(New) Paper on dryland ecosystem transitions and coverage in Deccan herald

Although I have tweeted quite a bit about this paper, I have been rather slow to announce this paper on this blog.

Chen Ning, Kailiang Yu, C Jayaprakash, Vishwesha Guttal, 2018, Rising variability, not slowing down, as a leading indicator of a stochastically driven abrupt transition in a dryland ecosystem, The American Naturalist, 191: E1 E14Data and Codes via Dryad. 

In this paper, we conduct an empirical test of early warning signals in a dryland ecosystem in China. This was based on a very cool email-collaboration with Chen Ning, a graduate student at that time.

The empirical analyses closely match with results of one of my PhD thesis paper with Prof C Jayaprakash, who is also a coauthor on this paper.

Suma from Gubbi Labs wrote this really nice popular article for Research Matters and it was also picked up by Deccan Herald, a very prominent English newspaper in South India !!!!

 

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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.

 

 

 

Congratulations to Sabiha Majumder and Jaideep Joshi for their successful completion of PhD!!!

2018 has been a fantastic year for our lab.

HUGE congratulations to two lab members (now, unfortunately, former lab members) — Sabiha Majumder and Jaideep Joshi – for the successfully defending their thesis.

Sabiha Majumder

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Sabiha Majumder defended her thesis on 26th February 2018. She joined IISc as an Integrated PhD student in the Department of Physics. Her Physics adviser was Prof Sriram Ramaswamy and with us she worked on “Multiple stable states and abrupt transitions in ecosystems”. She made some extremely important contributions to our understanding on patterns and dynamics ecosystems with multiple stable states, whether we can anticipate them via measuring simple quantities from field data, and whether we can even estimate threshold/critical points of such ecosystems.

Sabiha has joined as a postdoctoral fellow at Crowther Lab at ETH-Zurich. All the best for her future work. She will be badly missed in our lab.

Jaideep Joshi

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Jaideep defended his thesis on 30th January 2018. He joined IISc as a PhD student at CES and worked on some deeply insightly theoretical aspects of the evolution of cooperation in spatial systems. Apart from working with me, he also established his own collaborations as part of his thesis. After his PhD, he has joined as a postdoctoral researcher at Divecha Centre for Climate Change, IISc with prof Sukumar of CES. All the best to Jaideep for his future endeavours!

New paper: Jaideep Joshi’s paper on mobility and cooperation

We have a bunch of papers from the lab that I haven’t time to announce on the website (but I do active tweet about them!). Here, I briefly post about the first thesis chapter of Jaideep Joshi is now published in Plos Computational Biology. It’s a really cool theory paper on mobility can actually promote cooperation.

Active-Passive-CollBeh-Simulations

(The above picture is from Figure 1 of the manuscript Joshi et al 2017, Mobility can promote the evolution of cooperation via emergent self-assortment dynamics, PLoS Computational Biology, 13(9): e1005732).

The way we set up the problem is that can we have cooperation in mobile organisms if we exclude well known mechanisms that facilitate the evolution of cooperation. Yes, indeed, we can find cooperation via emergent assortment of cooperators. This paper shows this counter-intuitive using heavy simulations of active or self-propelled particles, simulations of passive particles in turbulent media, and an analytical theory. All of it packed into a single paper.

Here is a nice summary of this work written by Ananya from Research Matters, a popular science communication webpage:

Classically, it has been argued that cooperative interactions evolve mostly among genetic relatives or individuals in close-knit environments – like the lions or the buffaloes. There is also the factor that these animals are mobile and often split and merge depending on the availability of food. What, then, could be the motivation for cooperative interactions to emerge among such dynamic groups that are not genetically related?

“Much of the earlier research on cooperation thought that mobility was a hindrance to the evolution of cooperation. This is because mobility allows defectors to invade and destroy clusters of co-operators, which are necessary for cooperation to sustain”, says Mr. Joshi. In their study, published in the journal PLOS Computational Biology, the researchers have considered two scenarios for mobility – one, where the individuals move through self-propulsion such as fishes and birds, and second, where the individuals move due to the flow of the medium they live in such as microbes.

The study demonstrates that, rather than hinder it, mobility can help animals evolve cooperation to form groups even among unknown individuals without any kinship. “Our study is like a thought-experiment, but aided by sophisticated theoretical and computational tools. However, our model can easily be adapted to real systems by incorporating features specific to those systems. These could include cancer cells, quorum sensing bacteria, mixed species bird flocks, or even grouping mammals such as spotted deer, baboons and elephants”, signs off Dr. Joshi.