Shikhara Bhat
@shikharabhat.bsky.social
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
Past: BS-MS at IISER Pune, India. MS thesis at CES, IISc.
Webpage: https://thepandalorian.github.io
he/him
yes but have you considered
September 24, 2025 at 5:38 PM
yes but have you considered
Hey #ESEB2025 folk! I'll be presenting my work on describing evolution in finite populations at 11:30 am on Tuesday in S-03. Drop by to learn how taking ecology and variable population size seriously changes classic pop gen descriptions like the Price eqn, revealing novel directional eco-evo forces.
August 16, 2025 at 5:37 PM
Hey #ESEB2025 folk! I'll be presenting my work on describing evolution in finite populations at 11:30 am on Tuesday in S-03. Drop by to learn how taking ecology and variable population size seriously changes classic pop gen descriptions like the Price eqn, revealing novel directional eco-evo forces.
A beautiful read. I was rather reminded of the Preface of @arvidagren.bsky.social 's book :D
June 10, 2025 at 1:45 PM
A beautiful read. I was rather reminded of the Preface of @arvidagren.bsky.social 's book :D
Really cool paper from Anthony Sun et al. showing how we can use "symbolic regression" to fit functional forms to population growth data (by fitting things like + and /) and infer "the minimal number of independent resources theoretically required to reproduce the observed population dynamics." 🧬🧪🌍
June 5, 2025 at 7:03 AM
Really cool paper from Anthony Sun et al. showing how we can use "symbolic regression" to fit functional forms to population growth data (by fitting things like + and /) and infer "the minimal number of independent resources theoretically required to reproduce the observed population dynamics." 🧬🧪🌍
I've been teaching myself some mathematics around @tomospotter.bsky.social and @antisamourdani.bsky.social 's cat, and she seems fascinated. @kokkonut.bsky.social, I think we may be getting a new kokkonut (cattonut?) soon if there are open positions available ;)
May 14, 2025 at 3:38 PM
I've been teaching myself some mathematics around @tomospotter.bsky.social and @antisamourdani.bsky.social 's cat, and she seems fascinated. @kokkonut.bsky.social, I think we may be getting a new kokkonut (cattonut?) soon if there are open positions available ;)
Ex 4 is from ageing theory. Yashin et al showed that very different models (the 'Γ-Makeham model' based on frailty and heterogeneous pops and the Le-Bras model based on reliability theory-style damage accumulation) lead to the same mortality dynamics. Here, biology itself is different in the models.
April 22, 2025 at 3:59 PM
Ex 4 is from ageing theory. Yashin et al showed that very different models (the 'Γ-Makeham model' based on frailty and heterogeneous pops and the Le-Bras model based on reliability theory-style damage accumulation) lead to the same mortality dynamics. Here, biology itself is different in the models.
Ex 3 is my own (sorry). Stochastic evolution of quantitative traits in finite populations can be modelled either in terms of purely probabilistic properties via martingales (Champagnat et al, 2006 and successors) or in terms of their dynamics using SPDEs and heuristics from statistical physics
April 22, 2025 at 3:59 PM
Ex 3 is my own (sorry). Stochastic evolution of quantitative traits in finite populations can be modelled either in terms of purely probabilistic properties via martingales (Champagnat et al, 2006 and successors) or in terms of their dynamics using SPDEs and heuristics from statistical physics
Ex 2 is the Wright-Fisher diffusion. The fundamental soln to the eqn was found independently by Chen and Stroock (using probabilistic tools from SDE theory) and Epstein and Mazzeo (using purely analytic + algebraic tools from PDE theory based on the Fokker-Planck equation and semi-group techniques)
April 22, 2025 at 3:59 PM
Ex 2 is the Wright-Fisher diffusion. The fundamental soln to the eqn was found independently by Chen and Stroock (using probabilistic tools from SDE theory) and Epstein and Mazzeo (using purely analytic + algebraic tools from PDE theory based on the Fokker-Planck equation and semi-group techniques)
Ex 1 is the Feldman-Karlin conjecture, a famous conjecture about the number of equilibria in certain genetic systems. The conjecture was independently proven by Altenberg (using pop gen models + algebraic geometry) and Han, Traulsen, and @gokhalecs.bsky.social (using evolutionary game theory ideas)
April 22, 2025 at 3:59 PM
Ex 1 is the Feldman-Karlin conjecture, a famous conjecture about the number of equilibria in certain genetic systems. The conjecture was independently proven by Altenberg (using pop gen models + algebraic geometry) and Han, Traulsen, and @gokhalecs.bsky.social (using evolutionary game theory ideas)
I also now have a tattoo of Oecanthus henryi and the bushes (Hyptis sualovens) that are so important to determining the behavioural ecology of these fascinating insects, so I suppose these crickets are with me forever now :)
#sciart #tattoo #sci-art #artists #sciencetattoos
#sciart #tattoo #sci-art #artists #sciencetattoos
April 17, 2025 at 8:39 PM
I also now have a tattoo of Oecanthus henryi and the bushes (Hyptis sualovens) that are so important to determining the behavioural ecology of these fascinating insects, so I suppose these crickets are with me forever now :)
#sciart #tattoo #sci-art #artists #sciencetattoos
#sciart #tattoo #sci-art #artists #sciencetattoos
If you want to read more about this work, do check out our paper about it in Biology Open. It's open access, and made the cover!
doi.org/10.1242/bio....
doi.org/10.1242/bio....
April 17, 2025 at 8:39 PM
If you want to read more about this work, do check out our paper about it in Biology Open. It's open access, and made the cover!
doi.org/10.1242/bio....
doi.org/10.1242/bio....
But why? Bafflers, importantly, cannot move once they have committed to a baffle, because constructing a baffle is time and energy consuming, and you can't carry a leaf around. We show that if we similarly disallow movement of calling and silent males, mating success is no longer equal!
April 17, 2025 at 8:39 PM
But why? Bafflers, importantly, cannot move once they have committed to a baffle, because constructing a baffle is time and energy consuming, and you can't carry a leaf around. We show that if we similarly disallow movement of calling and silent males, mating success is no longer equal!
We found that the relative mating success of different tactics was radically different based on whether or not we included bushes in the landscape. No bushes? Baffling is always best, and by a large margin. With bushes? The different tactics do about equally well!
April 17, 2025 at 8:39 PM
We found that the relative mating success of different tactics was radically different based on whether or not we included bushes in the landscape. No bushes? Baffling is always best, and by a large margin. With bushes? The different tactics do about equally well!
To account for this ecological reality, we also ran simulations in which we included bush structure in a very simplistic way and allowed crickets to move either within a bush, or rarely, fly across bushes. We drew bush spatial distributions from empirical data.
April 17, 2025 at 8:39 PM
To account for this ecological reality, we also ran simulations in which we included bush structure in a very simplistic way and allowed crickets to move either within a bush, or rarely, fly across bushes. We drew bush spatial distributions from empirical data.
But remember, these are *TREE* crickets. In the real world, these individuals live in complex spatial landscapes structured by their host plant. Moving within the same bush is easy, but individuals need to FLY to get from one bush to another, something that's known to be rare because it's so hard
April 17, 2025 at 8:39 PM
But remember, these are *TREE* crickets. In the real world, these individuals live in complex spatial landscapes structured by their host plant. Moving within the same bush is easy, but individuals need to FLY to get from one bush to another, something that's known to be rare because it's so hard
So why doesn't everyone baffle? In other words, what maintains the different male tactics? In our work, we build an individual-based model using decades of empirical knowledge from Rohini's lab to answer this question. At first, we thought we'd do this the easy way with a simple 2D grid like shown
April 17, 2025 at 8:39 PM
So why doesn't everyone baffle? In other words, what maintains the different male tactics? In our work, we build an individual-based model using decades of empirical knowledge from Rohini's lab to answer this question. At first, we thought we'd do this the easy way with a simple 2D grid like shown
However, field observations indicate that only about 5% of individuals baffle on a given night. Indeed, empirical work shows that many males actually do not call at all, instead electing to stay silent for the entire night (doi.org/10.1101/2023...)
April 17, 2025 at 8:39 PM
However, field observations indicate that only about 5% of individuals baffle on a given night. Indeed, empirical work shows that many males actually do not call at all, instead electing to stay silent for the entire night (doi.org/10.1101/2023...)
A fantastic previous study (royalsocietypublishing.org/doi/10.1098/...) showed empirically that ♀️ prefer louder ♂️ . Work by @natashamhatre.bsky.social
has also shown biomechanically that baffles are constructed to be optimal for sound amplification (doi.org/10.7554/eLif...).
has also shown biomechanically that baffles are constructed to be optimal for sound amplification (doi.org/10.7554/eLif...).
April 17, 2025 at 8:39 PM
A fantastic previous study (royalsocietypublishing.org/doi/10.1098/...) showed empirically that ♀️ prefer louder ♂️ . Work by @natashamhatre.bsky.social
has also shown biomechanically that baffles are constructed to be optimal for sound amplification (doi.org/10.7554/eLif...).
has also shown biomechanically that baffles are constructed to be optimal for sound amplification (doi.org/10.7554/eLif...).
But the world can be big and noisy. What's a little cricket to do to make sure he's heard by his suitors? Well, O. henryi males have a trick up their sleeve: by making a hole in a leaf and calling through it ("baffling"), they can make their calls much louder! Pretty cool, right?
April 17, 2025 at 8:39 PM
But the world can be big and noisy. What's a little cricket to do to make sure he's heard by his suitors? Well, O. henryi males have a trick up their sleeve: by making a hole in a leaf and calling through it ("baffling"), they can make their calls much louder! Pretty cool, right?
Since we've moved platforms, I thought I'd make a new explainer thread for our (Aamir Sadiq, @vishuguttal.bsky.social, Rohini Balakrishnan, and I) recent paper on tree crickets.
Meet Oecanthus henryi. Like in many cricket species, O. henryi males call to attract mates.
#science #evobio 🌍 🧬
Meet Oecanthus henryi. Like in many cricket species, O. henryi males call to attract mates.
#science #evobio 🌍 🧬
April 17, 2025 at 8:39 PM
Since we've moved platforms, I thought I'd make a new explainer thread for our (Aamir Sadiq, @vishuguttal.bsky.social, Rohini Balakrishnan, and I) recent paper on tree crickets.
Meet Oecanthus henryi. Like in many cricket species, O. henryi males call to attract mates.
#science #evobio 🌍 🧬
Meet Oecanthus henryi. Like in many cricket species, O. henryi males call to attract mates.
#science #evobio 🌍 🧬
Some pretty arthropods from a morning walk in the Western Ghats rainforests. I'd missed how easy it is to find colorful biodiversity here :')
#photography #macro #macrophotography
#photography #macro #macrophotography
January 24, 2025 at 5:33 AM
Some pretty arthropods from a morning walk in the Western Ghats rainforests. I'd missed how easy it is to find colorful biodiversity here :')
#photography #macro #macrophotography
#photography #macro #macrophotography
I really missed the enormous, sprawling english bookshops of Bangalore. Always nice to pay a visit (with @dhanyabharath.bsky.social, as tradition dictates). Here's this time's book haul!!
#booksky
#booksky
January 17, 2025 at 6:54 AM
I really missed the enormous, sprawling english bookshops of Bangalore. Always nice to pay a visit (with @dhanyabharath.bsky.social, as tradition dictates). Here's this time's book haul!!
#booksky
#booksky
In my manuscript, I derive stochastic partial differential equations to describe evolutionarily important quantities like trait frequencies and trait means. Remarkably, these equations recover standard pop/quant gen results like Kimura-Crow and Lande's gradient eqn in the infinite population limit!
December 20, 2024 at 4:14 PM
In my manuscript, I derive stochastic partial differential equations to describe evolutionarily important quantities like trait frequencies and trait means. Remarkably, these equations recover standard pop/quant gen results like Kimura-Crow and Lande's gradient eqn in the infinite population limit!
We can also recover other results: for example, our equation for trait variances recovers the fact that drift causes loss of variation. Indeed, when the τ of all types are the same (as in WF and Moran), we recover the standard loss of heterozygosity formula from population genetics.
December 5, 2024 at 9:28 PM
We can also recover other results: for example, our equation for trait variances recovers the fact that drift causes loss of variation. Indeed, when the τ of all types are the same (as in WF and Moran), we recover the standard loss of heterozygosity formula from population genetics.
However, if you were to look at where the system tends to be, you'll notice that it spends more time in areas where it moves slowly. This effect is like 'viscosity': If you're stuck in mollasses, its harder to move out to a new area. Thus, you'll find more walkers above the origin if you wait!
December 5, 2024 at 9:28 PM
However, if you were to look at where the system tends to be, you'll notice that it spends more time in areas where it moves slowly. This effect is like 'viscosity': If you're stuck in mollasses, its harder to move out to a new area. Thus, you'll find more walkers above the origin if you wait!