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Charlie Nunn's chapter in Sexual Selection and Reproductive Competition in Primates: New Perspectives and Directions (C.B. Jones, ed.) was made initially available in the TPP Newsletter, 1(3). Nunn's file is in the Adobe Portable Document Format which requires the free Adobe Reader. To access the file right click on the hyperlink with your mouse and select "Save Target As..." A dialog box will pop up; save the file in the folder that you wish. The Adobe Reader is available free of charge through this hyperlink.

The abstract to Robin Dunbar's "Modelling Primate Behavioral Ecology" (International Journal of Primatology, August 2002) is available online. The International Journal of Primatology has a listing of various issues (abstracts to articles are freely accessible online). Although several researchers are notable for initiating and/or utilizing theoretical approaches to the study of primates, in particular, mathematical formulations (e.g., the Altmanns; Hausfater), perhaps no one is more identified with these approaches in primatology than ROBIN DUNBAR. Robin deserves special regard for his persistent and ongoing attempts to define theory in primatology as theory is defined in the natural sciences. I wonder how many traditional primatologists understand just how revolutionary this is and what a profound impact this persistence is likely to have for the field over the long run? Indeed, this posture is likely to impact not only primatology but also animal behaviorists in other social sciences when combined with the efforts of mathematically inclined scholars in those fields (e.g., psychology, anthropology, and, perhaps, sociology).

Matthew Beal announces the online availablity of his PhD thesis on Variational Bayesian techniques.

Continuing our consideration of the topic, "cooperation," (TPP Newsletter Vol. 1(11)) the following paper by Tim Clutton-Brock is a cogent review of selected literature as well as a goldmine of ideas for research on "cooperation," "cooperative breeding," "sociality," "parasitism," "reciprocity," "mutualism," and related topics. This paper is likely to have a major "ripple effect" in the field of social evolution--similar to Emlen and Oring (1977). While, in my opinion, Clutton-Brock underestimates the role of (social) parasitism (e.g., phenotypic manipulation), he provides numerous testable ideas, including his conclusion that mutualism, generalized reciprocity, and group size are variables likely to explain many cases of cooperative breeding as well as cooperation.
* Clutton-Brock, T. (2002). Breeding together: Kin selection and mutualism in
cooperative vertebrates. Science, 296, 69-72.
* Emlen, S.T., & Oring, L.W. (1977). Ecology, sexual selection and the evolution of mating systems. Science, 197, 215-223.

Continuing the discussion on mechanisms of "social parasitism" (e.g., phenotypic manipulation: Jones, 1986, 1997; Jones and Agoramoorthy, 2003; cf. Trivers, 1974), a paper by Johnstone and Bshary (2002) is very helpful. These authors point out that parasitism and mutualism (e.g., cooperation) coexist. Different optima for different individuals over time and space, then, are expected to favor different tactics and strategies and, importantly, Johnstone and Bshary show that the potential victim (host, "client") may exert control in an interaction (in a relationship?) by influencing the timing and duration of the interaction(s). Exploitation is constrained by the potential victim's ability to manipulate the interaction (see Jones, 2002). Additionally, Johnstone and Bshary provide support for the conclusion that cooperation is a function of the potential victim's ability to terminate an interaction.
* Johnstone, R.A., & Bshary, R. (2002). From parasitism to mutualism: Partner control in asymmetric interactions. Ecology Letters, 5, 634-639.
* Jones, C.B. (1986). Infant transfer behavior in humans: A note on the exploitation of young. Aggressive Behavior, 12, 167-173.
* Jones, C.B. (1997). Social parasitism in the mantled howler monkey, Alouatta palliata Gray (Primates: Cebidae): Involuntary altruism in a mammal? Sociobiology, 30, 51-61.
* Jones, C.B. (2002). Negative reinforcement in primate societies related to aggressive restraint. Folia Primatologica, 73, 140-143.
* Jones, C.B., & Agoramoorthy, G. (2003). Alternative reproductive behaviors in primates: Towards general principles. In C.B. Jones (ed.), Sexual selection and reproductive competition in primates: New perspectives and directions (pp. 103-139). Norman, OK: American Society of Primatologists.
* Trivers, R.L. (1974). Parent-offspring conflict. Amer. Zool. 14:249-264.

Bergman, et al. (2003) have recently shown "that baboons recognize that a dominance hierarchy can be subdivided into family groups" (p. 1234). These authors suggest that such capacities for discrimination imposed by social complexity may have favored higher order cognitive processing and represent a "precursor to some components of human cognition" (p. 1234). Relating these findings to our discussion of "social parasitism" (SP: e.g., "phenotypic manipulation"), it is important to note that SP may select for sociality in some regimes (see, for example, Crespi and Choe, 1997; Schwarz et al., 1997) and predicts exactly the sorts of discrimination capacities described for baboons by Bergman and his associates. It is important to determine why social parasitism and other selection pressures favoring sociality (e.g., predation) have apparently led, in some taxa (e.g., many primate species, including humans) to higher-order cognition and individuality but, in other taxa (e.g., social insects) to alternate discrimination and information-processing mechanisms and to castes ("true sociality"). Crespi and Choe (1997) identify the factors that may differentiate these alternative routes (trajectories) to complex sociality, and Hamilton and Dill (2002) present a preliminary model assessing the role of social parasitism in the evolution of complex social relations.
* Bergman, T.J., Beehner, J.C., Cheney, D.L., and Seyfarth, R.M. (2003). Hierarchical classification by rank and kinship in baboons. Science, 302, 1234-1236.
* Crespi, B.J., and Choe, J.C. (1997). Explanation and evolution of social systems. In J.C. Choe and B.J. Crespi (eds.), The evolution of social behavior in insects and arachnids, pp. 499-524. New York: Cambridge University Press.
* Hamilton, I.M., and Dill, L.M. (2002). Three-player social parasitism games: Implications for resource defense and group formation. American Naturalist, 159, 670-686.
* Schwarz, M.P., Silberbauer, L.X., and Hurst, P.S. (1997). Intrinsic and extrinsic factors associated with social evolution in allodapine bees. In J.C. Choe and B.J. Crespi (eds.), The evolution of social behavior in insects and arachnids, pp. 333-346. New York: Cambridge University Press.

Robert Poulin (University of Otago, NZ) has several papers on parasitism and phenotypic manipulation that may provide a rich source of ideas for studies of these and related phenomena in primates and other polygynous species. Like the work of other researchers, Poulin's research shows that parasitism can facilitate the evolution of behavioral flexibility and/or phenotypic plasticity.
* Poulin, R. (2000). Manipulation of host behaviour by parasites: A weakening paradigm? Proc. R. Soc. Lond. B, 267:787-792.
* Poulin, R. (2003). Phenotypic manipulation and parasite-mediated host evolution. In Legakis, A., Sienthourakis, S., Polymeni, R., and Thessalou-Legaki, M. (eds.), The New Panorama of Animal Evolution, pp. 205-212. Sofia/Moscow: Pensoft Publishers.
* Poulin, R., and Thomas, F. (1999). Phenotypic variability induced by parasites: Extent and evolutionary implications. Parasitology Today, 15:28-32.

"[No] instinct can be shown to have been produced for the good of other animals, though animals take advantage of the instincts of others."
Darwin (1859, p. 208, Modern Library Edition, New York: Random House)

"For each individual primate, [group living] sets up an environment favouring the use of social manipulation to achieve individual benefits at the expense of other group members...."
Byrne and Whiten [1997, Machiavellian intelligence. In A. Whiten and R.W. Byrne (Eds.), Machiavellian Intelligence II: Extensions and Evaluations, pp. 1-23. Cambridge: Cambridge University Press. (Empahsis in original.)]

Jeffrey S. Stevens (Harvard University) is promoting a straightforward interpretation of sharing which he calls "manipulation by harassment" (Stevens, 2004; Stevens and Stephens, 2002). Stressing "the selfish nature of generosity," Stevens' work provides an alternate way of interpreting sharing and cooperation based upon self-interest. This view might also be applied to some instances of grooming and other primate behaviors and should be read in association with other recent works (e.g., Hager, 2003a, b; Reeve, 2000). These papers are likely related to the topic of social parasitism in primates. See the following citations:
* Hager, R. (2003a). Models of reproductive skew applied to primates. In C.B. Jones (Ed.), Sexual selection and reproductive competition in primates: New perspectives and directions (pp. 65-102). Norman, OK: American Society of Primatologists.
* Hager, R. (2003b). The effects of dispersal costs on reproductive skew and within-group aggression in primate groups. Primate Report 67: 85-98. (This paper is accessible online.)
* Reeve, H.K. (2000). A transactional theory of within-group conflict. American Naturalist 155:365-382.
* Stevens, J.R. (2004). The selfish nature of generosity: Harassment and food sharing in primates. Proc. R. Soc. Lond. B, 271: 451-456, (DOI: 10.1098/rspb.2003.2625). (Online access to the full paper requires a subscription; however, the abstract is available online.)
* Stevens, J.R., and Stephens, D.W. (2002). Food sharing: A model of manipulation by harassment. Behavioral Ecology 13:393-400.

"Although parasitized altruism is really a form of selfish behavior, the actor being the recipient of the altruism,Bob Trivers we should note that all systems of altruism are vulnerable to parasitisms in which individuals pretend a degree of relatedness they do not possess or a degree of reciprocity they will not express."
Trivers, R.L. (1985). Social Evolution. Menlo Park, CA: The Benjamin/Cummings Publishing Company, Inc., pp. 51-52.
[The photograph of Bob Trivers is posted here through the courtesy of Dr. Peter Kappeler.
© Deutsches Primatenzentrum (German Primate Center), G–ttingen]

Students of primates have only recently begun to investigate the topic of genomic conflict [see Nunn (2003) link above]. It will be important for students of social vertebrates to incorporate the growing body of work on genomic conflict into their thinking and research (theoretical and empirical). William R. Rice, the leading researcher in this field, has several of his papers available online. I'd like to hear from anyone interested in this topic and/or with ideas about how these concepts might advance primatology (including studies of humans). Other publications related to this topic and that would be a good source of ideas for primatologists are:
* Gavrilets, S., Arnqvist, G., and Friberg, U. (2001). The evolution of female mate choice by sexual conflict. Proc. Roy. Soc. Lond. B 268:531-539.
* Hager, R. (2003). Behavioural Ecology. Encyclopedia of Life Sciences. London: Nature Publishing Group.
* Hager, R., and Johnstone, R. (2003). The genetic basis of family conflict resolution in mice. Nature 421:533-535.
* Haig, D. (2002). Genomic imprinting and kinship. The Rutgers Series in Human Evolution (Trivers, R.L., Cronk, L., Fisher, H., and Tiger, L., eds.). New Brunswick: Rutgers University Press.
* Jones, C.B., and Agoramoorthy, G. (2003). Alternative reproductive behaviors in primates: Towards general principles. In: Jones, C.B. (ed.), Sexual selection and reproductive competition in primates: New perspectives and directions, pp. 103-139. Norman, OK: American Society of Primatologists.
* Pomiankowski, A. (1999). Intragenomic conflict. In: Keller, L. (ed.), Levels of Selection in Evolution, pp. 121-152. Princeton: Princeton University Press.

The dissertation of Dr. Tom Wenseleers (University of Sheffield) offers a bold treatment of intragenomic conflict attempting to provide the theoretical architecture for a "general theory of conflict." Download Chapter 9 (2 meg pdf) (with Ratnieks). Importantly, Wenseleers and Ratnieks point out that Hamilton's rule operates only under "weak selection" (when mortality is not a "main effect"). The authors address this problem by deriving a new Hamilton's rule which is correct under any strength of selection. The resulting rule can be used not only to predict when animals should act cooperatively but also when genes within genomes should. Wenseleers and Ratnieks argue that "genetic societies are excellent, if largely overlooked, model systems for studying social evolution" (p. 167).
     Tom Wenseleers would like to receive feedback on this chapter at <t.wenseleers@sheffield.ac.uk>. Dr. Wenseleers also has a Web page.
     The complete citation for the chapter is: Wenseleers, T., and Ratnieks, F.L.W. (2001). Towards a general theory of conflict: The sociobiology of Mendelian segregation. Chapter 9 in Wenseleers, T., Conflict from Cell to Colony, pp. 163-173. Unpublished Ph.D. Dissertation, University of Leuven (Belgium).
     [Note that this file is in the Adobe Portable Document Format which requires the free Adobe Reader. To access the file right click on the hyperlink with your mouse and select "Save Target As..." A dialog box will pop up; save the file in the folder that you wish. The Adobe Reader is available free of charge through this hyperlink.]

Spencer, K.A., Buchanan, K.L., Goldsmith, A.R., and Catchpole, C.K., studying European starlings, show that developmental stress (measured as predictability of food supply) and dominance rank predict song complexity ["Developmental stress, social rank, and song complexity in the European starling (Sturnus vulgaris)," Biology Letters 271, 7 February 2004, S121-S123, DOI: 10.1098/rsbl.2003.0122. Abstract available here]. In brief, an unpredictable food supply (high environmental heterogeneity?) and low dominance rank are associated with a smaller "phrase type." These authors point out that their study "provides novel evidence that social as well as nutritional history may be important in shaping the song signal in this species." To my knowledge, comparable research has not been conducted with primates, including humans.

Continuing our discussion of "social parasitism," Eric L. Charnov's (The University of New Mexico) paper, "Evolution of eusocial behavior: Offspring choice or parental parasitism?" (JTB 75:451-465, 1978), may be of interest. This article, whose treatment is applicable to haplodiploid as well as diploid societies, addresses parasitism between adults (parents) and offspring showing that broods whose mothers are multiply mated are more likely to resist maternal parasitism (because the benefits from "helping" mothers raise siblings would be low). Related broods (i.e., where mothers are not multiply mated) are more susceptible to maternal parasitism, possibly setting the stage for the evolution of eusociality. It would be interesting to investigate these models in non-human (e.g., tamarin and marmoset) as well as human societies. Related to this, of course, would be an investigation of the extent to which "helping" is a function of force, coercion, and/or persuasion, in addition to manipulation and/or exploitation.

Theory guides empiricists to the questions worth asking and the data worth collecting. Skubic and her colleagues ask the question: When to parasitize? Using a model based upon cooperatively breeding male cichlids (Neolamprologus pulcher) that is applicable to other cooperatively-breeding societies (e.g., marmosets and tamarins), these authors show that reproductive parasitism (defined as a form of punishment: see Clutton-Brock & Parker, 1995; Jones, 2002), intra-group relatedness, and the "parasitism capacity"# of a male helper (reproductive parasite) should predict whether an individual parasitizes. Where expulsion risk is high, helpers should not parasitize reproduction at medium body size. Parasitism is favored, however, when body size is small or large##.
* Clutton-Brock, T.H., & Parker, G.A. (1995). Punishment in animal societies. Nature, 373, 209-216.
* Jones, C.B. (2002). Negative reinforcement in primate societies related to aggressive restraint. Folia Primatol., 73, 140-143.
* Skubic, E., Taborsky, M., McNamara, J.M., & Houston, A.I. (2004). When to parasitize? A dynamic optimization model of reproductive strategies in a cooperative breeder. Journal of Theoretical Biology, 227, 487-501.
#  As pointed out by these authors, the reproductive parasite obtains a share of the dominant's reproduction, concepts essential to "reproductive skew" [see Hager, 2003 in C.B. Jones (ed.) cited above].
##  Body size is expected, on average, to correspond to fighting ability which is expected, on average, to correspond to RHP.


Geoffrey F. Miller (1997) is interviewed by Edge magazine and advertises a number of clever ideas and questions (e.g., the need to explore the relationship between evolutionary psychology and behavioral genetics). Asking the question, "Why are there so many words?" (Indeed, why are there so many behaviors, cognitions and schemas, emotions, attitudes, etc.? Editor's note), another of his interests, one might suggest Hutchinson's (1959; also see Lewontin, 1957; Levins,1963) paper linking the phenotype with the niche in heterogeneous regimes. Miller's creative forms of evolutionary intelligence and narrative theorizing may lead to insights, theory, and data about numerous topics deserving attention by primatologists [e.g., cognitive parasitism, "soft selection" vs. "hard selection" in the evolution of primate (including human) behavior]. Hopefully, a theoretical primatologist will test some of Miller's notions with mathematical techniques to assess their potential utility within a Darwinian/Hamiltonian framework.
* Hutchinson, G.E. (1959). Homage to Santa Rosalia, or why are there so many kinds of animals? American Naturalist 93:145-159.
* Levins, R. (1963). Theory of fitness in a heterogeneous environment: Developmental flexibility and niche selection. American Naturalist 97:75-90.
* Lewontin, R.C. (1957). The adaptations of populations to varying environments. Cold Spring Harbor Symp. Quant. Biol. 22:395-408.
* Miller, G.F. (1997). Protean primates: The evolution of adaptive unpredictability in competition and courtship. In A. Whiten and R.W. Byrne (Eds.), Machiavellian Intelligence II: Extensions and Evaluations (pp. 312-340). Cambridge: Cambridge University Press.

Jerry O. Wolff and David W. Macdonald (W&M), mammalogists noted especially for their studies of bison and carnivores, respectively, have authored a paper in the current Trends in Ecology and Evolution persuasively arguing that Sarah Blaffer Hrdy's hypothesis (1979) for the evolution of multi-male mating (MMM) by mammalian females is correct (Abstract available: doi:10.1016/j.tree.2003.12.009).
Sarah Blaffer Hrdy as allomother holding Shanika, infant of Dr. Anula Jayasuriya, the photographer.
Sarah Blaffer Hrdy as allomother holding Shanika, infant of Dr. Anula Jayasuriya, the photographer.
Hrdy's hypothesis (1979) states that "MMM functions to confuse paternity, which, in turn, deters infanticide" (W&M, p. 127). Evaluating data for the 133 species of mammals in which MMM has been documented, Wolff and Macdonald strongly suggest that, of the 9 hypotheses attempting to explain MMM (Table 1, p. 128), Hrdy's explains most of the observed variance in the data set. Further, in Box 2 of this paper, the authors describe infanticide as a "pacemaker" (Wolff's original term, apparently) for the evolution of MMM based upon the "scenario" of van Schaik and Kappeler (1997) showing "a possible transition from polygyny to promiscuity and monogamy" (W&M, p. 131). Although W&M do not discuss their analysis in relation to thresholds of response or in relation to operational sex ratios (also see Queller, 1997), this review and its conclusions provide a very tight case for the utility of Hrdy's treatment given available research--both theoretical and empirical. It will be interesting to see what comments and/or critiques of this paper, if any, appear in future issues of TREE.
* Hrdy, S.B. (1979). Infanticide among animals: A review, classification, and examination of the implications for the reproductive strategies of females. Ethology and Sociobiology, 1, 13-40.
* Queller, D.C. (1997). Why do females care more than males? Proc. R. Soc. Lond. B, 264, 1555-1557.
* van Schaik, C.P., & Kappeler, P.M. (1997). Infanticide risk and the evolution of male-female association in primates. Proc. R. Soc. Lond. B, 264, 1687-1694.
* Wolff, J.O., & Macdonald, D.W. (2004). Promiscuous females protect their offspring. Trends Ecol. Evol., 19, 127-134.

Continuing reference to the Wolff & Macdonald paper mentioned above, these authors (W&M p. 130) argue that the origin of MMM was not sexually selected (i.e., did not occur in response to genetic or other benefits derived from mating with one male over another). Instead, W&M consider the benefits of MMM to be derived wholly from those gained by a female in protecting her living offspring from infanticide. W&M do point out that sexually selected benefits might be obtained secondarily "once MMM evolved for some other purpose" (p. 130). In light of other treatments of "promiscuity," it will be necessary to carefully unpack the relationship, if any, between MMM and sexual selection. Holland & Rice [1999 (access this paper at Rice's site linked above)], for example, demonstrate a relationship between sexual selection, "promiscuity," and "intersexual antagonistic coevolution." Hrdy (1974, 1979; also see van Schaik & Janson, 2000) originally claimed that infanticide by males was sexually selected and, consistent with Holland & Rice's arguments, MMM might be viewed as a response to intersexual conflict and a male trait (infanticide) increasing male fitness at a female's expense. To quote Holland & Rice (p. 5083), "Conflict between mates hinges on sexual infidelity.... ...whenever an individual has multiple mates, the lifetime reproductive success of that individual will differ from the success of its mates. Thus, promiscuity necessarily introduces the opportunity for sexual conflict through the evolution of novel traits that increase the reproductive success of members of one sex at a cost to members of the opposite sex." MMM, probably a ubiquitous trait among primates, implies, then, intersexual conflict, a topic in the early stages of investigation for the Primate Order.
* Hrdy, S.B. (1974). Male-male competition and infanticide among the langurs (Presbytis entellus) of Abu, Rajasthan. Folia Primatologica, 22, 19-58.
* Hrdy, S.B. (1979). Cited above.
* van Schaik, C.P., & Janson, C.H. (eds.). (2000). Infanticide by males and its implications. Cambridge: Cambridge University Press.

Following Hrdy's work, W&M's discussion may be viewed as a description of one class of transactions important to potential mates among social mammals and some other taxa. Shellman-Reeve & Reeve (2000) (mathematically) model interactions between males and females in accord with transaction theory, a category of reproductive skew models including "concession" and "constraint" models (see Hager, 2003). In this view, promiscuity is viewed as a "transaction between social mates." Females and males, then, are assumed to be in conflict over the most beneficial tradeoff of mating effort and parenting effort. Neff (2001) points out that, where males are larger than females (as for most primates), an amended "tug of war" model may be most appropriate, and he describes Shellman-Reeve & Reeve's treatment as showing that "the evolution of infidelity" requires an assessment of both female and male interests. Because Shellman-Reeve & Reeve model these states elegantly and with general import, Neff suggests that "transactional theory might provide the basis for a truly unifying theory of social interactions."
* Hager, R. (2003). In C.B. Jones (ed.) cited above.
* Neff, B.D. (2001. Infidelity as a transaction between social mates. Trends Ecol. Evol., 16, 175.
* Shellman-Reeve, J.S., & Reeve, H.K. (2000). Extra-pair paternity as the result of reproductive transactions between paired mates. Proc. R. Soc. Lond B, 267, 2543-2546.

Several recent treatments have argued that theories of "reproductive skew" may yield general formulations for the evolution of social behavior (see, for example, above). There is some disagreement, however, about the relative utility of "transactional" models on the one hand and "tug of war" or "indirect control" models on the other (see above). In a recent paper, Langer, Hogendoorn, and Keller (2004) have tested the predictions of these two categories of models with the social bee, Exoneura nigrescens. Consistent with Clutton-Brock's arguments, "tug of war" models are supported. Similar studies are required for primates (see Widdig et al., 2004 discussed in TPP Newsletter Volume 2, Issue 2, #8), including experimental tests since the possibility exists that transactional models and tug of war models will operate relative to taxon, environmental conditions, etc. (see Hager, 2003 cited above).
* Langer, P., Hogendoorn, K., and Keller, L. (2004). Tug-of-war over reproduction in a social bee. Nature, 428, 844-847.



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