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Rajendhran Rajakumar - One of the best experts on this subject based on the ideXlab platform.
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social regulation of a rudimentary organ generates complex worker Caste systems in ants
Nature, 2018Co-Authors: Rajendhran Rajakumar, Sophie Koch, Melanie Couture, Mariejulie Fave, Angelica Lillicoouachour, Travis Chen, Giovanna De Blasis, Arjuna RajakumarAbstract:The origin of complex worker-Caste systems in ants perplexed Darwin1 and has remained an enduring problem for evolutionary and developmental biology2-6. Ants originated approximately 150 million years ago, and produce colonies with winged queen and male Castes as well as a wingless worker Caste7. In the hyperdiverse genus Pheidole, the wingless worker Caste has evolved into two morphologically distinct subCastes-small-headed minor workers and large-headed soldiers8. The wings of queens and males develop from populations of cells in larvae that are called wing imaginal discs7. Although minor workers and soldiers are wingless, vestiges or rudiments of wing imaginal discs appear transiently during soldier development7,9-11. Such rudimentary traits are phylogenetically widespread and are primarily used as evidence of common descent, yet their functional importance remains equivocal1,12-14. Here we show that the growth of rudimentary wing discs is necessary for regulating allometry-disproportionate scaling-between head and body size to generate large-headed soldiers in the genus Pheidole. We also show that Pheidole colonies have evolved the capacity to socially regulate the growth of rudimentary wing discs to control worker subCaste determination, which allows these colonies to maintain the ratio of minor workers to soldiers. Finally, we provide comparative and experimental evidence that suggests that rudimentary wing discs have facilitated the parallel evolution of complex worker-Caste systems across the ants. More generally, rudimentary organs may unexpectedly acquire novel regulatory functions during development to facilitate adaptive evolution.
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Social regulation of a rudimentary organ generates complex worker-Caste systems in ants
Nature, 2018Co-Authors: Rajendhran Rajakumar, Sophie Koch, Melanie Couture, Mariejulie Fave, Travis Chen, Giovanna De Blasis, Arjuna Rajakumar, Angelica Lillico-ouachour, Dominic Ouellette, Ehab AbouheifAbstract:The origin of complex worker-Caste systems in ants perplexed Darwin1 and has remained an enduring problem for evolutionary and developmental biology2–6. Ants originated approximately 150 million years ago, and produce colonies with winged queen and male Castes as well as a wingless worker Caste7. In the hyperdiverse genus Pheidole, the wingless worker Caste has evolved into two morphologically distinct subCastes—small-headed minor workers and large-headed soldiers8. The wings of queens and males develop from populations of cells in larvae that are called wing imaginal discs7. Although minor workers and soldiers are wingless, vestiges or rudiments of wing imaginal discs appear transiently during soldier development7,9–11. Such rudimentary traits are phylogenetically widespread and are primarily used as evidence of common descent, yet their functional importance remains equivocal1,12–14. Here we show that the growth of rudimentary wing discs is necessary for regulating allometry—disproportionate scaling—between head and body size to generate large-headed soldiers in the genus Pheidole. We also show that Pheidole colonies have evolved the capacity to socially regulate the growth of rudimentary wing discs to control worker subCaste determination, which allows these colonies to maintain the ratio of minor workers to soldiers. Finally, we provide comparative and experimental evidence that suggests that rudimentary wing discs have facilitated the parallel evolution of complex worker-Caste systems across the ants. More generally, rudimentary organs may unexpectedly acquire novel regulatory functions during development to facilitate adaptive evolution. In the ant genus Pheidole the growth of rudimentary wing discs—which influence developmental allometry to produce Castes with distinct morphologies—is socially regulated to determine the worker-to-soldier ratio in Pheidole colonies.
David Mosse - One of the best experts on this subject based on the ideXlab platform.
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Outside Caste? The Enclosure of Caste and Claims to Castelessness in India and the United Kingdom
Comparative Studies in Society and History, 2020Co-Authors: David MosseAbstract:Caste has always generated political and scholarly controversy, but the forms that this takes today newly combine anti-Caste activism with counter-claims that Caste is irrelevant or non-existent, or claims to Castelessness. Claims to Castelessness are, in turn, viewed by some as a new disguise for Caste power and privilege, while castlessness is also an aspiration for people subject to Caste-based discrimination. This article looks at elite claims to “enclose” Caste within religion, specifically Hinduism, and the Indian nation so as to restrict the field of social policy that Caste applies to, to exempt Caste-based discrimination from the law, and to limit the social politics of Caste. It does so through a comparative analysis of two cases. The first is the exclusion of Christian and Muslim Dalits—members of Castes subordinated as “untouchable”—from provisions and protections as Scheduled Castes in India. The other case is that of responses to the introduction of Caste into anti-discrimination law in the UK. While Hindu organizations in the UK reject “Caste” as a colonial and racist term and deploy postcolonial scholarship to deny Caste discrimination, Dalit organizations, representing its potential victims, turn to scholarly discourse on Caste, race, or human rights to support their cause. These are epistemological disputes about categories of description and how “the social” is made available for public debate, and especially for law. Such disputes engage with anthropology, whose analytical terms animate and change the social world that is their subject.
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The Modernity of Caste and the Market Economy
Modern Asian Studies, 2019Co-Authors: David MosseAbstract:What place does the Caste system have in modern India with its globally-integrating market economy? The most influential anthropological approaches to Caste have tended to emphasize Caste as India’s traditional religious and ritual order, or (treating such order as a product of the colonial encounter) as shaped politically, especially today by the dynamics of Caste-based electoral politics. Less attention has been paid to Caste effects in the economy. This article argues that the scholarly framing of Caste mirrors a public policy ‘enclosure’ of Caste in the non-modern realm of religion and ‘Caste politics’, while aligning modernity to the Caste-erasing market economy. Village-level fieldwork in south India finds a parallel public narrative of Caste either as ritual rank eroded by market relations, or as identity politics deflected from everyday economic life. But locally and nationally the effects of Caste are found to be pervasive in labour markets and the business economy. In the age of the market, Caste is a resource, sometimes in the form of a network, its opportunity-hoarding advantages discriminating against others. Dalits are not discriminated by Caste as a set of relations separate from economy, but by the very economic and market processes through which they often seek liberation. The Caste processes, enclosures and evasions in post-liberalization India, suggest the need to rethink the modernity of Caste beyond orientalist and postcolonial frameworks, and consider the presuppositions that shape understanding of an institution, the nature and experience of which are determined by the inequalities and subject positions it produces.
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Caste and development contemporary perspectives on a structure of discrimination and advantage
World Development, 2018Co-Authors: David MosseAbstract:Abstract Inherited Caste identity is an important determinant of life opportunity for a fifth of the world’s population, but is not given the same significance in global development policy debates as gender, race, age, religion or other identity characteristics. This review asks why addressing Caste-based inequality and discrimination does not feature in intergovernmental commitments such as the Sustainable Development Goals, and whether it should. Taking India as its focus, it finds that Caste has been treated as an archaic system and source of historical disadvantage due compensation through affirmative action in ways that overlook its continuing importance as a structure of advantage and of discrimination in the modern economy, especially post-liberalization from the 1990s. A body of recent literature from anthropology, economics, history and political science is used to explore the modern life of Caste in society, economy and development. Questions are asked about Caste as social hierarchy, the role of Caste in post-liberalization rural inequality, in urban labor markets and in the business economy, and the effect of policies of affirmative action in public-sector education and employment. Caste is found to be a complex institution, simultaneously weakened and revived by current economic and political forces; it is a contributor to persisting national socioeconomic and human capital disparities, and has major impacts on subjective wellbeing. Caste effects are not locational; they travel from the village to the city and into virtually all markets. Caste persists in the age of the market because of its advantages – its discriminations allow opportunity hoarding for others; and the threat of the advancement of subordinated groups provokes humiliating violence against them. The evidence points to the need for policy innovation to address market and non-market discrimination and to remove barriers, especially in the informal and private sector; and to ensure Caste has its proper place in the global development policy debate.
Arjuna Rajakumar - One of the best experts on this subject based on the ideXlab platform.
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social regulation of a rudimentary organ generates complex worker Caste systems in ants
Nature, 2018Co-Authors: Rajendhran Rajakumar, Sophie Koch, Melanie Couture, Mariejulie Fave, Angelica Lillicoouachour, Travis Chen, Giovanna De Blasis, Arjuna RajakumarAbstract:The origin of complex worker-Caste systems in ants perplexed Darwin1 and has remained an enduring problem for evolutionary and developmental biology2-6. Ants originated approximately 150 million years ago, and produce colonies with winged queen and male Castes as well as a wingless worker Caste7. In the hyperdiverse genus Pheidole, the wingless worker Caste has evolved into two morphologically distinct subCastes-small-headed minor workers and large-headed soldiers8. The wings of queens and males develop from populations of cells in larvae that are called wing imaginal discs7. Although minor workers and soldiers are wingless, vestiges or rudiments of wing imaginal discs appear transiently during soldier development7,9-11. Such rudimentary traits are phylogenetically widespread and are primarily used as evidence of common descent, yet their functional importance remains equivocal1,12-14. Here we show that the growth of rudimentary wing discs is necessary for regulating allometry-disproportionate scaling-between head and body size to generate large-headed soldiers in the genus Pheidole. We also show that Pheidole colonies have evolved the capacity to socially regulate the growth of rudimentary wing discs to control worker subCaste determination, which allows these colonies to maintain the ratio of minor workers to soldiers. Finally, we provide comparative and experimental evidence that suggests that rudimentary wing discs have facilitated the parallel evolution of complex worker-Caste systems across the ants. More generally, rudimentary organs may unexpectedly acquire novel regulatory functions during development to facilitate adaptive evolution.
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Social regulation of a rudimentary organ generates complex worker-Caste systems in ants
Nature, 2018Co-Authors: Rajendhran Rajakumar, Sophie Koch, Melanie Couture, Mariejulie Fave, Travis Chen, Giovanna De Blasis, Arjuna Rajakumar, Angelica Lillico-ouachour, Dominic Ouellette, Ehab AbouheifAbstract:The origin of complex worker-Caste systems in ants perplexed Darwin1 and has remained an enduring problem for evolutionary and developmental biology2–6. Ants originated approximately 150 million years ago, and produce colonies with winged queen and male Castes as well as a wingless worker Caste7. In the hyperdiverse genus Pheidole, the wingless worker Caste has evolved into two morphologically distinct subCastes—small-headed minor workers and large-headed soldiers8. The wings of queens and males develop from populations of cells in larvae that are called wing imaginal discs7. Although minor workers and soldiers are wingless, vestiges or rudiments of wing imaginal discs appear transiently during soldier development7,9–11. Such rudimentary traits are phylogenetically widespread and are primarily used as evidence of common descent, yet their functional importance remains equivocal1,12–14. Here we show that the growth of rudimentary wing discs is necessary for regulating allometry—disproportionate scaling—between head and body size to generate large-headed soldiers in the genus Pheidole. We also show that Pheidole colonies have evolved the capacity to socially regulate the growth of rudimentary wing discs to control worker subCaste determination, which allows these colonies to maintain the ratio of minor workers to soldiers. Finally, we provide comparative and experimental evidence that suggests that rudimentary wing discs have facilitated the parallel evolution of complex worker-Caste systems across the ants. More generally, rudimentary organs may unexpectedly acquire novel regulatory functions during development to facilitate adaptive evolution. In the ant genus Pheidole the growth of rudimentary wing discs—which influence developmental allometry to produce Castes with distinct morphologies—is socially regulated to determine the worker-to-soldier ratio in Pheidole colonies.
Mariejulie Fave - One of the best experts on this subject based on the ideXlab platform.
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social regulation of a rudimentary organ generates complex worker Caste systems in ants
Nature, 2018Co-Authors: Rajendhran Rajakumar, Sophie Koch, Melanie Couture, Mariejulie Fave, Angelica Lillicoouachour, Travis Chen, Giovanna De Blasis, Arjuna RajakumarAbstract:The origin of complex worker-Caste systems in ants perplexed Darwin1 and has remained an enduring problem for evolutionary and developmental biology2-6. Ants originated approximately 150 million years ago, and produce colonies with winged queen and male Castes as well as a wingless worker Caste7. In the hyperdiverse genus Pheidole, the wingless worker Caste has evolved into two morphologically distinct subCastes-small-headed minor workers and large-headed soldiers8. The wings of queens and males develop from populations of cells in larvae that are called wing imaginal discs7. Although minor workers and soldiers are wingless, vestiges or rudiments of wing imaginal discs appear transiently during soldier development7,9-11. Such rudimentary traits are phylogenetically widespread and are primarily used as evidence of common descent, yet their functional importance remains equivocal1,12-14. Here we show that the growth of rudimentary wing discs is necessary for regulating allometry-disproportionate scaling-between head and body size to generate large-headed soldiers in the genus Pheidole. We also show that Pheidole colonies have evolved the capacity to socially regulate the growth of rudimentary wing discs to control worker subCaste determination, which allows these colonies to maintain the ratio of minor workers to soldiers. Finally, we provide comparative and experimental evidence that suggests that rudimentary wing discs have facilitated the parallel evolution of complex worker-Caste systems across the ants. More generally, rudimentary organs may unexpectedly acquire novel regulatory functions during development to facilitate adaptive evolution.
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Social regulation of a rudimentary organ generates complex worker-Caste systems in ants
Nature, 2018Co-Authors: Rajendhran Rajakumar, Sophie Koch, Melanie Couture, Mariejulie Fave, Travis Chen, Giovanna De Blasis, Arjuna Rajakumar, Angelica Lillico-ouachour, Dominic Ouellette, Ehab AbouheifAbstract:The origin of complex worker-Caste systems in ants perplexed Darwin1 and has remained an enduring problem for evolutionary and developmental biology2–6. Ants originated approximately 150 million years ago, and produce colonies with winged queen and male Castes as well as a wingless worker Caste7. In the hyperdiverse genus Pheidole, the wingless worker Caste has evolved into two morphologically distinct subCastes—small-headed minor workers and large-headed soldiers8. The wings of queens and males develop from populations of cells in larvae that are called wing imaginal discs7. Although minor workers and soldiers are wingless, vestiges or rudiments of wing imaginal discs appear transiently during soldier development7,9–11. Such rudimentary traits are phylogenetically widespread and are primarily used as evidence of common descent, yet their functional importance remains equivocal1,12–14. Here we show that the growth of rudimentary wing discs is necessary for regulating allometry—disproportionate scaling—between head and body size to generate large-headed soldiers in the genus Pheidole. We also show that Pheidole colonies have evolved the capacity to socially regulate the growth of rudimentary wing discs to control worker subCaste determination, which allows these colonies to maintain the ratio of minor workers to soldiers. Finally, we provide comparative and experimental evidence that suggests that rudimentary wing discs have facilitated the parallel evolution of complex worker-Caste systems across the ants. More generally, rudimentary organs may unexpectedly acquire novel regulatory functions during development to facilitate adaptive evolution. In the ant genus Pheidole the growth of rudimentary wing discs—which influence developmental allometry to produce Castes with distinct morphologies—is socially regulated to determine the worker-to-soldier ratio in Pheidole colonies.
Xuguo Zhou - One of the best experts on this subject based on the ideXlab platform.
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The soldiers in societies: defense, regulation, and evolution.
International journal of biological sciences, 2014Co-Authors: Li Tian, Xuguo ZhouAbstract:The presence of reproductively altruistic Castes is one of the primary traits of the eusocial societies. Adaptation and regulation of the sterile Caste, to a certain extent, drives the evolution of eusociality. Depending on adaptive functions of the first evolved sterile Caste, eusocial societies can be categorized into the worker-first and soldier-first lineages, respectively. The former is marked by a worker Caste as the first evolved altruistic Caste, whose primary function is housekeeping, and the latter is highlighted by a sterile soldier Caste as the first evolved altruistic Caste, whose task is predominantly colony defense. The apparent functional differences between these two fundamentally important Castes suggest worker-first and soldier-first eusociality are potentially driven by a suite of distinctively different factors. Current studies of eusocial evolution have been focused largely on the worker-first Hymenoptera, whereas understanding of soldier-first lineages including termites, eusocial aphids, gall-dwelling thrips, and snapping shrimp, is greatly lacking. In this review, we summarize the current state of knowledge on biology, morphology, adaptive functions, and Caste regulation of the soldier Caste. In addition, we discuss the biological, ecological and genetic factors that might contribute to the evolution of distinct Caste systems within eusocial lineages.
