Differences in olfactory sensitivity and odor detection correlate with foraging task specialization in honeybees Apis mellifera.

Division of labor is central to the ecological success of social insects. Among honeybees foragers, specialization for collecting nectar or pollen correlates with their sensitivity to gustatory stimuli (e.g. sugars). We hypothesize that pollen and nectar foragers also differ in their sensitivity to odors, and therefore in their likelihood to show odor-mediated responses. To assess foragers sensitivity to natural odors, we quantified the conditioning of the proboscis extension reflex (PER) to increasing concentrations (0.001; 0.01; 0.1; 1 M) of linalool or nonanal. Furthermore, we compared electroantennogram (EAG) recordings to correlate bees' conditioned responses with the electrophysiological responses of their antennae. To further explore differences of the antennal response of foragers in relation to task-related odors, we registered EAG signals for two behaviorally ''meaningful'' odors that mediate pollen collection: fresh pollen odors and the brood pheromone (E)-ß-ocimene. Pollen foragers performed better than nectar foragers in PER conditioning trials when linalool and nonanal were presented at low concentrations (0.001, 0.01 M). Consistently, their antennae showed stronger EAG signals (higher amplitudes) to these odors, suggesting that differences in sensitivity can be explained at the periphery of the olfactory system. Pollen and nectar foragers detect pollen odors differently, but not (E)-ß-ocimene. Pollen volatiles evoked EAG signals with hyper and depolarization components. In pollen foragers, the contribution of the hyperpolarization component was higher than in nectar foragers. We discuss our findings in terms of adaptive advantages to learn subtle olfactory cues that influence the ability to better identify/discriminate food sources.

Simultaneous biodegradation of phenolics and petroleum hydrocarbons from semi-coking wastewater: Construction of bacterial consortium and their metabolic division of labor.

Phenols and petroleum hydrocarbons were the main contributors to COD in semi-coking wastewater, and their removal was urgent and worthwhile. The microbial strains were selected to construct microbial community for the wastewater treatment. The concentration of phenols was decreased from 2450 ± 1.2 mg/L to 200 ± 0.9 mg/L, and the removal rate of petroleum hydrocarbons was up to 97.08 ± 0.09 % by microorganisms. After phenolic compounds with high toxicity were removed by bioaugmentation, the treated semi-coking wastewater was more biodegradable, and its water quality has been significantly improved. Through GC-MS and high-through sequencing technology, the metabolic division of labor in degradation of phenols, ring-cleavage of aromatic compounds, mineralization of metabolites was further revealed. The microbial community consisting of Pseudomonas stutzeri N2 and Rhodococcus qingshengii FF could effectively and simultaneously remove phenols and petroleum hydrocarbons, and these two strains possess great potential of being applied in aerobic biological treatment process of large-scale semi-coking wastewater.

Tachykinin signaling inhibits task-specific behavioral responsiveness in honeybee workers.

Behavioral specialization is key to the success of social insects and leads to division of labor among colony members. Response thresholds to task-specific stimuli are thought to proximally regulate behavioral specialization, but their neurobiological regulation is complex and not well understood. Here, we show that response thresholds to task-relevant stimuli correspond to the specialization of three behavioral phenotypes of honeybee workers in the well-studied and important Apis mellifera and Apis cerana. Quantitative neuropeptidome comparisons suggest two tachykinin-related peptides (TRP2 and TRP3) as candidates for the modification of these response thresholds. Based on our characterization of their receptor binding and downstream signaling, we confirm a functional role of tachykinin signaling in regulating specific responsiveness of honeybee workers: TRP2 injection and RNAi-mediated downregulation cause consistent, opposite effects on responsiveness to task-specific stimuli of each behaviorally specialized phenotype but not to stimuli that are unrelated to their tasks. Thus, our study demonstrates that TRP signaling regulates the degree of task-specific responsiveness of specialized honeybee workers and may control the context specificity of behavior in animals more generally.

Catabolic Division of Labor Enhances Production of D-Lactate and Succinate From Glucose-Xylose Mixtures in Engineered Escherichia coli Co-culture Systems.

Although biological upgrading of lignocellulosic sugars represents a promising and sustainable route to bioplastics, diverse and variable feedstock compositions (e.g., glucose from the cellulose fraction and xylose from the hemicellulose fraction) present several complex challenges. Specifically, sugar mixtures are often incompletely metabolized due to carbon catabolite repression while composition variability further complicates the optimization of co-utilization rates. Benefiting from several unique features including division of labor, increased metabolic diversity, and modularity, synthetic microbial communities represent a promising platform with the potential to address persistent bioconversion challenges. In this work, two unique and catabolically orthogonal Escherichia coli co-cultures systems were developed and used to enhance the production of D-lactate and succinate (two bioplastic monomers) from glucose-xylose mixtures (100 g L-1 total sugars, 2:1 by mass). In both cases, glucose specialist strains were engineered by deleting xylR (encoding the xylose-specific transcriptional activator, XylR) to disable xylose catabolism, whereas xylose specialist strains were engineered by deleting several key components involved with glucose transport and phosphorylation systems (i.e., ptsI, ptsG, galP, glk) while also increasing xylose utilization by introducing specific xylR mutations. Optimization of initial population ratios between complementary sugar specialists proved a key design variable for each pair of strains. In both cases, ∼91% utilization of total sugars was achieved in mineral salt media by simple batch fermentation. High product titer (88 g L-1 D-lactate, 84 g L-1 succinate) and maximum productivity (2.5 g L-1 h-1 D-lactate, 1.3 g L-1 h-1 succinate) and product yield (0.97 g g-total sugar-1 for D-lactate, 0.95 g g-total sugar-1 for succinate) were also achieved.

Clarifying workforce flexibility from a division of labor perspective: a mixed methods study of an emergency department team.

BACKGROUND: The need for greater flexibility is often used to justify reforms that redistribute tasks through the workforce. However, "flexibility" is never defined or empirically examined. This study explores the nature of flexibility in a team of emergency doctors, nurse practitioners (NPs), and registered nurses (RNs), with the aim of clarifying the concept of workforce flexibility. Taking a holistic perspective on the team's division of labor, it measures task distribution to establish the extent of multiskilling and role overlap, and explores the behaviors and organizational conditions that drive flexibly. METHODS: The explanatory sequential mixed methods study was set in the Fast Track area of a metropolitan emergency department (ED) in Sydney, Australia. In phase 1, an observational time study measured the tasks undertaken by each role (151 h), compared as a proportion of time (Kruskal Wallis, Mann-Whitney U), and frequency (Pearson chi-square). The time study was augmented with qualitative field notes. In phase 2, 19 semi-structured interviews sought to explain the phase 1 observations and were analyzed thematically. RESULTS: The roles were occupationally specialized: "Assessment and Diagnosis" tasks consumed the largest proportion of doctors' (51.1%) and NPs' (38.1%) time, and "Organization of Care" tasks for RNs (27.6%). However, all three roles were also multiskilled, which created an overlap in the tasks they performed. The team used this role overlap to work flexibly in response to patients' needs and adapt to changing demands. Flexibility was driven by the urgent and unpredictable workload in the ED and enabled by the stability provided by a core group of experienced doctors and nurses. CONCLUSION: Not every healthcare team requires the type of flexibility found in this study since that was shaped by patient needs and the specific organizational conditions of the ED. The roles, tasks, and teamwork that a team requires to "be flexible" (i.e., responsive and adaptable) are highly context dependent. Workforce flexibility therefore cannot be defined as a particular type of reform or role; rather, it should be understood as the capacity of a team to respond and adapt to patients' needs within its organizational context. The study's findings suggest that solutions for a more flexible workforce may lay in the organization of healthcare work.

Reconstructing sexual divisions of labor from fingerprints on Ancestral Puebloan pottery.

An understanding of the division of labor in different societies, and especially how it evolved in the human species, is fundamental to most analyses of social, political, and economic systems. The ability to reconstruct how labor was organized, however, especially in ancient societies that left behind few material remains, is challenged by the paucity of direct evidence demonstrating who was involved in production. This is particularly true for identifying divisions of labor along lines of age, sex, and gender, for which archaeological interpretations mostly rely upon inferences derived from modern examples with uncertain applicability to ancient societies. Drawing upon biometric studies of human fingerprints showing statistically distinct ridge breadth measurements for juveniles, males, and females, this study reports a method for collecting fingerprint impressions left on ancient material culture and using them to distinguish the sex of the artifacts' producers. The method is applied to a sample of 985 ceramic sherds from a 1,000-y-old Ancestral Puebloan community in the US Southwest, a period characterized by the rapid emergence of a highly influential religious and political center at Chaco Canyon. The fingerprint evidence demonstrates that both males and females were significantly involved in pottery production and further suggests that the contributions of each sex varied over time and even among different social groups in the same community. The results indicate that despite long-standing assumptions that pottery production in Ancient Puebloan societies was primarily a female activity, labor was not strictly divided and instead was likely quite dynamic.

Effects of nutritional deprivation on development and behavior in the subsocial bee Ceratina calcarata (Hymenoptera: Xylocopinae).

By manipulating resources or dispersal opportunities, mothers can force offspring to remain at the nest to help raise siblings, creating a division of labor. In the subsocial bee Ceratina calcarata, mothers manipulate the quantity and quality of pollen provided to the first female offspring, producing a dwarf eldest daughter that is physically smaller and behaviorally subordinate. This daughter forages for her siblings and forgoes her own reproduction. To understand how the mother's manipulation of pollen affects the physiology and behavior of her offspring, we manipulated the amount of pollen provided to offspring and measured the effects of pollen quantity on offspring development, adult body size and behavior. We found that by experimentally manipulating pollen quantities we could recreate the dwarf eldest daughter phenotype, demonstrating how nutrient deficiency alone can lead to the development of a worker-like daughter. Specifically, by reducing the pollen and nutrition to offspring, we significantly reduced adult body size and lipid stores, creating significantly less aggressive, subordinate individuals. Worker behavior in an otherwise solitary bee begins to explain how maternal manipulation of resources could lead to the development of social organization and reproductive hierarchies, a major step in the transition to highly social behaviors.

The cultural evolution of shamanism.

Shamans, including medicine men, mediums, and the prophets of religious movements, recur across human societies. Shamanism also existed among nearly all documented hunter-gatherers, likely characterized the religious lives of many ancestral humans, and is often proposed by anthropologists to be the "first profession," representing the first institutionalized division of labor beyond age and sex. In this article, I propose a cultural evolutionary theory to explain why shamanism consistently develops and, in particular, (1) why shamanic traditions exhibit recurrent features around the world; (2) why shamanism professionalizes early, often in the absence of other specialization; and (3) how shifting social conditions affect the form or existence of shamanism. According to this theory, shamanism is a set of traditions developed through cultural evolution that adapts to people's intuitions to convince observers that a practitioner can influence otherwise unpredictable, significant events. The shaman does this by ostensibly transforming during initiation and trance, violating folk intuitions of humanness to assure group members that he or she can interact with the invisible forces that control uncertain outcomes. Entry requirements for becoming a shaman persist because the practitioner's credibility depends on his or her "transforming." This contrasts with dealing with problems that have identifiable solutions (such as building a canoe), in which credibility hinges on showing results and outsiders can invade the jurisdiction by producing the outcome. Shamanism is an ancient human institution that recurs because of the capacity of cultural evolution to produce practices adapted to innate psychological tendencies.

Quantitative Neuropeptidome Analysis Reveals Neuropeptides Are Correlated with Social Behavior Regulation of the Honeybee Workers.

Neuropeptides play vital roles in orchestrating neural communication and physiological modulation in organisms, acting as neurotransmitters, neuromodulators, and neurohormones. The highly evolved social structure of honeybees is a good system for understanding how neuropeptides regulate social behaviors; however, much knowledge on neuropeptidomic variation in the age-related division of labor remains unknown. An in-depth comparison of the brain neuropeptidomic dynamics over four time points of age-related polyethism was performed on two strains of honeybees, the Italian bee (Apis mellifera ligustica, ITb) and the high royal jelly producing bee (RJb, selected for increasing royal jelly production for almost four decades from the ITb in China). Among the 158 identified nonredundant neuropeptides, 77 were previously unreported, significantly expanding the coverage of the honeybee neuropeptidome. The fact that 14 identical neuropeptide precursors changed their expression levels during the division of labor in both the ITb and RJb indicates they are highly related to task transition of honeybee workers. These observations further suggest the two lines of bees employ a similar neuropeptidome modification to tune their respective physiology of age polyethism via regulating excretory system, circadian clock system, and so forth. Noticeably, the enhanced level of neuropeptides implicated in regulating water homeostasis, brood pheromone recognition, foraging capacity, and pollen collection in RJb signify the fact that neuropeptides are also involved in the regulation of RJ secretion. These findings gain novel understanding of honeybee neuropeptidome correlated with social behavior regulation, which is potentially important in neurobiology for honeybees and other insects.