189 research outputs found

    Anarchy in the UK: Detailed genetic analysis of worker reproduction in a naturally occurring British anarchistic honeybee, Apis mellifera, colony using DNA microsatellites

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    Anarchistic behaviour is a very rare phenotype of honeybee colonies. In an anarchistic colony, many workers’ sons are reared in the presence of the queen. Anarchy has previously been described in only two Australian colonies. Here we report on a first detailed genetic analysis of a British anarchistic colony. Male pupae were present in great abundance above the queen excluder, which was clearly indicative of extensive worker reproduction and is the hallmark of anarchy. Seventeen microsatellite loci were used to analyse these male pupae, allowing us to address whether all the males were indeed workers’ sons, and how many worker patrilines and individual workers produced them. In the sample, 95 of 96 of the males were definitely workers’ sons. Given that ≈ 1% of workers’ sons were genetically indistinguishable from queen’s sons, this suggests that workers do not move any queen-laid eggs between the part of the colony where the queen is present to the area above the queen excluder which the queen cannot enter. The colony had 16 patrilines, with an effective number of patrilines of 9.85. The 75 males that could be assigned with certainty to a patriline came from 7 patrilines, with an effective number of 4.21. They were the offspring of at least 19 workers. This is in contrast to the two previously studied Australian naturally occurring anarchist colonies, in which most of the workers’ sons were offspring of one patriline. The high number of patrilines producing males leads to a low mean relatedness between laying workers and males of the colony. We discuss the importance of studying such colonies in the understanding of worker policing and its evolution

    The Seasonal Natural History of the Ant, Dolichoderus mariae, in Northern Florida

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    Dolichoderus mariae Forel, (Hymenoptera: Formicidae) is an uncommon, monomorphic but locally abundant, reddish-brown ant of peculiar nesting habits, whose range includes most of the eastern USA. In north Florida the ant excavates soil under wiregrass clumps or other plants with fibrous roots to form a single, large, shallow, conical or ovoid chamber broadly open to the surface around the plant base. Colonies are highly polygyne and, during the warm season, inhabit multiple nests connected only by above ground trails, over which nests exchange workers. Although monomorphic, worker size may differ significantly between colonies. The colony cycle is dominated by strong seasonal polydomy. From one or two over-wintering nests, the colonies expanded to occupy up to 60 nests by late summer, then retract once more to one or two nests by mid-winter. The worker-to-queen ratio changed greatly during this cycle, with over two thousand workers per queen during fall and winter, dropping to a low of about 300 during midsummer. Most of these summer queens probably die during the fall. Colonies reoccupy roughly the same area year to year even though they contract down to one or two nests in winter. Observation of fights in the contact zone between colonies suggested that the colonies are territorial. The ants subsist by tending aphids and scale insects for honeydew and scavenging for dead insects within their territories

    Complex hybrid origin of genetic caste determination in harvester ants

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    Caste differentiation and division of labour are the hallmarks of insect societies and at the root of their ecological success. Kin selection predicts that caste determination should result from environmentally induced differences in gene expression, a prediction largely supported by empirical data. However, two exceptional cases of genetically determined caste differentiation have recently been found in harvester ants. Here we show that genetic caste determination evolved in these populations after complex hybridization events. We identified four distinct genetic lineages, each consisting of unique blends of the genomes of the parental species, presumably Pogonomyrmex barbatus and P. rugosus. Crosses between lineages H1 and H2 and between J1 and J2 give rise to workers, whereas queens develop from within-lineage matings. Although historical gene flow is evident, genetic exchange among lineages and between lineages and the parental species no longer occurs. This unusual system of caste determination seems to be evolutionarily stable

    Prediction of social structure and genetic relatedness in colonies of the facultative polygynous stingless bee Melipona bicolor (Hymenoptera, Apidae)

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    Stingless bee colonies typically consist of one single-mated mother queen and her worker offspring. The stingless bee Melipona bicolor (Hymenoptera: Apidae) shows facultative polygyny, which makes this species particularly suitable for testing theoretical expectations concerning social behavior. In this study, we investigated the social structure and genetic relatedness among workers from eight natural and six manipulated colonies of M. bicolor over a period of one year. The populations of M. bicolor contained monogynous and polygynous colonies. The estimated genetic relatedness among workers from monogynous and polygynous colonies was 0.75 ± 0.12 and 0.53 ± 0.16 (mean ± SEM), respectively. Although the parental genotypes had significant effects on genetic relatedness in monogynous and polygynous colonies, polygyny markedly decreased the relatedness among nestmate workers. Our findings also demonstrate that polygyny in M. bicolor may arise from the adoption of related or unrelated queens

    Thelytokous Parthenogenesis in the Fungus-Gardening Ant Mycocepurus smithii (Hymenoptera: Formicidae)

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    The general prevalence of sexual reproduction over asexual reproduction among organisms testifies to the evolutionary benefits of recombination, such as accelerated adaptation to changing environments and elimination of deleterious mutations. Documented instances of asexual reproduction in groups otherwise dominated by sexual reproduction challenge evolutionary biologists to understand the special circumstances that might confer an advantage to asexual reproductive strategies. Here we report one such instance of asexual reproduction in the ants. We present evidence for obligate thelytoky in the asexual fungus-gardening ant, Mycocepurus smithii, in which queens produce female offspring from unfertilized eggs, workers are sterile, and males appear to be completely absent. Obligate thelytoky is implicated by reproductive physiology of queens, lack of males, absence of mating behavior, and natural history observations. An obligate thelytoky hypothesis is further supported by the absence of evidence indicating sexual reproduction or genetic recombination across the species' extensive distribution range (Mexico-Argentina). Potential conflicting evidence for sexual reproduction in this species derives from three Mycocepurus males reported in the literature, previously regarded as possible males of M. smithii. However, we show here that these specimens represent males of the congeneric species M. obsoletus, and not males of M. smithii. Mycocepurus smithii is unique among ants and among eusocial Hymenoptera, in that males seem to be completely absent and only queens (and not workers) produce diploid offspring via thelytoky. Because colonies consisting only of females can be propagated consecutively in the laboratory, M. smithii could be an adequate study organism a) to test hypotheses of the population-genetic advantages and disadvantages of asexual reproduction in a social organism and b) inform kin conflict theory

    Current Status of a Model System: The Gene Gp-9 and Its Association with Social Organization in Fire Ants

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    The Gp-9 gene in fire ants represents an important model system for studying the evolution of social organization in insects as well as a rich source of information relevant to other major evolutionary topics. An important feature of this system is that polymorphism in social organization is completely associated with allelic variation at Gp-9, such that single-queen colonies (monogyne form) include only inhabitants bearing B-like alleles while multiple-queen colonies (polygyne form) additionally include inhabitants bearing b-like alleles. A recent study of this system by Leal and Ishida (2008) made two major claims, the validity and significance of which we examine here. After reviewing existing literature, analyzing the methods and results of Leal and Ishida (2008), and generating new data from one of their study sites, we conclude that their claim that polygyny can occur in Solenopsis invicta in the U.S.A. in the absence of expression of the b-like allele Gp-9b is unfounded. Moreover, we argue that available information on insect OBPs (the family of proteins to which GP-9 belongs), on the evolutionary/population genetics of Gp-9, and on pheromonal/behavioral control of fire ant colony queen number fails to support their view that GP-9 plays no role in the chemosensory-mediated communication that underpins regulation of social organization. Our analyses lead us to conclude that there are no new reasons to question the existing consensus view of the Gp-9 system outlined in Gotzek and Ross (2007)

    Physical training in boys with Duchenne Muscular Dystrophy: the protocol of the No Use is Disuse study

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    Contains fulltext : 89740.pdf (publisher's version ) (Open Access)BACKGROUND: "Use it or lose it" is a well known saying which is applicable to boys with Duchenne Muscular Dystrophy (DMD). Besides the direct effects of the muscular dystrophy, the increasing effort to perform activities, the fear of falling and the use of personal aids indirectly impair leg and arm functions as a result of disuse. Physical training could oppose this secondary physical deterioration. The No Use is Disuse (NUD) study is the first study in human subjects with DMD that will examine whether a low-intensity physical training is beneficial in terms of preservation of muscle endurance and functional abilities. The study consists of two training intervention studies: study 1 "Dynamic leg and arm training for ambulant and recently wheelchair-dependent boys with DMD and, study 2 "Functional training with arm support for boys with DMD who have been confined to a wheelchair for several years". This paper describes the hypotheses and methods of the NUD study. METHODS: Study 1 is an explorative randomized controlled trial with multiple baseline measurements. Thirty boys with a DNA-established diagnosis of DMD will be included. The intervention consists of a six-months physical training during which boys train their legs and arms with active and/or assisted cycling training equipment. The primary study outcomes are muscle endurance and functional abilities, assessed with a Six-Minute Bicycle Test and the Motor Function Measure. Study 2 has a within-group repeated measurements design and will include ten boys with DMD who have already been confined to a wheelchair for several years. The six-months physical training program consists of 1) a computer-assisted training and 2) a functional training with an arm support. The primary study outcome is functional abilities of the upper extremity, assessed with the Action Research Arm Test. DISCUSSION: The NUD study will fill part of the gap in the current knowledge about the possible effects of training in boys with DMD and will increase insight into what type of exercise should be recommended to boys with DMD. The study will finish at the end of 2010 and results are expected in 2011. TRIAL REGISTRATION: The Netherlands National Trial Register1631

    Evaluating the Psychometric Quality of Social Skills Measures: A Systematic Review

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    Introduction - Impairments in social functioning are associated with an array of adverse outcomes. Social skills measures are commonly used by health professionals to assess and plan the treatment of social skills difficulties. There is a need to comprehensively evaluate the quality of psychometric properties reported across these measures to guide assessment and treatment planning. Objective - To conduct a systematic review of the literature on the psychometric properties of social skills and behaviours measures for both children and adults. Methods - A systematic search was performed using four electronic databases: CINAHL, PsycINFO, Embase and Pubmed; the Health and Psychosocial Instruments database; and grey literature using PsycExtra and Google Scholar. The psychometric properties of the social skills measures were evaluated against the COSMIN taxonomy of measurement properties using pre-set psychometric criteria. Results - Thirty-Six studies and nine manuals were included to assess the psychometric properties of thirteen social skills measures that met the inclusion criteria. Most measures obtained excellent overall methodological quality scores for internal consistency and reliability. However, eight measures did not report measurement error, nine measures did not report cross-cultural validity and eleven measures did not report criterion validity. Conclusions - The overall quality of the psychometric properties of most measures was satisfactory. The SSBS-2, HCSBS and PKBS-2 were the three measures with the most robust evidence of sound psychometric quality in at least seven of the eight psychometric properties that were appraised. A universal working definition of social functioning as an overarching construct is recommended. There is a need for ongoing research in the area of the psychometric properties of social skills and behaviours instruments
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