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Objectives: Basilar artery occlusion (BAO) may be etiologically attributed to embolism or in situ thrombosis due to basilar stenosis (BS). Patients with BAO due to BS (BAOS) are known to have worse outcomes than patients with embolic occlusions (BAOE). BAOS occurs more proximally in the basilar artery (BA) than BAOE. We hypothesize that differing brain stem infarct patterns contribute to outcome differences between these stroke etiologies. Methods: This retrospective study includes 199 consecutive patients with BAO who received endovascular treatment at a single center. Final infarction in brain parenchyma dependent on the posterior circulation was graded semiquantitatively on magnetic resonance imaging (MRI). Associations to underlying stenosis and angiographic and clinical outcome variables were tested. The primary endpoint was early good clinical outcome (EGCO, mRS score ≤ 3 at discharge). Results: Infarct extension of the medulla oblongata (OR = 0.25; 95% CI = 0.07–0.86; p = 0.03), the inferior pons (OR = 0.328; 95% CI = 0.17–0.63; p = 0.001), the superior pons (OR = 0.57; 95% CI = 0.33–0.99; p = 0.046), and the occipital lobes (OR = 0.46; 95% CI = 0.26–0.80; p = 0.006) negatively predicted EGCO. Infarct extension for other posterior-circulation-dependent brain regions was not independently associated with unfavorable early outcomes. Patients with BAOS had more proximal occlusions and greater infarct volumes in the inferior brain stem. Successful reperfusion (mTICI 2b-3) occurred more often in patients with BAOE than in BAOS (BAOE: 131 (96.3%); BAOS: 47 (83.9%), p = 0.005). Conclusion: Unfavorable early outcomes in patients with BAOS may be explained by a higher likelihood of inferior brain stem infarcts and lower rates of reperfusion success. Clinical relevance statement: Basilar artery occlusion due to underlying stenosis is associated with a poorer prognosis than that caused by embolism; these results suggest that aggressive endovascular therapy, usually involving the placement of a permanent stent, may be warranted in these patients. Key Points: Inferior brain stem and occipital infarcts are prognostically unfavorable in basilar artery occlusion. Basilar artery occlusion due to stenosis occurs more proximally and is associated with worse outcomes. Differentiating etiologies of basilar artery occlusion may influence how aggressively treated the occlusion is. [ABSTRACT FROM AUTHOR]

Magnetic resonance imaging (MRI) is an important imaging modality in stroke. Computer based automated medical image processing is increasingly finding its way into clinical routine. The Ischemic Stroke Lesion Segmentation (ISLES) challenge is a continuous effort to develop and identify benchmark methods for acute and sub-acute ischemic stroke lesion segmentation. Here we introduce an expert-annotated, multicenter MRI dataset for segmentation of acute to subacute stroke lesions (https://doi.org/10.5281/zenodo.7153326). This dataset comprises 400 multi-vendor MRI cases with high variability in stroke lesion size, quantity and location. It is split into a training dataset of n = 250 and a test dataset of n = 150. All training data is publicly available. The test dataset will be used for model validation only and will not be released to the public. This dataset serves as the foundation of the ISLES 2022 challenge (https://www.isles-challenge.org/) with the goal of finding algorithmic methods to enable the development and benchmarking of automatic, robust and accurate segmentation methods for ischemic stroke. [ABSTRACT FROM AUTHOR]

The Shamlugh polymetallic deposit located in the Alaverdi mining district, Armenia, is hosted by Middle Jurassic magmatic rocks of the Somkheto–Karabakh island arc, Lesser Caucasus. Lithogeochemistry and radiogenic isotope geochemistry indicate a subduction setting with an evolution from tholeitiic to transitional Middle Jurassic magmatism to calc-alkaline to high-K calc-alkaline Late Jurassic magmatism. A progressively more juvenile mantellic input in the magmatic source is noted. Ore consists of stratabound massive sulfide ore bodies, ore-bearing breccia, stockwork-style mineralization, and disseminated ore hosted by a pyroclastic host rock unit below a subvolcanic rhyolitic sill. Towards depth, the stratabound ore is connected to subvertical high-grade sulfide veins hosted by basaltic andesitic, andesitic, and dacitic tuff and lava breccia. Ore minerals include principally pyrite and chalcopyrite with minor sphalerite and hematite. Hydrothermal alteration consists of quartz, chlorite, carbonate, and sericite in the footwall pyroclastic rock, tuff, and lava breccia, which are also crosscut by late-stage carbonate and barite veins. The rhyolitic sill has been altered by silica and sericite and contains rare sulfides. Sulfur isotope values for sulfides range from + 0.7 to + 4.6‰ and suggest an essentially magmatic source for sulfur. Strontium isotopic compositions of hydrothermal carbonates and sulfates (0.70507–0.70660), sulfur isotopes of sulfates (+ 16.8 to + 17.3), and carbon and oxygen isotopic compositions of late-stage carbonates (δ18O VSMOW + 15.9 to + 17.6‰; δ13C VPDB − 1.8 to − 0.8‰) not only are permissive with seawater incursion in the ore-forming hydrothermal system but can also be attributed to fluid–rock interaction with hidden metamorphic basement rocks and Jurassic magmatic rocks. The lead isotopic composition of sulfides (206Pb/204Pb 18.505 to 18.586, 207Pb/204Pb 15.611 to 15.636, 208Pb/204Pb 38.516 to 38.640) implies leaching of the Middle Jurassic host rocks as the main source of Pb. LA-ICP-MS U–Pb zircon dating of the hanging wall rhyolitic sill affected by hydrothermal alteration yielded an age of 155.0 ± 1.0 Ma and provides a maximum age for mineralization. Ore formation at Shamlugh is younger than the immediate Middle Jurassic host rocks and is related to the Late Jurassic calc-alkaline and high-K calc-alkaline magmatic evolution. Late Jurassic magmatism includes a tonalite dated by LA-ICP-MS U–Pb zircon geochronology at 152.9 ± 0.7 Ma that hosts the 146-Ma-old Teghout porphyry deposit. In the absence of other age constraints, the genetic relationship of the polymetallic Shamlugh deposit with the Teghout porphyry deposit remains open to question. Nevertheless, hydrothermal minerals and alteration paragenesis and the lithologically and structurally controlled ore body geometry at Shamlugh are consistent with a low to intermediate sulfidation epithermal model. [ABSTRACT FROM AUTHOR]

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Heating of quartz crystals in order to study melt and high-temperature fluid inclusions is a common practice to constrain major physical and chemical parameters of magmatic and hydrothermal processes. Diffusion and modification of trace element content in quartz and its hosted melt inclusions have been investigated through step-heating experiments of both matrix-free quartz crystals and quartz crystals associated with sulfides and other minerals using a Linkam TS1500 stage. Magmatic and hydrothermal quartz were successively analyzed after each heating step for Cu, Al, and Ti using electron probe micro-analyzer. After the last heating step, quartz crystals and their hosted melt inclusions were analyzed by laser ablation inductively coupled plasma mass spectrometry and compared to unheated samples. Heated samples reveal modification of Cu, Li, Na, and B contents in quartz and modification of Cu, Li, Ag, and K concentrations in melt inclusions. Our results show that different mechanisms of Cu, Li, and Na incorporation occur in magmatic and hydrothermal quartz. Heated magmatic quartz records only small, up to a few ppm, enrichment in Cu and Na, mostly substituting for Li. By contrast, heated hydrothermal quartz shows enrichment up to several hundreds of ppm in Cu, Li, and Na, which substitute for originally present H. This study reveals that the composition of both quartz and its hosted melt inclusions may be significantly modified upon heating experiments, leading to erroneous quantification of elemental concentrations. In addition, each quartz crystal also becomes significantly enriched in Cu in the sub-surface layer during heating. We propose that sub-surface Cu enrichment is a direct indication of Cu diffusion in quartz externally sourced from both the surrounding sulfides as well as the copper pins belonging to the heating device. Our study shows that the chemical compositions of both heated quartz and its hosted inclusions must be interpreted with great caution to avoid misleading geological interpretations. [ABSTRACT FROM AUTHOR]

The nomadic, swarm-raiding army ant Labidus praedator (Smith, 1858) is an important arthropod predator in the Neotropics with a strong ecological impact on invertebrate communities. However, despite its high abundance and ubiquity over a large distribution range, it received relatively little scientific attention. Moreover, the taxonomic status is confusing because some morphological descriptions point towards the co-occurrence of several distinct taxa which are lumped together as L. praedator in most classical keys. Yet, clarifying genetic studies are lacking. Here, we show strong genetic differentiation within an L. praedator population in Mexico. Both microsatellite genotype patterns and phylogenetic analyses (concatenated nuclear and mtDNA sequences, including the coxI genetic barcoding region), reveal the occurrence of two strongly isolated lineages. Colonies from the very same location, clearly identified as the same species ( L. praedator) according to classical morphological keys, exhibit an extremely high average sequence divergence (9.7-12.8 %), which was well in the range of divergence among GenBank sequences from other Labidus species. Thus, our data very likely show genetic differentiation at species level or cryptic speciation within L. praedator, which should be recognized when investigating biodiversity and ecological importance of army ants (or other arthropods) in the Neotropics. [ABSTRACT FROM AUTHOR]

Introduction: The goal of this work was to describe the change of treatment paradigms for metastatic renal cell carcinoma (mRCC) since 2006.Patients and Methods: We retrospectively investigated all mRCC patients who were treated with targeted therapy between June 2006 and June 2012 at the University of Münster.Results: In all, 50 of 158 (31.6 %) patients were initially treated with immunotherapy. The most often used second line treatment after immunotherapy was sorafenib (29 patients, 58.0 %). The first line treatment chosen for therapy-naïve patients was sunitinib (68 patients, 63.0 %). There was no statistically significant difference between the two groups (572 vs. 554 days, p = 0.745). A total of 77 patients had synchronous metastasis (48.8 %), 55 of whom underwent cytoreductive nephrectomy. There was a significant survival benefit in favor of surgically treated patients (510 vs. 186 days, p = 0.002).Conclusion: After introduction of the new agents treatment paradigms have changed substantially. Immunotherapy is used only rarely. Cytoreductive nephrectomy may continue to be regarded as standard treatment until prospective data are available. [ABSTRACT FROM AUTHOR]

Evolutionary theory predicts that high genetic variation maintains plasticity in a species' response to parasite pressure. However, higher genetic diversity might also cause easier infiltration by social parasites, because odour diversity is high and nest-mate recognition poor. Here we test if the obligate myrmecophile Lycaenid butterfly Phengaris nausithous, a parasite of colonies of the highly polygynous ant Myrmica rubra causes local adaptation by enhancing genetic variance in parasitized versus non parasitized ant populations M. rubra colonies from six infested and three uninfested sites were assayed at five microsatellite loci to quantify genetic variation. Our results reveal isolation by distance and a significantly enhanced intracolonial variance due to the parasite pressure. [ABSTRACT FROM AUTHOR]

One of the main competing theories to describe the evolution of recombination is the Red Queen hypothesis (RQH). Presently, many theoretical analyses of the RQH typically examine fitness interactions in host-parasite frameworks. Less emphasis has been placed on understanding the impact of host ploidy in these systems. In this study, we look to investigate the high observed rates of recombination observed in two common haplodiploid species ( Apis mellifera and Bombus terrestris). We compared haplodiploid to diploid host populations under infection with haploid asexual parasites, using a matching allele model. Results from a simulation analysis showed that the Red Queen does not run in haplodiploid hosts and is therefore, probably not responsible for the high recombination rates observed so far in haplodiploid hosts. [ABSTRACT FROM AUTHOR]

Larvae of Phengaris ( Maculinea) butterflies are adopted by Myrmica workers and are obligate myrmecophiles. Brood recognition by Myrmica rubra workers was tested for concolonial larvae ( M. rubra) versus allocolonial larvae ( M. rubra and P. nausithous) to assay the mimetic efficiency of P. nausithous. In addition, we tested M. rubra ant colonies from different populations with and without the presence of Phengaris, to test for potential local adaptation in adoption behaviour. We show that M. rubra can distinguish between nest-mate and foreign larvae as well as between P. nausithous and their own larvae. Workers from the allopatric population inspected and rejected more P. nausithous larvae than workers from the sympatric population. This might reflect a local host adaptation in which the social parasite more efficiently mimes its sympatric host ants than allopatric ones. [ABSTRACT FROM AUTHOR]

Habitat degradation and fragmentation are widespread phenomena in tropical regions. Negative effects on the biota are numerous, ranging from interruption of gene flow among populations, to the loss of genetic diversity within populations, to a decline in species richness over time. Orchid bees (Hymenoptera: Apidae: Euglossini) are of major conservation interest due to their function as pollinators of numerous orchid species and other tropical plants. Here, we used microsatellite markers to investigate the effects of geographic distance and habitat fragmentation on gene flow among populations. Populations of Euglossa dilemma in three geographic regions-the Yucatán peninsula (Mexico), Veracruz (Mexico), and Florida (USA)-were genetically structured predominantly across the regions, with the strength of differentiation among populations being positively correlated with geographic distance. Within geographic regions only little substructure was found, suggesting that dispersal is substantial in the absence of geographic or ecological barriers. In a second study, patterns of genetic differentiation among eight species of Euglossa were not related to habitat fragmentation following deforestation in southern Mexico (Veracruz). Specifically, most bee populations in the 9,800 ha forest remnant of Los Tuxtlas (Volcano San Martin) were neither differentiated from, nor had less genetic diversity than, populations in near-continuous forest separated from Los Tuxtlas by 130 km of agricultural land. Either occasional long distance dispersal across open areas has buffered the expected genetic effects of fragmentation, or the history of fragmentation in southern Mexico is too recent to have caused measurable shifts in allelic composition. [ABSTRACT FROM AUTHOR]

Copyright of Der Urologe A is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bumblebees ( Bombus spp.) are commonly used for greenhouse pollination of tomatoes and other crop plants. The colonies used for this purpose are provided by commercial bumblebee breeders, which by now operate at a professional company level. As a result of this practice commercially bred bumblebee colonies are transported and used over large distances and national borders, introducing subspecies into non-endemic regions. The question whether and to what extends gene flow between such managed greenhouse and wild bumblebee populations exists, so far has not been addressed. Here we used samples from three greenhouses in Poland and the surrounding populations to address this question. Using microsatellite DNA data we found strong genetic introgression from the sampled greenhouse populations into the adjacent populations. Depending on the analysed population, the number of individuals assigned to the greenhouse populations ranged from 0.08 to 0.47. We also found that more distant populations were much less affected by genetic introgression from the greenhouses. [ABSTRACT FROM AUTHOR]

fter the transition from a savannah to a desert about 10,000 years ago the isolated Saharan oases offer a unique case for studying the effect of population fragmentation and isolation over a period of many thousand years. We use the honeybee, Apis mellifera, as a test system because they are an abundant wild species in the African dry savannahs but are particularly sensitive to drift and bottlenecks in small isolated populations due to the small effective size resulting from male haploidy, the sex determination system and sociality. We compared the non-fragmented coastal population with the oases of Brak and Kufra using 15 polymorphic microsatellite loci assessing the mating frequency, colony density, gene diversity, and population differentiation. We found that the honeybee population of the remote oasis of Kufra is well isolated whereas those of the oasis of Brak and the coastal regions show genetic foot prints of introgression by commercial beekeeping. The isolated Kufra population showed no indications of inbreeding suggesting that the endemic population size is sufficient to ensure sustainable local survival. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the clinical course of patients with the rare finding of regional lymph node metastasis (RLNM) from soft tissue sarcoma. Data from 28 out of 1,597 consecutive soft tissue sarcoma patients with RLNM were from the patients’ charts and interviewing patients and general practitioners. Survival, including possible influencing factors, was statistically calculated. RLNM was seen in 21.4% for epithelioid sarcoma and 17.6% for clear cell sarcoma. All other entities presented RLNM rates below 10%. At follow-up after an average of 9.6 years, only three patients were alive with no evidence of disease. Survival was independent from surgical resection status of the primary tumor and the RLNM as well as from adjuvant radiation and chemotherapy. Tumor entity as well as the length of the time period from primary to RLNM affect survival. Surgical treatment as well as radiation and chemotherapy may improve survival in selected cases but probably have their value much more in terms of local disease control and improvement life quality of patients who probably already suffer from an aggressive systemic disease at time of nodal involvement. [ABSTRACT FROM AUTHOR]

The evolution and maintenance of parthenogenetic species are a puzzling issue in evolutionary biology. Although the genetic mechanisms that act to restore diploidy are well studied, the underlying genes that cause the switch from sexual reproduction to parthenogenesis have not been analysed. There are several species that are polymorphic for sexual and parthenogenetic reproduction, which may have a genetic basis. We use the South African honeybee subspecies Apis mellifera capensis to analyse the genetic control of thelytoky (asexual production of female workers). Due to the caste system of honeybees, it is possible to establish classical backcrosses using sexually reproducing queens and drones of both arrhenotokous and thelytokous subspecies, and to score the frequency of parthenogenesis in the resulting workers. We found Mendelian segregation for thelytoky of egg-laying workers, which appears to be controlled by a single major gene (th). The segregation pattern indicates a recessive allele causing thelytoky. We found no evidence for maternal transmission of bacterial endosymbionts controlling parthenogenesis. Thelytokous parthenogenesis of honeybee workers appears to be a classical qualitative trait, because we did not observe mixed parthenogenesis (amphitoky), which might be expected in the case of multi-locus inheritance.Heredity (2005) 94, 533-537. doi:10.1038/sj.hdy.6800654 Published online 2 March 2005 [ABSTRACT FROM AUTHOR]

Honeybee queens (Apis mellifera) show extreme levels of polyandry, but the evolutionary mechanisms underlying this behaviour are still unclear. The “sperm-limitation hypothesis”, which assumes that high levels of polyandry are essential to get a lifetime sperm supply for large and long-lived colonies, has been widely disregarded for honeybees because the semen of a single male is, in principle, sufficient to fill the spermatheca of a queen. However, the inefficient post-mating sperm transfer from the queen’s lateral oviducts into the spermatheca requires multiple matings to ensure an adequate spermatheca filling. Males of the African honeybee subspecies A. m. capensis have fewer sperm than males of the European subspecies A. m. carnica. Thus, given that sperm limitation is a cause for the evolution of multiple mating in A. mellifera, we would expect A. m. capensis queens to have higher mating frequencies than A. m. carnica. Here we show that A. m. capensis queens indeed exhibit significantly higher mating frequencies than queens of A. m. carnica, both in their native ranges and in an experiment on a North Sea island under the same environmental conditions. We conclude that honeybee queens try to achieve a minimum number of matings on their mating flights to ensure a sufficient lifetime sperm supply. It thus seems premature to reject the sperm-limitation hypothesis as a concept explaining the evolution of extreme polyandry in honeybees. [ABSTRACT FROM AUTHOR]

Honeybee workers, Apis mellifera, usually do not reproduce but can activate their ovaries under queenless conditions to produce male offspring. As an exception to this rule, laying workers of the Cape honeybee, A. m. capensis, parthenogenetically produce diploid female offspring, usually developing into workers and occasionally into queens. Some of such workers can develop into pseudoqueens, which show high ovarial development and a queenlike pheromonal bouquet. Because there is high genetic variance for these characters, this results in an extreme intracolonial selection. This process is governed by a competition for reproductive dominance among workers, leading into a facultative social parasitic reproductive pathway as part of the life history of the Cape honeybee. A. m. capensis workers show an increased potential for invading foreign colonies. Inside of the host colony, parasitic A. m. capensis workers produce queenlike pheromones and swiftly activate the ovaries, despite the presence of a queen. Eventually they establish themselves as pseudoqueens and replace the host queen. The parasitic worker offspring is preferentially fed by the host workers, leading to highly virulent intercastes and thereby completing the social parasitic life cycle of laying A. m. capensis workers. Recently, a particularly virulent parasitic strain of A. m. capensis workers has invaded the neighboring subspecies A. m. scutellata (” capensis calamity”). Because male sexuals are completely lacking in this invasive strain and female reproductives are never reared in infested A. m. scutellata host colonies, this results in reproductive isolation of the parasitic clones from the host gene pool and sets the stage for the evolution of a queenless social parasitic honeybee. The Cape honeybee may therefore constitute a unique subject for studying sympatric speciation of a social parasite. [ABSTRACT FROM AUTHOR]

Individually labeled newly emerged honeybee workers were introduced into three queenright host colonies. The host colonies were housed in observation hives with one brood frame. The location of the workers during their first eleven days of life was monitored. In the initial phase of the experiment, the queen was allowed to roam freely in the colony. In a second phase of the experiment the queen was caged on one side of the frame. In all three colonies workers were observed either being attracted to or avoiding the queen. The mandibular gland secretions of workers attracted to the queen more often had the typical worker like mandibular gland secretion whereas workers avoiding the queen, produced a mandibular gland secretion more similar to that of a queen. This suggests that the workers avoiding the queen are attempting to escape queen control which otherwise suppresses the secretion of queen like pheromones. [ABSTRACT FROM AUTHOR]

A number of hypotheses have been proposed to explain the evolution of multiple mating in the honeybee queen. In particular, the consequences of reduced intracolonial relatedness provide plausible explanations for multiple mating with up to ten drones, but fail to account for the much higher mating frequencies observed in nature. In this paper, we propose an alternative mechanism which builds on non-linear relationships between intracolonial frequencies in genotypic worker specialization and colony fitness. If genes for any worker specialization confer an advantage on colony fitness only when they are rare, this would require a stable mix of sperm from a few drones which contribute that trait, and many which do not. To ensure both specific, low within-colony proportions of “rare specialist” genes, and to reduce random variation of these proportions would require mating with high numbers of drones. The quantitative implementation shows that moderate to very high numbers of matings are required to exploit colony advantages from genotypic allocation of workers to rare tasks. Extreme polyandry thus could result from colony selection dependent on the intracolonial frequency of rare genetic specialists. [ABSTRACT FROM AUTHOR]

We investigated absconding frequency and latency in queenright and queenless honeybee colonies in thelytokous Apis mellifera capensis, arrhenotokous Apis mellifera scutellata and their natural thelytokous hybrids. There was no significant difference in frequency of absconding among any of the queenright colonies. Absconding was significantly greater in thelytokous queenless colonies than in the queenless arrhenotokous ones. Latency to absconding did not differ among the three groups of queenright colonies nor between the queenright and queenless colonies of A.m. capensis and A.m. scutellata. There were significant differences in latency between queenright and queenless hybrids and significant differences in latency among the three groups of queenless colonies. Among queenless colonies, A.m. capensis absconded twice as readily as did A. m. scutellata and the hybrids were intermediate. Afterabsconding events include the fates of the absconding colony as well as nestmates left behind. One group of orphaned nestmates of A. m. capensis amalgamated with another queenright colony. In the case of A. m. scutellata either drones were produced or the residual queenless colony was joined by a queenless thelytokous group, subsequently reared a queen and then absconded. Differences in the rate and degree of ovarial development indicate that queenless thelytokous workers have the physiological capacity for reproduction, a trait that contributes to colony fitness. [ABSTRACT FROM AUTHOR]

The defensive behaviour of honey bee colonies ( Apis mellifera L.) was quantitated in the field throughout a three month season by the use of a standardized test in which numbers of stings in a leather target were counted after single colonies were opened and exposed to alarm pheromone. The main results show how the defensive behaviour of honey bees is highly dependent on weather factors. Eliminating genetic variance, the following meteorological variables account for 92.4% of the variation in defensive behaviour: air temperature, solar radiation intensity, wind velocity, relative humidity, and barometric pressure. [ABSTRACT FROM AUTHOR]

Patterns of restriction fragment length polymorphisms (RFLP) of European Vespinae were more similar within genera than between them. Distance trees were constructed that support the hypothesis of monophyly of the genera Vespula and Dolichovespula. Within the genus Vespula, V. germanica was more closely related to V. rufa than to V. vulgaris. The position of the genus Vespa remained uncertain due to the precision limits of the RFLP technique. [ABSTRACT FROM AUTHOR]

The ground nesting Trigona denoiti as well as the arboreal nesting T. gribodoi have nest cavities with only a single narrow entrance tube. For air exchange in the nest to occur, the bees have to ventilate the nest actively. As a consequence the air is exchanged in a similar way as in vertebrates with lungs. Phases of inspiration follow phases of expiration ('breathing' frequency in the range of 2-3 breaths/min) and tidal volumes range from 0.63±0.24 ml in T. denoiti to 1.13±0.32 in T. gribodoi. Ventilation during night time was strongly reduced. [ABSTRACT FROM AUTHOR]

Queens, homozygous for three marker genes, were inseminated with eight different types of semen, each carrying one combination of the markers. Intracolonial worker relationship (ř) was estimated by genotype frequencies in the offspring of the experimental queens. ř was larger than under random distribution of semen types in the spermatheca. Estimates of most quantitative genetical parameters will be more accurate using the presented estimator for intracolonial relationship. The insemination order affected genotype frequencies in the offspring, suggesting a weak 'last male advantage'. There was, however, no evidence of intra spermathecal sperm competition. [ABSTRACT FROM AUTHOR]

A new approach is presented to estimate the genetic variance of social behaviour of groups. Honeybees ( Apis mellifera L.) are used as an example for highly social organisms. Most characters of economic importance strongly rely on collective group characters of honeybee colonies. The average relatedness between small groups of workers of one honeybee colony can be estimated using a discrete multinomial distribution. The genetic variance of a social behaviour (alarm behaviour) of groups of honeybee workers is estimated with the intraclass correlation between groups within a colony. In two populations tested, the coefficient of genetic determination was high (0.96-0.98) indicating that the metabolic bio-assay used was only weakly affected by environmental effects. [ABSTRACT FROM AUTHOR]

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Genetic relatedness of the mound-building ant Formica pratensis was determined by means of microsatellite DNA polymorphism, and its impact on nestmate recognition was tested in a population in Southern Sweden (Oeland). Recognition between nests was measured by testing aggression levels between single pairs of workers. The genetic distances of nests (Nei's genetic distance) and the spatial distance of nests were correlated and both showed a strong relation to the aggression behavior. Multiple regression analysis revealed a stronger impact of genetic relatedness rather than spatial distances on aggression behavior. Neighbouring nests were more closely related than distant nests, which may reflect budding as a possible spreading mechanism. The genetic distance data showed that nestmate recognition was strongly genetically influenced in F. pratensis. [ABSTRACT FROM AUTHOR]

Two subspecies of honeybees, Apis mellifera capensis and A. m. scutellata provide an ideal model to test for the significance of reproductive workers in natural populations of honeybees. Laying workers of A.m.capensis parthenogenetically produce female offspring (thelytoky) whereas workers of the other subspecies produce male offspring (arrhenotoky). By using a two allele marker system in both the mitochondrial (mt) and in the nuclear (nuc) DNA, a deterministic population genetical model shows that through the differences in laying worker reproduction alone, clines of the mt and the nuc marker should be shifted. The stronger the impact of laying workers the further should the capensis mt type introgress into the scutellata population. The theoretical model is supported by empirical data from the hybrid zone between the two subspecies. The nuc hybrid zone begins 200 km south of the mt hybrid zone indicating a significant impact of the laying workers on colony reproduction. [ABSTRACT FROM AUTHOR]

The number and frequencies of subfamilies in a honey bee colony were determined by DNA fingerprinting. Queen and brood samples were taken from three colonies with artificially inseminated queens and from one colony with a naturally mated queen. Using Hae III restriction enzyme and (GATA) oligonucleotide, the number of subfamilies in the colonies with artificially inseminated queens corresponded with the number of drones used for insemination. In the colony with the naturally mated queen, 12 subfamilies were found in a random sample of 104 workers. Considering that subfamily frequencies range from 1 to 26%, introcolonial worker relationship was estimated to be 0.328, corresponding to a genetical effective number of 6.4 matings. [ABSTRACT FROM AUTHOR]

Kin recognition and nepotism between honeybee workers ( Apis mellifera L.) was analysed in a trophallactic bio-assay. Donor workers were fed dyed sugar syrup and introduced into a recipient group consisting of 12 to 15 workers of the same colony. After allowing for 1 hour of trophallaxis, the distribution of the dyed food was analysed with spectrophotometry. The subfamily composition in the recipient group was varied such that the donor bees had to discriminate between workers of 2 to 7 different patrilines. Donor bees preferentially fed super sisters if few patrilines were present in the recipient group. However, preferential feeding was not observed if the recipient group consisted of workers of more than three subfamilies. Since the natural degree of polyandry causes intracolonial genetic variance to exceed the genetic variability in the experiments, nepotistic behaviour among workers may not reveal intranidal subfamily recognition in honeybees. [ABSTRACT FROM AUTHOR]

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Copyright of Insectes Sociaux is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Insectes Sociaux is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Queenless workers of the Cape honeybee ( Apis mellifera capensis) can develop into reproductives termed pseudoqueens. Although they morphologically remain workers they become physiologically queenlike, produce offspring, and secrete mandibular gland pheromones similar to those of true queens. However, after queen loss only very few workers gain pseudoqueen status. A strong intracolonial selection governs which workers start oviposition and which remain sterile. The “queen substance”, 9-keto-2(E)-decenoic acid (9-ODA), the dominant compound of the queen's mandibular gland pheromones, suppresses the secretion of queenlike mandibular gland pheromones in workers. It may act as an important signal in pseudoqueen selection. By analysing the mandibular gland pheromones of workers kept in pairs, we found that A. m. capensis workers compete to produce the strongest queen-like signal. [ABSTRACT FROM AUTHOR]

Mitochondrial DNA (mtDNA), isolated from worker honeybee larvae, was digested by each of seven 6-base restriction enzymes. Only one enzyme ( BglII) showed a mtDNA difference between the three tested races ( Apis mellifera carcia, A. m. ligustica, A.m. caucasica). Both A.m. carnica and A.m. ligustica showed the same pattern, differing from A.m. caucasica. The degree of fragment pattern similarity revealed that there is only a small level of mtDNA variation between the three races tested. This is in line with previous investigations of enzyme polymorphisms. [ABSTRACT FROM AUTHOR]