Martijn Schenkel
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martijnschenkel.bsky.social
Martijn Schenkel
@martijnschenkel.bsky.social
330 followers 250 following 31 posts
Evolutionary biologist with an interest in conflicts, unusual genetics, sex, and all the other funny things that make biology tick | Postdoc at Wagening University | STN Internal Conflicts & Organismal Adaptation https://internalconflictsstn.wordpress.com
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Reposted by Martijn Schenkel
arvidagren.bsky.social
Speciation special with @jenncoughlan.bsky.social and @ecmoore.bsky.social!

Thursday November 13.
November 4, 2025 at 1:24 PM
martijnschenkel.bsky.social
New paper out with Manus Patten and @arvidagren.bsky.social in Biology & Philosophy! We propose a framework to capture the severity of different types of internal conflict and how this allows for a quantitative approach to evolutionary individuality across different biological collectives.
arvidagren.bsky.social Arvid Ågren @arvidagren.bsky.social · 10d
*NEW PAPER*

How much of a threat are within-organism conflicts, really?

In Biology & Philosophy, @martijnschenkel.bsky.social, Manus Patten, and I present a mathematical framework to measure evolutionary individuality in the face of internal conflicts. link.springer.com/article/10.1...
Screenshot of the abstract. It reads In biology, individuals can be identified at various levels of organization, ranging from the molecular and cellular—e.g., viruses and protists—to the organismal and societal—e.g., termites and termite colonies. This nested biological hierarchy results from evolutionary transitions in individuality, in which lower-lying entities (particles) come together to form higher-level entities (collectives). These collectives are then taken to be individuals in their own right, capable of being the units on which selection acts and where adaptations may reside. Challenges arise, however, when we recognize the possibility for internal conflict, for example from selfish genetic elements within organisms. Here we develop a quantitative approach to biological individuality, in which collectives qualify as individuals to the extent that their particles possess a unity of purpose—i.e., that they possess aligned fitness interests. We propose a mathematical framework that measures the degree of individuality exhibited by organisms and other biological collectives in the presence of internal conflicts. This framework not only helps pinpoint where in the hierarchy biological individuality sits, but also identifies the level at which adaptation may reside. We develop two metrics: fitness unity, which measures the threat posed by internal conflicts to a collective individual’s status as an optimizing agent; and trait unity, which measures differences in optimal strategies among its particles. Finally, we consider cases where internal conflicts become so disruptive to individualized biological collectives so that it no longer makes sense to think of them as individuals, but instead as compromises of multiple competing particles.
October 31, 2025 at 1:41 PM
Reposted by Martijn Schenkel
arvidagren.bsky.social
*NEW PAPER*

How much of a threat are within-organism conflicts, really?

In Biology & Philosophy, @martijnschenkel.bsky.social, Manus Patten, and I present a mathematical framework to measure evolutionary individuality in the face of internal conflicts. link.springer.com/article/10.1...
Screenshot of the abstract. It reads In biology, individuals can be identified at various levels of organization, ranging from the molecular and cellular—e.g., viruses and protists—to the organismal and societal—e.g., termites and termite colonies. This nested biological hierarchy results from evolutionary transitions in individuality, in which lower-lying entities (particles) come together to form higher-level entities (collectives). These collectives are then taken to be individuals in their own right, capable of being the units on which selection acts and where adaptations may reside. Challenges arise, however, when we recognize the possibility for internal conflict, for example from selfish genetic elements within organisms. Here we develop a quantitative approach to biological individuality, in which collectives qualify as individuals to the extent that their particles possess a unity of purpose—i.e., that they possess aligned fitness interests. We propose a mathematical framework that measures the degree of individuality exhibited by organisms and other biological collectives in the presence of internal conflicts. This framework not only helps pinpoint where in the hierarchy biological individuality sits, but also identifies the level at which adaptation may reside. We develop two metrics: fitness unity, which measures the threat posed by internal conflicts to a collective individual’s status as an optimizing agent; and trait unity, which measures differences in optimal strategies among its particles. Finally, we consider cases where internal conflicts become so disruptive to individualized biological collectives so that it no longer makes sense to think of them as individuals, but instead as compromises of multiple competing particles.
October 31, 2025 at 1:24 PM
Reposted by Martijn Schenkel
arvidagren.bsky.social
Working any sort of within-organism conflict?

Submit a paper to our special issue in @jevbio.bsky.social!
evoldir.bsky.social EvolDir @evoldir.bsky.social · 15d
Call for Papers for a special issue on "Foundations of Internal Conflicts" in the Journal of Evolutionary Biology. Submit by Feb 28, 2026. Contact Martijn Schenkel for details: martijn.schenkel@wur.nl
[jeb.office@eseb.org](mailto:jeb.office@eseb.org)
October 27, 2025 at 2:21 AM
martijnschenkel.bsky.social
Working on internal conflicts? Please submit to the Internal Conflicts STN special issue with @jevbio.bsky.social! We invite work on all forms of within-organism conflict, and are very keen to receive research manuscripts. See the link for more info, or reach out to me if you have any questions.
evoldir.bsky.social EvolDir @evoldir.bsky.social · 15d
Call for Papers for a special issue on "Foundations of Internal Conflicts" in the Journal of Evolutionary Biology. Submit by Feb 28, 2026. Contact Martijn Schenkel for details: martijn.schenkel@wur.nl
[jeb.office@eseb.org](mailto:jeb.office@eseb.org)
October 27, 2025 at 6:35 AM
Reposted by Martijn Schenkel
arvidagren.bsky.social
The second seminar of the year is on Thursday, October 16 at 10am Eastern.

@salazarafra.bsky.social + @ellenclarke.bsky.social

Join us!
internalconflictsstn.wordpress.com/seminars/
Afra Salazar (University of Lausanne): Can individuality help us improve community functions? Ellen Clarke (University of Leeds): Evolutionary unitization in bacteria
October 13, 2025 at 1:35 PM
Reposted by Martijn Schenkel
arvidagren.bsky.social
First seminar is this Friday, September 19 at 9am Eastern.

Laurence Hurst and Phil Madgwick.

Join us!
September 17, 2025 at 5:50 PM
martijnschenkel.bsky.social
Join us this Friday at 13:00 UTC for the first Internal Conflicts STN seminar of this academic year, featuring Laurence Hurst and Phil Madgwick! Details via internalconflictsstn.wordpress.com/seminars/, also on several upcoming seminars.
Information on the seminar, with pictures of Laurence Hurst (left) and Phil Madgwick (right).
September 15, 2025 at 9:23 AM
Reposted by Martijn Schenkel
arvidagren.bsky.social
Take a sneak peak at The Paradox of the Organism at Google books books.google.com/books?hl=sv&...

Don’t forget to pre-order!
September 14, 2025 at 10:35 PM
Reposted by Martijn Schenkel
arvidagren.bsky.social
If you work on the internal conflicts, do consider proposing a paper for our upcoming special issue in the Journal of Evolutionary Biology.

More info here: internalconflictsstn.wordpress.com/special-issue/
August 29, 2025 at 2:35 PM
Reposted by Martijn Schenkel
arvidagren.bsky.social
Getting ready for another semester of seminars for the @eseb.bsky.social STN Internal Conflicts and Organismal Adaptation.

First seminar on September 19 internalconflictsstn.wordpress.com/seminars/
August 28, 2025 at 6:27 PM
martijnschenkel.bsky.social
New paper out in Proc B on remote-control meiotic drive! Segregation distorters normally eliminate their chromosomal counterpart, but we show that meddling with other chromosomes may also be beneficial, with unusual results. See thread below, paper at royalsocietypublishing.org/doi/10.1098/...
August 27, 2025 at 5:36 AM
Reposted by Martijn Schenkel
arvidagren.bsky.social
Coming December 16!
August 26, 2025 at 4:41 PM
Reposted by Martijn Schenkel
tom-is-kean.bsky.social
At #ESEB2025 a high frequency of talks have ended with advertisements for PhDs and Postdocs. Grad students, crack in! You never know where a simple conversation might lead.
August 21, 2025 at 12:48 PM
Reposted by Martijn Schenkel
shikharabhat.bsky.social
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.
An illustration with populations on the left and mathematical representations of these populations in terms of birth-death processes on the right Stochastic differential equations for trait frequencies, mean value of a trait, and the variance of a trait in the population
August 16, 2025 at 5:37 PM
Reposted by Martijn Schenkel
gauravathreya.bsky.social
hello to everyone going to #ESEB2025! want to hear about the consequences of age-dependent plasticity in reproducing via sex vs. asex? I will give a talk at 11:15am on Thursday in S15.02. come for the pretty Hydra illustrations, stay for the novel evolutionary insights on facultative sex!
August 16, 2025 at 5:31 PM
martijnschenkel.bsky.social
Wonder if Bruce Wallace liked his dean.

From: B. Wallace (1975). Hard and soft selection revisited. Evolution 29:465-473.
Excerpt from a 1975 paper by Bruce Wallace which reads: "The relative ease with which homozygous mutant flies can be maintained in stock cultures fails to reflect the low survival values these same genotypes would exhibit were they to develop together with wild-type flies in a single culture bottle. In many respects an adult fly resembles the Dean of the Faculty at a university: the positions exists and needs filling; the creation of a dean does not require, however, the existence of faculty members with deanlike qualities because the position will be filled in any case."
July 16, 2025 at 8:24 AM
Reposted by Martijn Schenkel
romanzug.bsky.social
New paper out at Biological Reviews!! 🥳🥳

"Infection dynamics of endosymbionts that manipulate arthropod reproduction"
onlinelibrary.wiley.com/doi/10.1111/brv.70024

A joint effort with Franziska Brenninger (now a postdoc ‪@unibe.ch‬) and @kokkonut.bsky.social‬. (1/5)
Infection dynamics of endosymbionts that manipulate arthropod reproduction
A large proportion of arthropod species are infected with endosymbionts, some of which selfishly alter host reproduction. The currently known forms of parasitic reproductive manipulations are male-ki...
onlinelibrary.wiley.com
June 3, 2025 at 10:31 PM
Reposted by Martijn Schenkel
arvidagren.bsky.social
May 20, 2025 at 7:05 PM
Reposted by Martijn Schenkel
arvidagren.bsky.social
*SAVE THE DATE*

The next seminar of our Internal Conflicts and Organismal Adaptation virtual lectures series will be on April 30.

Talks from Perran Stott Ross and Filip Husnik.

Please note the time!

Sign up and check out recordings of previous talks here internalconflictsstn.wordpress.com
Perran Stott Ross (University of Melbourne): Evolutionary impacts of endosymbionts for pest and disease control Filip Husnik (Okinawa Institute of Science and Technology): The fate of obligate endosymbionts: reduction, integration, or extinction Date: April 30, 2025. Time: 08:00 UTC
April 28, 2025 at 3:35 PM
martijnschenkel.bsky.social
Join us tomorrow at 8:00 UTC (10:00 CEST) for the next Internal Conflicts STN seminar! Talks by Perran Stott Ross and Filip Husnik. For Zoom link + more info see internalconflictsstn.wordpress.com/seminars/
Overview of meeting details for the next Internal Conflicts STN seminar by Perran Stott Ross and Filip Husnik.
April 29, 2025 at 11:22 AM
Reposted by Martijn Schenkel
arvidagren.bsky.social
The second workshop of our @eseb.bsky.social STN Internal Conflicts and Organismal Adaptation will take place at the Princess Hotel, Barcelona on August 17, during the day before the ESEB congress evening reception.

More info and registration here: internalconflictsstn.wordpress.com/workshop-ii/
Logo of the STN
April 22, 2025 at 3:02 PM
Reposted by Martijn Schenkel
arvidagren.bsky.social
Now available for preorder!

The Paradox of the Organism:
Adaptation and Internal Conflict, edited by me and Manus Patten, will be published by @harvardpress.bsky.social this fall.

Cover coming soon.
April 16, 2025 at 8:04 PM
Reposted by Martijn Schenkel
martijnschenkel.bsky.social
Registration (free!) is now open for the second Internal Conflicts and Organismal Adaptation STN workshop in Barcelona on August 17! Like our first workshop, it will feature contributed talks and group-based discussions on key themes. Info + registration: internalconflictsSTN.wordpress.com. [1/2]
INTERNAL CONFLICTS AND ORGANISMAL ADAPTATION
ESEB Special Topic Network
internalconflictsSTN.wordpress.com
March 27, 2025 at 8:04 AM
martijnschenkel.bsky.social
Registration (free!) is now open for the second Internal Conflicts and Organismal Adaptation STN workshop in Barcelona on August 17! Like our first workshop, it will feature contributed talks and group-based discussions on key themes. Info + registration: internalconflictsSTN.wordpress.com. [1/2]
INTERNAL CONFLICTS AND ORGANISMAL ADAPTATION
ESEB Special Topic Network
internalconflictsSTN.wordpress.com
March 27, 2025 at 8:04 AM