scholarly journals Division of labour and colony efficiency in social insects: effects of interactions between genetic architecture, colony kin structure and rate of perturbations

2006 ◽  
Vol 273 (1595) ◽  
pp. 1815-1823 ◽  
Author(s):  
Markus Waibel ◽  
Dario Floreano ◽  
Stéphane Magnenat ◽  
Laurent Keller
Keyword(s):  
Genetic Architecture ◽  
Division Of Labour ◽  
Task Specialization ◽  
Complex Interactions ◽  
Probabilistic Mapping ◽  
Dynamic Mapping ◽  
Mapping System ◽  
Kin Structure ◽  
Colony Efficiency ◽  
Genetically Determined

The efficiency of social insect colonies critically depends on their ability to efficiently allocate workers to the various tasks which need to be performed. While numerous models have investigated the mechanisms allowing an efficient colony response to external changes in the environment and internal perturbations, little attention has been devoted to the genetic architecture underlying task specialization. We used artificial evolution to compare the performances of three simple genetic architectures underlying within-colony variation in response thresholds of workers to five tasks. In the ‘deterministic mapping’ system, the thresholds of individuals for each of the five tasks is strictly genetically determined. In the second genetic architecture (‘probabilistic mapping’), the genes only influence the probability of engaging in one of the tasks. Finally, in the ‘dynamic mapping’ system, the propensity of workers to engage in one of the five tasks depends not only on their own genotype, but also on the behavioural phenotypes of other colony members. We found that the deterministic mapping system performed well only when colonies consisted of unrelated individuals and were not subjected to perturbations in task allocation. The probabilistic mapping system performed well for colonies of related and unrelated individuals when there were no perturbations. Finally, the dynamic mapping system performed well under all conditions and was much more efficient than the two other mapping systems when there were perturbations. Overall, our simulations reveal that the type of mapping between genotype and individual behaviour greatly influences the dynamics of task specialization and colony productivity. Our simulations also reveal complex interactions between the mode of mapping, level of within-colony relatedness and risk of colony perturbations.

scholarly journals Polymorphism and division of labour in a socially complex ant: neuromodulation of aggression in the Australian weaver ant, Oecophylla smaragdina

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150704 ◽  
Author(s):  
J. Frances Kamhi ◽  
Kelley Nunn ◽  
Simon K. A. Robson ◽  
James F. A. Traniello
Keyword(s):  
Social Systems ◽  
Division Of Labour ◽  
Oecophylla Smaragdina ◽  
Minor Worker ◽  
Task Specialization ◽  
Territorial Defence ◽  
Weaver Ant ◽  
Eusocial Insects ◽  
Worker Size ◽  
Pharmacological Manipulations

Complex social structure in eusocial insects can involve worker morphological and behavioural differentiation. Neuroanatomical variation may underscore worker division of labour, but the regulatory mechanisms of size-based task specialization in polymorphic species are unknown. The Australian weaver ant, Oecophylla smaragdina , exhibits worker polyphenism: larger major workers aggressively defend arboreal territories, whereas smaller minors nurse brood. Here, we demonstrate that octopamine (OA) modulates worker size-related aggression in O. smaragdina . We found that the brains of majors had significantly higher titres of OA than those of minors and that OA was positively and specifically correlated with the frequency of aggressive responses to non-nestmates, a key component of territorial defence. Pharmacological manipulations that effectively switched OA action in major and minor worker brains reversed levels of aggression characteristic of each worker size class. Results suggest that altering OA action is sufficient to produce differences in aggression characteristic of size-related social roles. Neuromodulators therefore may generate variation in responsiveness to task-related stimuli associated with worker size differentiation and collateral behavioural specializations, a significant component of division of labour in complex social systems.

scholarly journals Cryptic lineages hybridize for worker production in the harvester ant Messor barbarus

2016 ◽  
Vol 12 (11) ◽  
pp. 20160542 ◽  
Author(s):  
Victoria Norman ◽  
Hugo Darras ◽  
Christopher Tranter ◽  
Serge Aron ◽  
William O. H. Hughes
Keyword(s):  
Reproductive System ◽  
Division Of Labour ◽  
Insect Larvae ◽  
Messor Barbarus ◽  
Harvester Ant ◽  
Mitochondrial Data ◽  
Genetic Caste Determination ◽  
Worker Castes ◽  
Genetically Determined ◽  
Reproductive Division

The reproductive division of labour between queen and worker castes in social insects is a defining characteristic of eusociality and a classic example of phenotypic plasticity. Whether social insect larvae develop into queens or workers has long been thought to be determined by environmental cues, i.e. larvae are developmentally totipotent. Contrary to this paradigm, several recent studies have revealed that caste is determined by genotype in some ant species, but whether this is restricted to just a few exceptional species is still unclear. Here, we show that the Mediterranean harvester ant Messor barbarus possesses an unusual reproductive system, in which the female castes are genetically determined. Using both nuclear and mitochondrial data, we show that Iberian populations have two distinct, cryptic lineages. Workers are always inter-lineage hybrids whereas queens are always produced from pure-lineage matings. The results suggest that genetic caste determination may be more widespread in ants than previously thought, and that further investigation in other species is needed to understand the frequency and evolution of this remarkable reproductive system.

scholarly journals Navigating cognition: Spatial codes for human thinking

Science ◽  
2018 ◽  
Vol 362 (6415) ◽  
pp. eaat6766 ◽  
Author(s):  
Jacob L. S. Bellmund ◽  
Peter Gärdenfors ◽  
Edvard I. Moser ◽  
Christian F. Doeller
Keyword(s):  
Hippocampal Formation ◽  
Wide Spectrum ◽  
Spatial Navigation ◽  
Grid Cell ◽  
Dynamic Mapping ◽  
Mapping System ◽  
Representational Format ◽  
Orthogonal Representations ◽  
Human Thinking ◽  
And Behavior

The hippocampal formation has long been suggested to underlie both memory formation and spatial navigation. We discuss how neural mechanisms identified in spatial navigation research operate across information domains to support a wide spectrum of cognitive functions. In our framework, place and grid cell population codes provide a representational format to map variable dimensions of cognitive spaces. This highly dynamic mapping system enables rapid reorganization of codes through remapping between orthogonal representations across behavioral contexts, yielding a multitude of stable cognitive spaces at different resolutions and hierarchical levels. Action sequences result in trajectories through cognitive space, which can be simulated via sequential coding in the hippocampus. In this way, the spatial representational format of the hippocampal formation has the capacity to support flexible cognition and behavior.

scholarly journals How within-group behavioural variation and task efficiency enhance fitness in a social group

2010 ◽  
Vol 278 (1709) ◽  
pp. 1209-1215 ◽  
Author(s):  
Jonathan N. Pruitt ◽  
Susan E. Riechert
Keyword(s):  
Prey Capture ◽  
Common Garden ◽  
Division Of Labour ◽  
Large Prey ◽  
Task Specialization ◽  
Capture Success ◽  
Social Phenotype ◽  
Individual Task ◽  
Task Efficiency

How task specialization, individual task performance and within-group behavioural variation affects fitness is a longstanding and unresolved problem in our understanding of animal societies. In the temperate social spider, Anelosimus studiosus , colony members exhibit a behavioural polymorphism; females either exhibit an aggressive ‘asocial’ or docile ‘social’ phenotype. We assessed individual prey-capture success for both phenotypes, and the role of phenotypic composition on group-level prey-capture success for three prey size classes. We then estimated the effect of group phenotypic composition on fitness in a common garden, as inferred from individual egg-case masses. On average, asocial females were more successful than social females at capturing large prey, and colony-level prey-capture success was positively associated with the frequency of the asocial phenotype. Asocial colony members were also more likely to engage in prey-capture behaviour in group-foraging situations. Interestingly, our fitness estimates indicate females of both phenotypes experience increased fitness when occupying colonies containing unlike individuals. These results imply a reciprocal fitness benefit of within-colony behavioural variation, and perhaps division of labour in a spider society.

scholarly journals Polygenic basis and biomedical consequences of telomere length variation

2021 ◽  
Vol 53 (10) ◽  
pp. 1425-1433
Author(s):  
Veryan Codd ◽  
Qingning Wang ◽  
Elias Allara ◽  
Crispin Musicha ◽  
Stephen Kaptoge ◽  
...  
Keyword(s):  
Telomere Length ◽  
Genetic Architecture ◽  
Cellular Proliferation ◽  
Genetic Regulation ◽  
Biological Traits ◽  
Length Variation ◽  
Leukocyte Telomere Length ◽  
Naturally Occurring ◽  
Bone Marrow Function ◽  
Genetically Determined

AbstractTelomeres, the end fragments of chromosomes, play key roles in cellular proliferation and senescence. Here we characterize the genetic architecture of naturally occurring variation in leukocyte telomere length (LTL) and identify causal links between LTL and biomedical phenotypes in 472,174 well-characterized UK Biobank participants. We identified 197 independent sentinel variants associated with LTL at 138 genomic loci (108 new). Genetically determined differences in LTL were associated with multiple biological traits, ranging from height to bone marrow function, as well as several diseases spanning neoplastic, vascular and inflammatory pathologies. Finally, we estimated that, at the age of 40 years, people with an LTL >1 s.d. shorter than the population mean had a 2.5-year-lower life expectancy compared with the group with ≥1 s.d. longer LDL. Overall, we furnish new insights into the genetic regulation of LTL, reveal wide-ranging influences of LTL on physiological traits, diseases and longevity, and provide a powerful resource available to the global research community.

scholarly journals Recent shifts in the genomic ancestry of Mexican Americans may alter the genetic architecture of biomedical traits

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Melissa L Spear ◽  
Alex Diaz-Papkovich ◽  
Elad Ziv ◽  
Joseph M Yracheta ◽  
Simon Gravel ◽  
...  
Keyword(s):  
Complex Traits ◽  
Mexican Americans ◽  
Genetic Architecture ◽  
Genome Wide Association Study ◽  
The United States ◽  
European Ancestry ◽  
Risk Scores ◽  
Health Study ◽  
Complex Interactions ◽  
Hispanic Community

People in the Americas represent a diverse continuum of populations with varying degrees of admixture among African, European, and Amerindigenous ancestries. In the United States, populations with non-European ancestry remain understudied, and thus little is known about the genetic architecture of phenotypic variation in these populations. Using genotype data from the Hispanic Community Health Study/Study of Latinos, we find that Amerindigenous ancestry increased by an average of ~20% spanning 1940s-1990s in Mexican Americans. These patterns result from complex interactions between several population and cultural factors which shaped patterns of genetic variation and influenced the genetic architecture of complex traits in Mexican Americans. We show for height how polygenic risk scores based on summary statistics from a European-based genome-wide association study perform poorly in Mexican Americans. Our findings reveal temporal changes in population structure within Hispanics/Latinos that may influence biomedical traits, demonstrating a need to improve our understanding of admixed populations.

scholarly journals Les gènes du visage

2021 ◽  
Vol 37 (3) ◽  
pp. 300-303
Author(s):  
Bertrand Jordan
Keyword(s):  
Recent Work ◽  
Genetic Architecture ◽  
Morphological Structure ◽  
Precise Definition ◽  
Face Shape ◽  
Depth Analysis ◽  
Definition Of ◽  
Genetically Determined

Face shape is genetically determined, but the underlying genetic architecture is complex, and precise definition of facial structures is essential for any serious study. Recent work, based on objective definition of facial segments and GWAS analyses of thousands of participants, defines a large number of loci (> 100) influencing face shape and begin to allow in-depth analysis of this complex morphological structure.

scholarly journals Worker caste determination in the army ant Eciton burchellii

2007 ◽  
Vol 3 (5) ◽  
pp. 513-516 ◽  
Author(s):  
Rodolfo Jaffé ◽  
Daniel J.C Kronauer ◽  
F Bernhard Kraus ◽  
Jacobus J Boomsma ◽  
Robin F.A Moritz
Keyword(s):  
Social Insects ◽  
Division Of Labour ◽  
Test System ◽  
Caste Differentiation ◽  
Caste Determination ◽  
Task Specialization ◽  
Army Ant ◽  
Genetic Components ◽  
Eciton Burchellii ◽  
Worker Caste

Elaborate division of labour has contributed significantly to the ecological success of social insects. Division of labour is achieved either by behavioural task specialization or by morphological specialization of colony members. In physical caste systems, the diet and rearing environment of developing larvae is known to determine the phenotype of adult individuals, but recent studies have shown that genetic components also contribute to the determination of worker caste. One of the most extreme cases of worker caste differentiation occurs in the army ant genus Eciton , where queens mate with many males and colonies are therefore composed of numerous full-sister subfamilies. This high intracolonial genetic diversity, in combination with the extreme caste polymorphism, provides an excellent test system for studying the extent to which caste determination is genetically controlled. Here we show that genetic effects contribute significantly to worker caste fate in Eciton burchellii . We conclude that the combination of polyandry and genetic variation for caste determination may have facilitated the evolution of worker caste diversity in some lineages of social insects.

scholarly journals The origins of human cumulative culture: from the foraging niche to collective intelligence

2021 ◽  
Vol 377 (1843) ◽  
Author(s):  
Andrea Bamberg Migliano ◽  
Lucio Vinicius
Keyword(s):  
Homo Sapiens ◽  
Collective Intelligence ◽  
Division Of Labour ◽  
Cultural Knowledge ◽  
Cognitive Mechanisms ◽  
Cumulative Culture ◽  
Task Specialization ◽  
Hunter Gatherers ◽  
Inheritance System ◽  
Foraging Niche

Various studies have investigated cognitive mechanisms underlying culture in humans and other great apes. However, the adaptive reasons for the evolution of uniquely sophisticated cumulative culture in our species remain unclear. We propose that the cultural capabilities of humans are the evolutionary result of a stepwise transition from the ape-like lifestyle of earlier hominins to the foraging niche still observed in extant hunter–gatherers. Recent ethnographic, archaeological and genetic studies have provided compelling evidence that the components of the foraging niche (social egalitarianism, sexual and social division of labour, extensive co-residence and cooperation with unrelated individuals, multilocality, fluid sociality and high between-camp mobility) engendered a unique multilevel social structure where the cognitive mechanisms underlying cultural evolution (high-fidelity transmission, innovation, teaching, recombination, ratcheting) evolved as adaptations. Therefore, multilevel sociality underlies a ‘social ratchet’ or irreversible task specialization splitting the burden of cultural knowledge across individuals, which may explain why human collective intelligence is uniquely able to produce sophisticated cumulative culture. The foraging niche perspective may explain why a complex gene-culture dual inheritance system evolved uniquely in humans and interprets the cultural, morphological and genetic origins of Homo sapiens as a process of recombination of innovations appearing in differentiated but interconnected populations. This article is part of a discussion meeting issue ‘The emergence of collective knowledge and cumulative culture in animals, humans and machines’.

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