The Evolution of Mammalian Sociality in an Ecological Perspective

118 Pages·2014·3.158 MB·English

by  Clara B. Jones (auth.)

SpringerBriefs in Ecology
Forfurthervolumes:
http://www.springer.com/series/10157
Clara B. Jones
The Evolution of Mammalian
Sociality in an Ecological
Perspective
2123
ClaraB.Jones
MammalsandPhenogroups(MaPs)
Asheville
NorthCarolina
USA
ISSN2192-4759 ISSN2192-4767(electronic)
ISBN978-3-319-03930-5 ISBN978-3-319-03931-2(eBook)
DOI10.1007/978-3-319-03931-2
SpringerChamHeidelbergNewYorkDordrechtLondon
LibraryofCongressControlNumber:2013958320
© ClaraB.Jones2014
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Preface
ThisSpringerBriefconcernsthecondition-dependenteffectsofintraspecificcompe-
titiononamammal’sreproductiverate,aswellasactionsavailabletoanindividual
(hereafter “type” [genotype and phenotype]) in the face of competition. Group-
formation,group-maintenance,andsocialitymaybefavoredbyselectionwhengenes
ofsocialtypesincreaserelativetonon-socialtypes,beyondsomethresholdlevelin
a population. When “social” and “sociality” are defined as responses facilitating
thereproductionofoneormoreconspecific, socialityisnotaconspicuousfeature
of Class, Mammalia. Facilitation appears in response to density-dependent condi-
tions characterized by “thermal stress” (stimuli negatively impacting reproductive
rate) when niche spaces (“thermal zones”) of (conspecific) types (genotypes and
phenotypes: individuals, organisms) overlap relative to variations in resource dis-
persion(distribution, abundance, and/orqualityoffood, mates, and/orspace).The
previousconditionsconstituteintermediateorhighlevelsofcompetitionforlimiting
resources, resources influencing the reproductive rates of types. Group-formation
and group-maintenance are necessary, but not sufficient, precursors to the evolu-
tion of sociality, and recent treatments show that coexistence of different types is
best studied using a “trait-based approach”. In theory, a type can be decomposed
intoasetofexpressibletraitswithvaryingvaluesdependentuponcondition.Social
traitsexpressedbytypesinclude“alloparenting”,cooperation,reciprocity,andaltru-
ism, unambiguous and measurable features of phenotypes permitting independent
quantitativeanalyseswithinandbetweenpopulationsandspecies.
MammalswerepreadaptedforsolitarylivingduringtheTriassicwhenmammal-
likereptilesescapedreptiliancompetitorsbyadoptingnocturnalhabits.Consistent
withtheancestralpatternsofextantmammalsandreptiles,theformerare,primarily,
nocturnal and solitary, the latter, primarily, diurnal. In general, extant adult male
mammalsareintolerantofothermalesandoftheyoung,whileadultfemales,unless
signalingsexualreceptivity,areintolerantofconspecificsotherthantheiroffspring
andofmales.Thewhole-organismphenotypeofonemammalisexposedtoabiotic
(soil, climate) and biotic (plants, predators) environments that may or may not be
correlatedacrossspaceandtime.Ultimately,selectionactsongenetically-correlated
phenotypictraitsand,fromagenotype’sperspective,copiesofallelesandtheiras-
sociatedtraitsmaybecarriedorexpressedthroughoutapopulationand,sometimes,
v
vi Preface
aregion(“metapopulation”).Foragivengenotype,phenotypeswillvaryspatiotem-
porally within and between individuals bearing a trait or traits. Mammals found
in aggregations (temporary assemblages of one or more than one species), or spa-
tiotemporally recurrent groups, may or may not occur in proximity to individuals
bearing the same genotype because dispersing types may travel near (“viscosity”)
or far from their natal groups. A type will be designed to do the best it can do to
maximizeitsrelativefitness(growthrate)inapopulation,eventhoughnichespaces
ofsimilartypeswilloverlap,yieldingcompetitionforlimitingresources(e.g.,food,
mates,space).Thus,interestsoftypesmaynotcoincide,particularlykinwhoseniche
spacesareboundtooverlap,andresponsesinfluencingreproductiveratesofsimilar
or different types may have beneficial or deleterious effects on per capita rates of
populationgrowth.
Expandingothertreatments,intensitiesofwithin-andamong-speciescompetition
in local (“patch”) and regional (population, metapopulation) regimes are expected
to determine benefits and costs to each mammal’s current and future reproduction
viacondition-dependentinteractionsbetweengenotypeandenvironment(“reaction
norms”),includinginteractionswithothermembersofanaggregationorintegrated
group. Throughout the present review, mammals are assumed to reside in a com-
petitivecontext,withintheindividualmammal’sgroup,betweengroups,andwithin
populations,communitiesandecosystems,andinteractionsbetweenoramongcon-
specificsmaybecategorizedasfacilitation,tolerance,orinhibition.Thetopicofthe
presentsynthesisismammaliansocialevolution,and,throughoutthetext,“facilita-
tion” is employed generically to mean facilitation of a type’s relative reproductive
interestsviathefacilitationofanothertype’sreproductiveinterests,usuallyanother
groupmemberandoftenarelative.
Evolutionary transitions to sociality within and between mammalian taxa are
central to a scientific understanding of sociality as a phenomenon, since the Class
constitutes the most ecologically dominant terrestrial vertebrate fauna, including
grades of population structure from “solitary” (“sexually-segregated”) to eusocial
(overlappinggenerations,cooperativebreeding,reproductivedivisionoflabor).Ster-
ilecasteshave,apparently,notevolvedamongmammals;thus,inthepresentbrief,
cooperativelybreedingandeusocialmoleratsareclassifiedas“primitivelyeusocial”.
In addition, this monograph discusses factors associated with group-formation,
group-maintenance, group population structure, and, other, events and processes
(e.g., physiology, behavior). Within- and between-lineages, features of prehistoric
and extant social mammals, patterns and linkages are discussed as components of
a possible social “tool-kit”, and “top-down” (predators to nutrients), as well as,
“bottom-up”(nutrientstopredators),effectsareassessed.Thepresentsynthesisalso
emphasizesoutcomesofHebbian(synaptic)“decisions”onMalthusianparameters
(growth rates of populations) and their consequences for (shifting) mean fitnesses
of populations. Ecology and evolution (EcoEvo) are connected via the organism’s
“normsofreaction”(genotype×environmentinteractions;life-historytradeoffsof
reproduction,survival,andgrowth)exposedtoselection,withthesuccessofgeno-
typesinfluencedbyintensitiesofselectionaswellasneutral(e.g., mutationrates)
and stochastic effects. At every turn, life history trajectories are assumed to arise
Preface vii
from “decisions” made by types responding to competition for limiting resources
constrainedbyHamilton’srule(inclusivefitnessoperations).
Thisandpreviousprojectswouldnothavebeenpossiblewithoutefforts,construc-
tivecriticisms,andotherinputsfrommanyindividuals.IthankJanetSlobodienand
herstaffforfacilitatingthecurrentproject.Mygraphicsassistants,MonicaE.Mc-
Garrity,LizWilliams,aswellasCharlaSchlueter,deservementionfortheirtechnical
talentsandpatience.IamverygratefultoKennethD.Angielczyk,LeeDrickamer,
TedFleming,StevenA.Frank,TarmoKetola,PhyllisC.Lee,JesseMarczyk,Daniel
J. Mennill, Peter Nonacs, Craig Packer, Michael Platt, Randy Thornhill, Robert
L. Trivers, Gene E. Robinson, two anonymous reviewers and, especially, Andrew
Bourke, for responding to my questions or commenting on one or more sections
of this brief. My children, Dalton Anthony, Julie Karin, and Miguel Luke Jones
providedinsight, goodhumor, andsupport.Thisbriefisdedicatedtomyteachers,
mentors,andcolleagues.
Contents
1 Introduction:Definitions,Background............................ 1
1.1 Different“Routes”toSociality ............................... 2
References..................................................... 6
2 CompetitionforLimitingResources,Hamilton’sRule,
andChesson’sR* .............................................. 9
2.1 Westetal.(2002)PlacesHamilton’sRuleintheContext
ofIntraspecificCompetition.................................. 10
2.2 GeneralizingChesson’sR*andLinkingittoHamilton’sRule...... 13
References..................................................... 17
3 Flexible and DerivedVarieties of Mammalian Social Organization:
PromiscuityinAggregationsMayHaveServedasaRecent“Toolkit”
Giving Rise to “Sexual Segregation,” Polygynous Social Structures,
Monogamy,Polyandry,andLeks ................................ 19
3.1 TheEvolutionofThermalNichesandtheEvolution
ofMammalianSociality ..................................... 25
3.2 AbioticandBiotic“Drivers”ofBodySizesandHome-Range
SizesinMammals .......................................... 26
3.3 WhatRolesDoMammalianMalesPlayinDeterminingPopulation
Structure? Interactions Between Intrasexual Selection, Sexual
Dimorphism in Home Range Sizes, and the Potential for Male
MonopolizationofFemales .................................. 28
3.4 “Promiscuous”Associations with Overlapping Home Ranges
WithoutMaleMonopolization:AMammalian“Toolkit” .......... 30
3.5 “Solitary”MammalsandSexualSegregationGradetoPolygyny ... 32
References..................................................... 33
4 Multimale-Multifemale Groups and “Nested” Architectures:
CollaborationAmongMammalianMales ......................... 37
4.1 IncipientDivision-of-LaborinMultimale-Multifemale
GroupsofMammals ........................................ 38
4.2 “Nested” (“Hierarchical,” “Modular”) Social Organization
and Management of Competition as Well as Competition
byQueuing................................................ 39
ix
x Contents
4.3 QueuingMayMinimizel*LevelsforSuperiorTypes............. 42
References..................................................... 43
5 Higher“Grades”ofSocialityinClassMammalia:
PrimitiveEusociality ........................................... 47
5.1 PrimitivelyEusocial“Cooperative”Breeders.................... 48
5.2 PrimitivelyEusocialMoleRats ............................... 49
5.3 TowardaSocial“Toolkit”.................................... 50
5.4 MammalianSocialityandSocialInsects:Convergent
PatternsEmerge............................................ 52
References..................................................... 53
6 EcologicalModelsasWorkingParadigmsfor“Unpacking”Positive
andNegativeInteractionsAmongSocialMammals ................ 55
6.1 TheBehavioralEcologyofGroupFormationandStable
MaintenanceofGroups...................................... 56
6.2 PredationMayFacilitateGroupFormation,aNecessary
PrecursortoSocialEvolution................................. 57
6.3 InterspecificCompetitionMayFacilitateMammalianGroup
Formation,aNecessaryPrecursortoSocialEvolution ............ 58
6.4 HowRobustarePredationandInterspecificCompetition
as Conditions for the Evolution of Group Maintenance, Possibly
LeadingtoSocialEvolutioninMammals....................... 59
References..................................................... 61
7 MechanismsUnderlyingtheBehavioralEcologyofGroupFormation 65
7.1 Behavioral Ecology, a Paradigm for the Evolution of Group
Structure:ExtrinsicFactorsShape“Decisions”MadebyTypes .... 66
7.2 Types Influence and Are Influenced by Abiotic and Biotic
Regimes:PositiveandNegativeEffectsAmongSpecies........... 68
7.3 A Case Study of Community Assembly: Superior
andInferiorCompetitors..................................... 73
References..................................................... 76
8 TheEvolutionofMammalianSocialitybySexualSelection ......... 81
8.1 TheEnergeticsofSexualAllocation ........................... 82
8.2 “Sexual Conflict” Between Mammalian Males and Group-Living
Females:EcologyInteractswithTraits ......................... 85
8.3 TheEco-EthologyofMaletoFemaleAggression ................ 85
8.4 ASimpleModelofMaletoFemaleAggressioninMammals ...... 88
8.5 Managing Conflict Where More than One Males Coreside
withReproductiveFemales .................................. 90
8.6 AFinalNoteonFemales:PotentialsandConstraints ............. 91
References..................................................... 93
Contents xi
9 ProximateCausation:FunctionalTraitsandtheUbiquityofSignaler
toReceiverInteractions:FromBiochemicaltoWholeOrganismLevels
ofMammalianSocialOrganization .............................. 97
9.1 AnIntegrationofSocialNeuroscienceandEcologyIsontheHorizon 99
9.2 MammalianSociogenetics:WhatGenesDoWhat,andHow?...... 99
9.3 ThePromiseofMammalianSociogenomicsHasYettoBeRealized 101
References..................................................... 101
10 Synopsis ...................................................... 105
10.1 Synopsis .................................................. 105
10.2 Coda ..................................................... 106
References..................................................... 109
Index ............................................................ 111