Thale-Harate’ podcast with Pavan Srinath and Ganesh Chakravarthi in Kananda (ಕನ್ನಡ)

Listen to my ‘Thale-Harate’ podcast with Pavan Srinath and Ganesh Chakravarthi in Kananda (ಕನ್ನಡ):

On topics ecology, physics, some of my research work and on doing science in India.

I thoroughly enjoyed the conversation during recording, and I hope you too! Any feedback welcome.

Since its an hour and a half long, here is roughly how the topics of discussions go:

0 – 33 minutes: On ecology, how principles and methods of physics/mathematics can be useful. Includes examples from my own research work on ecosystem collapse and collective animal movement.

33 – 55 minutes: How does research actually happen? Did you have eureka-moments? What is the life of a processor and scientist like at work?

55 mins to 1:25 hrs: On Indian science and global competitiveness.

New book-chapter by Jitesh Jhawar et al: A first principle derivation of models of collective behaviour that account for finite group size

I am really pleased that a new publication – a first book chapter from lab and first paper of 2019 – is now out! Its led by Jitesh Jhawar, a final year PhD student in our lab and in collaboration with Richard Morris – a former postdoc at NCBS.

Jitesh Jhawar, Richard Morris, and Vishwesha Guttal, 2019, Deriving mesoscopic models of collective behaviour for finite populations, In Handbook of Statistics Vol 40: Integrated Population Biology and Modeling  (edited by Arni Srini Rao and C R Rao), Part B, 551-594. DOI:;  Pre-print from Arxiv;  Codes and data on github.  Download PDF

Collective behaviours of animal groups are often modelled via agent-based simulations. They are relatively difficult to tract analytically. The main highlight here is that we present two analytical methods that are used in the literature (statistical physics and physical chemistry); we compare which method offers ease of model construction.

A second point worth highlighting is that most analytical methods often assume that group/population sizes are infinitely large. The methods we present accounts for the fact that real animal groups are finite in size and individuals interact with each other in inherently probabilistic ways! The resulting scale of description is also referred to as mesoscopic — a term that appears in the title of the book chapter.

The mesoscopic descriptions yield very counter-intuitive results,; for example, noise can actually facilitate collective order!!! Read the chapter for more details.

The writing style we have adopted is pedagogical so that even undergraduate students from physics and mathematics can understand the methods presented here.

Finally, I also want to highlight that the first author of the paper – Jitesh Jhawar – did his bachelor and masters degrees in Biotechnology – but in this chapter, he uses mathematical techniques like Fokker-Planck equations, Langevin equations, Ito Calculus, etc! So even biology background students can learn hard-core mathematical/theoretical biology if you really love doing theory! 



Sumithra Sankaran defends her PhD thesis!!!

I am super delighted to share this — somewhat belated — news that Sumithra Sankaran has defended her PhD thesis on 7th December 2018. Sumithra’s thesis was on understanding how local interactions, spatial patterns and ecosystem stability are related. Needless to say, Sumithra gave a fabulous presentation and the examiners (including external examiner Prof Partha Sarathi Dutta from IIT Ropar, Department of Mathematics) were super impressed.

It is worth noting – especially for prospective students to our lab – that Sumithra was formally trained in zoology and wildlife biology. Because of her exceptional interest in theory, she did a thesis in theoretical ecology involving fairly involved mathematical calculations, e.g., mean-field models, stochastic differential equations and their analyses via Fokker-Planck equations, cellular automata models. Finally, testing her predictions of theory with empirical data – which required another suite of skills in analysing remotely-sensed data, statistics, and making sense of results in light of theory!

Do check some of her papers here, here, here and here. There are two more being prepared.

Congratulations to Sumithra – its been so much fun collaboratingworking with you – which I hope we will continue!

Sumithra Sankaran showing a slide with spatially explicit model of patch dynamics.

Summer updates by Vishu Guttal: Teaching, travel, and talks

Its time for updates again!  Let me start with myself and will post separately on what students have been upto.

Teaching: In the Jan-April term, I taught the course EC 201, the introductory course on Theoretical and Mathematical Ecology. This was the fourth time that I was teaching this course, but one thing had been bothering me a lot: the course was becoming increasingly inaccessible to biology students (in particular, our own CES phd students). The reason was that once UG students of IISc who had much better math background began to take my course as an elective, the mathematical level of the course became too difficult for CES PhD students many of who come from Masters in Zoology/Botany/Wildlife biology programs where the emphasis on math is minimal to zero. I did not want to miss out either on the UG students so that they are exposed to cool ideas of mathematical ecology or the CES phd students who ought know basics of theoretical ecology. Based on various suggestions, I tried this new solution: which is to let UG students take my course only on alternate years.

So this year, I restricted the class to biology majors who have had little exposure to mathematics. The UG students of IISc were requested not to take the course this year (and they kindly obliged). I thought that this really helped the biology background students to learn at their pace — and they did really well. So I am going to keep this format for the future. Even years: the course is open for all. Odd years, the course is open only for non-math background students.

Travel:  In the second week of June, I went to visit my collaborator Dr Sonia Kefi at Montpellier, France to initiate collaboration on our Indo-French grant from IFCAM. We started off great on a project on spatial pattern formation that will be led by a member of Sonia’s group. Sonia and her team members will visit Bangalore in December and we hope to keep this on for several years!

Popular talk: I gave a couple of popular talks/workshops this summer. One was at Christ University, as a part of the initiative by National Network for Mathematical and Computational Biology (NNMCB) to reach out to local colleges and universities. I spoke about evolution and collective movement in animal groups.

Workshop: I then gave a set of lectures at NCBS at the Monsoon School on the Physics of Life. The audience here were basically a bunch of highly motivated kids from various parts of the country studying physics, math or engineering. The idea was to expose them to biology through the lens of mathematics. I started off showing a graph from Ives et al 2008 paper on how midge populations change over time, and how can we construct a mathematical theory of the same. At the end of four hours, students learnt all the way from building simple model of exponential growth to logistic models to constructing bifurcation diagrams for a consumer-resource model. They were all super delighted when they found that even small changes in external factors can lead to large changes in populations; mathematically, this is captured by saddle node bifurcations.

Ecology: Individuals to Collectives – article in Resonance

I would be writing a series for Resonance on some aspects of theoretical ecology, and from the perspective of a physicist turned ecologist!

The first of the series came out two months ago. I copy paste the abstract here, and here is the link to the pdf if you want to read it in full! Do leave a comment or suggest me how you liked the article and what would you like to cover in the series.

“Common people and even scientists think of ecology as a discipline that exclusively studies wildlife and topics related to environmental pollution. My friends both within and outside the scientific community are often baffled when they hear that I am a physicist doing research in ecology. The aim of this series of articles is to emphasize the less known fact that theory and mathematics have been central to ecology since the inception of this relatively young scientific field. In this first article, I will talk about the following three points. First, I will discuss how the emphasis of the basic science of ecology is much broader than its applied aspects involving the conservation of natural ecosystems. Second, I will discuss a fundamental parallel between statistical physics and ecology that arises because both disciplines emphasize macroscopic systems (e.g., magnetic materials in physics or flocks of birds in ecology) as collectives of interacting units that are more than the sum of their constituents. What makes them fascinating is that interactions at small scales typically give rise to unexpected properties at larger scales. Finally, I will discuss how ecology offers a new and rich set of challenges to mathematically trained scientists because of variations among biological organisms and the role of natural selection in shaping ecological systems, both of which have no parallels in the physical sciences.”

An ecology course at IISc from Aug-Nov 2013 for anyone interested

I will be offerring a course at IISc on the basics of ecology though the lens of mathematics. The details are as follows. Feel free to spread the word to those interested:
Course title: Ecology through numbers
Instructor: Dr. Vishwesha Guttal, Assistant Professor, Centre for Ecological Sciences, IISc (Website:
Class hours: Monday 6pm – 8pm. Wednesday: Computer lab hours to be decided.
Start-end dates: Aug 2013 to Nov 2013 (approximate).
About the course: Ecology is often understood to involve only field work. The aim of this course is to show how simple mathematics has played a central role in ecology. Syllabus includes how to develop simple mathematical Models in ecology; Models of population dynamics; Chaotic dynamics; Predator-prey cycles; Tragedy of the commons, etc.
Intended audience: Anyone outside the regular IISc academics with keen interest to learn ecology. CCE is a centre at IISc has been offerring regular semester long courses over years in the evening hours so that working professionals, scientists, conservation enthusiasts, engineers, amateur naturalists – pretty much anyone with a bachelor’s degree – is able to attend the course.
For more details on the CCE and its objectives, visit this webpage:

Eligibility: BE/B Tech./M.Tech in any disciplines, Or masters (M.Sc., MA, in any discipline.
Pre-requisites: Math at the level of High School (Basic calculus) and some Programming experience would be helpful, but not, MUST.
Course-fee: Rs 7000 for the entire semester. Please see the website for details of application procedure and how to make the payment (dont forget to check terms and conditions regarding fee payment):
Any questions regarding course content, etc can be sent to me at
For queries regarding procedure to enrol, etc, please contact the CCE office admin directly.

“Can the collapse of an ecosystem be foreseen?” – by Priyanka Pulla

Priyanka Pulla, an award winning freelance journalist [1], wrote a blog about our work (with my adviser Prof. Jayaprakash) on early warning signals of ecosystem collapses.

Here is the link.

As always, she writes really well (check her blog and her other articles). She also makes some connections to Indian Monsoon and the hypothesis about regime shifts in Monsoon.

[1] Priyanka’s article on Flock Theory and Synchronies of Nature in Open magazine won her the RedInk Awards for Journalism 2013. That article, if you haven’t read, is something you must read! Obviously, that is also relevant to my research work. She had written on the fascinating work of my colleague and collaborator Sriram Ramaswamy at Physics Department (now director, TCIS, Hyderabad). She had also interviewed me to get an ecologist’s perspective.

Article on our lab work in Fountain Ink

Here is a really nice longish article titled Tipping points and Phase transitions on our lab work (most of it from my PhD and postdoc) in a monthly magazine called Fountain Ink – published from Chennai.

To do this story, Mr. Varma (a freelance journalist based in Andhra Pradesh) visited our lab in the month of May for couple of days. We had long interesting conversations on the work. I really enjoyed talking to him, and I hope you will like reading the article.

Summary of course evaluation on Theoretical ecology course (EC 201) in Jan – April 2013 semester (Updated)

Like last year, I took students’ opinion/evaluation of my course. Unlike last year, this year the course was taught for the complete semester, allowing us to cover more topics and do better on projects. Before I go onto summarizing the course evaluation, here was the composition of the class:

* Undergraduate students: 10 (Nine of them from IISc and in their 4th semester; they were taking electives for the first time. Of the 9, six were from Math major, 2 from Biology major and 1 from Physics major. One UG student was an international visitor – from France – with computer science major).

* PG Students: 7 (4 CES PhD Students; 2 NCBS PhD Students and 1 M.E student from Chemical engineering).

* [UPDATE]: Auditing Students: I entirely forgot to add that there were roughly 6-10 students who audited the course; most of them fron non-math background. They were equally active in the class, in doing (most of) class assignments, etc.

Clearly, having 10 UG students was a major surprise but the overall mixture added lot of value to the class by allowing a diversity of perspectives and skills. Writing more about this requires a separate post! So, let me move onto the summary of course evaluation by students.

1) How do students self-evaluate their understanding of various components of the course? Course_understanding_EC201_2013Clearly, on an average the distribution peaks at “Good” and “Very Good”, which is great! Compared to last year, the distribution has moved towards “Very good”. More specifically, topics that were mostly rated as “Good” (Discrete population dynamics, continuous population dynamics and stability analysis) have now moved towards “Very good”.

However, the topics where I need to improve (so that students self-evaluate with higher scores!) are the topics I added this year, so I was teaching them for the first time. The reasons seem quite obvious! These are evolutionary dynamics and two-species interactions.

2) How good was the coverage of topics? Course_coverage_EC201_2013A very nice distribution that peaks at around “Adequate”. But with a clear right-skewed distribution, suggesting that most students wanted me to cover more of pretty much most of the topics – which is not possible given the time constraints. Here is what one of the students commented about this question:

the options given r not good, like a little more detail is always Helpful!! Adequate with respect to what?? w.r.t exams or w.r.t interest in the topic?? 😛 ( dnt mind!! 🙂 )

I thought that was a very good point, and that is clearly reflected in the average response of students. The response is exactly same as the previous years where the average response was that more details are needed on many topics! The best I could take away from the above plot is that more on two-species interactions and evolutionary dynamics would be appreciated. Anyway, the same student also said:

Coverage and depth both wer (sic) nice, as most of the times it went according to the students! It was good!

How should I rephrase the question next time, or should I entirely skip this altogether?

3) In general, the ratings on lecture notes and quality of teaching were pretty good (both above 4.25 on a scale of 5). Compared to last year, both have improved. In particular, I had hardly given any lecture notes last year. This year, we recorded all classes and they were available on the course website – typically within a week of the class. Lecture notes were prepared based on transcribing the videos and also posted on the website. I had employed two TA’s specifically for these purposes and they did a splendid job, I think. Although I don’t know if anyone really used these resources, we had made our effort.

Work load was rated at 3.58 – but I dont know what that means. Again poor phrasing of question (the options ranged from “Very poor” to “Very good”). I can make sense of “Very good” but what does average workload mean? Did students want more workload, or less workload? Last year, they explicitly said less workload would be better. Although it’s hard to imagine students asking for more work load, I think I can expect something counterintuitive from this class ;-).

4) What other topics would you have liked to learn?

Most commenters perhaps realized that it is difficult to cover more topics in the semester. But two suggestions that one student had was to include meta-population dynamics and island biogeography models. Great suggestions, even if I can not cover them in a class, I should consider doing a workshop at ces.

A very useful suggestion is to talk about interesting history behind mathematical models and concepts. I will try this next year, after learning myself more about them.

5) General comments to improve the class further: 

A common point that came in 4 of five comments was that

Mathematics is clearly very important for this course.

and since ecology students come with not much math background (some may have taken their last math course in their 10th class),

some fundamental Mathematics [and programming] classes would be useful for non-math students.

We did have TAs teach basic pre-requisite math in the course. But I suspect a full fledged course on math and programming prior to this course would make a difference to many ecology students. Unfortunately, there is no bandwidth in the CES, as of now, to add a new course.

Class room programming sessions cannot be called a success as not all students were well versed with the R language. …  Atleast 2 classes of basic R is mandatory to be freely usable even during exams.

I don’t know how to resolve the above problem on programming language. I thought that TAs did do tutorials on R – at least in some rudimentary way and were usually available during programming sessions to help students. And many students as far as I can tell did well in those sessions. No doubt it needs to be better done.  I Another related point was that

But probably due to a skewed structure of the class where majority of students have a strong mathematical background, the purpose of the course for ecology students ( who usually don’t have a strong mathematics foundation) tends to get lost.

I really hope that was not the case! If this course were really to be taught only to those with strong math skills, it would take a very different trajectory (and not necessarily a good one). I think having this extreme set of students added a great value to the course.

One possibility that some faculty at CES have been thinking is to make an online basic math and an R programming course (such as those from udacity or corsera taken in the Aug-Dec semester) a pre-requisite for my course (in Jan-April sem). Going through online classes can get boring, so we should assign some TAs and mentors so that there will also be some discussion sessions to clarify doubts and to ensure there is no attrition.  One thing that we have decided in our department now is that my colleague Kavita Isvaran’s course on Quantitative Ecology 1 will be offerred in the Aug semester from 2014. This course covers some stats and programming could also help students when they take my course. 

maths and ecology students should be assessed separately.

I have thought a bit about this since the beginning of the course but am unable to justify separate grading schemes. One way to think about this was that if a math student were to go and take a hard core biology course, would he/she be graded differently? Most likely not. Even within this course, standards of ecology were maintained same for both math and non-math students. Anyway, something worth thinking again but for the next year. Despite all these issues, I found non-math students who had very little math and programming experience did exceptionally well in the course.

Here is one other critical and very useful comment:

 Projects, I feel were not graded very satisfactorily. At the least the student should know the categories upon which the project was graded upon so that in the bare minimum, even if he/she gets a not so good grade he/she will at the least know how to do/present a project in futureby correcting appropriately.

Good point  about project grading. I am usually very careful in mentioning something like how grading is done, but as the course progressed, it slipped out of my mind to remind students about how things are graded in ase of projects. But point taken.

Its always good to end with a positive light-hearted comment:

Prof, TA’s, AC in the room, and cookies in the break..everything is Very nice!! 🙂 really liked and enjoyed the course!! 🙂 and I really appreciate the way the class was handled by prof, I mean extreme Bio n extreme maths people at same time!!! :O 😀

Thanks to all students for being part of the course! Special thanks to TAs Sabiha, Jaideep, Sumithra and Nitin for fantastic help that you all offerred throughout the course.