Colony Organization Research Articles

Porites superfusa mortality and recovery from a bleaching event at Palmyra Atoll, USA.

BackgroundThe demography of a coral colony is not a binary trajectory of life and death. Based on the flexibility afforded by colonial organization, most reef-building corals employ a variety of dynamic survival strategies, including growth and shrinkage. The demographic flexibility affects coral size, shape and reproductive output, among other factors. It is thus critical to quantify the relative importance of key dynamics of recruitment, mortality, growth and shrinkage in changing the overall cover of coral on a reef.MethodsUsing fixed photographic quadrats, we tracked the patterns of change in the cover of one common central Pacific coral, Porites superfusa, before and after the 2009 ENSO event.ResultsCoral colonies suffered both whole and partial colony mortality, although larger colonies were more likely to survive. In subsequent years, recruitment of new colonies and regrowth of surviving colonies both contributed to the modest recovery of P. superfusa.DiscussionThis study is unique in its quantitative comparisons of coral recruitment versus regrowth during periods of areal expansion. Our data suggest that recovery is not limited simply to the long pathway of settlement, recruitment and early growth of new colonies but is accelerated by means of regrowth of already established colonies having suffered partial mortality.

The reproductive division of labour but not worker age affects spatial sorting within the nest in a paper wasp

Spatial behaviour of colony members within a nest represents an essential aspect of colony organization. However, little attention has been devoted to the study of this aspect in social insects. A recent study based on a single day of observation showed that colony members of the paper wasp Polistes dominula were spatially arranged on the comb in a predictable way. Alpha females patrolled a small central area of the comb, while subordinates and workers were mostly active in the nest periphery. The present study investigated the existence of a spatial–temporal polyethism in P. dominula by studying whether workers and foundresses change their within-nest spatial behaviour over their lifespan. The results showed that while the age of a worker weakly influenced the probability that she performed a within-nest task or foraged outside, it did not account for any aspect of the wasp’s within-nest spatial behaviour. Precisely, the size of the patrolled area, the position on the comb, and the rate of superimposition with other nestmates were all not related to the age of the wasp. Moreover, no evident spatial segregation between young and old individuals occurred on the comb. These findings suggest that other proximate mechanisms underlie the observed colony spatial organization. As the reproductive division of labour was the only factor affecting wasp spatial sorting within the nest, dominance hierarchy and social interactions between and within foundress and workers represent good candidates responsible for the colony’s spatial organization.

Optimal feature selection for predicting soil CEC: Comparing the hybrid of ant colony organization algorithm and adaptive network-based fuzzy system with multiple linear regression

Soil CEC is a very important property that represents soil fertility status. Though difficult to measure, it can be predicted by soil physicochemical properties that can be easily measured. Researchers have used different input soil properties to derive pedo-transfer functions (PTFs) and predict soil CEC. To select properties that influence soil CEC, we have introduced a hybrid algorithm: an advance ant colony organization (ACO) in combination with an adaptive network-based fuzzy inference system (ANFIS). The potential power of the advance ACO-ANFIS algorithm in setting up a framework for identifying the most determinant parameters of agricultural soils CEC in an Iranian semiarid region (Rabor region, 29° 27′ N to 38° 54′ N and 56° 45′ E to 57° 16′ E) was also investigated. To make sure that ACO-AN FIS algorithm reaches its global minimum, features were selected by ANFIS. A multiple linear regression (MLR) model was constructed as benchmark for the comparison of performances. The results from ACO-ANFIS and ANFIS for feature selection and their RMSEs were the same. Results of ACO-ANFIS and ANFIS for selecting best dataset showed that five properties including soil organic matter (SOM), clay, silt, pH and bulk density (BD) had the lowest error. The ANFIS method resulted in higher model efficiency and coefficient of determination (R2=0.91) than MLR approach (R2=0.74). This study provides a strong basis for predicting soil CEC and identifying the most determinant parameters influencing soil CEC in the Iranian semiarid regions; however, its general analytical framework could be applied to other parts of the world with similar challenges.

Multifractality in individual honeybee behavior hints at colony-specific social cascades: Reanalysis of radio-frequency identification data from five different colonies.

Honeybees (Apis mellifera) exhibit complex coordination and interaction across multiple behaviors such as swarming. This coordination among honeybees in the same colony is remarkably similar to the concept of informational cascades. The multifractal geometry of cascades suggests that multifractal measures of individual honeybee activity might carry signatures of these colony-wide coordinations. The present work reanalyzes time stamps of entrances to and exits from the hive captured by radio-frequency identification (RFID) sensors reading RFID tags on individual bees. Indeed, both multifractal spectrum width for individual bees' inter-reading interval series and differences of those widths from surrogates significantly predicted not just whether the individual bee's hive had a mesh enclosure but also predicted the specific membership of individual bees in one of five colonies. The significant effects of multifractality in matching honeybee activity to type of colony and, further, matching individual honeybees to their exact home colony suggests that multifractality quantifies key features of the colony-wide interactions across many scales. This relevance of multifractality to predicting colony type or colony membership adds additional credence to the cascade metaphor for colony organization. Perhaps, multifractality provides a new tool for exploring the relationship between individual organisms and larger, more complex social behaviors.

Emergent structures and dynamics of cell colonies by contact inhibition of locomotion

Cells in tissues can organize into a broad spectrum of structures according to their function. Drastic changes of organization, such as epithelial-mesenchymal transitions or the formation of spheroidal aggregates, are often associated either to tissue morphogenesis or to cancer progression. Here, we study the organization of cell colonies by means of simulations of self-propelled particles with generic cell-like interactions. The interplay between cell softness, cell-cell adhesion, and contact inhibition of locomotion (CIL) yields structures and collective dynamics observed in several existing tissue phenotypes. These include regular distributions of cells, dynamic cell clusters, gel-like networks, collectively migrating monolayers, and 3D aggregates. We give analytical predictions for transitions between noncohesive, cohesive, and 3D cell arrangements. We explicitly show how CIL yields an effective repulsion that promotes cell dispersal, thereby hindering the formation of cohesive tissues. Yet, in continuous monolayers, CIL leads to collective cell motion, ensures tensile intercellular stresses, and opposes cell extrusion. Thus, our work highlights the prominent role of CIL in determining the emergent structures and dynamics of cell colonies.

Colonial Organization of Mine Labour in Charcas (Present-Day Bolivia) and Its Consequences (Sixteenth to the Seventeenth Centuries)

AbstractThis article analyses the changes in the organization of labour during the sixteenth and seventeenth centuries in colonial Charcas, present-day Bolivia, focusing on the role that different colonial authorities played in this process and its consequences. The Spanish took advantage of the pre-Hispanic organization of labour from the beginning of their conquest. However, in a colonial context, labour relations changed significantly, and the architect of those alterations was Viceroy Francisco de Toledo. We examine the transformations in mine labour carried out by the Spanish colonial polity; these had a significant effect not only on mining, but also on all labour relations in the southern colonial Andes.

Morphogenesis in the individual and historical development of marine post-Paleozoic Tubuliporida (bryozoa, Stenolaemata)

The principal features of the morphogenesis in the individual and historical development of marine post-Paleozoic bryozoans of the order Tubuliporida (=Cyclostomata, part.) are discussed. Throughout their history (Ordovician–Recent), Tubuliporida retained the morphological type of the tubu-lar zooid with a terminal aperture. This may suggest similarities not only between the zooidal anatomy of fossil and living Tubuliporida but also between the ontogenetic processes in their ancestrulae and zooids and similarities in astogeny in general. After the two types of reproduction, sexual and vegetative, which lead to the formation of new colonies that could only grow by budding, had been developed, the develop-ment of different types of colonial organization was of special importance in the evolution of the post-Pale-ozoic Tubuliporida.

Pheromone trail following in the ant Lasius niger: high accuracy and variability but no effect of task state

AbstractThe use of pheromone trails in ant colony organization is an important model for understanding collective decision‐making and complex adaptive systems. The ant Lasius niger L. (Hymenoptera: Fomicidae) is one of the main model organisms used for such studies. Key to understanding pheromone trail use by ants is knowing how well trails are followed. The results of a previous study suggest that L. niger trail following is poor, with between 60% and 70% accuracy at a T bifurcation. It is hypothesized that the true trail following accuracy is higher, and that the low accuracy reported previously is the result of a methodological error. Specifically, it is hypothesized that ‘task state’ (i.e. what the ants ‘thought they were doing’) affected pheromone following accuracy. In the present study, the task state of the ants is set experimentally to one of three states: scouting (completely naive), recruited (having information that food has been found, but not where it is) and shuttling (having a strong memory of the location of a food source). Trail following accuracy is tested for each group. Trail following is found to be more accurate than previously reported: 83%, 82% and 74% correct decisions for scouts, recruits and shuttlers, respectively. However, the difference between the three groups is not significant. Importantly, very high inter‐trial variation is reported both in the present study and in experiments from other research groups. This variation is unexplainable by trail strengths or colony‐level differences, and is highlighted as an important factor when experimentally measuring trail following.

Distribution and origin of intraspecific social variation in the California harvester ant Pogonomyrmex californicus

The California seed harvester ant Pogonomyrmex californicus exhibits striking differences in queen behavior and colony organization throughout its range. Most populations show the likely ancestral condition of single-queen colonies (monogyny). However, in one known population, cooperation between queens during colony founding (pleometrosis) occurs, and is suspected to persist to the mature colony stage (primary polygyny). To better understand this variation in social phenotype, we estimate relatedness among co-foundresses, measure the frequency of polygyny in adult colonies across three focal populations, and assess population genetic structure between populations. We additionally measure queen mating frequency (polyandry) across focal populations. With few possible exceptions, queens within pleometrotic associations are unrelated. We demonstrate a correlation between pleometrosis in incipient colonies and polygyny in adult colonies at the population level. Nuclear microsatellites and mtDNA barcoding indicate significant structure between focal populations. Queens from all three focal populations engage in relatively high levels of polyandry. These findings, when examined with previous data demonstrating that pleometrosis leads to polygynous colonies in the laboratory, strongly suggest that the same occurs in nature. However, the possibility of additional queen adoption in adult colonies (secondary polygyny) is not excluded. Thus, polygynous P. californicus colonies potentially represent long-term associations of unrelated family groups, containing multiple unrelated queens and their mixed-paternity offspring. Due to its pronounced variation in social behavior, P. californicus provides a unique opportunity to examine the evolutionary history and genetic underpinnings of cooperation among non-relatives, a strategy of intense interest in behavioral ecology.

Stiffness of the microenvironment upregulates ERBB2 expression in 3D cultures of MCF10A within the range of mammographic density.

The effects of the stiffness of the microenvironment on the molecular response of 3D colony organization, at the maximum level of mammographic density (MD), are investigated. Phenotypic profiling reveals that 3D colony formation is heterogeneous and increased stiffness of the microenvironment, within the range of the MD, correlates with the increased frequency of aberrant 3D colony formation. Further integrative analysis of the genome-wide transcriptome and phenotypic profiling hypothesizes overexpression of ERBB2 in the premalignant MCF10A cell lines at a stiffness value that corresponds to the collagen component at high mammographic density. Subsequently, ERBB2 overexpression has been validated in the same cell line. Similar experiments with a more genetically stable cell line of 184A1 also revealed an increased frequency of aberrant colony formation with the increased stiffness; however, 184A1 did not demonstrate overexpression of ERBB2 at the same stiffness value of the high MD. These results suggest that stiffness exacerbates premalignant cell line of MCF10A.

Dynamical Models of Task Organization in Social Insect Colonies.

The organizations of insect societies, such as division of labor, task allocation, collective regulation, mass action responses, have been considered as main reasons for the ecological success. In this article, we propose and study a general modeling framework that includes the following three features: (a) the average internal response threshold for each task (the internal factor); (b) social network communications that could lead to task switching (the environmental factor); and (c) dynamical changes of task demands (the external factor). Since workers in many social insect species exhibit age polyethism, we also extend our model to incorporate age polyethism in which worker task preferences change with age. We apply our general modeling framework to the cases of two task groups: the inside colony task versus the outside colony task. Our analytical study of the models provides important insights and predictions on the effects of colony size, social communication, and age-related task preferences on task allocation and division of labor in the adaptive dynamical environment. Our study implies that the smaller size colony invests its resource for the colony growth and allocates more workers in the risky tasks such as foraging while the larger colony shifts more workers to perform the safer tasks inside the colony. Social interactions among different task groups play an important role in shaping task allocation depending on the relative cost and demands of the tasks.

The organization of societal conflicts by pavement ants Tetramorium caespitum: an agent-based model of amine-mediated decision making.

Ant colonies self-organize to solve complex problems despite the simplicity of an individual ant’s brain. Pavement ant Tetramorium caespitum colonies must solve the problem of defending the territory that they patrol in search of energetically rich forage. When members of 2 colonies randomly interact at the territory boundary a decision to fight occurs when: 1) there is a mismatch in nestmate recognition cues and 2) each ant has a recent history of high interaction rates with nestmate ants. Instead of fighting, some ants will decide to recruit more workers from the nest to the fighting location, and in this way a positive feedback mediates the development of colony wide wars. In ants, the monoamines serotonin (5-HT) and octopamine (OA) modulate many behaviors associated with colony organization and in particular behaviors associated with nestmate recognition and aggression. In this article, we develop and explore an agent-based model that conceptualizes how individual changes in brain concentrations of 5-HT and OA, paired with a simple threshold-based decision rule, can lead to the development of colony wide warfare. Model simulations do lead to the development of warfare with 91% of ants fighting at the end of 1 h. When conducting a sensitivity analysis, we determined that uncertainty in monoamine concentration signal decay influences the behavior of the model more than uncertainty in the decision-making rule or density. We conclude that pavement ant behavior is consistent with the detection of interaction rate through a single timed interval rather than integration of multiple interactions.

BioSig3D: High Content Screening of Three-Dimensional Cell Culture Models.

BioSig3D is a computational platform for high-content screening of three-dimensional (3D) cell culture models that are imaged in full 3D volume. It provides an end-to-end solution for designing high content screening assays, based on colony organization that is derived from segmentation of nuclei in each colony. BioSig3D also enables visualization of raw and processed 3D volumetric data for quality control, and integrates advanced bioinformatics analysis. The system consists of multiple computational and annotation modules that are coupled together with a strong use of controlled vocabularies to reduce ambiguities between different users. It is a web-based system that allows users to: design an experiment by defining experimental variables, upload a large set of volumetric images into the system, analyze and visualize the dataset, and either display computed indices as a heatmap, or phenotypic subtypes for heterogeneity analysis, or download computed indices for statistical analysis or integrative biology. BioSig3D has been used to profile baseline colony formations with two experiments: (i) morphogenesis of a panel of human mammary epithelial cell lines (HMEC), and (ii) heterogeneity in colony formation using an immortalized non-transformed cell line. These experiments reveal intrinsic growth properties of well-characterized cell lines that are routinely used for biological studies. BioSig3D is being released with seed datasets and video-based documentation.

Nest Maintenance Activity of Dinoponera quadriceps in a Natural Environment

In social insects, task allocation can be more complex than workers merely falling into discrete task groups. Any activity performed by the colony cannot be fully understood in isolation from other activities because they may be interrelated. Investigating activities other than foraging is crucial to understanding the global functioning and organization of ant colonies. This study attempts to characterize the nest maintenance activity of the ponerine queenless ant, Dinoponera quadriceps, in its natural environment to determine the effects of environmental variables on the variations in both seasonal and daily rhythms and to discuss its differences and possible relationships to foraging. Four colonies of D. quadriceps were observed in an area of Atlantic Forest in northeastern Brazil. Data collection was performed over a period of 72 h every three months during an entire annual cycle. Nest maintenance activity in D. quadriceps colonies was observed during both the light and dark phases of the day. There was no significant difference between the day phases in the number of workers involved in this task. On the other hand, D. quadriceps colonies exhibited seasonal variation in nest maintenance activity, peaking in the early rainy season. The seasonal rhythm of nest maintenance was positively correlated with relative humidity and negatively correlated with prey availability and rainfall. Our results indicate the existence of an annual variation in the nest maintenance activity of D. quadriceps associated with environmental variables. However, it occurs equally both at night and day, countering the hypothesis that there is a daily rhythm.

Low relatedness and frequent inter-nest movements in a eusocial sweat bee

Halictid bees are good systems for studying the evolution and maintenance of eusociality, because they form small societies where females have multiple behavioural options (stay or leave, reproduce or help). Here, we investigate colony organization, inter-nest movements and patterns of reproduction in Halictus scabiosae, a species where foundresses rear a first brood of females that often behave as helpers to rear a second brood. Using non-destructive sampling and microsatellite genotyping, we monitored the genotypic composition of a sample of colonies over the entire reproductive season, which allowed us to reconstruct sibships and infer parentage within and across colonies. We detected that foundresses and females from the first brood often moved to foreign colonies. Moreover, foundresses were frequently replaced. At least 5 % of the females from the first brood reproduced. Eight of the ten cases of reproduction by first brood females occurred in foreign colonies. Because of extensive bee movements, many colonies contained offspring from unrelated individuals. The average genetic relatedness among bees sampled from the same colony was moderate (0.33 ± 0.02). The relatedness of the second brood to their colony foundresses and first brood females was only 0.14 and 0.21, respectively. The labile colony membership decreases the intra-colony relatedness and thus the inclusive fitness of helpers, but the behavioural flexibility of these bees may allow them to cope with variable environmental constraints.

Caste-Specific and Sex-Specific Expression of Chemoreceptor Genes in a Termite.

The sophisticated colony organization of eusocial insects is primarily maintained through the utilization of pheromones. The regulation of these complex social interactions requires intricate chemoreception systems. The recent publication of the genome of Zootermopsis nevadensis opened a new avenue to study molecular basis of termite caste systems. Although there has been a growing interest in the termite chemoreception system that regulates their sophisticated caste system, the relationship between division of labor and expression of chemoreceptor genes remains to be explored. Using high-throughput mRNA sequencing (RNA-seq), we found several chemoreceptors that are differentially expressed among castes and between sexes in a subterranean termite Reticulitermes speratus. In total, 53 chemoreception-related genes were annotated, including 22 odorant receptors, 7 gustatory receptors, 12 ionotropic receptors, 9 odorant-binding proteins, and 3 chemosensory proteins. Most of the chemoreception-related genes had caste-related and sex-related expression patterns; in particular, some chemoreception genes showed king-biased or queen-biased expression patterns. Moreover, more than half of the genes showed significant age-dependent differences in their expression in female and/or male reproductives. These results reveal a strong relationship between the evolution of the division of labor and the regulation of chemoreceptor gene expression, thereby demonstrating the chemical communication and underlining chemoreception mechanism in social insects.

Principles of organization of polistinae (Hymenoptera, Vespidae) population

The paper describes some invariant relations of the Polistinae population structure, including resistance to abiotic and biotic factors that occurs against the background of the hierarchy of biological systems and increasing autonomy of their functioning. A decrease in the dependence on the hostile environment is shown to be due to the activity of foundresses and workers adjusting to external rhythms, developing specialized responses to predators and parasites (predictable external noise of biotic nature), and creating new information. The population organization of Polistinae wasps is considered in the framework of Anokhin’s theory of functional systems and systemogenesis. There are specific processes in the population that unite individual colonies and their reproduction; they are accompanied by the formation of an advanced feedback and functional systems. Systemic processes can be simultaneously regarded as “adaptation” (reflecting the organization of environmental elements) and as “adaptiveness” (reflecting the organization of the activity of intra-colony processes and the organization of reproduction). The organization of the colony activity and reproduction in functional systems reflects the future survival rather than the preceding phenomena and events. The behavior of individuals in a colony is determined not only by the effects of abiotic and biotic factors (via transformation of cues into behavioral programs), but also by previous adaptations (stored in the “memory” as images of still absent events). General progress, limited or partial progress, and narrow specialization in the organization of polistine colonies and populations are considered using the examples of morphofunctional, environmental, energy and information criteria. The emphasis on invariant relations makes it possible to more fully describe biological systems in terms of such general categories as isomorphism, homeostasis or self-organization, and also enables us to use more effectively the theory of general functional systems in studying social insects.

Cell Differentiation and Spatial Organization in Yeast Colonies: Role of Cell-Wall Integrity Pathway.

Many microbial communities contain organized patterns of cell types, yet relatively little is known about the mechanism or function of this organization. In colonies of the budding yeast Saccharomyces cerevisiae, sporulation occurs in a highly organized pattern, with a top layer of sporulating cells sharply separated from an underlying layer of nonsporulating cells. A mutant screen identified the Mpk1 and Bck1 kinases of the cell-wall integrity (CWI) pathway as specifically required for sporulation in colonies. The CWI pathway was induced as colonies matured, and a target of this pathway, the Rlm1 transcription factor, was activated specifically in the nonsporulating cell layer, here termed feeder cells. Rlm1 stimulates permeabilization of feeder cells and promotes sporulation in an overlying cell layer through a cell-nonautonomous mechanism. The relative fraction of the colony apportioned to feeder cells depends on nutrient environment, potentially buffering sexual reproduction against suboptimal environments.

Blood transfusion in the Democratic Republic of Congo: efforts and challenges

The authors trace the history of blood transfusion in the Democratic Republic of Congo, as inherited through the colonial organization of the health system. The current configuration of transfusion system begins with the drafting of the national blood transfusion policy and the establishment of a national technical office within the Ministry of Health to coordinate transfusion activities and of its agents in each province. Despite countless difficulties, several positive points were noted. These involve essentially the drafting of all the necessary documents and standards and the integration of the blood safety system into the country's health system. Initially, the blood transfusion system applied a vertical approach, but with the reform of the country's health system, the performance of blood safety became transversal. In the 12 years from 2001 to 2012, it mobilized 112,882 volunteer blood donors; more than 80% of blood products were checked for safety and covered all blood needs; and 81,806 HIV infections were avoided by routine testing of blood products. During the same period, 7560 people were trained in blood transfusion. The prevalence of viral markers among donors has diminished sharply. Thus, HIV prevalence decreased from 4.7% to 2.1% between 2001 and 2012 that of hepatitis B dropped from 7.1% to 3.5% during the same period, and hepatitis C from 11.8% to 2.3% from 2004 to 2012. Despite this performance, enormous efforts are still required, for the organization of blood safety monitoring, the establishment of a safe supply of reagents and supplies, for sustaining the dynamics of voluntary associations of blood donors, and finally for providing stable funding for these blood safety activities.

REDISCOVERING AMERICA: POLITICAL ECONOMY OF SPANISH COLONIES ACCORDING TO THE EXPLORERS JUAN-ULLOA, MALASPINA AND HUMBOLDT

ABSTRACTTwo scientists and sailors from the Spanish Navy, Jorge Juan and Antonio de Ulloa, the Italian sailor and explorer Alessandro Malaspina, and the German sage Alexander von Humboldt were the main actors in three great voyages to Spanish America between the second-third of the 18thcentury and the beginning of the 19thcentury. This enabled them to provide three first hand«photographs»of the state of the Spanish empire in America at three different moments in time: approximately before, during and after the implementation of colonial reforms designed in the reigns of Ferdinand VI and Charles III. This work aims, in the first place, to compare the socio-economic views of Spanish America deriving from the three expeditions, highlighting similarities and differences. Second, this work aims to connect the analysis of the weaknesses of the politico-institutional organisation of Spanish colonies, which the four travellers did at first hand, with the present debate on the role of colonial institutions in long-term economic development.