Eusociality

The Melipona gut microbes differ from other social bees, with the absence of crucial corbiculate core gut symbionts and the high occurrence of environmental strains. We studied the microbial diversity and composition of three Melipona species and their honey to understand which strains are obtained by horizontal transmission (HT) from the pollination environment; or represent symbionts co-evolved with Melipona by HT from the hive/food stores or vertical transmission (VT) via social interactions. Bees harbored higher microbial alpha diversity and a different and more species-specific bacterial composition than honey...

Eusocial bees are declining due to anthropogenic actions. Individuals can be exposed to contaminants like Cd, which have been found in pollen. Thus, we evaluated the potential genotoxicity of Cd to the hepato-nephrocitic system of Bombus atratus foraging workers exposed to environmentally safe doses of Cd (0.001mg/kg and 0.003mg/kg) during 72h. To assess the genotoxicity of Cd, we conducted an alkaline comet assay. Doses of 0.001mg/kg of Cd caused comets of levels 2 and 3, and 0.003mg/kg of Cd induced comets of level 4, while controls exhibited regular nucleoids...

Domains as functional protein units and their rearrangements along the phylogeny can shed light on the functional changes of proteomes associated with the evolution of complex traits like eusociality. This complex trait is associated with sterile soldiers and workers, and long-lived, highly fecund reproductives. Unlike in Hymenotpera (ants, bees, and wasps), the evolution of eusociality within Blattodea, where termites evolved from within cockroaches, was accompanied by a reduction in proteome size, raising the question of whether functional novelty was achieved with existing rather than novel proteins...

Insects heavily rely on the olfactory system for food, mating, and predator evasion. However, the caste-related olfactory differences in Apis cerana , a eusocial insect, remain unclear. To explore the peripheral and primary center of the olfactory system link to the caste dimorphism in A. cerana , transcriptome and immunohistochemistry studies on the odorant receptors (ORs) and architecture of antennal lobes (ALs) were performed on different castes. Through transcriptomesis, we found more olfactory receptor genes in queens and workers than in drones, which were further validated by RT-qPCR, indicating caste dimorphism...

The naked mole-rat Heterocephalus glaber is a eusocial mammal exhibiting extreme longevity (37-year lifespan), extraordinary resistance to hypoxia and absence of cardiovascular disease. To identify the mechanisms behind these exceptional traits, metabolomics and RNAseq of cardiac tissue from naked mole-rats was compared to other African mole-rat genera (Cape, Cape dune, Common, Natal, Mahali, Highveld and Damaraland mole-rats) and evolutionarily divergent mammals (Hottentot golden mole and C57/BL6 mouse). We identify metabolic and genetic adaptations unique to naked mole-rats including elevated glycogen, thus enabling glycolytic ATP generation during cardiac ischemia...

As eusocial creatures, bees display unique macro collective behavior and local body dynamics that hold potential applications in various fields, such as computer animation, robotics, and social behavior. Unlike birds and fish, bees fly in a low-aligned zigzag pattern. Additionally, bees rely on visual cues for foraging and predator avoidance, exhibiting distinctive local body oscillations, such as body lifting, thrusting, and swaying. These inherent features pose significant challenges for realistic bee simulations in practical animation applications...

Reception of chemical information from the environment is crucial for insects' survival and reproduction. The chemosensory reception mainly occurs by the antennae and mouth parts of the insect, when the stimulus contacts the chemoreceptors located within the sensilla. Chemosensory receptor genes have been well-studied in some social hymenopterans such as ants, honeybees, and wasps. However, although stingless bees are the most representative group of eusocial bees, little is known about their odorant, gustatory, and ionotropic receptor genes...

We aimed to investigate the roles of dopamine in regulating caste-specific behaviors in bumble bees and mating-related behaviors in bumble bee gynes. We examined caste differences in behaviors, biogenic amine levels, and expression levels of genes encoding dopamine receptors in the brains of bumble bees, and analyzed the effects of dopamine-related drugs on bumble bee behavior. Locomotor and flight activities were significantly higher in 8-day-old gynes and light avoidance was significantly lower in 4-8-day-old gynes than in same-aged workers...

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...

Group-living animals sometimes cooperatively protect their offspring against predators. This behavior is observed in a wide range of taxa but, to the best of our knowledge, this is the first report of its occurrence in arthropods that are not eusocial. Adult female predatory mites Gynaeseius liturivorus protect their eggs against egg predators, the predatory mite species Neoseiulus californicus. In the field, several adult female G. liturivorus were often found on the same plant structures such as folded leaves...

Like humans, animals use plants and other materials as medication against parasites. Recent decades have shown that the study of insects can greatly advance our understanding of medication behaviors. The ease of rearing insects under laboratory conditions has enabled controlled experiments to test critical hypotheses, while their spectrum of reproductive strategies and living arrangements - ranging from solitary to eusocial communities - has revealed that medication behaviors can evolve to maximize inclusive fitness through both direct and indirect fitness benefits...

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 (H') for 85 bee taxa...

Eusocial insects such as termites, ants, bees, and wasps exhibit a reproductive division of labor. The developmental regulation of reproductive organ (ovaries and testes) is crucial for distinguishing between reproductive and sterile castes. The development of reproductive organ in insects is regulated by sex-determination pathways. The sex determination gene Doublesex (Dsx), encoding transcription factors, plays an important role in this pathway. Therefore, clarifying the function of Dsx in the developmental regulation of sexual traits is important to understand the social evolution of eusocial insects...

Division of labour is widely thought to increase the task efficiency of eusocial insects. Workers can switch their task to compensate for sudden changes in demand, providing flexible task allocation. In combination with automated tracking technology, we developed a robotic system to precisely control and spatiotemporally manipulate floor temperature over days, which allowed us to predictably drive brood transport behaviour in colonies of the ant Camponotus floridanus. Our results indicate that a small number of workers, usually minors belonging to the nurse social group, are highly specialised for brood transport...

Females of many species are polyandrous. However, polyandry can give rise to conflict among individuals within families. We examined the level of polyandry and paternity skew in the common eastern yellowjacket wasp, Vespula maculifrons, in order to gain a greater understanding of conflict in social insects. We collected 10 colonies of V. maculifrons and genotyped workers and prereproductive queens at highly variable microsatellite markers to assign each to a patriline. Genotypic data revealed evidence of significant paternity skew among patrilines...

Gut microbiomes are increasingly recognized for mediating diverse biological aspects of their hosts, including complex behavioral phenotypes. Although many studies have reported that experimental disruptions to the gut microbial community result in atypical host behavior, studies that address how gut microbes contribute to adaptive behavioral trait variation are rare. Eusocial insects represent a powerful model to test this, due to their simple gut microbiota and complex division of labor characterized by colony-level variation in behavioral phenotypes...

Eusocial insects have evolved specific defensive strategies to protect their colonies. In termite colonies, soldiers perform a colony-level defense by displaying mechanical biting, head-banging and mandible opening-closing behaviors. However, few studies have been reported on the factors modulating defensive behaviors in termites. Owing to JH (juvenile hormone) being involved in soldier differentiation, JH was speculated to affect defensive behaviors in termite soldiers. To determine the effect of JH on the defensive behaviors of termite soldiers, we performed a JHA-feeding and RaSsp1 -silencing experiment and then tested the changes in defense-related behaviors, alarm pheromones and key JH signaling genes...

Human disturbance including rapid urbanization and increased temperatures can have profound effects on the ecology of local populations. Eusocial insects, such as ants, have adapted to stressors of increasing temperature and urbanization; however, these evolutionary responses are not consistent among populations across geographic space. Here we asked how urbanization and incubation temperature influence critical thermal maximum (CTmax ) and various ecologically relevant behaviors in three ant species in urban and rural locations in Worcester, MA, USA...

Research on eusocial bee species like Bombus terrestris is primarily focused on the worker caste, which is why their morphology and anatomy are already well described. This includes the alimentary tract, which is adapted for feeding on nectar and pollen. Located at the transition between crop and ventriculus is a highly specialised compartment, the proventriculus. In female workers of B. terrestris, the proventriculus is surrounded by muscles and consists of four anterior lips. A detailed description, however, is only provided for B...

BACKGROUND: The highly eusocial stingless bees are crucial pollinators of native and agricultural ecosystems. Nevertheless, genomic studies within this bee tribe remain scarce. We present the genome assembly of the stingless bee Melipona bicolor. This bee is a remarkable exception to the typical single-queen colony structure, since in this species, multiple queens may coexist and share reproductive duties, resulting in genetically diverse colonies with weak kinship connections. As the only known genuinely polygynous bee, M...