Egg trading by hermaphrodite fish--evolutionary game theory by Peña, Nöldeke, and Puebla

Game theory is about how payoffs among multiple parties change the way they interact with each other. One of the most interesting areas of application is in the study of evolution of populations.  Here's a paper about reciprocity in reproductive strategies that depend on the thickness of various aspects of the market...

The Evolution of Egg Trading in Simultaneous Hermaphrodites
Jorge Peña, Georg Nöldeke, and Oscar Puebla

Abstract: Egg trading—whereby simultaneous hermaphrodites exchange each other’s eggs for fertilization—constitutes one of the few rigorously documented and most widely cited examples of direct reciprocity among unrelated individuals. Yet how egg trading may initially invade a population of nontrading simultaneous hermaphrodites is still unresolved. Here, we address this question with an analytical model that considers mate encounter rates and costs of egg production in a population that may include traders (who provide eggs for fertilization only if their partners also have eggs to reciprocate), providers (who provide eggs regardless of whether their partners have eggs to reciprocate), and withholders (cheaters who mate only in the male role and just use their eggs to elicit egg release from traders). Our results indicate that a combination of intermediate mate encounter rates, sufficiently high costs of egg production, and a sufficiently high probability that traders detect withholders (in which case eggs are not provided) is conducive to the evolution of egg trading. Under these conditions, traders can invade—and resist invasion from—providers and withholders alike. The prediction that egg trading evolves only under these specific conditions is consistent with the rare occurrence of this mating system among simultaneous hermaphrodites.

Here's the full text.

Diversity of methodology in science, interview with E.O. Wilson

The Chronicle of Higher Ed interviews E.O. Wilson on, among other things, diversity in scientific approaches:

A Legendary Scientist Sounds Off on the Trouble With STEM
E.O. Wilson on the next big thing, the gladiatorial nature of academe, and the world beyond the human senses

"There’s no question that we need all the ablest people that can be recruited to go into science and technology to keep this country strong. But STEM is an unnecessarily forbidding set of stairs.

"Consider a young person who’s thrilled by seeing a natural system, a remarkable geological formation that stirs the imagination, or a group of animals or plants. This youngster says, Boy, when I get to college, I would like to move on to a career in science, and biology especially. Now, the STEM-oriented teacher — if we are following the STEM ideology as we hear it — says: "I think that’s a good ambition. But remember that biology is based substantially upon chemistry. So, I advise you to start getting a good background in chemistry. Oh, and while you’re at it, you should keep in mind that chemistry is based upon, to a major degree, principles of physics. So consider starting to get a background in physics, too. And, oh, I almost forgot: To get into physics, and a lot of the best parts of chemistry, you’re going to need ‘M,’ mathematics. So I want you to get started on math courses right now."
...
"Those universities that have large collections of organisms have not come close to providing educational tools for students at the undergraduate and graduate level. Harvard is particularly short. I came there as a graduate student in 1951, and I’m now honorary curator of insects, now that I’ve retired. Harvard has some of the best collections in the world — plants and animals — and we have a great arboretum. And yet the collections are not being used effectively to train people in biodiversity. They’re being neglected.

"We should be putting much more emphasis in both undergraduate and graduate biology courses on biodiversity. Right now we have given formal names to a little more than two million species. How many species remain unknown? The answer: an estimated eight million. We’re not talking about bacteria; we’re talking about eukaryotic animals.

"We need more courses about different groups of organisms — courses in ornithology, or invertebrate zoology, or entomology. That’s the way you get students hooked.
...
"We certainly need research that involves modeling and statistical techniques, but that should be ancillary. What we need much more is a study of those 10 million species.

"I’m going to rattle off the names of some groups of organisms that desperately need experts to work on them.

...

"A. Schizomids: a kind of arachnid found all over the world. Spidery-like creatures. We know almost nothing about them.

"Oribatid mites: Go out to any bit of leaf litter, start digging up decaying leaves, and start shaking out the little things. Among them you’ll find oribatid mites.

"A few years ago I studied a group of ants that were very good at collecting oribatid mites for food. So I thought I’d better figure out what species of oribatid mites I was seeing in my work. I looked around and found that the number of oribatid mite specialists who could do that in the United States was two. One of them, fortunately, was very generous.

"Q. Why isn’t there enough of this work being done?

"A. The dominance of molecular biology and biological medicine. Which is a good thing. But it’s become an overwhelming emphasis.

"That’s going to change. We’re moving into a new era. We’re entering the environmental-science era, where we want to take care of the environment around us, treat the earth the way we would a person and keep it healthy. And we need to know about these species for the purposes of synthetic biology."

Dead pigs and live brain cells--with implications still to be understood

Dramatic scientific announcements get press coverage before they are well (or at all) understood, but that can still be exciting.  Here's some press coverage of an article that was published yesterday in Nature about restoring some cellular activity in the brains of pigs which had been slaughtered and decapitated.  It may eventually have implications for brain injuries, brain death and (hence) deceased organ donation.
(The Nature article and two commentaries published with it are also linked below.)

NY Times:
‘Partly Alive’: Scientists Revive Cells in Brains From Dead Pigs
In research that upends assumptions about brain death, researchers brought some cells back to life — or something like it.

"In a study that raises profound questions about the line between life and death, researchers have restored some cellular activity to brains removed from slaughtered pigs.

"The brains did not regain anything resembling consciousness: There were no signs indicating coordinated electrical signaling, necessary for higher functions like awareness and intelligence.

"But in an experimental treatment, blood vessels in the pigs’ brains began functioning, flowing with a blood substitute, and certain brain cells regained metabolic activity, even responding to drugs. When the researchers tested slices of treated brain tissue, they discovered electrical activity in some neurons."
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Washington Post:
Scientists restore some brain cell functions in pigs four hours after death
Ethicists advise caution with research that blurs the line between life and death.

"The researchers are mindful that this is controversial territory with great potential to stoke outrage or, simply, the heebie-jeebies. Such a head-snapping experiment inevitably generates nightmarish scenarios involving live brains in vats, brain transplants, the Zombie Apocalypse, and other mad-scientist story lines (brilliantly crafted, somehow, by neurons firing away inside the skulls of conventionally living human beings).
"The findings also lead to ethical quandaries, some of which are outlined in two commentaries simultaneously published by Nature. The ethicists say this research can blur the line between life and death, and could complicate the protocols for organ donation, which rely on a clear determination of when a person is dead and beyond resuscitation."
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Guardian:
Researchers 'reboot' pig brains hours after animals died
Scientists say ability to revive some brain functions will not change definition of death



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And here's the article in Nature:
Published: 17 April 2019

Restoration of brain circulation and cellular functions hours post-mortem
Zvonimir Vrselja, Stefano G. Daniele, John Silbereis, Francesca Talpo, Yury M. Morozov, André M. M. Sousa, Brian S. Tanaka, Mario Skarica, Mihovil Pletikos, Navjot Kaur, Zhen W. Zhuang, Zhao Liu, Rafeed Alkawadri, Albert J. Sinusas, Stephen R. Latham, Stephen G. Waxman & Nenad Sestan
Naturevolume 568, pages336–343 (2019) | Download Citation

Abstract
The brains of humans and other mammals are highly vulnerable to interruptions in blood flow and decreases in oxygen levels. Here we describe the restoration and maintenance of microcirculation and molecular and cellular functions of the intact pig brain under ex vivo normothermic conditions up to four hours post-mortem. We have developed an extracorporeal pulsatile-perfusion system and a haemoglobin-based, acellular, non-coagulative, echogenic, and cytoprotective perfusate that promotes recovery from anoxia, reduces reperfusion injury, prevents oedema, and metabolically supports the energy requirements of the brain. With this system, we observed preservation of cytoarchitecture; attenuation of cell death; and restoration of vascular dilatory and glial inflammatory responses, spontaneous synaptic activity, and active cerebral metabolism in the absence of global electrocorticographic activity. These findings demonstrate that under appropriate conditions the isolated, intact large mammalian brain possesses an underappreciated capacity for restoration of microcirculation and molecular and cellular activity after a prolonged post-mortem interval.
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Here are two commentaries published in the same issue of Nature:
COMMENT  17 APRIL 2019
Part-revived pig brains raise slew of ethical quandaries
Researchers need guidance on animal use and the many issues opened up by a new study on whole-brain restoration, argue Nita A. Farahany, Henry T. Greely and Charles M. Giattino.
^^^^^^^^^

COMMENT  17 APRIL 2019
Pig experiment challenges assumptions around brain damage in people
The restoration of some structures and cellular functions in pig brains hours after death could intensify debates about when human organs should be removed for transplantation, warn Stuart Youngner and Insoo Hyun.

Biological markets--from primates to cleaner wrasses to plants

Evolution as the designer of market exchange between and among members of different species: here's a Bloomberg article about the work of the primatologist Ronald Noe, the mathematical biologist Peter Hammerstein and a variety of other biologists.

The Secret Economic Lives of Animals
Wasps do it, baboons do it. Economics isn’t just a human activity.

"In 1994, Noë and Hammerstein laid out their new theory of biological markets in the journal Behavioral Ecology & Socialbiology. The paper fused the biologists’ different styles: Hammerstein developed the mathematical models, while Noë dug through the scientific literature for evidence from the field. Examples turned up across the animal kingdom. Male scorpion flies offer females a “nuptial gift” of prey before mating. In some species of bird, such as the purple martin, a male will allow another male to occupy part of his territory in exchange for help raising his young. Lycaenid butterfly caterpillars produce a sweet “nectar” whose only purpose is to attract ants, which eat the nectar and protect the caterpillars from predators.
...
"Noë and Hammerstein admit that one of the hardest parts of their theory is to fix quantities and exchange rates; most of the time they can only say how a change in supply and demand will influence an exchange. And they are also careful to draw distinctions between human and biological markets. Animals obviously can’t use currency or sign contracts. And the animal kingdom has no third-party institutions to punish cheaters. Evolution may have produced fish dentists, but it has yet to produce fish lawyers."


Here are my earlier posts about work by Ronald Noe

Markets and microbes

Economists are sometimes accused of scientific imperialism, but what is it when biologists find market models useful, as in this paper from PNAS?

Evolution of microbial markets

Abstract: Biological market theory has been used successfully to explain cooperative behavior in many animal species. Microbes also engage in cooperative behaviors, both with hosts and other microbes, that can be described in economic terms. However, a market approach is not traditionally used to analyze these interactions. Here, we extend the biological market framework to ask whether this theory is of use to evolutionary biologists studying microbes. We consider six economic strategies used by microbes to optimize their success in markets. We argue that an economic market framework is a useful tool to generate specific and interesting predictions about microbial interactions, including the evolution of partner discrimination, hoarding strategies, specialized versus diversified mutualistic services, and the role of spatial structures, such as flocks and consortia. There is untapped potential for studying the evolutionary dynamics of microbial systems. Market
theory can help structure this potential by characterizing strategic investment of microbes across a diversity of conditions.

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Update: my joke about imperialism was a bit opaque it turns out. To be clear, I'm a big admirer of cross fertilization between fields. Here's an earlier post about Noe's work...

Tuesday, April 13, 2010

Biological markets: exchange of goods and services among non-human species

From the web pages of the French scientist Ronald Noe:

Is market design like synthetic biology?

Synthetic biology is concerned with the creation of new kinds of cells and organisms, and an interesting blog post by the economic sociologist/sociologist of science Juan Pablo Pardo-Guerra at LSE riffs on some possible connections between synthetic biology and market design: Will the Real Engineers Please Stand Up

He concludes:

"Talking with the language of design provides, as Martha Poon rightly pointed out, a more productive approach to the study of markets. But it also makes possible imagining a bolder version of market design than that currently advocated within economics. While the markets created by Roth and Milgrom are truly feats, much more can be done. Indeed, market design need not be a type of ‘consultancy economics’. Rather, it can follow an alternative metaphor that is pragmatic, perhaps even civic, an image of the future closer to that of the (biological) engineers who today work away in their labs redesigning the fundamental building blocks of nature."

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Pardo-Guerra is working in the emerging sociological/science-studies tradition of "performativity". Here's his paper Making markets: infrastructures, engineers and the moral technologies of finance which tracks the development of electronic financial exchanges through the electronic order book:

"How do markets change? Conventional sociological accounts answer this question by stressing the weight of social structures on the transactional core of  the marketplace. This paper provides an alternative approach. Market change is identified as an infrastructural transformation in which novel market devices and classifications are defined as the legitimate platforms for exchange. Rather than focusing on the traditional subjects of sociological enquiry, this study looks at the developers of market infrastructures in order to appraise the evolution and reinvention of markets. Empirically, the paper focuses on four historical episodes relating to the invention and dissemination of the electronic order book, a device that is central to global financial capitalism. These show how infrastructural work was implicated in creating the politics and structures of modern finance by criticising established institutions, mounting competitive challenges against incumbent institutions, establishing expansive projects of marketization and integrating otherwise disconnected marketplaces."
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He also has coauthored an interesting looking paper on high frequency trading (that I haven't yet read, only the abstract is on his site):  Drilling Through the Allegheny Mountains: Liquidity, Materiality and High Frequency Trading

(it will be interesting to compare the work of economic sociologists with that of market designers on this topic, see e.g. this recent post Budish, Cramton and Shim on The High-Frequency Trading Arms Race)
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He and his colleagues seem to be bringing some thought about market design into the discussion of the sociology of markets.

Gastroeconomics

There has been a lot of interest in neuroeconomics lately, focusing on decision-making and the brain. But there are also a lot of neurons in the gut, which raises the possibility of a part of neuroeconomics that might be called gastroeconomics.

This Scientific American article brought all this to mind:
Microbes Manipulate Your Mind: Bacteria in your gut may be influencing your thoughts and moods

(This shouldn't be confused with the gastroeconomics associated with the market for gastroenterologists:)

Matching, mate choice, and...speciation

Perspective: Matching, Mate Choice, and Speciation

Author(s): Puebla, O., Bermingham, E., Guichard, F.

Source: INTEGRATIVE AND COMPARATIVE BIOLOGY  Volume: 51   Issue: 3   Pages: 485-491     SEP 2011

Abstract: Matching was developed in the 1960s to match such entities as residents and hospitals, colleges and students, or employers and employees. This approach is based on "preference lists," whereby each participant ranks potential partners according to his/her preferences and tries to match with the highest-ranking partner available. Here, we discuss the implications of matching for the study of mate choice and speciation. Matching differs from classic approaches in several respects, most notably because under this theoretical framework, the formation of mating pairs is context-dependant (i.e., it depends on the configuration of pairings in the entire population), because the stability of mating pairs is considered explicitly, and because mate choice is mutual. The use of matching to study mate choice and speciation is not merely a theoretical curiosity; its application can generate counter-intuitive predictions and lead to conclusions that differ fundamentally from classic theories about sexual selection and speciation. For example, it predicts that when mate choice is mutual and the stability of mating pairs is critical for successful reproduction, sympatric speciation is a robust evolutionary outcome. Yet the application of matching to the study of mate choice and speciation has been largely dominated by theoretical studies. We present the hamlets, a group of brightly colored Caribbean coral reef fishes in the genus Hypoplectrus (Serranidae), as a particularly apt system to test empirically specific predictions generated by the application of matching to mate choice and speciation.

Biological markets: exchange of goods and services among non-human species

From the web pages of the French scientist Ronald Noe:

Biological Markets. "The label 'biological markets' was proposed by Noë & Hammerstein (1994; 1995) for all interactions between organisms in which one can recognise different classes of 'traders' that exchange commodities, such as goods (e.g. food, shelter, gametes) or services (e.g. warning calls, protection, pollination). "
"The characteristics of biological markets are found in mating systems ('mating markets'), mutualisms between members of different species and cooperation among conspecifics

"The term 'market' was chosen because it is assumed that shifts in supply and demand cause changes in the exchange value of the commodities traded. Important phenomena are: partner choice and outbidding.

"Formal properties of Biological Markets
Commodities are exchanged between individuals that differ in the degree of control over these commodities
Trading partners are chosen from a number of potential partners.
There is competition among the members of the chosen class to be the most attractive partner. This competition by 'outbidding' causes an increase in the value of the commodity offered.
Supply and demand determine the bartering value of commodities exchanged.
Commodities on offer can be advertised. As in commercial advertisements there is a potential for false information."

"Explicitly excluded is the use of physical force or threat to appropriate commodities or to eliminate the competition. The use of force is common, of course, as are theft and foul play in human markets, but one needs different paradigms to describe these phenomena.

"Examples of Biological Markets:
Obligate pollination mutualisms (to be added)
Ant protection mutualisms (to be added)
Mycorrhiza & rhizobia
Cleaner fish
Grooming in primates
Cooperative breeders
Delayed plumage maturation
Nest building in red bishops
links to further examples"

See also Market Models, on papers using game theory and comparative advantage to explore biological markets, which includes a bibliography of "Related theoretical approaches that also revolve around phenomena such as partner choice and competition by outbidding ..."