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Shikhara Bhat

@shikharabhat.bsky.social

1.7K followers 1.1K following 160 posts

Theoretical evolutionary ecologist. Fond of math, coffee, natural history, and metal music. Kokkonut and PhD student at Uni Mainz, Germany. Past: BS-MS at IISER Pune, India. MS thesis at CES, IISc. Webpage: https://thepandalorian.github.io he/him

thepandalorian.github.io

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Shikhara Bhat @shikharabhat.bsky.social · Jan 10

Our (@vishuguttal.bsky.social and I) Synthesis of the effects of demographic stochasticity on eco-evolutionary dynamics is now out in @asn-amnat.bsky.social ! Feel free to message/email me if you need a copy or want to chat about the paper :)

🧬🌍🧪

American Naturaliﬆ / ASN 🐌 @asn-amnat.bsky.social · Jan 9

Does evolution always favor individuals with higher fitness? Bhat & Guttal generalize standard equations of evolution to show that populations experience a novel force called noise-induced biasing that can reverse the predicted direction of evolution.
www.journals.uchicago.edu/doi/10.1086/...

Eco-Evolutionary Dynamics for Finite Populations and the Noise-Induced Reversal of Selection | The American Naturalist: Vol 205, No 1

Abstract Theoretical studies from diverse areas of population biology have shown that demographic stochasticity can substantially impact evolutionary dynamics in finite populations, including scenario...

www.journals.uchicago.edu

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Shikhara Bhat @shikharabhat.bsky.social · 13h

I'm not sure what (a) means biologically, but (b) seems to me to imply that we assume such mutations should arise (infinitely!) many times in the same mutational background - otherwise, why is a statement about expected/average behaviour meaningful given that we only observe a single realisation?

Shikhara Bhat @shikharabhat.bsky.social · 13h

Maybe I'm being obtuse, but isn't it still true that this benefit is either (a) over time, conditioned on non-extinction of the allele, or (b) over realizations, which is some sort of assumption about how often such alleles arise via mutation (?) if we are looking within a species.

Shikhara Bhat @shikharabhat.bsky.social · 13h

Why do we think these averages should tell us something meaningful about any given gene? Populations are typically not very large, and neither are clutch sizes so why is the average a useful metric?

Shikhara Bhat @shikharabhat.bsky.social · 13h

I'm likely missing something, but why do the averages matter? Doesn't "average" rely on a LLN argument, either over crosses (if these genotypes meet many times, you share the gene with your sib more often than not) or over clutch size (if you have many sibs, you share the gene with half of them)?

Shikhara Bhat @shikharabhat.bsky.social · 14h

*Maybe* if there were a large number of crosses of each type in every generation, LLN can kick in and ensure that IBD helps an individual estimate IBS.

This feels like a very strong, unjustified assumption given how wild populations of multicellular organisms typically work. What am I missing here?

Shikhara Bhat @shikharabhat.bsky.social · 14h

So why is IBD relevant?

Naively, I would think that for helping to spread, either individuals should be able to detect IBS (= some sort of greenbeard) rather than IBD. In particular, this means you ignore siblings/pedigree and only look for the green beard, so relatedness can be entirely ignored.

Shikhara Bhat @shikharabhat.bsky.social · 14h

the precise way to say "more likely" really depends on a law of large numbers (LLN) argument. In particular, LLN says that *on average*, half the siblings of a helper will be helpers, *given sufficiently many realisations*. This says nothing about what happens if your number of offspring is small.

Shikhara Bhat @shikharabhat.bsky.social · 14h

Ignoring other assortment processes (ex: spatial structure/limited dispersal), this means that helping spreads if you can detect which individuals are identical by state (IBS) at the helping locus. While we like to say a sibling is "more likely" to be IBD (and thus IBS) than a random individual,

Shikhara Bhat @shikharabhat.bsky.social · 14h

For simplicity, let's fix n=1 and say you believe that one locus models of "a gene for helping" (or similar) are plausible.

Classic theory suggests that if helping is costly, a mutant with the helping allele will spread if helpers can preferentially direct interactions towards other helpers.

Shikhara Bhat @shikharabhat.bsky.social · 14h

#evosky, a naive, theory-pilled question: Why is anybody who believes in n-locus models of cooperation for small n allowed to care about relatedness in the pedigree (IBD) sense?

A quick thread (please excuse any hyperbole, misrepresentation, or strawman arguments and point them out for me lol):

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Reposted by Shikhara Bhat

Daniel Bolnick @danielbolnick.bsky.social · 1d

This:
www.nature.com/articles/d41...
Absolutely yes. And I'm proud that @asn-amnat.bsky.social has led the way on this with requiring code and data editors checking code for about five years now!

Stop treating code like an afterthought: record, share and value it

Scientists, research institutions, funders, libraries and publishers must all improve software practices.

www.nature.com

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Reposted by Shikhara Bhat

Society for the Study of Evolution @sse-evolution.bsky.social · 3d

Nominations are now open for the Dobzhansky Prize, which recognizes the accomplishments and future promise of an outstanding early-career evolutionary biologist. The award includes $5000 and an award talk at the in-person Evolution meeting. Deadline: December 1
shorturl.at/p70wY

Text: Society for the Study of Evolution Dobzhansky Prize to recognize the accomplishments and future promise of an outstanding early-career evolutionary biologist. Nominations due December 1, 2025.

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Reposted by Shikhara Bhat

subvariety sarah @scgriffith.bsky.social · 2d

from now on I'm just going to truncate the taylor series for sin at the first term. sin(x) = 0 for all x. this approximation

- is efficient to compute
- has bounded error
- has excellent analytic properties
- has very high accuracy for small values, which occur frequently in applications

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Shikhara Bhat @shikharabhat.bsky.social · 2d

"When asked by the BBC whether he thought it might be a trick that his wife might play on him, Dr Ramsdell said: "I have a lot of friends, but they're not coordinated enough to pull off this joke""

Incredible

Unofficial BBCNews (World) Bot @bbcnews-world-rss.bsky.social · 3d

Scientist on three-week off-grid hike finds out he's won the Nobel prize

Dr Fred Ramsdell was "living his best life" offline when the Nobel committee tried to contact him.

www.bbc.com

Reposted by Shikhara Bhat

E. Yağmur Erten @yagmurerten.bsky.social · 25d

New paper out! 🤩 "Shrinking to bird size with dinosaur-level cancer defences: Evolution of cancer suppression over macroevolutionary time" with @kokkonut.bsky.social and @marcanthonytollis.bsky.social. doi.org/10.1371/jour... A short thread:

Shrinking to bird size with dinosaur-level cancer defences: Evolution of cancer suppression over macroevolutionary time

Author summary Humans are not the only species suffering from cancer, yet cancer does not impact all life equally. Body size is relevant because maintaining a large number of cells in a tumour-free st...

doi.org

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Reposted by Shikhara Bhat

Szymek Drobniak @szymekdr.bsky.social · 8d

Our newest paper is out in Methods in Ecol Evol @methodsinecoevol.bsky.social :) amazing team effort - we show that the traditional way of analyzing comparative data lacks finesse. besjournals.onlinelibrary.wiley.com/action/oidcS... w/ @itchyshin.bsky.social Yefeng Yang, Losia Lagisz & Ayumi Mizuno

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Reposted by Shikhara Bhat

Joe Brennan @biologyjoe87.bsky.social · 8d

Excited to share a new pre-print in collaboration with @sebastianschreiber.bsky.social, "Using Modern Coexistence Theory to understand community disassembly"! We set out to understand how techniques used to study coexistence can be extended to understand community disassembly. (1/X)

Using modern coexistence theory to understand community disassembly

Community disassembly examines how species extinction alters ecological communities. Sometimes, the extinction of one species can trigger the loss of others, known as secondary extinction. These secon...

www.biorxiv.org

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Reposted by Shikhara Bhat

Ed Ivimey-Cook @eivimeycook.bsky.social · 8d

A fantastic few days of ageing talks, great people, and excellent food!

Massive thanks to (Hanna!) @kokkonut.bsky.social, Margaux Bieuville, Victor Ronget, and the fantastic people at The Gutenberg Workshops in the Life Sciences

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Reposted by Shikhara Bhat

POPGROUP59 @popgroup2026.bsky.social · 12d

Exciting news!
The next #PopGroup meeting will take place in Lille 🍟, France, 7–9 January 2026 – just 1 hour by train from London, Brussels, and Paris.

This year, PopGroup will also host ALPHY, the annual meeting of Evolutionary Genomics.

More info: populationgeneticsgroup.org.uk

See you there !

Population Genetics group 59

populationgeneticsgroup.org.uk

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Shikhara Bhat @shikharabhat.bsky.social · 16d

yes but have you considered

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Shikhara Bhat @shikharabhat.bsky.social · 16d

So real

Reposted by Shikhara Bhat

Liam U. Taylor @liamtaylor.bsky.social · 16d

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Reposted by Shikhara Bhat

Liam U. Taylor @liamtaylor.bsky.social · 16d

Understanding the tradeoff between the tradeoff between the tradeoffs between current and future tradeoffs between future and current reproductive success is critical for evaluating long term trends in tradeoffs between current and future reproductive success.

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Reposted by Shikhara Bhat

Catherine Sheard @sheardcat.bsky.social · 18d

As with all advice, ymmv, but these takes on success in grad school resonate a lot with my experiences: dorsaamir.medium.com/modest-advic...

Modest Advice for New Graduate Students

Throughout the course of my years in graduate school, I kept a running list of the best advice given to me, and the strategies that helped…

dorsaamir.medium.com

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Reposted by Shikhara Bhat

Ed Ivimey-Cook @eivimeycook.bsky.social · 23d

Our latest #SORTEE-led paper is out now in #ProcB!

We reviewed data/code-sharing policy clarity, strictness & timing across 275 EcoEvo journals

We also worked with #ProcB & #EcologyLetters to assess initial compliance with sharing mandates. Huge team effort! 👉 doi.org/10.1098/rspb...

From policy to practice: progress towards data- and code-sharing in ecology and evolution | Proceedings of the Royal Society B: Biological Sciences

Data and code are essential for ensuring the credibility of scientific results and facilitating reproducibility, areas in which journal sharing policies play a crucial role. However, in ecology and evolution, we still do not know how widespread data- and ...

doi.org

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