scholarly journals Morphological and genomic shifts in mole-rat ‘queens’ increase fecundity but reduce skeletal integrity

2020 ◽  
Author(s):  
Rachel A. Johnston ◽  
Philippe Vullioud ◽  
Jack Thorley ◽  
Henry Kirveslahti ◽  
Leyao Shen ◽  
...  
Keyword(s):  
Division Of Labor ◽  
Morphological Plasticity ◽  
Skeletal Morphology ◽  
Eusocial Insects ◽  
Mole Rat ◽  
Gene Regulatory ◽  
Reproductive Division Of Labor ◽  
Reproductive Division ◽  
Skeletal Integrity ◽  
Vertebral Growth

AbstractIn some mammals and many social insects, highly cooperative societies are characterized by reproductive division of labor, in which breeders and nonbreeders become behaviorally and morphologically distinct. While differences in behavior and growth between breeders and nonbreeders have been extensively described, little is known of their molecular underpinnings. Here, we investigate the consequences of breeding for skeletal morphology and gene regulation in highly cooperative Damaraland mole-rats. By experimentally assigning breeding ‘queen’ status versus nonbreeder status to age-matched littermates, we confirm that queens experience vertebral growth that likely confers advantages to fecundity. However, they also up-regulate bone resorption pathways and show reductions in femoral mass, which predicts increased vulnerability to fracture. Together, our results show that, as in eusocial insects, reproductive division of labor in mole-rats leads to gene regulatory rewiring and extensive morphological plasticity. However, in mole-rats, concentrated reproduction is also accompanied by costs to bone strength.

scholarly journals Morphological and genomic shifts in mole-rat 'queens' increase fecundity but reduce skeletal integrity

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Rachel A Johnston ◽  
Philippe Vullioud ◽  
Jack Thorley ◽  
Henry Kirveslahti ◽  
Leyao Shen ◽  
...  
Keyword(s):  
Division Of Labor ◽  
Morphological Plasticity ◽  
Skeletal Morphology ◽  
Eusocial Insects ◽  
Mole Rat ◽  
Gene Regulatory ◽  
Reproductive Division Of Labor ◽  
Reproductive Division ◽  
Skeletal Integrity ◽  
Vertebral Growth

In some mammals and many social insects, highly cooperative societies are characterized by reproductive division of labor, in which breeders and nonbreeders become behaviorally and morphologically distinct. While differences in behavior and growth between breeders and nonbreeders have been extensively described, little is known of their molecular underpinnings. Here, we investigate the consequences of breeding for skeletal morphology and gene regulation in highly cooperative Damaraland mole-rats. By experimentally assigning breeding 'queen' status versus nonbreeder status to age-matched littermates, we confirm that queens experience vertebral growth that likely confers advantages to fecundity. However, they also up-regulate bone resorption pathways and show reductions in femoral mass, which predicts increased vulnerability to fracture. Together, our results show that, as in eusocial insects, reproductive division of labor in mole-rats leads to gene regulatory rewiring and extensive morphological plasticity. However, in mole-rats, concentrated reproduction is also accompanied by costs to bone strength.

scholarly journals Experimental increase of worker diversity benefits brood production in ants

2021 ◽  
Author(s):  
Marina N. Psalti ◽  
Dustin Gohlke ◽  
Romain Libbrecht
Keyword(s):  
Division Of Labor ◽  
Genetic Relatedness ◽  
Lasius Niger ◽  
Brood Production ◽  
Eusocial Insects ◽  
Colony Performance ◽  
Positive Correlations ◽  
Reproductive Division Of Labor ◽  
Reproductive Division ◽  
Eusocial Species

AbstractThe reproductive division of labor of eusocial insects, whereby one or several queens monopolize reproduction, evolved in a context of high genetic relatedness. However, many extant eusocial species have developed strategies that decrease genetic relatedness in their colonies, suggesting some benefits of the increased diversity. Multiple studies support this hypothesis by showing positive correlations between genetic diversity and colony fitness, as well as finding effects of experimental manipulations of diversity on colony performance. However, alternative explanations could account for most of these reports, and the benefits of diversity on fitness in eusocial insects still await validation. In this study, we experimentally increased worker diversity in the ant Lasius niger while controlling for typical confounding factors. We found that experimental colonies composed of workers coming from three different source colonies produced more larvae and showed more variation in size compared to groups of workers coming from a single colony. We propose that the benefits of increased diversity stemmed from an improved division of labor. Our study confirms that worker diversity enhances colony performance, thus providing a possible explanation for the evolution of multiply mated queens and multiple-queen colonies in many species of eusocial insects.

scholarly journals Experimental increase of worker diversity benefits brood production in ants

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Marina N. Psalti ◽  
Dustin Gohlke ◽  
Romain Libbrecht
Keyword(s):  
Division Of Labor ◽  
Genetic Relatedness ◽  
Lasius Niger ◽  
Brood Production ◽  
Eusocial Insects ◽  
Colony Performance ◽  
Positive Correlations ◽  
Reproductive Division Of Labor ◽  
Reproductive Division ◽  
Eusocial Species

Abstract Background The reproductive division of labor of eusocial insects, whereby one or several queens monopolize reproduction, evolved in a context of high genetic relatedness. However, many extant eusocial species have developed strategies that decrease genetic relatedness in their colonies, suggesting some benefits of the increased diversity. Multiple studies support this hypothesis by showing positive correlations between genetic diversity and colony fitness, as well as finding effects of experimental manipulations of diversity on colony performance. However, alternative explanations could account for most of these reports, and the benefits of diversity on performance in eusocial insects still await validation. In this study, we experimentally increased worker diversity in small colonies of the ant Lasius niger while controlling for typical confounding factors. Results We found that experimental colonies composed of workers coming from three different source colonies produced more larvae and showed more variation in size compared to groups of workers coming from a single colony. Conclusions We propose that the benefits of increased diversity stemmed from an improved division of labor. Our study confirms that worker diversity enhances colony performance, thus providing a possible explanation for the evolution of multiply mated queens and multiple-queen colonies in many species of eusocial insects.

scholarly journals Chemical Variation among Castes, Female Life Stages and Populations of the Facultative Eusocial Sweat Bee Halictus rubicundus (Hymenoptera: Halictidae)

2021 ◽  
Author(s):  
Iris Steitz ◽  
Robert J Paxton ◽  
Stefan Schulz ◽  
Manfred Ayasse
Keyword(s):  
Chemical Communication ◽  
North American ◽  
Specific Chemical ◽  
Eusocial Insects ◽  
Queen Signal ◽  
Ovarian Activation ◽  
Chemical Profiles ◽  
Reproductive Division Of Labor ◽  
Reproductive Division ◽  
Eusocial Species

AbstractIn eusocial insects, chemical communication is crucial for mediating many aspects of social activities, especially the regulation of reproduction. Though queen signals are known to decrease ovarian activation of workers in highly eusocial species, little is known about their evolution. In contrast, some primitively eusocial species are thought to control worker reproduction through physical aggression by the queen rather than via pheromones, suggesting the evolutionary establishment of chemical signals with more derived sociality. However, studies supporting this hypothesis are largely missing. Socially polymorphic halictid bees, such as Halictus rubicundus, with social and solitary populations in both Europe and North America, offer excellent opportunities to illuminate the evolution of caste-specific signals. Here we compared the chemical profiles of social and solitary populations from both continents and tested whether (i) population or social level affect chemical dissimilarity and whether (ii) caste-specific patterns reflect a conserved queen signal. Our results demonstrate unique odor profiles of European and North American populations, mainly due to different isomers of n-alkenes and macrocyclic lactones; chemical differences may be indicative of phylogeographic drift in odor profiles. We also found common compounds overproduced in queens compared to workers in both populations, indicating a potential conserved queen signal. However, North American populations have a lower caste-specific chemical dissimilarity than European populations which raises the question if both use different mechanisms of regulating reproductive division of labor. Therefore, our study gives new insights into the evolution of eusocial behavior and the role of chemical communication in the inhibition of reproduction.

scholarly journals Topological constraints in early multicellularity favor reproductive division of labor

2019 ◽  
Author(s):  
David Yanni ◽  
Shane Jacobeen ◽  
Pedro Márquez-Zacarías ◽  
Joshua S Weitz ◽  
William C. Ratcliff ◽  
...  
Keyword(s):  
Division Of Labor ◽  
Resource Sharing ◽  
Evolutionary Biology ◽  
Large Body ◽  
Concave Function ◽  
Cellular Interactions ◽  
Wide Range ◽  
Classical Models ◽  
Reproductive Division Of Labor ◽  
Reproductive Division

Reproductive division of labor (e.g., germ-soma specialization) is a hallmark of the evolution of multicellularity, signifying the emergence of a new type of individual and facilitating the evolution of increased organismal complexity. A large body of work from evolutionary biology, economics, and ecology has shown that specialization is beneficial when further division of labor produces an accelerating increase in absolute productivity (i.e., productivity is a convex function of specialization). Here we show that reproductive specialization is qualitatively different from classical models of resource sharing, and can evolve even when the benefits of specialization are saturating (i.e., productivity is a concave function of specialization). Through analytical theory and evolutionary individual based simulations, our work demonstrates that reproductive specialization is strongly favored in sparse networks of cellular interactions, such as trees and filaments, that reflect the morphology of early, simple multicellular organisms, highlighting the importance of restricted social interactions in the evolution of reproductive specialization. More broadly, we find that specialization is strongly favored, despite saturating returns on investment, in a wide range of scenarios in which sharing is asymmetric.

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