Behavioral plasticity: levels of sociality in bees.
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Animals↗
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Results for “social evolution”
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The Raw and the Stolen. Cooking and the Ecology of Human Origins.
Cooking is a human universal that must have had widespread effects on the nutrition, ecology, and social relationships of the species that invented it. The location and timing of its origins are unknown, but it should have left strong signals in the fossil record. We suggest that such signals are detectable at ca. 1.9 million years ago in the reduced digestive effort (e.g., smaller teeth) and increased supply of food energy (e.g., larger female body mass) of early Homo erectus. The adoption of cooking required delay of the consumption of food while it was accumulated and/or brought to a processing area, and accumulations of food were valuable and stealable. Dominant (e.g., larger) individuals (typically male) were therefore able to scrounge from subordinate (e.g., smaller) individuals (typically female) instead of relying on their own foraging efforts. Because female fitness is limited by access to resources (particularly energetic resources), this dynamic would have favored females able to minimize losses to theft. To do so, we suggest, females formed protective relationships with male co-defenders. Males would have varied in their ability or willingness to engage effectively in this relationship, so females would have competed for the best food guards, partly by extending their period of sexual attractiveness. This would have increased the numbers of matings per pregnancy, reducing the intensity of male intrasexual competition. Consequently, there was reduced selection for males to be relatively large. This scenario is supported by the fossil record, which indicates that the relative body size of males fell only once in hominid evolution, around the time when H. erectus evolved. Therefore we suggest that cooking was responsible for the evolution of the unusual human social system in which pair bonds are embedded within multifemale, multimale communities and supported by strong mutual and frequently conflicting sexual interest.
Journal Article↗
Genetic diversity, asymmetrical aggression, and recognition in a widespread invasive species.
The evolution and persistence of cooperative social units depends on the ability to distinguish group members from nonmembers. The precision of discrimination, in turn, relies on variation in the labels that individuals use to recognize group members. However, this same variation can be selected against if individuals that are rejected as nonmembers incur a high cost. Here we provide evidence that selection against individuals from genetically diverse groups has contributed to the formation of the unicolonial colony structure that characterizes introduced populations of the invasive Argentine ant (Linepithema humile). Studies in both the laboratory and the field showed that individuals from less genetically diverse colonies attack individuals from more diverse colonies and that attackers survived agonistic encounters more than six times as often as recipients of aggression. This selection, in concert with reductions in genetic diversity after a founder event, likely creates a barrier to the establishment of new, genetically diverse introductions from the native range and may reduce genetic diversity within established populations in the introduced range.
Aggression↗
Molecular phylogeny of the large carpenter bees, genus Xylocopa (Hymenoptera: apidae), based on mitochondrial DNA sequences.
Carpenter bees, genus Xylocopa Latreille, a group of bees found on all continents, are of particular interest to behavioral ecologists because of their utility for studies of the evolution of mating strategies and sociality. This paper presents phylogenetic analyses based on sequences of two mitochondrial genes cytochrome oxidase 1 and cytochrome b for 22 subgenera of Xylocopa. Maximum-parsimony and maximum-likelihood methods were used to infer phylogenetic relationships. The analyses resulted in three resolved clades of subgenera: a South American group (including the subgenera Stenoxylocopa, Megaxylocopa, and Neoxylocopa), a group including the subgenera Xylocopa s.s. and Ctenoxylocopa, and an Ethiopean group (including the subgenera Afroxylocopa, Mesotrichia, Alloxylocopa, Platynopoda, Hoploxylocopa, and Koptortosoma). The relationships between the 11 other subgenera and the resolved clades are unclear. Within the Ethiopian group we found a clear separation of the African and the Oriental taxa and apparent polyphyly of the subgenus Koptortosoma. Using an evolutionary rate for ants, we investigated whether Gondwana vicariance or more recent dispersal events could best explain the present-day distribution of subgenera. Although some taxa show divergences that approach Gondwanan breakup times, most divergences between geographic groups are too recent to support a vicariance hypothesis.
Animals↗
Planet of the apes.
What makes us humans so special? Our language, our genes, our culture, our cognitive skills? At the Max-Planck-Institute for Evolutionary Anthropology in Leipzig, psychologists, linguists and biologists tackle this old question in a truly multidisciplinary way. Their results have implications not just for our understanding of human evolution--they also touch directly on many social and environmental issues. Florian Maderspacher reports.
Academies and Institutes↗
Aspects of bioenergetics and civilization.
By means of an allometric relation between the oxygen consumption rate and the body mass of an animal a metabolic coefficient is derived that can be used as a measure of standard metabolism in different animal species. This coefficient increased in the course of evolution corresponding to the time of appearance of each class of animal. It reached its highest values in Primates and passerine birds. A further increase across an energetic threshold was only possible with human civilization. A similar approach to evolution is performed through an encephalization coefficient showing that in all phases of evolution, species existed with a much larger relative brain volume than the other members of their class. These species might have established a non-human civilization on Earth if evolution would have taken another path. Finally, social activities of insects and the use of external energy sources by animals are discussed to show further implications of this bioenergetic approach to evolution.
Animals↗
Effects of Wolbachia on mtDNA variation in two fire ant species.
Wolbachia are endosymbiotic bacteria that infect arthropods. As they are maternally transmitted, the spread of Wolbachia variants within host populations may affect host mtDNA evolution. We sequenced a portion of the mitochondrial cytochrome oxidase I gene from numerous individuals of two Wolbachia-infected fire ant species, Solenopsis invicta and S. richteri, to determine how these bacteria influence patterns of mtDNA variation. As predicted, there was a strong association between Wolbachia strain and host mtDNA lineage within and between these fire ant species. However, there was no consistent association between the presence of Wolbachia and a reduction in mtDNA diversity. Moreover, patterns of mtDNA variation within Wolbachia-infected populations did not differ consistently from neutral expectations, despite our prediction that strong positive selection acting on Wolbachia influences the evolutionary dynamics of other cytoplasmic genomes. Specifically, while values of Tajima's D consistently were less than zero for all six samples of fire ants harbouring Wolbachia, MacDonald-Kreitman tests suggested that the patterns of variation were different from those expected under neutrality in only two of the samples. We conclude that these neutrality tests do not unambiguously reveal a clear effect of Wolbachia infection on patterns of mtDNA variation and substitution in fire ants. Finally, consistent with an earlier study, our data revealed the presence of two divergent mtDNA haplotype lineages and Wolbachia strains within S. invicta. Recognition of these two lineages has important consequences for interpreting patterns of mtDNA evolution and genetic differentiation between conspecific social forms of this species.
Animals↗
Animal cognition. Man's best friend(s) reveal the possible roots of social intelligence.
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Animals↗
[Social and economic impact of multiple sclerosis].
The evolution of multiple sclerosis is unforeseeable; it can induce disability and fatigue; thus, it has a socio-economical impact. Married and family life, relationships and work are the most affected areas. Financial problems can also occur. Counselling and aid services must be provided. All these social impacts induce an indirect cost which is the major component of the total cost of multiple sclerosis. Data show that there are great differences between countries and that the cost increases when there is a disability. The economic impact of the "new" drugs is unknown and must be assessed.
Counseling↗
Sympatric speciation through intraspecific social parasitism.
Sympatric speciation through intraspecific social parasitism has been proposed for the evolution of Hymenopteran workerless parasites. Such inquilines exploit related host taxa to produce their own sexual offspring. The relatedness of inquilines to their hosts has been generalized in Emery's rule, suggesting that social parasites are close or the closest relatives to their host species. If the closest relative of each parasite is its host, then multiple independent origins of the parasite species are implied even within a single genus, probably through sympatric speciation. To test the plausibility of sympatric speciation in inquilines, we conducted a mitochondrial DNA phylogenetic analysis in three inquiline-host pairs of Myrmica ant species. We show that congeneric inquilines have originated independently several times. We also show that two of the inqulines are more closely related to their hosts than to any other species. Our results suggest sympatric speciation of Myrmica inquilines. Sympatric speciation is probably facilitated by the social biology and ecology of Myrmica, with polygyny as a prerequisite for the evolution of intraspecific parasitism.
Animals↗
What is a marmoset?
Callitrichid primates typically give birth to twin offspring that are somatic chimeras of cells derived from two products of conception. Each individual is thus the phenotype of two sibling genotypes, one of which may be more closely related to the germ line of the individual's parents than to the individual's own germ line. Chimerism could therefore help to explain the evolution of alloparental care and social suppression of reproduction in callitrichids. Placental chimerism may also have important implications for understanding kin interactions within the womb: on one side of the coin, the intimate juxtaposition of genotypes provides unique opportunities for antagonistic interactions between embryos; on the other side, chimerism could facilitate cooperation between sibling genotypes.
Animals↗
Changes in physical activity and psychosocial determinants of physical activity in children and adolescents treated for obesity.
The purpose of this study was to describe changes in physical activity and determinants in youngsters treated for obesity. Self-reported physical activity and determinants were assessed at start, during and after an intervention in 24 obese patients (mean age 13.5+/-2.1 years). Participation in activities of moderate to high intensity increased during treatment, but 6-months after treatment this decreased again to pre-treatment levels. Participation in activities of low intensity and television watching decreased during treatment and increased following treatment. Very little change was found in perceived benefits, barriers or self-efficacy scores. Modelling of siblings decreased after treatment, whereas there was no evolution in modelling of parents. Social support by family members increased during treatment, but decreased following treatment. We can conclude that the intervention was successful in activating obese youngsters to move at the desirable exercise intensity and frequency; however, maintenance of the exercise habit after treatment was not successful.
Adolescent↗
Basic emotions, relations among emotions, and emotion-cognition relations.
From the cognitive theory perspective that emotions are cognition dependent and contain cognitive components, Ortony and Turner (1990) questioned the validity of the concept of basic emotions. They argued that the so-called basic emotions were neither psychologically or biologically "primitive" nor "irreducible building blocks" for generating the "great variety of emotional experiences." In the biosocial theory tradition, researchers have identified multiple noncognitive activators of emotion and demonstrated the usefulness of defining the essential components of emotion as phenomena that do not require cognitive mediators or constituents. In this framework, emotions are seen as basic because their biological and social functions are essential in evolution and adaptation. Particular emotions are called basic because they are assumed to have innate neural substrates, innate and universal expressions, and unique feeling-motivational states. The great variety of emotional experiences is explained as a function of emotion-cognition interactions that result in affective-cognitive structures.
Arousal↗
A literature review of advanced clinical nursing practice in the United States of America.
Advanced nursing practice in the United States of America has evolved over the past decades in two related but distinct directions:- the nurse practitioner (NP) and the clinical nurse specialist (CNS). This two-role evolution was in response to social demands for increased access to affordable, quality primary health care, and at the same time to the specialised nursing care requirements of increasingly complex patients. Thus, nurse practitioners became synonymous with primary and clinical nurse specialists with specialised, acute care. There is evidence that there is an advanced practice role for both the CNS and the NP and that much of the knowledge, skills and competencies are shared depending on the clinical situation. There have been successes and failures in the development of the two roles. The clinical nurse specialists have a more respectable image among the powerful nursing education elite, but nurse practitioners are widely recognised by consumers and other health care professionals and are valued by cost-conscious managers as a viable, cheaper alternative to physicians. The literature suggests it may well be time to take the best attributes of the two roles and merge them under the term 'advanced nurse practitioner'.
Education, Nursing↗
Differences in color vision make passerines less conspicuous in the eyes of their predators.
Sexual selection often favors brighter and exaggerated traits, which also increase the risk of detection by predators. Signals that are preferentially conspicuous to conspecifics would reduce the predation cost of signaling and, therefore, might facilitate the evolution of stronger sexual and social signals. This selective signaling is possible if predators and prey have differently tuned sensory systems. By using a retinal model to compare reflectance from the plumages of Swedish songbirds to the reflectance of their natural backgrounds, we found their color badges to be significantly more conspicuous to other songbirds (which have a UV-tuned visual system) than to raptors and corvids (which have a violet-tuned system) in both coniferous and deciduous forests, consistent with an adaptive private communication system.
Adaptation, Physiological↗
Psychosocial adjustment and employment outcome 2, 5 and 10 years after TBI.
OBJECTIVE: A patient's return to work has been considered a good indicator of his/her overall adaptation after suffering from TBI. A study has been designed at the Hospital del Trabajador to evaluate patients' psycho-pathological and social situations and to describe evolution and return-to-work predictors. Particular attention was paid to subjects' employment situations 2, 5 and 10 years after TBI. METHOD: TBI patients who had also suffered spinal cord injuries, amputations and other physical impairments were excluded. A total of 202 individuals were evaluated by a psychologist and an occupational therapist during clinical interviews using the Hamilton Anxiety and Depression Rating Scale and the Neurobehavioural Rating Scale (NRS-R). Work situations were evaluated by interviewing the subjects and family members and, whenever possible, a patient's immediate supervisor at his or her place of employment. RESULTS: Unemployed patients presented more severe symptoms of anxiety and depression than those who were working. Significant differences were observed in the NRS-R between employed and unemployed patients. There was no change in the marital status for at least 10 years after TBI. CONCLUSION: Factors determining a poor prognosis for adaptation and re-insertion into the workplace are age, a low educational level, a lack of job qualifications and greater cognitive impairments. The significant differences found between the NRS-R of employed and unemployed patients suggest that this variable may be used to predict a subject's ability to return to work.
Adaptation, Psychological↗
Active use of the metapleural glands by ants in controlling fungal infection.
Insect societies face constant challenges from disease agents. Ants deploy diverse antimicrobial compounds against pathogens and the key sources are metapleural glands (MGs). Are MG products passively secreted and used indiscriminately or are they selectively used when ants are challenged by pathogens? In 26 species from five subfamilies, ants use foreleg movements to precisely groom the MG opening. In the absence of experimental infection, MG grooming rates are low and workers groom themselves after contacting the MGs. The derived leaf-cutter ants (Atta and Acromyrmex) also groom their fungal gardens, substrata (leaves), queens and nest-mates after MG grooming. Atta respond to a challenge by fungal conidia by increasing the rate of MG grooming, but do not do so when an inert powder is applied. This increase occurs in the first hour after a potential infection, after which it returns to baseline levels. Ants with open MGs produce more infrabuccal pellets (IP) than ants with sealed MGs and conidia within pellets from the former are less likely to germinate. Thus, ants selectively groom their MGs when disease agents are present, suggesting that they also selectively use their MG secretions, which has important implications for understanding the evolution of hygienic behaviour in social groups.
Animals↗
Genomic analysis in the sting-2 quantitative trait locus for defensive behavior in the honey bee, Apis mellifera.
We have sequenced an 81-kb genomic region from the honey bee, Apis mellifera, associated with a quantitative trait locus (QTL) sting-2 for aggressive behavior. This sequence represents the first extensive study of the honey-bee genome structure encompassing putative genes in a QTL for a behavioral trait. Expression of 13 putative genes, as well as two transcripts that were present in a honey-bee EST database, was confirmed through reverse transcription analysis of mRNA from the honey-bee head. Whereas most transcripts exhibited little or no variation between European and Africanized honey-bee alleles, one transcript demonstrated significant nonsynonymous substitutions, deletions, and insertions. All 13 putative genes lacked similarity to known invertebrate or vertebrate proteins or transcripts. This observation may be reflective of the processes that determine the genomic evolution of an insect with social behavior and/or haplo-diploidy and are an indication of the unique nature of the honey-bee genome. These results make this sequence an invaluable research tool for the ongoing honey-bee whole-genome sequencing effort.
Animals↗