Poster at the von Humboldt conference

The last three days I attended the annual von Humboldt conference. It was great fun meeting my fellow research fellows and learning about their (extremely diverse!) work. Quite surprised to learn I was the only Dutch research fellow this year among the many nationalities. Had the chance to present my work during the poster session, which was great fun, and exciting to showcase my new tracking software live using a mobile projector. Got many new ideas these last couple days by chatting with the other researchers at such an inter-discplinary level.

New MSc student joins the lab

Today French MSc student Pauline joins the lab! She starts a three-month project to investigate the mechanisms underlying the boldness personality trait and will run a range of behavioural experiments with three-spined sticklebacks.

Started von Humboldt & Zukunftskolleg fellowship

Today is the start of a new research period for me. I was very lucky to be awarded both a von Humboldt postdoctoral fellowship as well as a Zukunfstkolleg fellowship. These fellowships will give me the freedom to fully develop and pursue my own research ideas and set up my own interdisciplinary research program.

The next couple years I will aim to set up a unified framework for investigating the link between consistent behavioural variation, the emergence of collective properties, group functioning, and ultimately individual fitness and between-group dynamics. I will employ a combination of detailed laboratory experiments, field surveys, and computational modelling to study consistent behavioural phenotypes and collective behaviour of three-spined sticklebacks (Gasterosteus aculeatus).

By developing this framework and fully bridging the gap between the fields of Animal Personality and Collective Behaviour, I aim for this project to yield crucial new insights into the ecological and evolutionary implications of consistent behavioural phenotypes and the evolution of sociality.

New paper out in Proceedings of the Royal Society B!

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.

Read further…

Finished student experiment

The last 6 weeks master students Jana and Fe did an exciting project with me to understand if and how fish school under different light conditions, including complete darkness. They did an excellent job and although still preliminary we already got some exciting results, giving insights into what senses sticklebacks use for schooling and how they manage to school even under very low light conditions. More about this soon!

Awarded public engagement grant

An important aspect of science is the dialogue with the general public. Most public outreach is however rather static, only focused on transferring knowledge, and quite uni-directional. I wanted to find a way to convey my research about collective animal behaviour in a format that people can engage with and appreciate.

An excellent opportunity for more interactive outreach is to bridge science with art. Not only may this lead to a better understanding of science by the general public and more appreciation about the hidden beauty of the world around us, it may also generate new ideas and perspectives about my own work.

I am excited to say that I have been awarded a Zukunftskolleg Intersectoral grant that enables me to set-up a professional collaboration with Toer, a Dutch design studio known for their curiosity-driven work and interactive art installations. This long-term program will bridge the disciplines of science, art, and technology with the aim to not only inform and educate the public about collective behaviour but to inspire and make science accessible in a playful way.

The project is called Under the surface, of which soon we will launch a brand new website at www.under-the-surface.com!

Awarded mentorship grant

I am excited to have been awarded a Zukunftskolleg Mentorship grant to continue my collaboration with Shaun Killen. Shaun and I started working together last year to unravel the fundamental mechanisms of individual traits in the collective behaviour of animal groups. Besides setting-up some new experiments on fish physiology, personality and collective behaviour, we are writing an opinion paper on this important topic.

Reviewing and Publons

As a scientist, I think it is important to contribute to the community. One of the ways I have been doing this the last couple years is by reviewing a fair share of papers (currently 44 reviews for 20 different journals). Even if I am busy I try to accept review invitations if I think I can give a proper assessment of the paper.

I have recently decided to join Publons to have an actual official log of my reviewing activity. After adding my whole backlog of reviews it is now as simple as a simple as forwarding an email to Publons to keep track of my reviews. I think it is great scientists get credit or their reviewing and editorial contributions and think that potentially a website like Publons may help provide further incentive for academics to keep fulfilling this important job.

Snorkling in the Seerhein

Today after work I went snorkeling with some friends from work. We decided to start near the heart of Konstanz and swim down the Seerhein for about one and a half kilometer. I must say people looked a bit surprised to see three guys walking in wetsuit across the street. Although the water was not as clear as I hoped we still managed to see a couple groups of huge Carp, a number of single adult Pike of 1m+ at about 5-8m depth on the river floor, and some huge stickleback schools swimming in the shallows.

A huge Carp, my friend Ziga, and a large adult Pike somewhere in the green of the Seerhein

New paper out in Current Biology!

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).

Highly coordinated school of three-spined sticklebacks swimming in the blue waters of the Bodensee near Konstanz, Southern Germany. Photo: Jolle W. Jolles

Highly coordinated school of three-spined sticklebacks swimming in the blue waters of the Bodensee near Konstanz, Southern Germany. Photo: Jolle W. Jolles

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.

Read further…

MSc project final presentation

During the lab meeting today Lauren gave a great final presentation today of her Masters project on the effects of the group personality composition on group learning ability in three-spined sticklebacks. Looking forward to her MSc thesis in a month’s time!

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Invited seminar Glasgow University

jolle-seminar-glasgow-collectivebehaviour This week I visited Shaun Killen in Glasgow and gave a seminar at the Institute of Biodiversity, Animal Health and Comparative Medicine. Three stimulating days with lots of productive discussion and research ideas for collaboration on the relationship between physiology, personality differences and collective behaviour. Really great to meet the Killen lab and drink some proper Ales and Whiskeys. Thanks to Shaun for hosting me!

Learning a new skill: LaTeX

The last few weeks I delved into learning \LaTeX, a code language for more aesthetically pleasing article writing, especially in terms of mathematical formulas. As my research has increasingly been focused on the mechanisms underlying collective behaviour, for which I do a lot of mathematical computations, such an advanced yet simple text-editor is very helpful and overcomes the many pains I have with MS word!

(1)   \begin{equation*} v_i(t) = |\mathbf v_i(t)| = \sqrt{u_i^2(t)+w_i^2(t)}. \end{equation*}

(2)   \begin{equation*} \mathbf a_i(t)= \frac{\mathbf v_i(t+\Delta t) - \mathbf v_i(t)}{\Delta t} = \frac{\mathbf r_i(t+\Delta t) - \mathbf 2r_i(t)+\mathbf r_i(t-\Delta t)}{\Delta t^2}, \end{equation*}

(3)   \begin{equation*} \rho(t)=\frac{1}{n}\sqrt{\left( \sum_{i=1}^{n}\sin(\psi_i(t))\right)^2+\left( \sum_{i=1}^{n}\cos(\psi_i(t))\right)^2} \end{equation*}

It was quite a steep learning curve, but I managed to write my first paper with it last week. The great thing is that it is also possible to use \LaTeX in wordpress (which I used to create this website). It is also the standard language for drafting preprint articles, which is increasingly suggested and done in the biological sciences, thus a very relevant skill to learn.

Field trip in Catalunya

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.

Hiking up the beautiful Gorge of Sadernes, Catalunya.

Hiking up the beautiful Gorge of Sadernes, Catalunya.

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.

A shoal of Mediterranean barbel foraging on limestone rocks.

A shoal of Mediterranean barbel foraging on limestone rocks.

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Featured on German television

Yesterday our research at the Department of Collective Behaviour was featured in a half hour show on the German television: “Schwarmverhalten – Die Intelligenz der Vielen“. You can see the full program below or at this link. My postdoc supervisor Iain Couzin is featured from 01:18 and I make my appearance at 06:44.

Fische, Ameisen, Heuschrecken: Schwärme verhalten sich schlau, ohne, dass die einzelnen Tiere besonders intelligent sind. Der Schwarm ist die Intelligenz der Vielen. Können Menschen auch Schwarmverhalten nutzen – und Roboter?

Read further…

Camera calibration and reconstruction for fish experiments

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.

Me calibrating a camera with a checkerboard pattern, with colours showing the output of my python script, with a school of 1000 moderlieschen in the background :)

Me calibrating a camera with a checkerboard pattern, with colours showing the output of my python script, with a school of 1000 moderlieschen in the background :)

It works pretty well already, even with non-optimal videos. Next step will be to stitch the videos of multiple linked camera’s.

Stickleback experiments with Schistocephalus

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.

Three-spined stickleback before and after removing four Schistocephalus worms

Three-spined stickleback before and after removing four Schistocephalus worms

New sticklebacks from the Bodensee

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.