Negative Impacts of the Social Sciences on Behavioral Ecology & Social Biology

 

Clara B. Jones

Email: foucault03@gmail.com; mapcbj@gmail.com

Twitter: @cbjones1943

Date: 8/28/2022

In many ways, the Social Sciences have a disproportionate & unfortunate influence on Behavioral Ecology, including, Social Biology, some of which follow [in no particular order]:

The Social Sciences Approach to Behavioral Ecology, including, Social Biology, and, Animal Behavior, in general, might be viewed as the Scala Naturae Approach since it centers Homo sapiens as the measure of and pinnacle of Social Evolution, especially, as derived from the purported complexity of human societies driven by higher-order cognitive traits, including, an obsession with "big brains." A fundamental principle of Complexity Theory is that complexity emerges from simple rules [after which it may be acted upon by Natural Selection, in the cases of evolved traits, see Duarte et al., 2011].

The Social Sciences Approach begins with the assumption that humans are complex [contrast with the Major Transitions Approach]. Instead of making the a priori assumption that humans are complex, practitioners of the Social Sciences approach should begin with the null hypothesis, Humans are not complex.

It is common for Anthropologists to suggest that human phenotypic diversity is too complex to figure out ["irreducible complexity" as per Stephen Wolfram] or that it has no adaptive value. One of a scientist's responsibilities is to search for patterns and to "unpack" variation. Social scientists have made no headway on this score. For example, the ideas in the field, "evolutionary cultural Anthropology" are tortuously complex [sic] & obfuscating. This field is an example of investigators of human behavior starting with the assumption that humans are complex, rather than beginning with the above null hypothesis, as well as, simple hypotheses & mechanisms.

The Social Sciences Approach [Scala Naturae Approach] is not based on 1st Principles [Physics; Ecology (acquisition; consumption; allocation)].

The Social Sciences do not define theory as mathematics, as the Sciences do. In the Social Sciences, theory is, generally, verbal, & many studies are purely descriptive Natural History, without quantitative treatment beyond Descriptive Statistics.

Social Science research is generally not hypothetico-deductive.

Social Science researchers, in Behavioral Ecology, including, Social Biology, are, generally, averse to field experiments, math modeling, & simulation modeling. It is rare to find studies in the previous fields using Individual- [Agent-] Based simulations to conduct experiments.

Social Science researchers have generally not studied Introductory Ecology & Population Ecology taught by specialists. Behavioral Ecologists, including, Social Biologists, are Autecologists & Population Ecologists. Social Scientists, in general, seem unaware of the literature in Ecology, Population Biology, & Social Biology [e.g., EO Wilson's 1971, The Insect Societies, arguably, the greatest book written to date in Animal Behavior]. Even JH Crook's 1964, classic weaver bird monograph, arguably, marking the inception of the field, Behavioral Ecology, seems unknown to the majority of Social Scientists.

Social Science researchers rarely link their work to [population-level] Evolutionary causes & outcomes. 

Social Science researchers are fond of Group Selection.

Social Science research rarely uses terminology consistently [e.g., "aggregation" is often used synonymous to "group"].

Terminology in Social Science research is not standardized. To be fair, terminology is not standardized or used consistently in Animal Behavior, generally, including, Behavioral Ecology & Social Biology. For an introductory discussion on "terminology" in the previous fields, see my YouTube video.

Most Social Scientists studying Behavioral Ecology, including, Social Biology, seem to misunderstand WD Hamilton's Rule, rb - c >0, by assuming that the formulation predicts that it is always in Actor's [reproductive] interest to benefit the reproduction of kin.

To my knowledge, where social evolutionary transitions are discussed by Social Scientists [including, Evolutionary Psychologists] at all, the Major Transitions Approach, a general model, has not influenced the Social Sciences, including, Anthropology. Readers are referred to my YouTube video, Mammal Social Evolution: A Major Transitions Approach, for an introduction, as well as, to the first blogpost of this blog.. In the MTA applied to social evolution, Cooperation is the gateway to Complex Sociality [Reproductive Division-of-Labor; Specialization]. In his 2019 book, Genesis, Wilson broadens the definition of "eusocial," limiting it to the character trait, Reproductive Division-of-Labor, & denotes Humans, as well as, some other Mammals as "eusocial." It is important to note that Wilson creates a series of 6 transitions from simple to complex sociality that differ in significant ways from the classical formulation. Wilson's [and, some others'] pinnacle stage of social complexity is "language," consistent with a social scientific, Scala Naturae Approach.

References

Crook JH (1964) The evolution of social organization and visual communication in the weaver birds (Ploceinae). Behaviour Supplement #10: 1-201.

Duarte ANA, Weissing FJ, Pen I, Keller L (2011) An evolutionary perspective on self-organizing division-of-labor in social insects. Ann Rev Ecol Syst 42: 91-110.

Wilson EO (1971) The insect societies. Belknap (Harvard), Cambridge, MA.

Wilson EO (2019) Genesis: the deep origins of societies. Liveright, NY.

Review of Tim Clutton-Brock's, Mammal Societies (by Clara B. Jones, 2016)

Mammal Societies

Tim Clutton-Brock

2016

Wiley-Blackwell (Oxford, UK)

744 pp

ISBN 97811119095323

“The key to the sociobiology of mammals is milk.” E.O. Wilson (1975)

Reviewed by Clara B. Jones (2016; revised 2020)*

Knowledge about group-living mammals may contribute to an understanding of vertebrate social evolution and the evolution of gregariousness in animals with generalized phenotypes [specialization being a signature of high "grades" of social evolution (specialization, reproductive division-of-labor]. Compared to social insects and birds, the social biology of mammals is poorly known with the exception of ungulates, carnivores, and primates (3 of ~25 Orders). Among many similar papers in the mammalian literature on Social Paleontology, in 2011, Ladevèze et al. reported fossil evidence appearing to document mammalian gregariousness and its associated ecology from the basal Tertiary of Bolivia. These findings suggested that extinct, marsupial-like Pucadelphys andinus were group-living, probably exhibiting frequent interactions, strong sexual dimorphism, and male-male competition, as well as, polygyny. Based on the spatial and ecological settings of their specimens, as well as, the climate, in addition to, physical and situational associations and patterning of adult, sub-adult, and juvenile remains in their sample, these authors speculated that the species may have been "social" [gregarious]. In 2012, employing phylogenetic analyses, Briga et al. showed that relatedness and allomaternal¹ care are positively correlated in Class Mammalia. These papers indicate that, though the population dispersion of most extant mammals is sexually segregated (“solitary”) and though fossil remains cannot definitively preserve Behavior, group-living may have a long history in this Class (also see Jones 2014, Table 3.1, pp 19-25).

Tim Clutton-Brock (henceforth, “TC-B”) is a highly-regarded empiricist at the University of Cambridge (UK), recognized, particularly, for his field studies on primates, red deer, and meerkats. He is a prolific scientist with a knack for asking good questions and choosing animal models that have yielded flagship research. The author will be familiar to most animal behaviorists and behavioral ecologists as a specialist of cooperative breeding and evolutionary aspects of reproduction (e.g., female mating strategies, sexual selection). In the book under review, TC-B notes that his undergraduate training was in Anthropology and that he completed his doctorate under Robert Hinde, an animal behaviorist that Psychology typically claims as one of its own. I have been familiar with TC-B's work since the 1970s, and my personal favorites among his copious publications are his 1995 paper with Geoff Parker and the 2003 volume edited with R.M. Sibley & J. Hone. I am pleased to have the opportunity to review Mammal Societies. I have interacted with TC-B on several occasions, once face-to-face, and, more than once, via e-mail. He has always been generous and courteous to me. 

Previous books by JH Crook, “Griff” Ewer, J Eisenberg, EO Wilson, R Estes, D MacDonald, CB Jones, and others, have treated mammalian social biology to one degree or another. Mammal Societies, however, is the first attempt to provide a comprehensive literature review of the topic. The publisher's description of the volume states that it is intended for “behavioral ecologists, ecologists, and anthropologists,” and TC-B self-identifies as a “behavioral ecologist.” The book is, to all purposes, a literature review emphasizing publications on Old World taxa [a tradition attributable, in particular, to Primatology]. While the Table of Contents presents a detailed outline of topics of interest to social biologists, the book is not organized using ecological [e.g., JH Crook] or evolutionary models [e.g., the "major transitions"]. To provide context, professors using Mammal Societies as a course textbook or reference work are strongly advised to acquaint their students early on with Wilson's (1975) treatment (pp 456-574) presenting an explicitly articulated conceptual framework for mammalian social biology, including, trends, conventional terminology, general and comparative features in the Class, an extensive glossary, as well as, case studies and summary tables, figures, and diagrams. John Eisenberg's [1981], "mammalian radiations," is, also, an invaluable source of information on mammalian patterns, including, behavior, as well as, mating & group architectures.

Chapter 1, “Social evolution,” omits definitions of terms the first time they appear in the book (e.g., “aggregation,” “social”, “cooperation”), leading to obfuscation throughout, particularly, since there is no discussion of how to measure social traits (cooperation, altruism) and to discuss their pertinence to reproductive success. In this chapter, the author might have defined “Mammal” and should tell the reader why mammalian social biology is of import. The reader will want to understand possible trajectories to cooperation and altruism from aggregations to group-formation to group-maintenance and how the (spatial and temporal) distribution of limiting resources favor or disfavor the evolution of mammalian sociality. Chapter 1 is, in great part, a selective account of the history of Animal Behavior combined with some mention of theoretical issues (e.g., Darwinism, competition, reciprocity, game theory). However, for rigorous discussions of verbal and quantitative theory in Behavioral Ecology, as well as, overviews of Methods and G x E interactions, readers are referred to Davies et al. (2012) and Westneat & Fox (2010).

Chapters 2-9 address topics related to features of female behavior, particularly, as they pertain to mating, maternal tendencies, and gregariousness. Focusing on females, their strategies, and their energetic requirements as the primary driver of group-living and patterns of male behavior and dispersion is fundamental to an understanding of mammal societies because fertilizable females are a limiting resource for males and, subsequently, an ultimate determinant of male “fitness." Though these and other important concepts are implicit in some of TC-B's discussions, explicit use of many principles inherent to Behavioral Ecology are unclear or lacking (e.g., integration of Hamilton's rule [rb > c] throughout chapters, acknowledgment of the many competing hypotheses in Ecology pertaining to dispersal or multiple-mating by females, use of optimality formulations). As an example from Chapter 5 (“Maternal care”), TC-B's treatment asserts, accurately, that mammalian females invest heavily in current offspring, but theory holds that, after parturition, female resources, above some critical minimum, are channeled into future reproduction and lifetime reproductive success--“fitness.”

Chapters 10-16 pertain to males, especially, mating strategies, relations with females, and paternal care. Characteristic of Mammal Societies as a whole, these chapters are literature reviews of mostly descriptive publications from the Animal Behavior literature. Life history evolution is addressed in this chapter without mentioning the importance of tradeoffs, the distinction between semelparity and iteroparity (“fast” and “slow” life history trajectories, respectively), the importance of life-tables and the role of mortality as a driver of life-history evolution (Stearns 2000). Chapter 17 reviews “Cooperative breeding,” one of TC-B's specializations, and Chapter 18 presents a discussion of “Sex differences." Throughout the book, the author impresses the reader with the centrality of sex, sexual competition, and mating—topics of import in TC-B's career, though one is surprised that more attention is not given to Sexual Selection, per se. Chapters 19 and 20 address hominoids and hominids, including, modern humans, topics often missing or skimmed in other Animal Behavior texts.

TC-B presents at least one controversial formulation in Mammal Societies by asserting, with no supporting evidence or logical arguments, that no mammals are “eusocial”²—that the highest grade of sociality in mammals is “cooperative breeding.” This view is orthogonal to standard practice in Mammalian Social Biology whereby the social mole rats are typically classified as “primitively” eusocial. Technically, according to common usage, “cooperative breeders” might, as well, be classified “primitively” eusocial because of the presence of reproductive division of labor [cooperation between specialists] in the form of totipotent “helpers” (see Jones 2014, p 48-52). Mammal Societies exemplifies the need for practitioners of Natural History, Animal Behavior, and Behavioral Ecology to revisit topics such as standardization of terminology, advancement of the Hamiltonian Project, the roles of quantitative theory and modeling (in particular, agent-based modeling), field experiments, as well as, hypothesis-testing [including, the role of null-hypotheses] based on 1^st principles. The text will appeal to professors wanting a Natural History, mostly, non-quantitative, review allowing supplementary reading to be incorporated into a syllabus. Future syntheses of Mammalian Social Biology will rely on mainstream schemas from Ecology & Evolution, in particular, employing a Major Transitions Approach (cf. West et al. 2015), in addition to, Population Ecology, of which Behavioral Ecology is a sub-field.

¹Care of offspring by conspecifics other than the mother

²”The evolution of eusociality, here defined as the emergence of societies with reproductive division of labour and cooperative brood care, has occurred under specific ecological, genetic, and life history conditions. Although sophisticated levels of cooperation have evolved in the largest and more complex societies, conflicts among individuals are still common because, in contrast to cells of an organism, they are not genetically identical,”--i.e., not "clones" (Keller & Chapuisat, 2010)

References

Bradbury JW (1981) The evolution of leks. In Natural selection and social behavior. (RD Alexander, DW Tinkle, eds). Chiron Press, New York, pp 138-169.

Briga M, Pen I, Wright J (2012) Care for kin: within-group relatedness and allomaternal care are positively correlated and conserved throughout the mammalian phylogeny. Biology Letters: p.rsbl20120159

Clutton-Brock TH (2021) Social evolution in mammals. Science 373(6561): doi:10.1126/science.abc9699. 

Clutton-Brock TH, Parker GA (1995) Punishment in animal societies. Nature 373: 209-216.

Davies NB, Krebs JR, West SA (2012) Introduction to behavioral ecology. Wiley-Blackwell, 4^th edition. Oxford, UK.

Eisenberg JF (1981) Mammalian radiations. U Chicago Press.

Jones CB (2014) Evolution of mammalian sociality in an ecological perspective. Springer, New York.

Keller L, Chapuisat M (2010) Eusociality and cooperation. In Encyclopedia of life sciences. Macmillan, published online: DOI: 10.1002/9780470015902.a0003670.pub

Ladevèze S, de Muizon C, Beck RMD, Germain D, Cespedes-Paz R (2011) Earliest evidence of mammalian social behaviour in the basal Tertiary of Bolivia. Nature 474: 83-86.

Sibley RM, Hone J, Clutton-Brock TH (eds) (2003) Wildlife population growth rates. The Royal Society: Cambridge University Press, Cambridge University Press, UK.

Stearns SC (2000) Life history evolution: successes, limitations, and prospects. Naturwissenschaften 87: 476-486.

West SA, Fisher RM, Gardner RA, Kiels ET (2015) Major evolutionary transitions in individuality. PNAS 112(33): 10112-10119.

Westneat D, Fox C (eds) (2010) Evolutionary behavioral ecology. Oxford University Press, Oxford University Press, UK.

Wilson EO (1971) The insect societies. Belknap (Harvard), Cambridge, MA.

Wilson EO (1975) Sociobiology: the new synthesis. Belknap (Harvard), Cambridge, MA.

*Originally published in International Society for Behavioral Ecology Newsletter, 2016.


Addendum: I want to apologize to Tim Clutton-Brock for this review which expresses, as much as anything else, my disappointment in his text--of which I had great expectations. My expectations were so high--I expected a synthetic masterpiece in the context of evolution and the Major Transitions Approach--something on the order of EO Wilson's, The Insect Societies (1971), but, for Mammals. Even a book like JF Eisenberg's, mammalian "radiations" (1981), but about mammalian social evolution--extending Eisenberg's relevant chapters--would have been a major advance for the field. Instead, Clutton-Brock's book, whose title is a misnomer, is little more than a review of many highly selected publications without a conceptual framework [e.g., The Hamiltonian Project (the General Law of Social Evolution); Major Transitions, including, Sociality (Cooperation, after Hamilton 11964), as well as, Complex Sociality: SPECIALIZATION: division-of-labor (Cooperation between specialists); reproductive DoL, task, role, &/or morphological specialization] without any treatment of general patterns, without standardization of terminology, with only a nod to, systematic, quantitative theory--including, Hamilton's rule, and all in the context of a colonial historical-academic framework [e.g., every photograph of people of African descent is of primitive groups save one, and that one of an African guide, apparently, on a hunting safari with white male tourists. Unless I am mistaken, only a very few women are highlighted. Surely, TC-B might have provided a nod to changing worldviews by highlighting one or more of his African & female colleagues who must exist since TC-B has been conducting research in Africa for decades; if TC-B has not had African collaborators, volumes are silently spoken [admittedly, I know nothing about his personal or academic or research affiliations or his views on race, ethnicity, class or gender; and, I "get" it--the "greats" in Animal Behavior are, mostly, white men--even, until recently, in Anthropology, & I defer to the historical record ... nonetheless, it would have been generous to include, say, "Griff" Ewer, as deserving of recognition, for example--if only for the sake of appearances, but, then, my own biases are showing; in the final event, it would not detract from C-B's legacy for him to have been more generous in his historical acknowledgements].In short, as one who has admired TC-B's exhaustively rendered empirical work for decades, my expectations and anticipations, as well as, intellectual curiosity, were totally deflated by the long  literature review treated herein. A synthesis of mammalian Ecology & Evolutionary Biology, in other words, a text on Mammal Societies, awaits future treatment. John F. Eisenberg's 1981 book, "radiations," is the closest thing we have so far to a synthesis of mammalian social biology. 5/9/2020; slight edit, 12/30/2023 ...

http://vertebratesocialbehavior.blogspot.com/2019/09/my-comments-on-eisenberg-jf-1981mammal.html

Review of E.O. Wilson's new book, Genesis (Clara B. Jones, 2019)

Genesis: the deep origin of societies.

Edward O. Wilson

2019

Liveright Pub. Co. (W.W. Norton & Co.)

153 pp

$15.88

Reviewed by Clara B. Jones, Ph.D. (2019)

"The key to the sociobiology of mammals is milk." EO Wilson (1975)

Social evolution is an important topic of investigation by behavioral ecologists and evolutionary biologists. The two categories of sociality, cooperation and altruism (Hamilton 1964), have arisen infrequently across vertebrate taxa because, in propitious environmental regimes, group-level coordination and control is usually derailed by “cheaters” who fail to comply with group norms. As Wilson pointed out in 1971, groups of cooperators and altruists characterize the most “successful” (i.e., widely distributed) extant terrestrial taxa—social insects and humans. In his new book, Genesis [sic], the entomologist, E.O. Wilson, winner of the Crafoord Prize in 1990 and America's premier social biologist*, assesses the emergence of eusociality, the highest social “grade” (Wilson 1971). 

Perhaps the primary contribution of this brief book is that Wilson classifies humans as eusocial, a system characterized by overlap of generations, cooperative brood-care, and non-reproductive "helpers." If Wilson is correct, humans would be classified, "primitively" eusocial (Wilson, 1971) or Totipotent Eusocial [TE; see "General Mammalian Patterns" blogpost, this blog, #28, 9/19/19], since most human "helpers" (except post-menopausal females or other sterile persons) are expected to be "totipotent"—"helpers" capable of independent reproduction, able to reverse their non-reproductive status [TE]. Members of permanently sterile “castes,” are labeled, “advanced” eusocial (Wilson, 1971), and Wilson's treatments in this book suggest to me that he might be inclined to label permanently non-reproductive human groups as “caste”-like, associations that should be investigated, as well, for the possible presence of "temporal division-of-labor" ("age polyethism": see Wilson, 1971)..

The first five chapters of Genesis include limited explications of some topics (e.g., “multi-level” selection, “phenotypic plasticity”). Wilson clearly explains that the conceptual frameworks of Genesis are Maynard Smith & Szathmáry's (1995) classic treatment of “major transitions of evolution,” as well as, “multi-level” and “group selection,” terms used interchangeably. In Chapter 6, Wilson appears to be primarily interested in proffering a defense for Charles Darwin's explanation for the evolution of sterile castes—an argument based on group selection which Wilson defines as follows: "...within groups, selfish individuals win against altruists, but groups of altruists beat groups of selfish individuals" [attributed to David Sloan Wilson]. Among impediments to "proofs" of "group selection," defenders need to show how "cheaters" are controlled within groups, demonstrations that will require empirical studies.

Here and throughout the book, Wilson fails to incorporate the ecological literature showing, for example, that intragroup competition is generally stronger than intergroup competition or that behavioral ecologists have, since the early 1980s, advanced general criteria for the evolution of cooperative groups (e.g., Emlen 1982) and of eusociality (e.g., Crespi 1994; also see, Choe & Crespi 1997, Crespi et al. 2004 [see, especially, p 66 & pp 73-74], Bourke & Franks 1995, Bourke 2011); West-Eberhard 1975 on p 169, col. 3, par. 2 in Queller & Strassmann 1998 pp 169-170). More specifically, Wilson fails to cite other researchers who have advanced the idea that humans are eusocial (e.g., Foster & Ratnieks 2005, Jones 2011, Crespi 2014).

Nonetheless, combined with related studies (e.g., Emlen 1982, Emlen 1984, Hrdy 2011), there seems to be an expanding literature justifying systematic and quantitative investigation of eusociality in humans, in particular, and in vertebrates, broadly, including, standardization of terminology, experiments, and modeling (e.g., “agent-based” modeling). For an early, published paper that might generate ideas for these future projects, Lotka (1928) is suggested.

The final chapter (7), titled, “The human story,” reviews “transitions” to eusociality across apes, from chimpanzees (Pan troglodytes), as well as, bonobos (P. paniscus) continuing to Australopithecus and the Homo line. Unlike other chapters, this one emphasizes the importance of ecological factors (habitat) for the evolution of social mechanisms among hominids and their ancestors, and Wilson endorses the “social brain hypothesis” as well as the importance of fire for the “rapid evolution” of large brains and the facilitation of group-life, respectively—as well as, their consequent adaptations. Interestingly, in this chapter (p 114), the author compares human eusociality to other social mammals, in particular, African wild dogs, demonstrating that he is prepared to classify “other mammal species,” eusocial, in addition to the social mole rats (see Jones 2014, pp 48-52)****. For another interesting example, see Dwarf Mongoose.

Wilson does not dismiss “kin selection;” but, he holds that “multi-level” or “group” selection is the primary driver of the route to eusociality, behind which kin effects may follow [he may be right; see this lecture, "Ecology Of Societies," by Simon Levin of Princeton:

 https://www.youtube.com/watch?v=rQUsApf3RHs ].

Most social biologists are certain to be surprised to read Wilson's claims that "Hamilton's Rule" suffers "fatal weaknesses" and is no longer "useful (see Bourke 2011, Bourke & Franks 1995)." Wilson does not support these flippant statements with mainstream literature about which there is wide consensus in favor of Hamilton's Rule, and nowhere in his text does he assess assumptions underlying considerations of differential benefits to recipients of social behavior (cooperation or altruism) or differential costs to "donors," terms subsumed in Hamilton's Rule (see, for example, Bourke 2011, Marshall 2015). Related to this, Wilson all but completely avoids optimality [cost-benefit] thinking, and social biologists will, I think, find his explication of group selection obfuscating when applied to genetics, including the assertion that population geneticists have shown the verity of group selection.

Nonetheless, researchers, including, evolutionary psychologists, human biologists, and anthropologists, will derive many testable hypotheses from Wilson's claims, among the more provocative of them, the statement that division of labor by human professional categories is evidence of eusociality and group selection (that they are "caste-like)." I am led to wonder if some human guilds might be characterized by high r (coefficient of relationship), a possibility that would be easy to test. Likewise, guilds, and other formal human groups (e.g., fraternities and sororities, political groups, and the like), should be investigated for evidence of "temporal division-of-labor" ('age polyethism": see Wilson, 1971).

In service to economy, organization, and clarity, Genesis might have been more wisely presented as a "tight" technical paper rather than a manifesto in book form, though Wilson deserves to be applauded for advancing bold ideas, for insisting that human social behavior be subjected to the same analyses that we apply to non-human animals, and that, ultimately, evolutionary explanations will need to be "gene-centered," a long-standing hallmark of Wilson's approach (e.g., Wilson 1975) and that of the heralded evolutionary biologist, Robert Trivers (see, e.g., Trivers 1985 and the remarkable Trivers & Hare, 1976**; also see citations by Bernie Crespi). I recommend this creative and controversial text to specialists, students, and the general audience. It will raise many questions, stimulate thought, and, hopefully, generate conversations*** and research** about variations in human socio-sexual units, as well as, the origins and evolution, the causes and consequences, of group life across all vertebrates.

References

Bourke AFG (2011) Principles of social evolution. Oxford University Press, Oxford.
----, Franks NR (1995) Social evolution in ants. Princeton [NJ] University Press.

Choe JC, Crespi BJ (1997) The evolution of social behavior in insects and arachnids. Cambridge University Press, London.

Crespi BJ (1994) Three conditions for the evolution of eusociality: are they sufficient? Insectes Sociaux 41(4): 395-400.

Crespi BJ (2014) The insectan apes. Human Nature 25(1): 6-27.
Crespi BJ, Morris DC, Mound LA (2004) Evolution of ecological and behavioural diversity: Australian Acacia thrips as model organisms. Australian Biological Resources Study, Canberra.

https://www.environment.gov.au/science/abrs/publications/thrips

Emlen ST (1982) The evolution of helping I: an ecological constraints model. American Naturalist 119: 29-39.

Emlen ST (1984) Cooperative breeding in birds and mammals. Pp 305-339 in Behavioral ecology an evolutionary approach, 2^nd ed. (JR Krebs, NB Davies, eds.). Sinauer, Sunderland, MA.
Emlen ST, Oring L (1977) Ecology, sexual selection, and the evolution of mating systems. Science 197: 215-223.

Foster KR, Ratnieks FLW (2005) A new eusocial vertebrate? Trends in Ecology and Evolution 20(7): 363-364.
Frank SA (1995) Mutual policing and repression of competition in the evolution of cooperative groups. Nature 377: 520-522.
----(2003) Repression of competition and the evolution of competition. Evolution 57(4): 693-705.

Hamilton WD (1964) The genetical evolution of social behavior. Journal of Theoretical Biology 7: 1-52.
Holldobler B, Wilson EO (1990) The ants. Belknap (HUP). Cambridge.

Hrdy SB (2011) Mothers and others. Belknap-Harvard.

Jones CB (2011). Are humans cooperative breeders? A call for research. Archives of Sexual Behavior 40(3): 479-481.
----(2014) The evolution of mammalian sociality in an ecological perspective. Springer, NY.

Lotka AJ (1928) Sterility in American marriages. PNAS 14(1): 99-108.

Marshall JAR (2015) Social evolution and inclusive fitness theory: an introduction. Princeton University Press, Princeton, NJ.

Maynard Smith J, Szathmáry E (1995) The major transitions of evolution. W.H. Freeman Spektrum, New York.

Queller DC, Strassmann JE (1998) Kin selection and social insects. BioScience 48(3): 165-175.
Trivers RL (1985) Social evolution. Benjamin-Cummings Pub. Co., San Francisco.
Trivers RL (2015) Wild Life. Biosocial Research. New Brunswick, NJ. [& e-book, amazon.com] 

http://vertebratesocialbehavior.blogspot.com/2019/04/review-of-robert-l-trivers-memoir-wild.html

----, Hare H (1976) Haplodiploidy and the evolution of the social insects. Science 191(4224): 249-263.

West-Eberhard MJ (1975) The evolution of social behavior by kin selection. Quarterly Review of Biology 50: 1-33.
Wilson EO (1971) The insect societies. Belknap/Harvard, Cambridge, MA.

----(1975) Sociobiology. Belknap/Harvard, Cambridge, MA.
Wittenberger JF (1980) Group size and polygamy in social mammals. Am. Nat. 115: 197-222.
Yamamura N, Higashi M (1992) An evolutionary theory of conflict resolution between relatives: altruism, manipulation, compromise. Evolution 46: 1236-1239.

*First, no American social biologist can compete with Wilson's expertise as a student of a single social group, ants, in Wilson's case. Second, IMO, The Insect Societies (1971) is the greatest technical book ever written to date (and The Ants [Holldobler & Wilson, 1990] the greatest popular book ever written to date) in Animal Behavior and Ethology.

Third, unlike E.O. Wilson, Robert L. Trivers, also a renowned social biologist, winner of the Crafoord Prize in 2007, is not a synthesizer, though Trivers' most heralded papers have broad import. Trivers has not communicated much interest in a search for general patterns--within, between, and across taxa. Also, again, in contrast to E.O. Wilson, Trivers' canon pays scant attention to Genotype<----->Phenotype<----->Environment<-----> causes and effects. One seeks, for the most part, in vain, to locate Ecology--abiotic & biotic Environments (however conceptualized)--in Trivers' writings. Furthermore, to my knowledge,

Trivers has not emphasized the topics--group-formation, group maintenance, and the environmental conditions facilitating the emergence of sociality (which may or may not follow group-formation). Especially pertaining to the latter are the topics, competition and differential access to limiting resources, as well as, limiting resource dispersion (distribution and abundance in time and space). A litany of Behavioral Ecology is that, in some environmental regimes, kin may be ego's worst enemy. Such conditions may occur, for example, where there is intense local competition for limiting resources [above some critical threshold of decreasing reproductive gains].

Trivers may be one of the last remaining extreme genetic thinkers among living social biologists (see my review of his memoir, Wild Life [2015] linked above). He typically asks a question, then, considers what consequences would obtain given alternate, pairwise combinations of related individuals [parents, full sibs: 1/2; first cousins: 1/8, etc.]. Trivers' canon is about mechanisms, not, about causes. His approach has yielded several fundamental papers; however, Trivers' work does not satisfactorily address variations in inter-individual interactions nor evolution in heterogeneous regimes nor phenotypic plasticity nor the principle that behavior is condition-dependent nor the litany of Behavioral Ecology that patterns of  group-living will "map" onto dispersion [distribution and abundance in time & space and abiotic phenomena (e.g., climate)] of limiting resources nor the ideas that females are energy maximizers--males, time minimizers. Trivers does not seem to be sensitive to Hamilton's "b" & "c" whereby an actor & a recipient, whatever their "r" [coefficient of relationship], will respond relative to "b" [benefits to recipient] and "c" [costs to actor ("donor"--of reproductive units)], rather than, strictly, "r" [Hamilton's Rule: rb - c >0].

Trivers' literal logic based, apparently, on "r" alone, may reveal one unfortunate consequence of the term, "kin selection" that leads many to assume that it is always in ego's favor to exhibit social behavior towards kin. The latter assumption may be an assumption behind Trivers' (very successful and justifiably heralded) publications. Furthermore, as I [and several others before me (thanks to James Marshall and Andrew Bourke for making me aware of this literature)] have suggested, it may be useful to consider the role of competition influencing behavior between actor [donor] and recipient (see Yamamura & Higashi, 1992)  and to question whether Hamilton's Rule adequately incorporates the consequences for actor and recipient and for the expression or non-expression of cooperation or altruism (i.e., "social behavior") of interindividual competition for limiting resources (e.g., food, mates, space, etc.).

Thus, sometimes, kin may be ego's "worst enemy" [it may not be beneficial for ego to assist the reproduction of kin; it may be in the interest of ego to assist the reproduction--depending upon environmental regime] where predation is non-random by genotype [where cooperation or altruism toward a relative would increase ego's chances of becoming prey]. But, complicating the matter, in certain conditions, death, however, defined [e.g., self-induced, other-induced], can benefit kin. Clearly, systematic empirical and theoretical studies, in addition to modeling, are needed.

In the final analysis, however, the impressive success of Trivers' verbal models based on "r" may demonstrate the power of Hamilton's Rule to predict a very broad array of the social acts (cooperation, altruism) observed in Nature, including, Human Nature. However, we should not only ask, "What is "r"?, but, also (or rather?), "'r' relative to what?" According to Hamilton's Rule, the effects of "r" are expected to be constrained by the factors comprising "b" & "c". For example, when and under what conditions are kin, enemies?

**See comments on this paper in Holldobler & Wilson (1990, p 184)

***For example, cooperation and altruism might occur by way of "mutual policing," coercion, force, or persuasion, in addition to, "self-restraint" (see, especially, Steve Frank's work, in particular. 1995 and 2003).

****Addendum 4/26/2019: Regarding the ideas that humans are "cooperative brreeders" (e.g., Hrdy 2011) and that "cooperatively-breeding" mammals should be classified, "eusocial" (Jones 2014), I am going to go out on a limb to suggest that, based upon my reading to date on mammal, including, human, group-living patterns, mammalian "cooperative breeding" evolved from groups of communal females, and their offspring, that may or may not, then, evolve to share "economic" tasks, including care of young [see epigraph]...since females, ceteris paribus, are expected to be "energy-maximizers," thermal efficiency, broadly defined, will be paramount as a selective factor and in determining optimal "inclusive fitness maximizing" (see Jones 2014, Chapter 3). Anthropologists specializing in human "cooperative breeding" hold that the system evolved via monogamy, as it is thought to have done in insects and birds. However, mammalian sociosexual systems generally exhibit "sexual segregation" ("solitary" dispersion between the sexes) and, in mammals, monogamy is derived. Related, Mammal sociosexual systems and group structure are thought to result from the tendency of females to select rich patches of [limiting] food and that of males to select the largest possible number, sometimes, an aggregation, of females (Wittenberger 1980, Emlen & Oring 1977).

In summary, it seems to me that the more likely "route" to eusociaity in humans would have been via communally nesting mammalian ancestors, particularly, since monogamy is "derived," mammals are very likely to exhibit a "sexually-segregated" ["solitary"] socio-sexual organization, monogamy is relatively rare, and, in humans, at least, monogamy is often imposed by some authority. Routes to eusociality that might be applied to humans have, also, been proposed by West-Eberhard (1975) and by Queller & Strassmann (1998: "fortress defenders" and "life insurers") [see Queller & Strassmann (1998) for a brief summary of these ideas on pp 169-170]. These issues need to be unpacked.

Clara B. Jones is a retired behavioral ecologist living in Silver Spring, MD (USA).