On the 14th of April, my first bat paper came online in the journal Scientific Reports. In this paper, led by the talented Theresa Schabacker, we studied how bats explore novel roost-like environments using a newly developed maze-type testing arena. We here show that individuals differ in how they use echolocation to explore, with some bats consistently under-sampling a novel environment while others over sample.
Through exploration animals gain vital information about the availability of resources, the distribution of conspecifics, and the presence of predators. It also helps them to pick up changes in the environment quicker. Studies on how animals explore novel environments are usually conducted by measuring spatial movements. Yet, when exploring, not only where an animal goes is relevant, but also, or even especially, the information it acquires. Birds get new information primarily by using vision, which is challenging to measure. Bats, on the other hand, primarily use echolocation, which we can measure!
We developed a maze-like test arena in which tree-roosting bats could explore small chambers that were connected through ports. This arena is designed so it can easily be brought to the field, in this case the Pape Ornithological Station in Latvia, and so the bats do not need to be transported away from their habitat. Using a night-vision camera and a sensitive microphone we recorded the spatial and acoustic behavior of migratory Nathusius’ pipistrelles (Pipistrellus nathusii) for two minutes after they voluntarily entered the maze (some never entered). We did this twice for over 50 individual bats and discovered that not only the echolocation behavior and the number of chambers they visited was strongly correlated (more chambers meant more echo calls), individuals also consistently differed in how many calls they made per chamber. Some were just more thorough in sampling these new chambers than others. This sampling behavior was also correlated to another seemingly explorative behavior: the number of times they took peeks (but did not enter) other chambers.
These bats remind me of how people differ when going through a museum. Some go and look at every painting in a room while others are satisfied with just a few highlights. Bats are not so different as it turns out. Of course, this raises tons of new questions, like: do more thorough exploring bats indeed detect changes in their environment sooner? Does this bring them a fitness-benefit? Or is it actually very costly to echo-locate this much? And does a quickly changing environment select for more thoroughly exploring bats?
Still so much to explore!
Schabacker T, Lindecke O, Rizzi S, Marggraf L, Pētersons G, Voigt CC, Snijders L (2021). In situ novel environment assay reveals acoustic exploration as a repeatable behavioral response in migratory bats. Scientific Reports: Online.
On 20-01-2021 the latest fruit of our Trinidadian guppy research project came online in the Open Access journal Communications Biology. With this experimentalfield study, we provide rare causal evidence for the adaptive benefits of social foraging in the wild. For both sexes!
For the complete story, check out the paper here. For the popular science summary, check below (Dutch version here)
Guppies with friends eat more
Guppies that socialise with more conspecifics get more food. This applies to both males and females, despite the common assumption that males are not very social. This is revealed through a unique field study conducted by Wageningen University & Research in Trinidad in collaboration with Leibniz-Institute of Freshwater Ecology and Inland Fisheries.
‘Much research has already been done under lab conditions on the impact of group size on animals’, says Lysanne Snijders. ‘Still, you never know whether the results such studies show, apply equally in nature’. Moreover, in the wild, other factors such as predators’ presence also influence animals’ social behaviour.
Benefits of social behaviour
As far as we know, this is the first time a causal relationship was found between the number of animals of the same vertebrate species and it’s benefits to individuals. In Trinidad, Snijders and her colleagues were able to get a close look at the influence of size and composition of groups under natural circumstances by distributing the guppies over different pools. The behaviour of the fish in different group sizes was extensively analysed and recorded.
Snijders and her team showed that guppies living in larger groups were often more successful at obtaining food. From an evolutionary perspective this is interesting: apparently, an increased food intake is a direct benefit of being social in the wild (as is protection from predators), and may thus partly explain why we often see guppies engage in social associations.
Moreover, the study, published in Communication Biology, shows that males and females alike benefit from larger groups. This is remarkable, as females are generally perceived as more social.
Snijders: ‘In the vast majority of guppy research, the study is limited to females because males are thought to be predominantly occupied with mating opportunities. This study, under natural circumstances, clearly shows that males also benefit from social behaviour and that this advantage is not solely restricted to them obtaining females. Assumptions about a lower level of sociability do thus not necessarily translate into fewer social benefits.’
A new start in a place that is very familiar to me, the Behavioural Ecology Group of Wageningen University, the university where I defended my PhD in April 2016. Now I am very excited to be back as an Assistant Professor.
My PhD project focused on the role of personality in the social networks of territorial songbirds. In my years away, I have expanded on these topics and added some additional interests and fascinating study models to it. I investigate(d) the role of social behavior and the social environment in the foraging performance of wild guppies. I designed an in situ personality test for wild bats to investigate a potential link with migration behavior and I became part of a wonderful network of behavioral ecologists, passionate to contribute to conservation.
I still can’t quite believe I get to do this work as a profession and I am truly grateful for this incredible opportunity. I will continue with my work on social foraging in guppies, working together with the Leibniz-IGB, and with my systematic map on the effectiveness of animal conditioning in Human-Wildlife Conflicts. I am also very enthusiastic to start and collaborate on new projects involving conservation behavior, social behavior and animal personality. And, of course, to supervise students who are motivated and curious to explore these topics with me!
For our Exploring Conservation Conflicts blog, we are trying out a new format: personal contributions. We already got two wonderful personal stories tackling very different but important questions in conservation. Check them out!
Climate change is one of the greatest challenges humans have ever faced. This exploration is a personal account of the role that climate change plays in the daily life of researcher Dr Yann Gager. Yann explains to us what individual researchers can (and should?) do to help the fight against climate change. Read more
In conservation, often a choice has to be made for the lesser of two evils. How can conservationists cope with such situations of seemingly inevitable loss? Here, we share a personal contribution from Dr Chelsea Batavia, in which she takes us along in the background story of her recent publication The moral residue of conservation, addressing exactly this issue. Read more
Remember those friends you never see anymore after they got hitched? Not in geese!
In our recently published paper, we show that barnacle geese keep hanging out with there favourite early-life social companions also after they pair up. Females show a break during the breeding season but display their social preferences again in the following winter. Males keep their prefered companions throughout the breeding and wintering season and these companionships were predicted by familiarity and genetic relatedness.
We also show that especially males were aggressive during the breeding season towards both males and females and this possibly hampered their female partners to hang out with their own ‘friends’ during breeding but not winter.
In summary, our study reveals the robustness of social preferences formed early in life, carrying over across pair formation, even after extended temporal disruptions. Our findings thus highlight how the early-life social environment can have life-long consequences on individuals’ social life, even in monogamous species.
RHJM Kurvers, L Prox, DR Farine, C Jongeling, L Snijders (2019)
Tanja and I recently published our fifth Conservation Conflict Exploration. We asked experts from a wildlife ecology and a human dimensions background to share their perspectives on wind turbines and wildlife with us.
The development of wind turbines in Germany is a controversial topic. While wind turbines promise to contribute to climate conservation goals in this century, the ongoing negative impact of wind turbines on airborne wildlife such as bats and birds is undeniable. Hence, the situation around wind turbines is labelled by some as a green versus green dilemma. In this exploration, we asked two experts, Marcus Fritze, a wildlife biologist, and Sophia Kochalski, a conservation social scientist, the following three questions:
In your own words, could you briefly describe the situation to us?
Why do you think is it so difficult to find consensus among stakeholders?
Considering your expertise, what could be one approach to mitigate this conflict?
I think that it is possible to run wind turbines bird- and bat-friendly and economically acceptable at the same time. The difficulty is greed. – Marcus Fritze
Compromises can be made by both sides when planning wind farms. – Sophia Kochalski
Interested in how these expert’s views on this ‘wicked problem’ and their solutions? Then check out the blog post here. And while you’re at it, have a look at our twitter account.
Recently, I received the honourable request to comment on an article about the rewilding of captive Asian elephants. It’s not a topic I am very familiar with, so writing this commentary actually became a wonderful learning experience for me.
Several strong commentaries from cultural, ethical and psychological perspectives were already written. Here I tried to also add a relevant ecological & evolutionary perspective, focussing on the behavioural ecology of Asian elephants and their functional role in the ecosystem.
Abstract:Baker & Winkler make a thought-provoking contribution to the discussion of what role captive animals could play in nature conservation and how we could get there through rewilding. There certainly is potential for captive Asian elephants, Elephas maximus, to become targets of conservation efforts, but there are also many questions: (1) How much do (behavioural) traits of captive-origin animals differ from their free conspecifics? (2) What predicts the likelihood and strength of social reintegration of captive animals into free populations? (3) How much of an Asian elephant’s functional role in the environment can captive animals still fulfil and how may this influence the evolutionary dynamics of Asian elephant populations? These questions are challenging, but also an opportunity to gain crucial knowledge and insight into the elephant’s ecological role, as well as our own.
If you are interested in reading the complete commentary (approx. 1000 words) see here.
Just how much of a sensitive topic this particular case study is, we noticed by how difficult it was for us to find contributors. Luckily we found two experts from Moral Philosophy that shared their insight with us:
Carlos Gray Santana is an Assistant Professor in Philosophy at the University of Utah. Dr Santana’s uses ethics to shed light on complicated issues such as the environment and human cognition. William S. Lynn is a Research Scientist in the George Perkins Marsh Institute at Clark University. The focus of Bill’s work is the ethics and politics of animal protection and sustainability.
For optional guidance, we asked the experts the following questions:
Why is the matter of cats and wildlife so controversial?
Why do you think politicians focus on culling cats rather than on habitat loss (as suggested in Doherty et al. 2019) and could open discussions be fostered to move beyond culling?
How do you think the public would respond when culling of cats turns out not to be effective in halting endemic species decline?
Curious about what they had to say? Read our blog post here.
And you can also follow us on Twitter!
When it comes to finding patchy and sporadic food resources, being at the right place at the right time is of the essence. Our recent paper published in the Journal of Animal Ecology provides experimental field evidence that male guppies (Poecilia reticulata), in the presence of females, more often reach sporadically available food patches. In contrast, female guppies did not reach more (or less) food patches in the presence of males.
“Imagine you are in a new city and looking for a place to have a good meal, what do you do? You can walk around and see what restaurants you encounter, but chances are that this will take a lot of time and you might still end up at a mediocre place. Alternatively, you can see where others are going. When you have incomplete information about your environment, taking advantage of the information of others (i.e. social information) can be incredibly helpful.”
Many animals find themselves in situations of incomplete information about where to find resources, for example, because important resources are patchy and sporadically distributed. One such animal is the Trinidadian guppy.
Trinidadian guppies live in rainforest streams. Those guppies that live in the resource-poor sections of the streams can take advantage of high-quality food resources, such as fruits and insects that fall sporadically into the water. But such resources are difficult to find. Interestingly, a previous study we discovered that guppies that spent more time near others were more successful in locating these unpredictable food resources. Possibly, spending time with conspecifics results in greater exposure to social information about when and where to find important resources.
But in this study, we also found that males reached more food patches than females, particularly males that were in groups with proportionally more females. The presence of females may have increased the time male guppies spent socially and consequently affected how many novel food patches they reached.
To experimentally test if sex composition indeed influences social time and food discovery, we conducted a new study in which we manipulated the guppy sex compositions (all male, all female or mixed) in the wild. For a total of 18 experimental guppy groups, we performed social observations and foraging trials.
First, we tested whether sex composition affected food patch discovery in individual males and females. This was true for males, which reached more food patches when there were females present. Females reached a similar number of patches either with or without males present. Second, we tested whether sex composition affected the time an individual male or female spent socially. The variation in time spent socially mirrored variation in patch discovery, with males spending less time socially in the absence of females, but no effects again for females. Third, we analysed if this time spent socially was linked to patch discovery success. Indeed, in agreement with our previous study, more social guppies reached more food patches.
Conclusion: The foraging success of an individual thus depended on a combination of its own sex and the sex composition of its social environment.
Take home message: When hungry—and male—spending time in the company of females can get you at just the right place at the right time.
Our newest open access paper on repeatability of avian signalling (song) traits just came online in the journal Frontiers in Zoology.
Repeatability, consistent individual differences, in signalling behaviour is interesting because it means that those receiving the signal (i.e. listening to the song) could reliably learn something about how the individual singer compares to other singers/competitors.
We repeatedly recorded the dawn song of great tit males throughout the breeding season and show that start time of dawn song and repertoire size are individually repeatable both before and during the egg-laying stage of the mate (when she is fertile). Surprisingly the time a male started singing appeared to be more repeatable (consistent) than repertoire size, despite that the start time was also influenced by variable overnight temperatures. Start time was also more repeatable before than during egg-laying and we suggest that this is related to the behaviour of the (assumingly) intended receivers of the song, the females.
For a subset of the singers, we also explored a potential link between the absolute song trait values, the repeatability of these values and personality. We did not find a link but follow-up studies with a larger sample size, and including additional song traits, will be needed to confirm the true absence of such a link.
Our systematic map protocol, outlining the background and methods of our approach to map and review the effectiveness of animal conditioning interventions in reducing human-wildlife conflict, is now online.
This map is part of a special initiative of a team of behavioural ecologists, who all committed to systematically map and/or review a topic in conservation behaviour. Read more about our plans and the protocols of the other team members here.
“The art and science of asking questions is the source of all knowledge” – Thomas Berger –
Tanja Straka and I like asking questions. Even more so, we like animals, nature and people. Unfortunately, these three do not always mix well and we want to learn why.
Coming from our respective backgrounds in social sciences and animal sciences, we want to learn about the ins and outs of wildlife conservation conflicts by exploring different perspectives. Because we are convinced that understanding the diverse aspects of conservation conflicts could also open our minds to a diversity of (new) ways to address them.
For Valentine’s Day, two colleagues and I conducted a fun writing exercise: we made a loving tribute to our study animals. Thank you, Cecilia and Tanja for all the fun!
Here is my little poetic contribution:
A Biologist Love Story
Who do I love the most? I cannot choose
My first love affair was with a barnacle goose
We spent a whole winter together, out in the cold
With only a blanket and each other to hold
But in the end, I still had to let you loose
Then came you, with your beautiful black tie
Oh, dazzling great tit, you certainly weren’t shy
Many days we spent, together in the wood
We had so much fun, those times were good
But in the end, we still had to say goodbye
To forget my sorrow, I travelled very far
And in the tropical waters, I found my little star
Pretty little guppy, it was love at first sight
In the dark rainforest, you are my shiny light
I can’t stop thinking of you, it is very bizarre
Even so, I feel alone with you far away
I don’t know what to do, I don’t know what to say
Suddenly, a stranger appeared in the middle of the night
A bat swooped me off my feet and took me to a great height
What will happen, who should I choose at the end of the day?
Last year, I unexpectedly received an invitation to give a plenary at the Swedish Oikos Meeting in Uppsala. A plenary is a presentation for which all the conference members come together. It usually lasts 45 minutes + 15 minutes questions. Commonly these types of presentations are given by ‘silverbacks’, people with an impressive track record in academia. So imagine my surprise to receive such an invitation.
Why me? Are you sure you did not mistake me for someone else? What could I possibly have to say that a whole conference could find interesting? A little voice in my head was whispering: “RUN”. Then, shortly after my initial shock and fear, I realized what a great opportunity it could be. Not just for me, but for early-career woman researchers in general. Showing that we do have something interesting and inspiring to say.
So I started focussing on my presentation. I quickly decided on the main topic and the structure. For me, visualizing a tree helped a lot. ‘Animal social networks’ would be my trunk, ’causes’, ‘consequences’ and ‘applications/future directions’ my main branches, my studies the twigs and pretty pictures, quotes and movie clips the leaves. A good friend told me about SlideCarnival.com, a website with really cool free powerpoint templates and one of them I used to inspire my own. Personally, I like a bit of humour in a presentation, so I also decided that I needed manipulated pictures of movie stars, to refer to my study species (of course). Incorporating humour and beautiful pictures is mostly a tool for me because it makes me really enjoy making the presentation even if the audience would not actually care so much about it.
It took quite a bit of time to get the number of slides right because I was not used to giving a presentation of that length. And then I needed to practice, practice, practice. For this, I figured that I (of course) needed my own remote clicker/pointer. It’s maybe a bit nerdy, but I can really recommend this to everyone!
And then it was time to give the presentation. I was very nervous, but not paralysing. I had met the organisation, the other plenary speakers and some other participants at the conference the day before and they were all very nice people. Knowing that there would be kind and interested people in the audience helped me a lot in calming down and actually enjoying giving my talk. Still, I thought I saw a lot of uninterested and sceptical faces while I was speaking. Luckily, I know from experience with other (shorter) talks, that this is usually just in my head and I managed to not let it influence me too much.
The talk went very well, I think. I forgot some things (I always do), but nothing essential. And afterwards, I got a lot of positive feedback. Of course, nobody (except for sadists) would come to you afterwards and say your talk sucked. But overall I had a really good feeling about it. I was very happy that I had accepted the invitation and felt ‘brave’ in a way.
I hope that more and more conferences will also start giving early-careers an opportunity to present themselves and their work via a plenary. We do have some interesting things to say :-).
Autumn 2018, friend and colleague Edwin van Leeuwen asked me an intriguing question: if I was interested in co-authoring a comment on an essay about Nonhuman rights? This was a topic we had talked about before and I find very fascinating, timely and relevant. So of course I said yes.
The central essay and our comment, together with other comments, are part of a special issue on the topic of Great Ape Personhood, published by the ASEBL Journal (Association for the Study of (Ethical Behavior)•(Evolutionary Biology) in Literature; St. Francis College, Brooklyn Heights, N.Y.). As so nicely explained by the editors (Gregory Tague and Christine Webb) in the introduction of this special issue: with his essay, Professor Thompson tries to bridge the false divide between natural science and humanities. Working from the foundations of philosophy and legal theory [and subsequently discussing important focus points for future research], he tries to reach scientists and their thinking in the battle for great ape personhood.
“Thompson relies on Nonhuman Rights Project attorney Steven Wise, who calls on scientists to awaken the thinking of judges deciding the fate of great apes. Perhaps it’s an unfair analogy, but Thompson attempts to do with primatology what climatologists from several generations tried to do – demonstrate how science is part of and can dramatically affect public policy. Thompson shows how what is empirically rational in science is treated differently in the legal arena, and that difference poses a real problem in the question of granting personhood status and other rights to great apes.”
Several interesting comments were made on the essay, both from philosophers and scientists. Edwin and me commented i.a. by suggesting some alternative ways science could support the quest for Great Ape Rights.
This project was definitely out of my comfort zone. And I see that as a good thing. Thompson’s essay and also the philosophers’ brief, written in support by a group of philosophers, have given me many new insights about the role of philosophy and science in society. How together, philosophy and science can have some very important things to say about the way we live in this world.
The complete issue can be found here.
And (only) the comment made by Edwin and me, here.
Reference van Leeuwen E.J.C., Snijders L. (2019) A comment on Thompson “Supporting Ape Rights: Finding the Right Fit Between Science and the Law.” ASEBL Journal 14 (1), 46-48.
After my good experience with the first preprint publication, I recently uploaded my second preprint on the BioRxiv server. I am really excited to share these cool new findings, especially since this study almost did not happen.
Fieldwork is always full of surprises, including flash floods (2018) and cars being stolen (2016). The year of this study (2017), we got stuck on Curacao because our airline was grounded (due to airplane safety concerns, we found out later). Curacao is a great island to spend some time, but it just lacked our favourite little fish: guppies. Luckily, we were able to get new flights and make it to Trinidad a couple of days later.
I love working with guppies, because they allow us to answer some very interesting questions about social living. Guppies live in rainforest streams and in the dry season they often end up in separate pools. These little fish thus naturally experience a variety of physical environments (pools) and social environments (the other fish in the pool). We take advantage of this natural system by trans-locating individual fish to different pools with different social compositions. Most animals would try to go back to their original environment, but for guppies experiencing new physical and social surroundings is just part of their ecology. That we can experimentally control their (social) environment is important, because it allows us to go beyond correlation and ask questions about causality, e.g. how does social composition influence individual foraging success?
To answer this question, we introduced individually marked wild guppies in single sex (male or female) or 50:50 sex compositions, to different pools and studied individuals’ social behavior and their ability to locate novel (experimentally introduced) food patches.
Male guppies found fewer novel food patches in the absence of female guppies, while female patch discovery did not differ between single-sex or mixed compositions. We argue that these results were driven by sex-dependent mechanisms of social association: males reduced sociality when females were absent, while less social individuals found fewer patches. Females were, however, similarly social with or without males. Finally, males, but not females, preferred to join females over males at food patches.
Our study’s take-home message: for a more thorough understanding of social evolution, it is important to consider how individual (e.g. sex) and (sub)population-level traits (e.g. sex composition) interact in shaping the adaptive value of social living in the wild.
Maybe also: don’t fly with Insel Air.
Reference Snijders L, Kurvers R.H.J.M, Krause S., Tump A.N., Ramnarine I.W., Krause J. (2018) Females facilitate male patch discovery in a wild fish population. BioRxiv.
Yeah! Our recent open access paper on systematic maps and reviews in behavioural ecology is now available in, how appropriate, Behavioral Ecology. It is the first concrete output of a group of behavioral ecologists, passionate to effectively contribute to wildlife conservation. This is just the beginning! Many thanks to Oded Berger-Tal, Alison Greggor and Dan Blumstein for bringing us all together.
Summary of the paper:
Although examples of successful applications of behavioral ecology research to policy and management exist, knowledge generated from such research is in many cases under-utilized by managers and policy makers. On their own, empirical studies and traditional reviews do not offer the robust syntheses that managers and policy makers require to make evidence-based decisions and evidence-informed policy.
Similar to the evidence-based revolution in medicine, the application of formal systematic review processes has the potential to invigorate the field of behavioral ecology and accelerate the uptake of behavioral evidence in policy and management. Systematic reviews differ from traditional reviews and meta-analyses in that their methods are peer reviewed and prepublished for maximum transparency, the evidence base is widened to cover work published outside of academic journals, and review findings are formally communicated with stakeholders. This approach can be valuable even when the systematic literature search fails to yield sufficient evidence for a full review or meta-analysis; preparing systematic maps of the existing evidence can highlight deficiencies in the evidence base, thereby directing future research efforts.
To standardize the use of systematic evidence syntheses in the field of environmental science, the Collaboration for Environmental Evidence (CEE) created a workflow process to certify the comprehensiveness and repeatability of systematic reviews and maps, and to maximize their objectivity. We argue that the application of CEE guidelines to reviews of applied behavioral interventions will make robust behavioral evidence easily accessible to managers and policy makers to support their decision-making, as well as improve the quality of basic research in behavioral ecology.
Reference O Berger-Tal, AL Greggor, B Macura, CA Adams, A Blumenthal, A Bouskila, U Candolin, C Doran, E Fernandez-Juricic, KM Gotanda, C Price, B Putman, M Segoli, L Snijders, BBM Wong, DT Blumstein. (2018) Systematic reviews and maps as tools for applying behavioral ecology to management and policy.” Behavioral Ecology.
I am very proud to share my latest publication in Nature Ecology Evolution (NEE). It is the first paper from my ‘guppy’ postdoc at the Leibniz-IGB. It is also the first time (I think) that a manuscript of mine got accepted by the first journal I sent it to, which is also nice for a change :-). Guppies were also the topic of my final year’s highschool science project o, which makes this publication extra special for me. Fish are amazing creatures and I am happy I get to share their stories.
Next to our scientific article, I wrote two background stories:
Social individuals find more food – IGB-website How do you find food when the food is never exactly present at the same place or time? Wild guppies living in the rainforest of Trinidad are faced with this vital question every day. Looking at guppies, it turns out that there are a few keys to finding unpredictable food: being social and surrounding yourself with females. Read more.
Being consistent in a dynamic environment: a guppy story – NEE-website Sometimes things happen that can give you a whole new appreciation of the study system you are working with. For me this thing happened this year. Read more.
If you are more of a visual person, I also made a little Youtube video.
The research article can be viewed for free, but please contact me, for example via ResearchGate, if you would like to have the PDF.
Reference Snijders L, Kurvers RHJM, Krause S, Ramnarine IW, Krause J (2018). Individual- and population-level drivers of consistent foraging success across environments. Nature Ecology and Evolution.
This month, I officially started with my two-year postdoc fellowship at the Leibniz Institute for Zoo and Wildlife Research (IZW), granted by the Alexander von Humboldt-Stiftung. As of now, I am part of the Evolutionary Ecology Department, or more specifically: the Batlab, and I will study the role of personality and social associations in the movement behaviour of partially migratory noctule bats, Nyctalus noctula. In Germany they are called Abendsegler, meaning something like ‘Evening sailor’. Beautiful isn’t it? I am very much looking forward to my work at IZW and I hope to learn many new things, meet many passionate wildlife researchers and contribute some fascinating new insights into noctule bat behaviour.
Abstract of my awesome bat project:
Migratory animals vitally connect distant ecosystems worldwide, impacting key ecological processes by transporting nutrients, seeds, parasites and pathogens. As the only flying mammals, bats represent a unique and widespread group of migratory animals, serving important ecosystem functions as pollinators and pest controllers. Bats comprise one fifth of all mammal species, but little is known about their migration strategies. Yet understanding animal migration strategies provides important insights into ecosystem connectivity. Therefore, I aim to gain a better understanding of the key mechanisms that drive variation in bat migration strategies.
A single bat population can contain resident as well as migrating individuals. Such populations offer an excellent opportunity to study individual differences in migration strategies within populations. Hitherto, research on migration has mostly focused on birds, yet novel tools have recently become available to study partial migration in bats. Migration poses a trade-off: migration can lead individuals to more favourable habitats, but is also risky and energetically costly. Individuals have to balance these costs and benefits of migration and are likely to differ in how they do so. Bats fundamentally differ from many migrating bird species in key life-history traits that profoundly impact migration decisions. Knowledge about bat migration strategies, may thus lead to crucial insights into the maintenance of animal migration over evolutionary timescales.
New and improved techniques, such as non-invasive isotopic geolocation, allow for novel insights into the migration strategies of this poorly understood migratory taxon. Using this novel technique in combination with bat personality assays, social network analyses and bat banding, I will test whether individual bats consistently or plastically differ in their migration strategies and investigate the key social, physiological and behavioural factors underlying these differences.
This weekend I came back from a three-week fieldtrip to Trinidad. We went there to collect behavioural data for our guppy research project. However, on the plane back I had some time to reflect on the past weeks and realized that fieldwork is about so much more than just collecting data points.
For me, I realized, fieldwork is about all the little big things that come along with it. For example, living closely with people who all contribute in their own unique ways: someone who plays the guitar in the evening, who bakes tasty tortillas for dinner, who makes funny jokes at the end of a hard working day or who takes the team on expeditions in search of remarkable birds, snakes, insects and spiders.
Its about the surprising new people you meet, which can result in eating ‘Guinness icecream’ and making Chinese dumplings while on a tropical island.
Its about seeing your entire fieldsite get flooded in about an hour and having to ‘survival’ your way out of the rainforest. And lying in a hammock shortly after.
Its about seeing all the other critters that occupy your fieldsite: the little greedy crab, the colourful jumpy lynx spider, the small vocal male frog (sometimes with tadpoles on its back), but also the forever annoying killifish and the hundreds of biting insects.
Its about getting to know a little patch of nature very well, but never completely. Its about learning about your study species by observing it in between the actual trials. Its about getting new exciting ideas for next year’s fieldtrip.
Its about all these things and so much more. So the next time you see the datapoints of a fieldstudy, remember that they are not just units of analysis, they are stories, experiences, insights and surprises as well. For me, each one is a reminder of why I love being a biologist.
This week I submitted a manuscript to a preprint server for the first time. This is a bit scary because a preprint is not peer-reviewed and so is missing a ‘security check’, something that always makes me feel a bit more at ease when communicating my results [but see: http://thebrainissocool.com/2017/12/19/peer-review-is-not-all-that-is-cracked-up-to-be/%5D. However, I think preprint servers are a great idea, because you don’t have to wait for months before you can finally share your results and show people what you are working on. More importantly, preprint servers provide a way, for those interested, to read your findings without having to pass a pay-wall. A version of your study will thus always stay open-access. So, I put my fears (somewhat) aside and decided to submit my recent manuscript to BioRxiv, before submitting it to a scientific journal.
In the manuscript, we describe a field experiment with wild guppies in Trinidad by which we studied foraging success in the wild. We tested if foraging success in the wild differs consistently between individuals and if these differences can be explained by individual traits such as sex and social type, but also by population traits such as sex-ratio. I think the results are very exciting and also somewhat unexpected. If you would like to find out more, then please read the preprint on BioRxiv.
How can a behavioural ecologist contribute to conservation? It is a question I often ask myself. Therefore I am very happy to have become part of a team of behavioural ecologists that asks the same question. Together we followed a workshop by Mistra EviEM on how to conduct a systematic map or review and are now answering questions about the effectiveness of conservation interventions. In our case, behavioural interventions.
It is not an easy challenge, to gather and review all the literature that is out there on a given intervention, academic and grey. But, without a good overview of the best evidence available, how are we going to stop ourselves from doing the same thing over and over again? Are certain interventions effective, also on the long-term, or not at all? Are there certain conditions to be met for them to be of use?
I set out to answer these questions for an intervention in a very urgent and increasingly bigger conservation challenge: Human-Wildlife-Conflict (HWC). More specifically, I will map and review studies on the effectiveness of conditioning-interventions in reducing HWC with vertebrate carnivores. In other words Can carnivores be taught to stay away?
It will be a long, challenging, but useful task and I am very keen to work on it!
The platform Traces.Dreams asked me if I would like to be interviewed about my work passion for animal behaviour? They did not have to ask me twice :-).
“Traces.Dreams is a place on the web for people interested in the past, passionate about the present and curious about the future. Traces.Dreams is where you can find inspiration through a multidisciplinary and multi-regional perspective. Our vision is to make the big questions and dreams of today’s researchers visible. We interview researchers from different disciplines and countries to get their perspective on their work, their views on life, their “whys”, their motivation and their wishes.”
Last week, June 22, a for me very important paper was published online in the scientific journal Trends in Ecology and Evolution. With this Opinion paper, me and my co-authors hope to stimulate a closer collaboration between animal social network scientists and conservation practitioners. You can read more about it in our press release below. If you are interested in reading the complete scientific article, but do not have access, please send me a message/email.
As with humans, most animals prefer to associate with some individuals and not with others. The social structure can influence how a population responds to changes in its environment. Examining social networks is a promising technique for understanding, predicting and – if for the better – manipulating this structure. However, whereas the contribution of behavioural biology to conservation is already well recognized, the usefulness of animal social network analysis as a conservation tool has not yet been addressed. A group of behavioural ecologists led by Lysanne Snijders from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) outlines how the understanding of relationships between animals could be applied by wildlife managers and conservationists to support their work in disease management, breeding programs, reintroductions or relocations, or for controlling problem behaviours – to name just a few.
Animal social network studies examine how the individuals of a population are socially connected, how they interact and associate. Knowledge of the social structure can help to identify the flow of information or the spread of disease, and has potential to be used as an indicator of upcoming population changes. Information of that kind would be less – or not at all – noticeable using methods purely based on population size or the observation of single individuals.
Dr Lysanne Snijders, Post Doctoral Researcher at the Department of Biology and Ecology of Fishes at IGB, describes this approach with the help of Aristotle: “The whole is greater than the sum of its parts. Combined effects of social interactions in wildlife populations do not only have important theoretical but also practical implications. Linking animal social network theory to practice can therefore stimulate the design of new practical conservation tools and generate novel insights into how animal social networks change over time.”
An example from real wildlife
For many species, it is not just diseases that can spread rapidly. Social information can also be transmitted via various routes within a group, for instance, innovative ways to search for food. In the case of the California sea lion, novel foraging strategies have led to conflict with a fishery conservation scheme. The sea lions had discovered that salmonids migrating upriver became more concentrated at a dam, making them easy prey. Unfortunately, those salmonids were endangered species. A recent study  showed that knowledge of the network structure could have helped wildlife managers to detect that at first it was only a few successful individuals who “recruited” the others, and that the selective removal of these information spreaders could have contained the problem. In this case social network analysis could therefore have assisted in protecting the endangered salmonids while culling fewer sea lions.
Snijders also suggests a possible example for how animal social network analysis could be used in conservation work in Europe: “In cases of recently reintroduced group living animals, such as the European bison, social network analyses could give insights into how a population’s long-term persistence might vary with particular behavioural processes within the group. But also into how group and individual movements might be effectively manipulated to avoid human-wildlife conflicts such as entering restricted areas like farm land.”
Perspectives for implementation
In a field in which funds and time are limited, any newly suggested approach should have a distinct added value. Not every conservation challenge that is linked to a species’ social behaviour will require a social network approach to address it. The scientists also acknowledge that their proposal has to overcome another important hurdle first: before applying the knowledge of social relationships to management practices, it should become feasible and cost-effective to collect the required data in the first place. But with technological options becoming more common and affordable, an animal social network analysis approach could increasingly become an option.
There are several methods out there that have been successfully applied to map wildlife social networks, ranging from sampling individuals at fixed locations, to walking transects, to automatically spatially tracking the animals. Rapid advancements in technology, like proximity loggers and GPS tags, allow for ever smaller animal species to be tracked, while at the same time becoming more affordable. In addition, collaborations between research institutes and conservationists might provide opportunities for sharing the costs or the technology.
 Zachary A. Schakner, Michael G. Buhnerkempe, Mathew J. Tennis, Robert J. Stansell, Bjorn K. van der Leeuw, James O. Lloyd-Smith, Daniel T. Blumstein (2016): Epidemiological models to control the spread of information in marine mammals. Published 14 December 2016. DOI: 10.1098/rspb.2016.2037
Would you consider yourself to be social? More or less social than average? And try to think back, were you always like this or did you become more or less social later in life?
I think it is safe to say that humans are a social species. In Germany, people live with 120 people per one square kilometre, in Berlin with over 4000! That we still sort of like each other tells us we have a high social tolerance. Indeed, we humans even tend to be attracted to places with other people present.
But, as you may have realized, from one person to the next, we also differ in how social we are. Ranging from loners to people with 20.000 Facebook friends. There is plenty of variation. Partly because of how we were born, our genes, and partly because of our experiences.
This is true, not only for humans, but for many animal species as well. Individuals of one species can differ in how social they are. But there is one important thing to note here, something which we ‘social’ humans can easily forget, and that is that some species cannot stand each other! Take the giant panda. Males and females live by themselves. They guard their own area and chase out everyone who dares to enter. Even females chase away other females. Only for a short moment a male is allowed, but after he has done his thing, he has to go.
We have also animal species that are part time social, like the blue tit. In spring and summer, when the weather is nice and there is enough food around, these blue tits prefer to keep other birds at a distance. Only a partner is welcome. But in winter, when it is cold and food is difficult to find, they join flocks. Groups of other birds. Together they search for food. If you have a garden and leave some food for the birds in winter, you will probably have seen them.
Finally, there are animals that are social just all the time. Many bat species, for example. They often eat together, sleep together and even take care of their babies together in so-called ‘nurseries’.
So why do we see these differences in social behaviour between and within animal species? And what are the consequences of being social or asocial? These are the kind of questions I try to answer with my research.
Why is this relevant?
Finding the answers to such questions can be important for several reasons. (1) To increase our basic knowledge of nature. For the sake of knowledge itself, but also to inform other scientific fields, such as applied animal science, psychology, behavioural economics and sociology. (2) To help better manage and protect species and (3) to increase the welfare of the animals we live with.
In our homes, we have a variety of pets that also differ in how social they are. Dogs are classic group living animals, just think about the wolves living in packs. Also, rabbits are very social and prefer to be with other rabbits. Cats, however, are actually asocial (not a big surprise). The wild cat lives by itself. Most hamsters also don’t like others around, but certain hamster species, such as the Russian hamster, do like to have a companion from the opposite sex. They form pairs for live and can become depressed when they are not together.
In general, you can say that asocial species which are housed together become stressed. Imagine that you have to spent your whole life living with someone you really dislike. Yet social species, when housed alone, can become fearful and depressed. For dogs, humans can become their companions, but for most other animals this doesn’t work like that. When it comes to animals in captivity it is thus important to know whether they are social, live in pairs or are asocial.
Tracking the social live of a small songbird
In my studies, I focus on animals in the wild. How are their social lives structured and what benefits does it bring them? Since I was a little girl I have been fascinated with how and why animals behave the way they do. So it was not difficult for me to decide what I wanted to become: a biologist. I studied biology and did a PhD studying the daily social behaviour of a songbird: the great tit, a small bird you can often find in your garden and in the forest.
But how do you study a bird that is hiding in the trees most of the time? I did this by putting small transmitters on their back (Figure 2). In this way, I could track where the birds were going and who was meeting whom. More than 150 receivers (small boxes with an antenna) recorded where the birds were going in the forest.
I was especially interested in knowing whether the social behaviour of the birds was related to their personality. Because also animals have personality, they differ in how they handle new or risky situations. Something that is well established now in science. If you have had several pets you will probably have noticed that one is not like the other. This is also true for wild animals.
So, basically, I wanted to know if bold birds were more social than shy birds. Bold birds are birds that take more risks and approach novel object quicker than shy birds. We tested the personality traits of wild birds in the lab before we spatially tracked them in the wild.
Are bold birds more social? This would make sense, right? Also in humans, bolder individuals usually seem the most popular. To answer this question, I analysed the spatial tracking data to find out who was hanging out with whom. In this way, I could construct a social network. A sort of Facebook for birds. And what did I find? Bolder birds (Bigger dots in Figure 3), were more central in the network, they spent relatively the most time close to other birds. While shy birds (Smaller dots in Figure 3), were on the edge of the network. They spent less time with other birds .
Playback experiments with songbirds
Still, being popular (i.e. having many social connections), like having 10000 Twitter followers, does not necessarily mean that you are also a more social individual. Even Donald Trump has more than 30 million twitter followers.
Being more ‘popular’ could be caused by other factors than being social. For example, these birds could be hanging out on spots that happen to attract a lot of other birds, like places where there is plenty of food. Also, other birds might be socially attracted to bolder individuals without these popular birds actively socializing themselves. So, Donald Trump has over 30 million followers on Twitter, but can anyone guess how many people he follows himself? Last time I checked: 45, including his own family, his business, his golf course and his campaign team. A little side note just to illustrate that you don’t have to be a social individual to be popular.
Thus, to find out if bolder birds are actually actively approaching other birds. I performed two different experiments
The first experiment involved pretending to be another bird. So how do you pretend to be another songbird…? By singing! Via a speaker I broadcasted the song of an unfamiliar great tit in the territory of another great tit, which goes a bit like this and I observed how the bird responded. Such an experiment is called a playback experiment. As expected, the bolder birds tried to get really close to the speaker, which they thought was another bird, while the shyer birds kept more of a distance .
However, this behaviour is of course also not really ‘social’. It is aggressive. Bolder birds are more aggressive than shy birds. Maybe also not a big surprise when you think of humans.
Thus secondly, I designed another test in which the birds got to meet an unfamiliar great tit, but without this great tit posing a threat. I did this by showing the birds a High Definition life-size video of a great tit in a neutral lab environment (Figure 4). This kind of experiment is called a video playback experiment. It maybe sounds a bit strange, but the birds respond to this as if there is another bird in the room. Here the birds could choose if they wanted to approach the video great tit or rather stay near a video showing an empty cage. Both videos were played on screens in a small cage so that the birds could not look behind the screen and see that there was not an actual bird there. Surprisingly, in this test, bolder birds did not spent more time with another great tit. Actually, if anything, the shy birds showed more social attraction. They spent most time near the video great tit .
What have I learned from my PhD studies? (1) Individuals of the same species can differ in their personality traits and the time they spent close to others and (2) being bold and popular does not per definition make you a social individual.
If you are interested in finding out more about my studies and animal behaviour in general, please follow me on Twitter. And, unlike Trump, I will follow you back.
Snijders, L.et al. (2014) Social networking in territorial great tits: slow explorers have the least central social network positions.Animal Behaviour98: 95-102.
[2} Snijders, L. et al. (2015) Dawn song predicts behaviour during territory conflicts in personality-typed great tits. Animal Behaviour109: 45-52.
 Snijders, L.et al. (2017) Dominance rank and boldness predict social attraction in great tits. Behavioral Ecology28: 398-406.
Tracking small songbirds generates important insights into avian ecology, but does not always work out the way you planned. We published a paper about these experiences in the Journal of Avian Biology:
This Massive Open Online Course (MOOC) ran the first time from August to October 2016 and is now archieved on the EdX platform, so that the videos are still accessible. You can explore the various behaviours animals adopt in order to meet the challenges of their daily lives. The course is aimed at anyone looking to broaden their understanding of animal behaviour beyond nature documentaries or a typical high school education.
We designed the course with three people of the Behavioural Ecology Group of Wageningen University & Research. Dr James Savage (now part of University College Cork) was the driving force behind this fantastic idea. Together with James and Prof Marc Naguib, I designed and recorded a number of short lectures too (max. 7 min.). Since I am especially fascinated with animal social behaviour, most of my lectures have something to do with sociality, for example my lectures on ‘social networks’ and ‘social learning’. Also, we thought it was really important to give people more insight into the scientific process of studying animal behaviour. So we additionally created lectures such as ‘the scientific method’ and ‘good scientific practice’.
Discover how animals learn, communicate, find food, avoid predators, and interact socially. Watch this welcome video and find out if this course might be something for you. You can subscribe for free via the EdX platform.
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