbers of stickleback fish on various personality traits and expose them in groups to different ecological scenario’s. I have written custom tracking software in Python using the OpenCV library to be able to accurately track the position of individual fish in the freely-moving schools.
Today I wanted to share a simple visual that highlights the detailed individual-based tracking of a small fish school over time. Each fish is represented by a different colour, with the arrow showing its vectorized movement, with larger arrows indicating a higher speed. The video is centred around the vector of the group as a whole to better visualize the structure of the group over time. Lines indicate the smallest polygon encompassing all individuals and Individual Centre Distances. The moving axes indicate the relative speed of the group in a large circular arena.
In this short section of a 30-min long experimental trial it is clear that the group speed, cohesion, and structure fluctuate over time. At the same time, individuals also maintain to some extent their positions relative to the group centre, such as the green and yellow individual clearly having a stronger pulling power on the movements of the group as a whole.
I used RaspberryPi computers to film the fish, custom Python tracking scripts to acquire individual X,Y coordinates for each individual in the group, R to process the tracking data and acquire movement characteristics, and R with ffmpeg to create the visual.
I have been trying to improve my drawing skills to better illustrate how my sticklebacks behave and in what way personalities matter in collective behaviour. I still have a far way to go but this is my latest quick sketch that shows four sticklebacks with different morphologies. When I get more time on my hands after I hand in I will try to get some more elaborate drawings done!
Just over three years ago I was standing up to my waist in cold water, somewhere in the vicinity of Cambridge. I was catching sticklebacks for the first experiments of my PhD. Now, 37 months later, I am in the final stages of writing-up and will actually hand in my thesis in ten days time! During this last chapter of my PhD, I have also become a dad and am actually writing this with my 5 month-old son in the carrier on my chest. Luckily, after a nice walk with our dog in the cold autumn air, he has fallen vast asleep.
If it wasn’t for all funding falling away at the 3 year mark, one and a half month ago, I would be continuing with some additional exciting data chapters of which I already got the data. However, with five data chapters, two of which are published and two have been accepted, I have enough exciting work to talk about. In the months to come, I will be wrapping up a lot of small and large stickleback projects that I have done over the years and that have not made it into my thesis, besides some nice collaborative studies, and will continue with further experiments on the link between personality and collective behaviour as a Postdoc!
Now, time to get back to thesis writing..
Recently I was invited to participate in the latest episode of the fantastic Naked Scientists podcasts series to highlight why sticklebacks are the most incredible animal on the planet!
Colour-switching sticklebacks, geckos with enough adhesive power to hold up a human, bats with built-in sonar and moles with amazing noses – this week we go in search of the world’s most incredible animals. Scientists passionate about their species put their cases to our panel. But which animal will be crowned king?
To make clear to the radio audience why sticklebacks, perhaps ordinary looking fish to most, are actually an amazing animal species I brought along 10 fellow stickles and made them change colour over the time of the hour long interactive show! You can listen to the full podcast here or just listen to my part here where I also discuss a range of other cool abilities of this great little fish.
The Naked Scientists show was brilliantly hosted by Ginny Smith, had some amazing other speakers including Hannah Rowland, Corina Logan, Nick Crumpton, and Jade Cawthray, and also aired on BBC Radio 5.
Very recently two part IB students of mine finished a nice little experiment on the spine-use of three-spine sticklebacks. We were interested to see how personality might be related to the raising of the spines of three-spine sticklebacks as it helps them in protection against predators. Watch this close-up video that I took that nicely shows one individual stickleback raising its spines and lowering them again after feeling threatened by my presence. Hopefully soon we have the manuscript out with the findings of our study!
Today I finished my last experiment that will be part of my PhD! I have been locked away in the lab for a couple weeks, testing hundreds of fish on their personality and collective behaviour, but now analysis and writing can fully start. I must have tested close to a thousand fish in the two and a half year since the start of my PhD, most of which are now enjoying a happy end of their lives back in the wild. I have all the data of a number of exciting projects that will not need me to go back to the lab for at least half a year but I can actually not wait to test my next hypothesis! The three-spine stickleback is an amazing species to work with and I will definitely continue working with them after my PhD.
Recent research of colleagues and I at the University of Cambridge has revealed that sticklebacks with bolder personalities are not only better leaders but also less sociable than more timid fish. The behaviour of these bolder fish shapes the dynamics of the group.
See a 4min video about the paper here: http://youtu.be/5TSim9TkXiw
Throughout the animal kingdom, individuals often live and move together in groups, from swarms of insects to troops of primates. Individual animals may benefit from being part of groups, which provide protection from predators and help in finding food. To ensure that individuals reap the benefits of togetherness, group members coordinate their behaviour. As a result, leaders and followers emerge.
Within groups, animals differ from each other in how they cope with their environment and often exhibit distinctive traits, such as boldness or sociability. Even three-spined sticklebacks, the ‘tiddlers’ collected from streams and ponds by generations of schoolchildren, can be described in terms of their personalities: some are bolder and take more risks, while others are more timid and spend more of their time hiding in the weeds.
Research carried out in the Zoology Department at the University of Cambridge suggests that observations of these tiny fish, and how they interact with one another, could provide important insights into the dynamics of social groups, including humans.
Jolle Jolles, lead author of the study, said: “Although we now know that the spectacular collective behaviours we find throughout the animal kingdom can often be explained by individuals following simple rules, little is known about how this may be affected by the personality types that exist within the group.
“Our research shows that personality plays an important role in collective behaviour and that boldness and sociability may have significant, and complementary, effects on the functioning of the group.”
In the study, the researchers studied the behaviours of sticklebacks in tanks containing gravel and weed to imitate patches of a riverbed. The tanks were divided into two lanes by transparent partitions and randomly-selected pairs of fish were placed one in each lane. Separated by the see-through division, the fish were able to see and interact with one another.
The positions and movements of the individual sticklebacks were recorded using sophisticated tracking technology, enabling accurate comparisons to be made of each fish’s role in the collective movement of the pair.
“We found that individuals differed considerably and consistently in their tendency to approach their partner,” said Jolles. The study showed that more sociable individuals tended to be coordinated in their behaviour while less sociable individuals were more inclined to lead.
Dr Andrea Manica, reader at the Department of Zoology and co-author of the paper, added: “Our research revealed that the tendency of fish to approach their partner was strongly linked to their boldness: bolder fish were less sociable than their more timid group mates.”
Jolles explains that sociability may form part of a broader behavioural syndrome. “Our results suggest that bolder, less sociable individuals may often lead simply because they are less reluctant to move away from their partners, whereas shyer, more sociable, individuals become followers because they prioritise staying close to others,” he said.
“Differences in boldness and sociability may be expressions of underlying risk-prone or risk-averse behavioural types, as risk-averse individuals may be more motivated to group together and to respond to other individuals in order to avoid predation.”
The findings of this study suggest that leadership and group coordination can be strongly affected by personality differences in the group and that boldness and sociability may play important but complementary roles in collective behaviour.
Jolles added: “Now we know these personality traits affect the collective movements of pairs of fish, the next step is to understand their role in the functioning and success of larger, more dynamic groups.”
See a 4min video in which we explain our paper in more detail below:
Click here to download the paper.
Jolles JW, et al. (2015) The role of social attraction and its link with boldness in the collective movements of three-spined sticklebacks. Animal Behaviour, published online 2 Dec. Doi: 10.1016/j.anbehav.2014.11.004
Leadership behaviour is affected by social experiences from previous partners and depends on an individual’s personality, as shown by our latest study with three-spined stickleback fish, now published in Behavioral Ecology.
From the political affairs we see on the news, to making decisions with your friends, leadership is all around us. But next to humans, leaders and followers can also be found in many group-living animals, such as fish, birds, and primates.
Social animals may receive benefits from grouping such as protection from predators and help in finding food. But to ensure individuals reap the benefits of grouping, they must time and coordinate their behaviour with the emergence of potential leaders and followers as a result.
Continuing on from yesterday’s post about the personality testing for boldness, today I made a time-lapse video from one of the sessions to get a quick overview of the actual running of the experiment. For most experiments I work with 40-64 fish per batch and potentially run multiple batches. Therefore, to be able to test all fish on the same day I test 8 fish simultaneously in 8 separate lanes for one hour and run 8 consecutive sessions in a row.
Throughout the animal kingdom, individuals have been found to behave consistently different from one another over time or across different contexts. This is now mostly referred to as “animal personality”. As part of my PhD I want to understand what role such personality traits play in the structuring and functioning of social groups, i.e. in collective behaviour.
Today I am running an experiment to investigate the consistency of risk-taking behaviour, also known as the boldness personality trait. I work with three-spined sticklebacks that I caught in wild streams near Cambridge. The three-spined stickleback is a wonderful little fish that is not only easy to work with and keep in the lab but a model system for collective behaviour and animal personality.