Search

The shift to a pollen diet and the evolution of more highly organized societies, i.e. eusocial, were key milestones in bee diversification over their evolutionary history, culminating in a high dependence on feeding broods with a large variety of floral resources. Here, we hypothesized that obligatory eusocial bees have a wider diet diversity than their relatives with solitary lifestyles, and this would be related to colony size. To test both hypotheses, we surveyed diet breadth data (palynological analysis) based on the Shannon–Wiener index (Hʹ) for 85 bee taxa. We also obtained colony size for 47 eusocial bee species. These data were examined using phylogenetic comparative methods. The results support the generalist strategy as a derived trait for the bee taxa evaluated here. The dietary diversity of eusocial bees (Hʹ: 2.1, on average) was 67.5% higher than that of noneusocial bees (Hʹ: 1.21, on average). There was, however, no relationship between diet breadth and colony size, indicating that smaller colonies can harvest a pollen variety as diverse as larger colonies. Taken together, these results provide new insights into the impact of lifestyle on the diversity of collected pollen. Furthermore, this work sheds light on an advantage of living in more highly structured societies irrespective of the size of the colony. [ABSTRACT FROM AUTHOR]

Social insect reproductives and non‐reproductives represent ideal models with which to understand the expression and regulation of alternative phenotypes. Most research in this area has focused on the developmental regulation of reproductive phenotypes in obligately social taxa such as honey bees, while relatively few studies have addressed the molecular correlates of reproductive differentiation in species in which the division of reproductive labour is established only in plastic dominance hierarchies. To address this knowledge gap, we generate the first genome for any stenogastrine wasp and analyse brain transcriptomic data for non‐reproductives and reproductives of the facultatively social species Liostenogaster flavolineata, a representative of one of the simplest forms of social living. By experimentally manipulating the reproductive 'queues' exhibited by social colonies of this species, we show that reproductive division of labour in this species is associated with transcriptomic signatures that are more subtle and variable than those observed in social taxa in which colony living has become obligate; that variation in gene expression among non‐reproductives reflects their investment into foraging effort more than their social rank; and that genes associated with reproductive division of labour overlap to some extent with those underlying division of labour in the separate polistine origin of wasp sociality but only explain a small portion of overall variation in this trait. These results indicate that broad patterns of within‐colony transcriptomic differentiation in this species are similar to those in Polistinae but offer little support for the existence of a strongly conserved 'toolkit' for sociality. [ABSTRACT FROM AUTHOR]

The coexistence of multiple reproductives in eusocial insects is widespread, yet the decisions leading to additional queen acceptance are not well understood. Unlike in vertebrates, acceptance decisions are likely controlled by the more numerous helper population rather than the parent reproductive. Yet there are likely to be queen-worker differences in acceptance criteria because workers and queens differ in their relatedness to a secondary queen. We develop a model that examines queen-worker conflict in two scenarios: accepting a queen's sister or daughter. We additionally ask how the mating frequency and split sex ratios affect the outcomes of these conflicts. Our results reveal that conflict over queen acceptance is highest in monandrous mating systems. We identify a "window of conflict" in which a queen is selected to accept her sister but her workers do not. Our result, that polyandry neutralizes conflict over acceptance thresholds, suggests that conflict suppression may be an additional contributor to the maintenance of polyandrous mating systems. [ABSTRACT FROM AUTHOR]

Evolutionary psychology (EP) has become an important metatheory over the past three decades. EP is centered upon Darwin's theory of natural selection and how this process has played an important role in the development of the human brain and behavior. Evolutionary psychology attempts to explain biological phenomena in terms of evolutionary forces, in this case brain structure and function, which directly impacts human behavior. There has been a remarkable increase in empirical evidence in regards to the merits of this theory and it has been able to partially explain certain features of aggression, sexual behavior, anxiety, depression, and numerous other aspects of cognition, emotions, and psychopathology. This literature review examines the origins, actors, principles, and evidence in the development of this theory and how evolutionary psychology can be applied to the social work profession. [ABSTRACT FROM AUTHOR]

In the first description of evolution, the fundamental mechanism is the natural selection favoring the individuals best suited for survival and reproduction (selection at the individual level or classical Darwinian selection). However, this is a very reductive description of natural selection that does not consider or explain a long series of known phenomena, including those in which an individual sacrifices or jeopardizes his life on the basis of genetically determined mechanisms (i.e., phenoptosis). In fact, in addition to (i) selection at the individual level, it is essential to consider other types of natural selection such as those concerning: (ii) kin selection and some related forms of group selection; (iii) the interactions between the innumerable species that constitute a holobiont; (iv) the origin of the eukaryotic cell from prokaryotic organisms; (v) the origin of multicellular eukaryotic organisms from unicellular organisms; (vi) eusociality (e.g., in many species of ants, bees, termites); (vii) selection at the level of single genes, or groups of genes; (viii) the interactions between individuals (or more precisely their holobionts) of the innumerable species that make up an ecosystem. These forms of natural selection, which are all effects and not violations of the classical Darwinian selection, also show how concepts as life, species, individual, and phenoptosis are somewhat not entirely defined and somehow arbitrary. Furthermore, the idea of organisms selected on the basis of their survival and reproduction capabilities is intertwined with that of organisms also selected on the basis of their ability to cooperate and interact, even by losing their lives or their distinct identities. [ABSTRACT FROM AUTHOR]

The standard evolutionary theory of aging predicts a negative relationship (trade-off) between fecundity and longevity. However, in principle, the fecundity–longevity relationship can become positive in populations in which individuals have unequal resources. Positive fecundity–longevity relationships also occur in queens of eusocial insects such as ants and bees. Developmental diet is likely to be central to determining trade-offs as it affects key fitness traits, but its exact role remains uncertain. For example, in Drosophila melanogaster , changes in adult diet can affect fecundity, longevity, and gene expression throughout life, but it is unknown how changes in developmental (larval) diet affect fecundity–longevity relationships and gene expression in adults. Using D. melanogaster , we tested the hypothesis that varying developmental diets alters the directionality of fecundity–longevity relationships in adults, and characterized associated gene expression changes. We reared larvae on low (20%), medium (100%), and high (120%) yeast diets, and transferred adult females to a common diet. We measured fecundity and longevity of individual adult females and profiled gene expression changes with age. Adult females raised on different larval diets exhibited fecundity–longevity relationships that varied from significantly positive to significantly negative, despite minimal differences in mean lifetime fertility or longevity. Treatments also differed in age-related gene expression, including for aging-related genes. Hence, the sign of fecundity–longevity relationships in adult insects can be altered and even reversed by changes in larval diet quality. By extension, larval diet differences may represent a key mechanistic factor underpinning positive fecundity–longevity relationships observed in species such as eusocial insects. [ABSTRACT FROM AUTHOR]

In evolutionary terms, life is about reproduction. Yet, in some species, individuals forgo their own reproduction to support the reproductive efforts of others. Social insect colonies for example, can contain up to a million workers that actively cooperate in tasks such as foraging, brood care and nest defence, but do not produce offspring. In such societies the division of labour is pronounced, and reproduction is restricted to just one or a few individuals, most notably the queen(s). This extreme eusocial organisation exists in only a few mammals, crustaceans and insects, but strikingly, it evolved independently up to nine times in the order Hymenoptera (including ants, bees and wasps). Transitions from a solitary lifestyle to an organised society can occur through natural selection when helpers obtain a fitness benefit from cooperating with kin, owing to the indirect transmission of genes through siblings. However, this process, called kin selection, is vulnerable to parasitism and opportunistic behaviours from unrelated individuals. An ability to distinguish kin from non‐kin, and to respond accordingly, could therefore critically facilitate the evolution of eusociality and the maintenance of non‐reproductive workers. The question of how the hymenopteran brain has adapted to support this function is therefore a fundamental issue in evolutionary neuroethology. Early neuroanatomical investigations proposed that social Hymenoptera have expanded integrative brain areas due to selection for increased cognitive capabilities in the context of processing social information. Later studies challenged this assumption and instead pointed to an intimate link between higher social organisation and the existence of developed sensory structures involved in recognition and communication. In particular, chemical signalling of social identity, known to be mediated through cuticular hydrocarbons (CHCs), may have evolved hand in hand with a specialised chemosensory system in Hymenoptera. Here, we compile the current knowledge on this recognition system, from emitted identity signals, to the molecular and neuronal basis of chemical detection, with particular emphasis on its evolutionary history. Finally, we ask whether the evolution of social behaviour in Hymenoptera could have driven the expansion of their complex olfactory system, or whether the early origin and conservation of an olfactory subsystem dedicated to social recognition could explain the abundance of eusocial species in this insect order. Answering this question will require further comparative studies to provide a comprehensive view on lineage‐specific adaptations in the olfactory pathway of Hymenoptera. [ABSTRACT FROM AUTHOR]

La relación de los pueblos mayas con las abejas es una realidad viva y vigente que tiene una profundidad temporal que abarca al menos los últimos dos mil años. Es fruto de la observación detallada y cuidadosa de distintos insectos eusociales que producen miel, principalmente de las abejas nativas (Meliponini) y de su entorno. [ABSTRACT FROM AUTHOR]

Reproductive skew and variance in reproductive success describe uneven distributions of reproduction where disparity is extreme or smaller in extent, respectively, but remains relevant. Theoretical reproductive skew models often assume allocation of reproduction under dominant control. We propose to revert this view and consider a bilateral decision rather than a top-down manipulation. Strategic self-regulation of reproduction represents an evolutionary stable and parsimonious resolution of the conflict, where each individual makes reproductive decisions based on current social/ecological conditions. Less successful breeders can still gain indirect and/or future benefits. We describe a unifying framework for understanding the uneven sharing of reproduction in animals from invertebrates to vertebrates, and from separate-sex animals to sequential and simultaneous hermaphrodites. Traditionally, dominant breeders have been considered to be able to control the reproduction of other individuals in multimember groups that have high variance in reproductive success/reproductive skew (e.g., forced sterility/coercion of conspecifics in eusocial animals; sex-change suppression in sequential hermaphrodites). These actions are typically presented as active impositions by reproductively dominant individuals. However, how can individuals regulate the reproductive physiology of others? Alternatively, all contestants make reproductive decisions, and less successful individuals self-downregulate reproduction in the presence of dominant breeders. Shifting perspective from a top-down manipulation to a broader view, which includes all contenders, and using a multitaxon approach, we propose a unifying framework for the resolution of reproductive skew conflicts based on signalling rather than control, along a continuum of levels of strategic regulation of reproduction. [ABSTRACT FROM AUTHOR]

Background: Venoms, which have evolved numerous times in animals, are ideal models of convergent trait evolution. However, detailed genomic studies of toxin-encoding genes exist for only a few animal groups. The hyper-diverse hymenopteran insects are the most speciose venomous clade, but investigation of the origin of their venom genes has been largely neglected. Results: Utilizing a combination of genomic and proteo-transcriptomic data, we investigated the origin of 11 toxin genes in 29 published and 3 new hymenopteran genomes and compiled an up-to-date list of prevalent bee venom proteins. Observed patterns indicate that bee venom genes predominantly originate through single gene co-option with gene duplication contributing to subsequent diversification. Conclusions: Most Hymenoptera venom genes are shared by all members of the clade and only melittin and the new venom protein family anthophilin1 appear unique to the bee lineage. Most venom proteins thus predate the mega-radiation of hymenopterans and the evolution of the aculeate stinger. [ABSTRACT FROM AUTHOR]

Conflict and conflict resolution have been argued to be fundamental to the major transitions in evolution. These were key events in life's history in which previously independently living individuals cooperatively formed a higher-level individual, such as a multicellular organism or eusocial colony. Conflict has its central role because, to proceed stably, the evolution of individuality in each major transition required within-individual conflict to be held in check. This review revisits the role of conflict and conflict resolution in the major transitions, addressing recent work arguing for a minor role. Inclusive fitness logic suggests that differences between the kin structures of clones and sexual families support the absence of conflict at the origin of multicellularity but, by contrast, suggest that key conflicts existed at the origin of eusociality. A principal example is conflict over replacing the founding queen (queen replacement). Following the origin of each transition, conflict remained important, because within-individual conflict potentially disrupts the attainment of maximal individuality (organismality) in the system. The conclusion is that conflict remains central to understanding the major transitions, essentially because conflict arises from differences in inclusive fitness optima while conflict resolution can help the system attain a high degree of coincidence of inclusive fitness interests. [ABSTRACT FROM AUTHOR]

Eusocial insects divide labor between reproductive and non-reproductive individuals. The molecular mechanisms underlying the evolution of these castes have remained mysterious. A comparative genomic study of sweat bees points to a familiar factor as a regulator of behavioral specialization: juvenile hormone. [ABSTRACT FROM AUTHOR]

Background: The standard evolutionary theory of ageing proposes that ageing occurs because of a trade-off between reproduction and longevity. Eusocial insect queens exhibit positive fecundity-longevity associations and so have been suggested to be counter-examples through not expressing costs of reproduction and through remodelling conserved genetic and endocrine networks regulating ageing and reproduction. If so, eusocial evolution from solitary ancestors with negative fecundity-longevity associations must have involved a stage at which costs of reproduction were suppressed and fecundity and longevity became positively associated. Using the bumblebee (Bombus terrestris), we experimentally tested whether queens in annual eusocial insects at an intermediate level of eusocial complexity experience costs of reproduction, and, using mRNA-seq, the extent to which they exhibit a remodelling of relevant genetic and endocrine networks. Specifically, we tested whether costs of reproduction are present but latent, or whether a remodelling of relevant genetic and endocrine networks has already occurred allowing queens to reproduce without costs. Results: We experimentally increased queens’ costs of reproduction by removing their eggs, which caused queens to increase their egg-laying rate. Treatment queens had significantly reduced longevity relative to control queens whose egg-laying rate was not increased. Reduced longevity in treatment queens was not caused by increased worker-to-queen aggression or by increased overall activity in queens. In addition, treatment and control queens differed in age-related gene expression based on mRNA-seq in both their overall expression profiles and the expression of ageing-related genes. Remarkably, these differences appeared to occur principally with respect to relative age, not chronological age. Conclusions: This study represents the first simultaneously phenotypic and transcriptomic experimental test for a longevity cost of reproduction in eusocial insect queens. The results support the occurrence of costs of reproduction in annual eusocial insects of intermediate social complexity and suggest that reproductive costs are present but latent in queens of such species, i.e. that these queens exhibit condition-dependent positive fecundity-longevity associations. They also raise the possibility that a partial remodelling of genetic and endocrine networks underpinning ageing may have occurred in intermediately eusocial species such that, in unmanipulated conditions, age-related gene expression depends more on chronological than relative age. [ABSTRACT FROM AUTHOR]

Eusociality in insects has evolved independently many times. One of the most notable characteristics of eusociality is the reproductive division of labor. In social insects, the reproductive division of labor is accomplished by queens and workers. Transcriptome analyses of queens and workers have been conducted for various eusocial species. However, the genes that regulate the reproductive division of labor across all or multiple eusocial species have not yet been fully elucidated. Therefore, we conducted a meta-analysis using publicly available RNA-sequencing data from four major groups of social insects. In this meta-analysis, we collected 258 pairs (queen vs. worker) of RNA-sequencing data from 34 eusocial species. The meta-analysis identified a total of 20 genes that were differentially expressed in queens or workers. Out of these, 12 genes have not previously been reported to be involved in the reproductive division of labor. Functional annotation of these 20 genes in other organisms revealed that they could be regulators of behaviors and physiological states related to the reproductive division of labor. These 20 genes, revealed using massive datasets of numerous eusocial insects, may be key regulators of the reproductive division of labor. [ABSTRACT FROM AUTHOR]

Genomic imprinting is known from flowering plants and mammals but has not been confirmed for the Hymenoptera even though the eusocial Hymenoptera are prime candidates for this peculiar form of gene expression. Here, the kin selection theory of genomic imprinting is reviewed and applied to the eusocial Hymenoptera. The evidence for imprinting in eusocial Hymenoptera with the typical mode of reproduction, involving the sexual production of diploid female offspring, which develop into workers or gynes, and the arrhenotokous parthenogenesis of haploid males, is also reviewed briefly. However, the focus of this review is how atypical modes of reproduction, involving thelytokous parthenogenesis, hybridisation and androgenesis, may also select for imprinting. In particular, naturally occurring hybridisation in several genera of ants may provide useful tests of the role of kin selection in the evolution of imprinting. Hybridisation is expected to disrupt the coadaptation of antagonistically imprinted loci, and thus affect the phenotypes of hybrids. Some of the limited data available on hybrid worker reproduction and on colony sex ratios support predictions about patterns of imprinting derived from kin selection theory. [ABSTRACT FROM AUTHOR]

Termites (Insecta, Blattodea, Termitoidae) are a widespread and diverse group of eusocial insects known for their ability to digest wood matter. Herein, we report the draft genome of the subterranean termite Reticulitermes lucifugus, an economically important species and among the most studied taxa with respect to eusocial organization and mating system. The final assembly (~813 Mb) covered up to 88% of the estimated genome size and, in agreement with the Asexual Queen Succession Mating System, it was found completely homozygous. We predicted 16,349 highly supported gene models and 42% of repetitive DNA content. Transposable elements of R. lucifugus show similar evolutionary dynamics compared to that of other termites, with two main peaks of activity localized at 25% and 8% of Kimura divergence driven by DNA, LINE and SINE elements. Gene family turnover analyses identified multiple instances of gene duplication associated with R. lucifugus diversification, with significant lineage‐specific gene family expansions related to development, perception and nutrient metabolism pathways. Finally, we analysed P450 and odourant receptor gene repertoires in detail, highlighting the large diversity and dynamical evolutionary history of these proteins in the R. lucifugus genome. This newly assembled genome will provide a valuable resource for further understanding the molecular basis of termites biology as well as for pest control. [ABSTRACT FROM AUTHOR]

That humans might undergo future evolutionary transitions in individuality (ETIs) seems fanciful. However, drawing upon recent thinking concerning the origins of properties that underpin ETIs, I argue that certain ETIs are imminently realizable. Central to my argument is recognition that heritable variance in fitness at higher levels of organization can be externally imposed (scaffolded) by specific ecological structures and cultural practices. While ETIs to eusociality seem highly improbable, ETIs involving symbioses between humans and artificial intelligence (AI) can be readily envisaged. A necessary requirement is that fitness-affecting interactions between humans and AI devices are inherited by offspring. The Mendelian nature of human reproduction ensures that offspring resemble parents. Reproduction of AI devices requires nothing more than transference of algorithms from parental AI devices to devices that are assigned to offspring. This simple copying, combined with societal structures that require humans to carry AI devices, ensures heritable variance in fitness at the level of both interacting partners. Selection at the collective level will drive alignment of replicative fates and increase co-dependency, thus alleviating need for continual imposition of externally imposed scaffolds. I conclude by drawing attention to the immediacy of such transitions and express concern over possibilities for malevolent manipulation. [ABSTRACT FROM AUTHOR]

Simple Summary: The naked mole-rat is a small, long-lived mammal that lives in large colonies in subterranean burrows. The lifestyle of naked mole-rats makes their study difficult, and many details about their biology remain enigmatic. For evolutionary biologists and ecologists, a special trait exhibited by this species, their eusocial lifestyle, is of particular interest. In this study, we explored the determinants of early offspring survival using data from observations of 14 captive colonies over a total period of seven years. Our study revealed that early pup survival was significantly improved by higher pup body mass and maternal number of mammae and significantly reduced by increased maternal body mass and colony size. The latter negative effect may, however, be an artifact of the captive conditions in which colonies were kept. We further discuss the implications of the similarities and differences of naked mole-rats to eusocial insects and cooperatively breeding mammals in these determinants to shed light on the origin and maintenance of eusociality in mammals. In eusocial insects, offspring survival strongly depends on the quality and quantity of non-breeders. In contrast, the influence of social factors on offspring survival is more variable in cooperatively breeding mammals since maternal traits also play an important role. This difference between cooperative insects and mammals is generally attributed to the difference in the level of sociality. Examining offspring survival in eusocial mammals should, therefore, clarify to what extent social organization and taxonomic differences determine the relative contribution of non-breeders and maternal effects to offspring survival. Here, we present the first in-depth and long-term study on the influence of individual, maternal, social and environmental characteristics on early offspring survival in a eusocial breeding mammal, the naked mole-rat (Heterocephalus glaber). Similarly to other mammals, pup birth mass and maternal characteristics such as body mass and the number of mammae significantly affected early pup survival. In this eusocial species, the number of non-breeders had a significant influence on early pup survival, but this influence was negative—potentially an artifact of captivity. By contrasting our findings with known determinants of survival in eusocial insects we contribute to a better understanding of the origin and maintenance of eusociality in mammals. [ABSTRACT FROM AUTHOR]

Simple Summary: Termites are eusocial insects that live in large colonies made up of queens, kings, workers, and soldiers. Queens and kings start new colonies and continually reproduce. Workers are responsible for many crucial roles, including colony husbandry, foraging, and nest construction. Soldiers are adapted for colony defense, usually with large heads and mandibles to ward off predators, but their defensive adaptations prevent them from caring for themselves or performing tasks within the nest. The soldiers of some termite species participate in foraging, either directly by scouting food sources and recruiting workers, or indirectly by influencing worker foraging behavior through their presence. Colonies of the Formosan subterranean termite maintain relatively large soldier proportions compared to termites in their invasive range, but the potential soldier influence on foraging workers has not yet been studied. Since the soldiers of other termite species can influence food exploration, we hypothesized that soldier presence also influences foraging behavior in this species. We compared the exploratory behavior of foraging groups of 100 workers and either 0, 2, 10, or 30 soldiers to determine whether soldier concentration influenced tunnel complexity, tunnel speed, food location, or food collection. In the context of this study, soldier presence did not influence worker foraging behavior, which suggests that workers of the Formosan subterranean termite can maintain foraging efficiency regardless of fluctuations in soldier presence. Termites are eusocial insects that live in organized colonies consisting of reproductives, workers, and soldiers. Soldiers are specialized for defense but are expensive to maintain, as they are incapable of husbandry and must be fed and groomed by workers. The soldiers of several species influence foraging behavior by acting as scouts that initiate foraging or by mediating worker behavioral plasticity during food exploration. These behaviors imply that soldiers may play a keystone role in termite colony function, apart from defense. Subterranean termite workers tunnel through soil in search of food while accompanied by varying proportions of soldiers, depending on the species and colony conditions. Previous studies have shown that soldiers accelerate worker exploratory tunneling behavior in two Reticulitermes species, the colonies of which contain fewer than 2% soldiers. This effect, however, is unknown in other subterranean species with different soldier proportions. In this study, we examined the influence of soldiers on exploratory foraging behavior in the Formosan subterranean termite, Coptotermes formosanus Shiraki, which is an economically devastating invasive species that maintains a relatively high soldier proportion (about 10%). When 100 foraging workers were grouped with 0, 2, 10, or 30 soldiers in two-dimensional foraging arenas, we found no significant effect of soldiers on the tunnel length, branch pattern, food source interception, or food collected within 96 h. These results suggest that C. formosanus colonies maintain food exploration efficiency regardless of soldier proportion variation. [ABSTRACT FROM AUTHOR]

How the role of dopamine differs according to the evolution of eusociality and how it is required in the flexible society of Polistes paper wasps need further clarification. In the present study, we compared the storage and usage of dopamine-related substances in brains between the castes of paper wasps. The head widths, lipid stores in the abdomen, and levels of biogenic amines in the brains were measured in newly emerged females before male emergence (workers) and after male emergence (gynes) in four Polistes species. The head widths and the lipid stores were significantly larger in gynes than workers in P. snelleni, P. rothneyi, and P. jokahamae, whereas they did not differ between castes in P. chinensis. The levels of dopamine precursors in the brains were significantly higher in gynes than workers in P. snelleni, P. chinensis, and P. rothneyi, whereas those of dopamine and its metabolites did not differ between castes in these species. In P. jokahamae, the levels of dopamine precursors and dopamine in the brains did not differ between castes, but those of a dopamine metabolite were significantly higher in gynes than workers. Thus, the caste differences in the levels of dopamine-related substances did not always match body sizes and nutritional reserves. Foundresses in P. rothneyi had significantly lower levels of dopamine precursors and higher levels of dopamine and its metabolite than newly emerged gynes. These results suggested that in several Polistes species, dopamine precursors were stored in the brain without dopamine biosynthesis at emergence, and then converted into dopamine in foundresses during colony founding. These neuroendocrinal states in Polistes species largely differed from those in eusocial bees. [ABSTRACT FROM AUTHOR]

Termites (Blattodea: Isoptera) have evolved specialized defensive strategies for colony protection. Alarm communication enables workers to escape threats while soldiers are recruited to the source of disturbance. Here, we study the vibroacoustic and chemical alarm communication in the wood roach Cryptocercus and in 20 termite species including seven of the nine termite families, all life-types, and all feeding and nesting habits. Our multidisciplinary approach shows that vibratory alarm signals represent an ethological synapomorphy of termites and Cryptocercus. In contrast, chemical alarms have evolved independently in several cockroach groups and at least twice in termites. Vibroacoustic alarm signaling patterns are the most complex in Neoisoptera, in which they are often combined with chemical signals. The alarm characters correlate to phylogenetic position, food type and hardness, foraging area size, and nesting habits. Overall, species of Neoisoptera have developed the most sophisticated communication system amongst termites, potentially contributing to their ecological success. The vibroacoustic and chemical alarm communication in the wood roach Cryptocercus and in 20 termite species are studied to reveal that the Neoisoptera species have developed the most sophisticated communication system, which could contribute towards their ecological success. [ABSTRACT FROM AUTHOR]

Background: Eusociality is widely considered to evolve through kin selection, where the reproductive success of an individual's close relative is favored at the expense of its own. High genetic relatedness is thus considered a prerequisite for eusociality. While ants are textbook examples of eusocial animals, not all ants form colonies of closely related individuals. One such example is the ectatommine ant Rhytidoponera metallica, which predominantly forms queen-less colonies that have such a low intra-colony relatedness that they have been proposed to represent a transient, unstable form of eusociality. However, R. metallica is among the most abundant and widespread ants on the Australian continent. This apparent contradiction provides an example of how inclusive fitness may not by itself explain the maintenance of eusociality and raises the question of what other selective advantages maintain the eusocial lifestyle of this species. Results: We provide a comprehensive portrait of the venom of R. metallica and show that the colony-wide venom consists of an exceptionally high diversity of functionally distinct toxins for an ant. These toxins have evolved under strong positive selection, which is normally expected to reduce genetic variance. Yet, R. metallica exhibits remarkable intra-colony variation, with workers sharing only a relatively small proportion of toxins in their venoms. This variation is not due to the presence of chemical castes, but has a genetic foundation that is at least in part explained by toxin allelic diversity. Conclusions: Taken together, our results suggest that the toxin diversity contained in R. metallica colonies may be maintained by a form of group selection that selects for colonies that can exploit more resources and defend against a wider range of predators. We propose that increased intra-colony genetic variance resulting from low kinship may itself provide a selective advantage in the form of an expanded pharmacological venom repertoire. These findings provide an example of how group selection on adaptive phenotypes may contribute to maintaining eusociality where a prerequisite for kin selection is diminished. [ABSTRACT FROM AUTHOR]

The neotropical apoid wasp genus Microstigmus is of particular interest biologically because it represents an origin of eusociality independent of vespid wasps and bees, and is part of the only eusocial lineage among the approximately 10,000 solitary species of apoid wasps. Females construct nests made of silk and the species exhibit an unusual diversity of nesting strategies. However, research is hampered because many species remain undescribed and the basic nesting biology of only a few species is known. I describe three new species from north-west Ecuador related to M. bicolor Richards, including diagnostic morphological characters, altitudinal ranges and molecular data as well as descriptions of their nests and nesting biologies. M. rosae sp. nov. is a mass provisioner that preys on nymphal Thysanoptera, while M. lydiae sp. nov. and M. mirandae sp. nov. are progressive provisioners that prey on nymphal leafhoppers (Cicadellidae). Nests of all three species can contain multiple adult females but more than half of nests contain only a single female. [ABSTRACT FROM AUTHOR]

Termites are keystone species and play an essential role in the ecosystem by decomposing plants and wood materials with adapted endogenous and symbiotic cellulase systems to obtain food and energy. However, some termites are also pests that have significant economic impacts directly or indirectly on the agricultural system, such as pastures, orchards, nurseries, and eucalyptus forests, and globally the estimated loss is $40 billion annually. Recently, scientists have focused on RNAi technology to protect plants against insect pests, and the utilization of RNAi against termites is confounded because of their social nature and habitats. Many termite species transcriptomes and genome sequencing projects are currently underway, and the outputs open new avenues for the species-specific design of RNAi-based termiticides. With these genomes, symbiotic biological agents such as fungi, bacteria, viruses, and nematodes can be screened and evaluated to express RNAi bioactive molecules (dsRNA, siRNA, and shRNA). In parallel, dsRNA/siRNA can also be delivered through nanocarriers against termites. In this perspective, we highlight existing RNAi-based functional genomic studies against eusocial termite pests and further discuss the prospects for RNAi-termiticides, considering unique challenges in terms of dsRNA delivery, target efficiency, environmental risks and termite eusociality. [ABSTRACT FROM AUTHOR]

The evolution of eusociality requires that individuals forgo some or all their own reproduction to assist the reproduction of others in their group, such as a primary egg-laying queen. A major open question is how genes and genetic pathways sculpt the evolution of eusociality, especially in rudimentary forms of sociality—those with smaller cooperative nests when compared with species such as honeybees that possess large societies. We lack comprehensive comparative studies examining shared patterns and processes across multiple social lineages. Here we examine the mechanisms of molecular convergence across two lineages of bees and wasps exhibiting such rudimentary societies. These societies consist of few individuals and their life histories range from facultative to obligately social. Using six species across four independent origins of sociality, we conduct a comparative meta-analysis of publicly available transcriptomes. Standard methods detected little similarity in patterns of differential gene expression in brain transcriptomes among reproductive and non-reproductive individuals across species. By contrast, both supervised machine learning and consensus co-expression network approaches uncovered sets of genes with conserved expression patterns among reproductive and non-reproductive phenotypes across species. These sets overlap substantially, and may comprise a shared genetic "toolkit" for sociality across the distantly related taxa of bees and wasps and independently evolved lineages of sociality. We also found many lineage-specific genes and co-expression modules associated with social phenotypes and possible signatures of shared life-history traits. These results reveal how taxon-specific molecular mechanisms complement a core toolkit of molecular processes in sculpting traits related to the evolution of eusociality. [ABSTRACT FROM AUTHOR]

Bees provide important ecosystem services and are subjects of extensive studies on their α‐diversity, which is generally calculated with indices that integrate the number of species with their abundances. Variation in social behaviour, though expected to impact genetic diversity, is still largely neglected in such studies.We propose a simple method to show how sociality may affect diversity indices, when a surrogate of genetic diversity is taken into account. This method weighs the number of sampled females (N) to obtain new abundance values (NW), by taking into account relevant biological traits affecting genetic structure of populations, that is, the number of (natal) nests from which the sampled females originated (which depends on brood productivity and sex ratio) and the genetic relatedness among such females.Solitary species tend to have greater NW than eusocial ones especially at larger sample sizes. Across studies on 121 bee communities, we found that Taxonomic distinctness, Shannon–Wiener diversity and Gini–Simpson dominance tended to be greater when based on NW rather than on N. Such differences increased in communities with decreasing number of eusocial species and with increasing proportion of individuals from eusocial species.The results suggest that taking into account the social organisation of wild bees may have important consequences in estimating α‐diversity, thus claiming for future efforts in collecting biological data on as many wild bee species as possible to improve the precision of NW estimations. For example, stressors affecting more solitary bees could impoverish communities dominated by few but abundant eusocial species, more than expected by using unweighted abundances. [ABSTRACT FROM AUTHOR]

In eusocial organisms, cooperative brood care within a colony represents a situation where the ancestral parental care duties have shifted away from the reproductive parent(s) towards their offspring. The shift to alloparental care was often instrumental in the initial emergence of eusociality, as it ultimately contributed to the establishment of the reproductive division of labour.Remarkably, eusocial taxa such as ants and termites, which still display an ancestral independent colony foundation phase, must go through an obligatory parental care period, as a temporary subsocial family unit. In termites specifically, an incipient colony inherently remains a woodroach family unit until alloparental care is established. Colony foundation success can then be limited by a series of factors that may include environmental, behavioural, symbiotic and physiological constraints.In this study, 450 incipient termite colonies (Coptotermes gestroi) were established to investigate the timing of physiological changes in founders during the transition from biparental to alloparental care. Results showed that the finite initial internal nutritional resources that alates carry during the dispersal flight are a primary limiting factor for successful colony establishment. The Coptotermes queen and king must rapidly establish (<150 days) their first cohort of offspring to reach alloparental care or simply run out of resources and die. Alates, therefore, carry just enough internal resources to produce the first few alloparents (< 15 workers) to prime the system towards colony ergonomic growth, with a definitive shift to solely reproductive functions.Eusocial insect primary reproductive traits were optimized for three successive functions within the life cycle of a colony: alate dispersal (sexual reproduction), colony foundation (parental care) and colony growth (increased egg production towards colony maturity). However, results suggest that trade‐offs involving these functions appear to primarily favour dispersal ones (quantity vs. quality of alates), as founder(s) carry minimal resources and have no room for parental care inefficiency and as they then fully rely on their alloparents for further reproductive output.The transition towards alloparental care during colony foundation of eusocial insects may, therefore, reflect on the initial evolutionary transition from ancestral subsociality to eusociality. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Same-sex sexual behaviours (SSBs) are widespread across the animal kingdom, yet little consensus exists regarding their potential adaptive functions or evolutionary history. To fully address questions such as why or how a trait has evolved, it is important to first understand its natural history. Here, we present evidence of SSBs in two male naked mole-rats for the first time. Due to extreme natal philopatry, most naked mole-rats never disperse, making encounters with potential mates valuable in fitness terms. However, in captive colonies of naked mole-rats, a rare disperser morph has been described. We speculate that such dispersing individuals may be indiscriminatory in their mating strategy, copulating with conspecifics regardless of sex, to counter the risk of missed reproductive opportunities. This behavioural strategy would contrast with the common characterisation of naked mole-rats, which describes them as fiercely xenophobic and hostile to unfamiliar individuals. Further, the observation of an indiscriminate mating strategy in a species with limited opportunities for dispersal provides interesting context for the study of the evolution of SSBs. [ABSTRACT FROM AUTHOR]

(1) Unravelling the molecular basis underlying major evolutionary transitions can shed light on how complex phenotypes arise. The evolution of eusociality, a major evolutionary transition, has been demonstrated to be accompanied by enhanced gene regulation. Numerous pieces of evidence suggest the major impact of transposon insertion on gene regulation and its role in adaptive evolution. Transposons have been shown to be play a role in gene duplication involved in the eusocial transition in termites. However, evidence of the molecular basis underlying the eusocial transition in Blattodea remains scarce. Could transposons have facilitated the eusocial transition in termites through shifts of gene expression? (2) Using available cockroach and termite genomes and transcriptomes, we investigated if transposons insert more frequently in genes with differential expression in queens and workers and if those genes could be linked to specific functions essential for eusocial transition. (3) The insertion rate of transposons differs among differentially expressed genes and displays opposite trends between termites and cockroaches. The functions of termite transposon-rich queen- and worker-biased genes are related to reproduction and ageing and behaviour and gene expression, respectively. (4) Our study provides further evidence on the role of transposons in the evolution of eusociality, potentially through shifts in gene expression. [ABSTRACT FROM AUTHOR]

Eusociality, where workers typically forfeit their own reproduction to assist their mothers in raising siblings, is a fundamental paradox in evolutionary biology. By sacrificing personal reproduction, helpers pay a significant cost, which must be outweighed by indirect fitness benefits of helping to raise siblings. In 1983, Jon Seger developed a model showing how in the haplodiploid Hymenoptera (ants, wasps and bees), a partially bivoltine life cycle with alternating sex ratios may have promoted the evolution of eusociality. Seger predicted that eusociality would be more likely to evolve in hymenopterans where a foundress produces a male-biased first brood sex ratio and a female-biased second brood. This allows first brood females to capitalize on super-sister relatedness through helping to produce the female-biased second brood. In Seger's model, the key factor driving alternating sex ratios was that first brood males survive to mate with females of both the second and the first brood, reducing the reproductive value of second brood males. Despite being potentially critical in the evolution of eusociality, however, male survivorship has received little empirical attention. Here, we tested whether first brood males survive across broods in the facultatively eusocial sweat bee Halictus rubicundus. We obtained high estimates of survival and, while recapture rates were low, at least 10% of first brood males survived until the second brood. We provide empirical evidence supporting Seger's model. Further work, measuring brood sex ratios and comparing abilities of first and second brood males to compete for fertilizations, is required to fully parameterize the model. [ABSTRACT FROM AUTHOR]

The past diversity of Isoptera is relatively poorly documented. Many early-diverging families are only represented today by relicts of their Mesozoic and Cenozoic richness. Therefore, the onset of their evolutionary history and the transitions between families, or even between subsocial and eusocial ways of life, remain difficult to decipher and require additional fossil occurrences. Here, we report the oldest worker/pseudergate trapped in amber and a new Mastotermitidae, both from Hkamti amber. We document a diverse assemblage of species representing early-diverging families from the 'Mid'-Cretaceous of Myanmar, including two new genera and four new species in as many different genera: Anisotermes bourguignoni sp. nov. , Longitermes pulcher gen. et sp. nov. , Magnifitermes krishnai gen. et sp. nov. and Mastotermes myanmarensis sp. nov. These descriptions provide significant morphological evidence to discuss the placement of the genus Anisotermes , confidently place the new genera and confirm the monophyly of Mastotermitidae. The diversity of Cretaceous isopterans, in light of the biology of their extant representatives, is used to discuss palaeoecological implications and highlights the radiation of early diverged Isoptera in the complex Cretaceous ecosystem. The validity of the species Meiatermes cretacicus is discussed. [ABSTRACT FROM AUTHOR]

Compared to many other biological disciplines, evolutionary biology has been rather slow to self-consciously assert and promulgate its practical value to society - even though evolutionary scientists have contributed to plant and animal breeding, agriculture more broadly, and epidemiology for about a century. Johnson illustrates the real practical value of evolutionary biology in describing possible control measures, including release of sterile male mosquitoes and especially gene drive (the widely used term for meiotic drive and segregation distortion). Also, in this chapter, Johnson revives Herbert Baker's analysis of the essential features of weeds, and updates it with a discussion of genome size. [Extracted from the article]

The article discusses the cellular aspects of gene flow and the evolution of sexuality. It explores the complex process of meiosis and how it contributes to genetic diversity. The article also examines different examples of gene flow in various organisms, including the Green Alga family Characeae, New World Maxillariinae orchids, and eusocial termites. These case studies highlight the control and regulation of gene flow in different species. Overall, the article emphasizes the importance of understanding the cellular mechanisms behind gene flow in order to comprehend the evolution of sexuality. [Extracted from the article]

The social Hymenoptera have contributed much to our understanding of the evolution of sensory systems. Attention has focussed chiefly on how sociality and sensory systems have evolved together. In the Hymenoptera, the antennal sensilla are important for optimizing the perception of olfactory social information. Social species have denser antennal sensilla than solitary species, which is thought to enhance social cohesion through nestmate recognition. In the current study, we test whether sensilla numbers vary between populations of the socially plastic sweat bee Halictus rubicundus from regions that vary in climate and the degree to which sociality is expressed. We found population differences in both olfactory and hygro/thermoreceptive sensilla numbers. We also found evidence that olfactory sensilla density is developmentally plastic: when we transplanted bees from Scotland to the south‐east of England, their offspring (which developed in the south) had more olfactory hairs than the transplanted individuals themselves (which developed in Scotland). The transplanted bees displayed a mix of social (a queen plus workers) and solitary nesting, but neither individual nor nest phenotype was related to sensilla density. We suggest that this general, rather than caste‐specific sensory plasticity provides a flexible means to optimize sensory perception according to the most pressing demands of the environment. Sensory plasticity may support social plasticity in H. rubicundus but does not appear to be causally related to it. [ABSTRACT FROM AUTHOR]

It is generally assumed that Cretaceous stem ants were obligately eusocial, because of the presence of wingless adult females, yet the available evidence is ambiguous. Here, we report the syninclusion of a pupa and adult of a stem ant species from Mid-Cretaceous amber. As brood are immobile, the pupa was likely to have been transported by an adult. Therefore, the fossil substantiates the hypothesis that wingless females were cooperators, thus these were true 'workers'. Re-examination of all described Cretaceous ant species reveals that winged–wingless diphenism – hence a variable dispersal capacity – may have been ancestral to the total clade of the ants, and that highly specialized worker-specific phenotypes evolved in parallel between the stem and crown groups. The soft-tissue preservation of the fossil is exceptional, demonstrating the possibility of analysing the development of the internal anatomy in stem ants. Based on the highest-resolution µ-CT scans of stem ants to date, we describe † Gerontoformica sternorhabda sp. nov. , redescribe † G. gracilis , redefine the species group classification of † Gerontoformica , and provide a key to the species of the genus. Our work clarifies the species boundaries of † Gerontoformica and renders fossils relevant to the discussion of eusocial evolution in a way that has heretofore been intractable. [ABSTRACT FROM AUTHOR]

Paper wasps are a model system for the study of social evolution due to a high degree of inter- and intraspecific variation in cooperation, aggression, and visual signals of social status. Increasing the taxonomic coverage of genomic resources for this diverse clade will aid comparative genomic approaches for testing predictions about the molecular basis of social evolution. Here, we provide draft genome assemblies for two well-studied species of paper wasps, Polistes exclamans and Mischocyttarus mexicanus. The P. exclamans genome assembly is 221.5 Mb in length with a scaffold N50 of 4.11 Mb. The M. mexicanus genome assembly is 227 Mb in length with a scaffold N50 of 1.1 Mb. Genomes have low repeat content (9.54–10.75%) and low GC content (32.06–32.4%), typical of other social hymenopteran genomes. The DNA methyltransferase gene, Dnmt3  , was lost early in the evolution of Polistinae. We identified a second independent loss of Dnmt3 within hornets (genus: Vespa). [ABSTRACT FROM AUTHOR]

Eusocial insects—ants, bees, wasps, and termites—are being recognized as model organisms to unravel the evolutionary paradox of aging for two reasons: (1) queens (and kings, in termites) of social insects outlive similarly sized solitary insects by up to several orders of magnitude and (2) all eusocial taxa show a divergence of long queen and shorter worker life spans, despite their shared genomes and even under risk-free laboratory environments. Traditionally, these observations have been explained by invoking the classical evolutionary aging theory: well-protected inside their nests, queens are much less exposed to external hazards than foraging workers, and this provides natural selection the opportunity to favor queens that perform well at advanced ages. Although quite plausible, these verbal arguments have not been backed up by mathematical analysis. Here, for the first time, we provide quantitative models for the evolution of caste-specific aging patterns. We show that caste-specific mortality risks are in general neither sufficient nor necessary to explain the evolutionary divergence in life span between queens and workers and the extraordinary queen life spans. Reproductive monopolization and the delayed production of sexual offspring in highly social colonies lead natural selection to inherently favor queens that live much longer than workers, even when exposed to the same external hazards. Factors that reduce a colony's reproductive skew, such as polygyny and worker reproduction, tend to reduce the evolutionary divergence in life span between queens and workers. Caste-specific extrinsic hazards also affect life span divergence, but to a much smaller extent than reproductive monopolization. [ABSTRACT FROM AUTHOR]

TThrough a review of the main assumptions that support sociology, the relevance of an anti-protagorist perspective was analyzed. This implies talking about socio-human sciences, which study the institutional reality created by human beings from their language. It is an institutionalized and articulated reality through genetic and cultural coevolution. Based on the analysis of the premises and conclusions among the main authors of sociology, the central argument of this paper articulates the need for advancement in the construction of a social science anchored in anti-protagorism. It is concluded that a genocultural coevolutionary turn in sociology and socio human sciences improves our understanding of contemporary cultural problems. Examples include machismo and heterosexual patriarchy, behaviors accentuated in the dominant culture of the peasant world, as was evidenced in the Congress "Rights of Peasants". [ABSTRACT FROM AUTHOR]

The problem of whether haplodiploidy is responsible for the frequent evolution of eusociality in the Hymenoptera remains unresolved. The little‐known "protected invasion hypothesis" posits that because a male will transmit a new allele for alloparental care to all his daughters under haplodiploidy, such an allele has a higher probability of spreading to fixation under haplodiploidy than under diploidy. This mechanism is investigated using the mating system and lifecycles ancestral to eusocial lineages. It is shown that although haplodiploidy increases the probability of fixation of a new allele, the effect is cancelled by a higher probability of the allele arising in a diploid population. However, the same effect of male haploidy results in a 30% lower threshold amount of reproductive help by a worker necessary to favor eusociality if the sex ratio of dispersing first‐brood offspring remains even. This occurs because when first‐brood daughters become workers, the sex ratio of dispersing first‐brood offspring becomes male‐biased, selecting for an overall female‐biased first‐brood sex ratio. Through this mechanism, haplodiploidy may favor eusociality in the absence of a female‐biased sex ratio in dispersing reproductive offspring. The gene‐centric approach used here reveals the critical role of male haploidy in structuring the social group. [ABSTRACT FROM AUTHOR]

To understand the earliest stages of social evolution, we need to identify species that are undergoing the initial steps into sociality. Amphylaeus morosus is the only unambiguously known social species in the bee family Colletidae and represents an independent origin of sociality within the Apoidea. This allows us to investigate the selective factors promoting the transition from solitary to social nesting. Using genome-wide SNP genotyping, we infer robust pedigree relationships to identify maternity of brood and intracolony relatedness for colonies at the end of the reproductive season. We show that A. morosus forms both matrifilial and full-sibling colonies, both involving complete or almost complete monopolization over reproduction. In social colonies, the reproductive primary was also the primary forager with the secondary female remaining in the nest, presumably as a guard. Social nesting provided significant protection against parasitism and increased brood survivorship in general. We show that secondary females gain large indirect fitness benefits from defensive outcomes, enough to satisfy the conditions of inclusive fitness theory, despite an over-production of males in social colonies. These results suggest an avenue to sociality that involves high relatedness and, very surprisingly, extreme reproductive skew in its earliest stages and raises important questions about the evolutionary steps in pathways to eusociality. [ABSTRACT FROM AUTHOR]

The Mesozoic is a key era for the rise of the modern insect fauna. Among the most important evolutionary events in Mesozoic insects are the radiation of holometabolous insects, the origin of eusocial and parasitoid insects, diversification of pollinating insects, and development of advanced mimicry and camouflage. These events are closely associated with the diversification of insect ecological behaviors and colonization of new ecospaces. At the same time, insects had evolved more complex and closer ecological associations with various plants and animals. Mesozoic insects played a key and underappreciated ecological role in reconstructing and maintaining terrestrial ecosystems. A greater understanding of the history of insects may help to mitigate future changes in insect diversity and abundance. Holometabolous insects underwent a distinct radiation during the Early–Middle Triassic because they were probably more resilient to environmental disturbance. Four lineages of insects (termites, ants, corbiculate bees, and wasps) had evolved eusociality at least by the Cretaceous. The Mid-Mesozoic Parasitoid Revolution, a dramatic radiation of parasitoid lineages during the Middle Jurassic to Early Cretaceous, is a major biological event in terrestrial food-web history. Insect pollination of gymnosperms was already widespread prior to the rise of angiosperms and was an evolutionary and ecological prelude to later interactions between early angiosperms and their insect pollinators during the mid-Cretaceous. Mimicry and camouflage among insects went through an increasingly sophisticated evolution in the Mesozoic in response to selective pressures. [ABSTRACT FROM AUTHOR]

Ants (Hymenoptera: Formicidae) are one of the most dominant terrestrial organisms worldwide. They are hugely abundant, both in terms of sheer numbers and biomass, on every continent except Antarctica and are deeply embedded within a diversity of ecological networks and processes. Ants are also eusocial and colonial organisms—their lifecycle is built on the labor of sterile worker ants who support a small number of reproductive individuals. Given the climatic changes that our planet faces, we need to understand how various important taxonomic groups will respond; this includes the ants. In this review, we synthesize the available literature to tackle this question. The answer is complicated. The ant literature has focused on temperature, and we broadly understand the ways in which thermal changes may affect ant colonies, populations, and communities. In general, we expect that species living in the Tropics, and in thermally variable microhabitats, such as the canopy and leaf litter environments, will be negatively impacted by rising temperatures. Species living in the temperate zones and those able to thermally buffer their nests in the soil or behaviorally avoid higher temperatures, however, are likely to be unaffected or may even benefit from a changed climate. How ants will respond to changes to other abiotic drivers associated with climate change is largely unknown, as is the detail on how altered ant populations and communities will ramify through their wider ecological networks. We discuss how eusociality may allow ants to adapt to, or tolerate, climate change in ways that solitary organisms cannot and we identify key geographic and phylogenetic hotspots of climate vulnerability and resistance. We finish by emphasizing the key research questions that we need to address moving forward so that we may fully appreciate how this critical insect group will respond to the ongoing climate crisis. [ABSTRACT FROM AUTHOR]

Natural history of facultative social taxa is important for understanding the evolution of Eusociality. However, data for the social status of many species are missing. Social status of seven European Ceratina bees was studied in Cyprus. Multifemale nests were found in five species of three different subgenera: C. (Euceratina) mandibularis, C. (E.) cypriaca, C. (E.) chrysomalla, C. (Dalyatina) parvula and C. (Neoceratina) bispinosa. No social nests were found in C. (E.) dallatoreana and C. (N.) schwarzi, in which the sample size was also small. We compared nest productivity between solitary and multifemale nests in C. cypriaca, C. mandibularis, and C. parvula. It is apparent that multifemale nests have a higher number of brood cells than solitary nests. Per capita productivity was equal in both nest types. We can conclude that facultative sociality is common in Ceratina bees of subtropical climate and social nesting is the successful strategy. [ABSTRACT FROM AUTHOR]

The evolution of effectively sterile workers in the aculeate Hymenoptera (ants, bees, and stinging wasps) requires that a female's life span largely overlap that of her daughters. The evolution of long nest foundress life spans in eusocial species from the short life spans of solitary species is investigated. Analyses that control for phylogeny show for the first time that foundress adult life span increases and first-brood offspring development time decreases with increasing colony size, resulting in the ratio of foundress adult life span to worker total life span increasing with increasing colony size. These patterns support the hypothesis that the reproductive division of labor increases with increasing colony size, explaining the evolution of effectively sterile workers in species with large colonies. However, there is a discrete increase in foundress adult life span in the transition from noneusociality to eusociality that is independent of colony size. An analysis of life history characters suggests that this increase is explained by nests being founded by multiple females and progressive feeding of larvae as they develop. A reduced rate of senescence of a dominant cofoundress may be selected as a plastic response to social status if high-risk tasks performed by subordinate cofoundresses reduce the dominant's extrinsic mortality rate. Multiple-foundress nests in which one female is responsible for most or all of the reproduction (semisociality) and in which foundresses are full sisters are favored by haplodiploidy, perhaps explaining why eusociality is so common in the Hymenoptera. [ABSTRACT FROM AUTHOR]

Dinocampus coccinellae (Hymenoptera: Braconidae) is a generalist parasitoid wasp that parasitizes >50 species of predatory lady beetles (Coleoptera: Coccinellidae), with thelytokous parthenogeny as its primary mode of reproduction. Here, we present the first high-quality genome of D. coccinellae using a combination of short- and long-read sequencing technologies, followed by assembly and scaffolding of chromosomal segments using Chicago + HiC technologies. We also present a first-pass ab initio and a reference-based genome annotation and resolve timings of divergence and evolution of (1) solitary behavior vs eusociality, (2) arrhenotokous vs thelytokous parthenogenesis, and (3) rates of gene loss and gain among Hymenopteran lineages. Our study finds (1) at least 2 independent origins of eusociality and solitary behavior among Hymenoptera, (2) 2 independent origins of thelytokous parthenogenesis from ancestral arrhenotoky, and (3) accelerated rates of gene duplications, loss, and gain along the lineages leading to D. coccinellae. Our work both affirms the ancient divergence of Braconid wasps from ancestral Hymenopterans and accelerated rates of evolution in response to adaptations to novel hosts, including polyDNA viral coevolution. [ABSTRACT FROM AUTHOR]

The naked mole‐rat (Heterocephalus glaber) has fascinated zoologists for at least half a century. It has also generated considerable biomedical interest not only because of its extraordinary longevity, but also because of unusual protective features (e.g. its tolerance of variable oxygen availability), which may be pertinent to several human disease states, including ischemia/reperfusion injury and neurodegeneration. A recent article entitled 'Surprisingly long survival of premature conclusions about naked mole‐rat biology' described 28 'myths' which, those authors claimed, are a 'perpetuation of beautiful, but falsified, hypotheses' and impede our understanding of this enigmatic mammal. Here, we re‐examine each of these 'myths' based on evidence published in the scientific literature. Following Braude et al., we argue that these 'myths' fall into four main categories: (i) 'myths' that would be better described as oversimplifications, some of which persist solely in the popular press; (ii) 'myths' that are based on incomplete understanding, where more evidence is clearly needed; (iii) 'myths' where the accumulation of evidence over the years has led to a revision in interpretation, but where there is no significant disagreement among scientists currently working in the field; (iv) 'myths' where there is a genuine difference in opinion among active researchers, based on alternative interpretations of the available evidence. The term 'myth' is particularly inappropriate when applied to competing, evidence‐based hypotheses, which form part of the normal evolution of scientific knowledge. Here, we provide a comprehensive critical review of naked mole‐rat biology and attempt to clarify some of these misconceptions. [ABSTRACT FROM AUTHOR]

All social insects defend their colony from predators, parasites, and pathogens. In Oster and Wilson's classic work, they posed one of the key paradoxes about defense in social insects: Given the universal necessity of defense, why then is there so much diversity in mechanisms? Ecological factors undoubtedly are important: Predation and usurpation have imposed strong selection on eusocial insects, and active defense by colonies is a ubiquitous feature of all social insects. The description of diverse insect groups with castes of sterile workers whose main duty is defense has broadened the purview of social evolution in insects, in particular with respect to caste and behavior. Defense is one of the central axes along which we can begin to organize and understand sociality in insects. With the establishment of social insect models such as the honey bee, new discoveries are emerging regarding the endocrine, neural, and gene regulatory mechanisms underlying defense in social insects. The mechanisms underlying morphological and behavioral defense traits may be shared across diverse groups, providing opportunities for identifying both conserved and novel mechanisms at work. Emerging themes highlight the context dependency of and interaction between factors that regulate defense in social insects. [ABSTRACT FROM AUTHOR]

The evolution of sociality in insects is a highly discussed topic in biology. Fossil findings are rarely included into the consideration, although they have a great potential to add also behavioural aspects to evolutionary reconstructions and can provide information about the minimum age of specific lifestyles in deep time. We briefly summarise concepts of reconstructing behaviour based on fossils and give a short overview of the concept of eusociality. The focus of this paper is the description of new findings of fossilised cases of aggregations in Cretaceous Myanmar amber. All specimens enclosed in these amber pieces are immatures. These findings come from four different lineages of Insecta: Neuroptera, Dermaptera, Orthoptera and Collembola. Some of these groups are usually not considered as typical examples for social interactions, but several grades of aggregation behaviour can be observed in all of these groups in different species living today. Active aggregation behaviour (or gregarious behaviour) can be seen as part and prerequisite of further social behaviour. Therefore, the investigation of this aspect can add new insights for a more comprehensive understanding of the evolution of complex strategies of social behaviour. [ABSTRACT FROM AUTHOR]