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Animal Societies (animal + society)
Selected AbstractsCryptic Kin Selection: Kin Structure in Vertebrate Populations and Opportunities for Kin-Directed CooperationETHOLOGY, Issue 3 2010Ben J. Hatchwell Animal societies of varying complexity have been the favoured testing ground for inclusive fitness theory, and there is now abundant evidence that kin selection has played a critical role in the evolution of cooperative behaviour. One of the key theoretical and empirical findings underlying this conclusion is that cooperative systems have a degree of kin structure, often the product of delayed dispersal, that facilitates interactions with relatives. However, recent population genetic studies have revealed that many non-cooperative animals also have kin-structured populations, providing more cryptic opportunities for kin selection to operate. In this article, I first review the evidence that kin structure is widespread among non-cooperative vertebrates, and then consider the various contexts in which kin selection may occur in such taxa, including: leks, brood parasitism, crèches, breeding associations, territoriality and population dynamics, foraging and predator deterrence. I describe the evidence that kin-selected benefits arise from interacting with kin in each of these contexts, notwithstanding the potential costs of kin competition and inbreeding. I conclude that as the tools required to determine population genetic structure are readily available, measurement of kin structure and the potential for kin selection on a routine basis is likely to reveal that this process has been an important driver of evolutionary adaptation in many non-cooperative as well as cooperative species. [source] Models of reproductive skew: A review and synthesis (Invited Article)ETHOLOGY, Issue 1 2000Rufus A. Johnstone Animal societies vary markedly in reproductive skew, the extent to which breeding is monopolised by dominant individuals. In the last few years, a large number of different models have been developed to explain this variation. Here, I review existing models of reproductive skew, distinguishing between two basic types. Transactional models focus on group stability and the constraints this places on the division of reproduction. Compromise models, by contrast, ignore issues of group stability and view the division of reproduction as the outcome of a conflict in which each group member has a limited or partial ability to enforce its own optimum. I go on to show, however, that the division between transactional and compromise models is somewhat artificial, and that both approaches may be combined in a single, synthetic treatment. Different models of reproductive skew are thus better seen as special cases of a general underlying theory, rather than alternative paradigms. I conclude with a brief discussion of the possibilities and problems of empirically testing this unified theory of skew, and the prospects for future theoretical advances. [source] Emergence and Consequences of Division of Labor in Associations of Normally Solitary Sweat BeesETHOLOGY, Issue 4 2009C. Tate Holbrook Division of labor is a pervasive feature of animal societies, but little is known about the causes or consequences of division of labor in non-eusocial cooperative groups. We tested whether division of labor self-organizes in an incipient social system: artificially induced nesting associations of the normally solitary sweat bee Lasioglossum (Ctenonomia) NDA-1 (Hymenoptera: Halictidae). We quantified task performance and construction output by females nesting either alone or with a conspecific. Within pairs, a division of labor repeatedly arose in which one individual specialized on excavation and pushing/tamping while her nestmate guarded the nest entrance. Task specialization could not be attributed to variation in overall activity, and the degree of behavioral differentiation was greater than would be expected due to random variation, indicating that division of labor was an emergent phenomenon generated in part by social dynamics. Excavation specialists did not incur a survival cost, in contrast to previous findings for ant foundress associations. Paired individuals performed more per capita guarding, and pairs collectively excavated deeper nests than single bees , potential early advantages of social nesting in halictine bees. [source] Institutionalization of the Family and Marriage: Questioning Their Cognitive and Relational RealitiesJOURNAL OF FAMILY THEORY & REVIEW, Issue 1 2009Jetse Sprey This paper argues that to explain the institutionalization processes named the family and marriage, it is necessary to recognize the ontological distinction between their cognitive and relational realities. Institutionalization is an ordering process analogous to instinct in animal societies. In that capacity the human family and marriage collectively order the care and social placement of offspring. Given the biology of Homo sapiens, the family preceded the onset of the human race by millions of years, whereas marriage, the contract that legitimates the social placement of offspring, represents a strictly cultural aspect of human social evolution. The current state and uncertain future of the cognitive and relational components of the institutions of the family and marriage are addressed. [source] Eviction and dispersal in co-operatively breeding banded mongooses (Mungos mungo)JOURNAL OF ZOOLOGY, Issue 2 2001Michael A. Cant Abstract The mode by which individuals disperse, and the cost of dispersal, are of great importance in attempts to understand variation in reproductive skew in animal societies. In this paper we report detailed information on dispersal and pack formation in banded mongooses Mungos mungo. Six pack fission events were recorded among 11 packs over 22 months. Pack fission occurred under two distinct circumstances. First, groups of individuals were evicted from their natal group as a result of intense aggression from other group members. A small fraction of group members was responsible for most of the aggression. Both sexes helped to attack and evict individuals from the group, and both males and females were driven out of their natal groups en masse. The second mode of pack fission occurred when groups of same-sex individuals left their natal group voluntarily to join dispersing individuals of the opposite sex, thereby forming new packs. Dispersing groups were more frequently involved in fights with rival packs of mongooses compared to established groups, and in one instance these fights seemed to be responsible for severe injury and increased mortality among members of a dispersing group. The observations of eviction provide one line of evidence that the presence of subordinates is sometimes detrimental to dominants, contrary to the assumptions of concession models of reproductive skew. [source] Shift from independent to dependent colony foundation and evolution of ,multi-purpose' ergatoid queens in Mystrium ants (subfamily Amblyoponinae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009MATHIEU MOLET Division of labour improves fitness in animal societies. In ants, queens reproduce, whereas workers perform all other tasks. However, during independent colony founding, queens live as solitary insects and must be totipotent, especially in species where they need to forage. In many ants, solitary founding has been replaced by dependent founding, where queens are continuously helped by nestmate workers. Little is known about the details of this evolutionary transition. Mystrium rogeri from Madagascar and Mystrium camillae from Southeast Asia (subfamily Amblyoponinae) have winged queens, but three congeneric species from Madagascar reproduce with permanently wingless queens instead. We show that this ,ergatoid' caste has distinct body proportions in all three species, expressing a mixture of both queen and worker traits. Ergatoid queens have functional ovaries and spermatheca, and tiny wing rudiments. They can be as numerous as workers within a colony, but only a few mate and reproduce, whereas most behave as sterile helpers. The shape of their mandibles makes them unsuited for hunting and, together with a lack of metabolic reserves (i.e. in the form of wing muscles), this means that ergatoid queens cannot be solitary foundresses. In comparison with winged queens, ergatoid queens are less costly per capita and they experience lower mortality. They remain in their natal colonies where they can either reproduce or function as helpers, making them a ,multi-purpose' caste. Within the Amblyoponinae, ergatoid queens replace winged queens in Onychomyrmex as well. However, in this genus, ergatoid queens are ,sole-purpose', few are produced each year and they reproduce but do not work. Hence, different types of ergatoid queens evolved to replace winged queens in ants. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 198,207. [source] | ||||||||||