New paper by Gokul and Athmanathan (UG students): Fission-fusion dynamics in heterogeneous populations

Very happy that a very cool paper led by two former UG students of the lab – Gokul Nair and Athmanathan – is now published!

Screenshot 2019-03-14 at 11.11.26 AM

 

Gokul Nair, Athmanathan Senthilnathan, Srikanth Iyer, and Vishwesha Guttal, 2019, Fission-fusion dynamics and group-size dependent composition in heterogeneous populations, Physical Review E99, 032412, arXiv:1711.06882 [nlin.AO], Data and codes,  Download PDF. 

 

This is the first analytical model of fission-fusion dynamics in heterogeneous systems. Previous studies had looked at only homogeneous populations. We make interesting predictions: smaller groups are likely to be homogeneous while larger groups will be heterogeneous.

I really enjoyed working with these students and also with Prof Srikanth Iyer, who is a professor of Mathematics at IISc. My collaboration with Srikanth started with this project when we jointly advised Athmanathan, a UG student majoring in Math at IISc, for his UG project (Sept 2014- May 2015). While Athma formulated the model and got preliminary results, Gokul Nair (a UG physics Major from IISc) carried this on during his free-time, resolved many tricky mathematical issues, did more simulations and finally wrote the paper.

Although the paper is quite mathematical (perhaps most mathematical of all my papers so far), many sections are written in a way that is accessible to nonspecialists (you can easily skip mathsy parts without losing the essence – that was the attempt of our writing). I hope you will read and enjoy it!


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: https://doi.org/10.1016/bs.host.2018.10.002;  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! 

 

 


Understanding Behaviour – 2019 at Kolkata and Jitesh Jhawar wins best talk/poster prize

A number of folks from our lab — Abhratanu Saha (UG student), Akanksha (PhD student), Jitesh Jhawar (PhD student), Priya Iyer (postdoc), Preethi Rajasekaran (Project assistant), Nitin Saxena (PhD student) — attended the Understanding Behaviour – 2019 conference, organised by IISER-Kolkata.

Congratulations to Jitesh Jhawar – who won the best speed-talk cum poster award for his presentation on inferring local rules of interactions among fish from collective behaviour studies.

 

 


Research project position for a duration of 5-6 months in the departments of Chemical engineering and CES [Update: Position filled]

UPDATE: The position has been filled.

Applications are invited for a research project position for a duration of 5-6 months in the departments of Chemical engineering and Centre for ecology, IISc Bangalore, India (Deadline for application: 06 Nov 2018). 

Broad research area: Understanding the agent-level interactions that give rise to the observed collective behaviour.

Project details: Project will be computational in nature; Project will involve developing optimization based methods to identify underlying interactions between a group of agents (like a school of fish or traffic) from the data of their motion and collective dynamics

About the project supervisor:

Dr Danny Raj M, INSPIRE faculty, Dept. of Chemical Engineering, IISc [dannym@iisc.ac.in– contact]

Website (for more details): http://dannyrajm.wixsite.com/danny-raj-m

The work will be done in collaboration with Dr Vishwesha Guttal, Associate Professor, Centre for ecological sciences, IISc Bangalore.https://teelabiisc.wordpress.com

Eligibility: Bachelor’s or Master’s degree from Engineering, Physics, Mathematics, Biological sciences; Final year projects for students in a Bachelor’s or Master’s degree

Skills desirable: Comfortable with building algorithms and coding (preferably in MATLAB; other packages like Python, Mathematica are also welcome); Penchant for analysing and understanding non-linear dynamics of systems

Details of salary: Candidates joining as project assistant or associate would get a salary commensurate of their experience and qualification; Candidates applying here for their final year projects are not eligible for a salary

Deadline for application: 06 Nov 2018

Contact: Interested candidates should email their resume to dannym@iisc.ac.in with the subject RESEARCH PROJECT POSITION- REG, stating why they are interested in the project (in brief) and how long they can commit to it. [The resume should detail any projects or interesting ventures undertaken that would be relevant for the post being offered].

Other details: An interview or test, will be held with the interested candidate following which the decision to offer the position will be made. The position is extendable based on the performance of the individual.


New paper by Jaideep Joshi: Demographic noise and cost of greenbeard can facilitate greenbeard cooperation

We are delighted to announce a new paper from the lab!

Jaideep Joshi and Vishwesha Guttal, 2018, Demographic noise and cost of greenbeard can facilitate greenbeard cooperation, Evolution, DOI: https://doi.org/10.1111/evo.13615

This is the second paper of our former PhD student Jaideep Joshi. Fantastic work, involving some hard-core analytical and simulational work to address an interesting problem on the evolution of greenbeard cooperation.

Congratulations to Jaideep!

While you are here, you must also check the previous paper of Jaideep on how mobility promotes cooperation, published last year in Plos Computational Biology.

 


Hari Sridhar’s recent paper on Mixed-species flocks covered in Indian Express

Amitabh Sinha at Indian Express has a nice summary of Hari Sridhar’s recently published paper on “Friendship across species borders: factors that facilitate and constrain heterospecific sociality”.

Click here for the Indian Express article with the nice title: “Costs and benefits: Why birds of a feather sometimes don’t flock together”. This is how it looks in the newspaper!

Sridhar-Guttal-Indian_express-Coverage

Click here for the original research article.

 

 



New paper: Friendship across species borders: factors that facilitate and constrain heterospecific sociality

Check out this new paper by Hari Sridhar, an INSA postdoctoral fellow in our lab.

Hari Sridhar and Vishwesha Guttal, 2018, Friendship across species borders: factors that facilitate and constrain heterospecific sociality, Phil. Trans. Royal Society of London B, 373: 20170014. http://dx.doi.org/10.1098/rstb.2017.0014PDF

Hari did some fabulous work on mixed-species flocks during his Ph.D. thesis, advised by my colleague Kartik Shanker. Hari continues that trend with another piece of fundamental contribution to the field. I am quite lucky to have been involved with him on this and had lots of new things to learn from him on the topic. The main proposal of the paper is nicely captured in the abstract:

Our understanding of animal sociality is based almost entirely on single-species sociality. Heterospecific sociality, although documented in numerous taxa and contexts, remains at the margins of sociality research and is rarely investigated in conjunction with single-species sociality. This could be because heterospecific and single-species sociality are thought to be based on fundamentally different mechanisms. However, our literature survey shows that heterospecific sociality based on mechanisms similar to single-species sociality is reported from many taxa, contexts and for various benefits. Therefore, we propose a conceptual framework to understand conspecific versus heterospecific social partner choice. Previous attempts, which are all in the context of social information, model partner choice as a trade-off between information benefit and competition cost, along a single phenotypic distance axis. Our framework of partner choice considers both direct grouping benefits and information benefits, allows heterospecific and conspecific partners to differ in degree and qualitatively, and uses a multi-dimensional trait space analysis of costs (competition and activity matching) and benefits (relevance of partner and quality of partner). We conclude that social partner choice is best-viewed as a continuum: some social benefits are obtainable only from conspecifics, some only from dissimilar heterospecifics, while many are potentially obtainable from conspecifics and heterospecifics.

This is published as part of theme issue on “Collective movement ecology” – a must read for everyone interested in movement ecology.

 



We have been awarded an UGC-UKIERI grant for collaboration with Colin Torney

We are delighted that we have been awarded an UGC-UKIERI grant for collaboration with Colin Torney in the School of Mathematics and Statistics, University of Glasgow and my colleague Dr Kavita Isvaran at CES. The grant amount is around 25,000 UK Pounds (equivalent to around 25 lakhs) and is valid from March 2018 – March 2020.

The ideas and work proposed here are by PhD student Akanksha Rathore who is jointly advised by me and Kavita. The grant will help both of our groups to travel back and forth, and work on investigating collective behaviour of blackbuck in the wild.

This is our second collaborative grant with Colin Torney, the previous one being funded by Royal Society which was instrumental in starting our collaboration as well as getting this grant.