Sperm limitation and the evolution of extreme polyandry in honeybees (Apis mellifera L.)

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 queens 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.Communicated by R.E. Page     

Contribution of olfactory navigation and non-olfactory pilotage to pigeon homing

Summary By means of training flights (mostly flock releases), two groups of young homing pigeons were made familar with a larger area asymmetrically extending from the loft toward SW and NE, respectively. Thereafter, birds of both groups were released within each of the training areas with which one sort of birds was familiar (F⁺), the other unfamiliar (F^-). Even the F⁺ pigeons had never been released at the test site itself (nearest previous release 10 km apart). Half of each group was allowed to smell environmental odors (O⁺); the other half breathed charcoal-filtered air during transportation and at the release site until a few minutes before release when they were deprived of olfaction by intranasal application of Xylocain (O^-). The two test sites were 53 km distant from home. There was little difference in initial orientation as well as in homing performance between pigeons that were allowed to smell natural air and were familiar with the area (F⁺O⁺) and those that were privileged in only one respect (F⁺O^- and F^-O⁺). Yet if none of the preconditions was met (F^-O^-), performances were drastically reduced. The findings show that pigeons make use of two independent homing methods, olfactory navigation (presumably based on a navigational map) and non-olfactory pilotage (presumably based on a topographical map). The latter method is restricted to a more or less familiar area determined by individual experience. Its boundaries are poorly defined and can be estimated by the experimenter only in rough approximation. Within this area, the homing system takes advantage of more or less redundant inputs. Outside of it, olfactory information seems indispensable.     

Forest damage assessments in Austria

Different types of assessments of forest damage are conducted in Austria. Faced with forest dieback reports, a needle and leaf sampling programme and a terrestrial crown assessment have been started after 1983, in addition to the forest inventory. In order to obtain more comprehensive and detailed information for the analysis of cause-effect relationships, as many investigations concerning forest health status as possible were concentrated on permanent plots out of the grid of the Austrian National Forest Inventory. This new, long-term project, started in 1987, was called the Forest Damage Monitoring System. An overview of the investigations and assessments, as they have been conducted by the end of 1991, is given in this paper.     

Open workshops as sites of innovative socio-economic practices: approaching urban post-growth by assemblage theory

ABSTRACT

Current debates on knowledge-based and creative locational development have come to deal with small urban places of novelty that formerly remained unnoticed. A plethora of new forms of producing and working recently emerged in unplanned and uncoordinated ways, bearing odd names such as FabLabs, Open Worklabs, RealLabs, Open Design Cities, Techshops, Repair Cafés, and more (Smith, A., M. Fressoli, D. Abrol, E. Arond, and A. Ely. 2017. Grassroots Innovation Movements. London: Routledge). Political initiatives have been taken by surprise; at the same time, standard epistemic tools of the social sciences and economics have been rendered unfit. More concise analytical reconstructions are needed to adequately capture the variety and complexity of these “labs”, their heterogeneous causation, their contingent proceedings, their surplus of latency, their peculiar power relations and their local embeddings. Urban social contexts have a strong triggering function as they help to re-configure older, and create new, combinations of heterogeneous social and economic agency. Meanwhile strong elements of grassroots innovation (Smith et al. 2017) have informed the formation of various models of alternative work and production. Taking the phenotype of open workshops as a revealing example, we take assemblage theory to describe the constitutive features of these new types of self-organised work, and the associated places of innovation. A fresh gaze on the complexity and open-endedness of socio-material formations may help to better understand the nature of emerging post-growth economies.     

Multi-scale scenarios of spatial-temporal dynamics in the European livestock sector

The European livestock sector has changed rapidly in the recent past and further changes are expected in the near future due to reforms in the European Common Agricultural Policy (CAP), increasing environmental concerns and changing consumer awareness. We developed a multi-scale modeling approach for exploring spatial and temporal dynamics of livestock distribution by accounting for drivers at different spatial scales. Such approach can provide a basis for environmental impact assessments of livestock farming at broad spatial scales. Assessment of change in both quantity and location was made for six livestock types. Four contrasting scenarios were applied ranging from globalization to regionalization, as well as from low regulation levels and dominance of market forces towards a higher degree of governmental regulation. National level livestock numbers as calculated by a macro-economic model were spatially distributed at the landscape scale according to the scenario assumptions considering biophysical, socio-economic, and political forces. Results indicate for most of the old European Union (EU) member countries a decrease in livestock numbers. In the new EU member countries sheep, goats and pigs are expected to decline while beef cattle and poultry are expected to grow. Livestock densities are expected to increase both within and outside current livestock hotspot regions in absence of environmental legislations. Environmental pressure as result of high livestock densities may, however, also remain in regulated scenarios where environmental policies are implemented and income support remains stable over time due to path dependencies in the livestock sector. But contrary to the non-regulated scenario it is less likely that new areas with high risk of negative environmental impacts due to livestock farming will develop.     

An efficient approach to sulfate metabolites of polychlorinated biphenyls

Polychlorinated biphenyls (PCBs), a major class of persistent organic pollutants, are metabolized to hydroxylated PCBs. Several hydroxylated PCBs are substrates of cytosolic phase II enzymes, such as phenol and hydroxysteroid (alcohol) sulfotransferases; however, the corresponding sulfation products have not been isolated and characterized. Here we describe a straightforward synthesis of a series of ten PCB sulfate monoesters from the corresponding hydroxylated PCBs. The hydroxylated PCBs were synthesized by coupling chlorinated benzene boronic acids with appropriate brominated (chloro-)anisoles, followed by demethylation with boron tribromide. The hydroxylated PCBs were sulfated with 2,2,2-trichloroethyl chlorosulfate using DMAP as base. Deprotection with zinc powder/ammonium formate yielded the ammonium salts of the desired PCB sulfate monoesters in good yields when the sulfated phenyl ring contained no or one chlorine substituent. However, no PCB sulfate monoesters were isolated when two chlorines were present ortho to the sulfated hydroxyl group. To aid with future quantitative structure activity relationship studies, the structures of two 2,2,2-trichloroethyl-protected PCB sulfates were verified by X-ray diffraction.     

A DECISION SUPPORT SYSTEM TO MANAGE SUMMER STREAM TEMPERATURES1

ABSTRACT: Warm summer stream temperatures due to low flows and high air temperatures are a critical water quality problem in many western United States river basins because they impact threatened fish species’habitat. One way to alleviate this problem is for local and federal organizations to purchase water rights to be used to increase flows, hence decrease temperatures. Presented is a Decision Support System (DSS) that can be used in an operations mode to effectively use water acquired to mitigate warm stream temperatures. The DSS uses a statistical model for predicting daily stream temperatures and a rule‐based module to compute reservoir releases. Water releases are calculated to meet fish habitat temperature targets based on the predicted stream temperature and a user specified confidence of the temperature predictions. Strategies that enable effective use of a limited amount of water throughout the season have also been incorporated in the DSS. The utility of the DSS is demonstrated by an example application to the Truckee River near Reno, Nevada, using hypothetical operating policy and 1988 through 1994 inflows. Results indicate that the DSS could substantially reduce the number of target temperature violations (i.e., stream temperatures exceeding the target temperature levels detrimental to fish habitat).     

Neurophysiological and behavioral development in birds: Song learning as a model system

The avian song system is a particularly good model for studying the behavioral and physiological aspects of animal development. One seemingly trivial but very important reason for this is that the sound spectrograph enables sounds to be described, measured and analyzed objectively and in detail. Secondly, birdsong is one of the few behaviors which is performed by a separate chain of brain regions and is therefore relatively easy to investigate neurophysiologically. Work on song also provides a clear illustration of the subtle way in which birds are influenced by their internal and external environments during development.     

Sources and toxicities of phenolic polychlorinated biphenyls (OH-PCBs)

Polychlorinated biphenyls (PCBs), a group of 209 congeners that differ in the number and position of chlorines on the biphenyl ring, are anthropogenic chemicals that belong to the persistent organic pollutants (POPs). For many years, PCBs have been a topic of interest because of their biomagnification in the food chain and their environmental persistence. PCBs with fewer chlorine atoms, however, are less persistent and more susceptible to metabolic attack, giving rise to chemicals characterized by the addition of one or more hydroxyl groups to the chlorinated biphenyl skeleton, collectively known as hydroxylated PCBs (OH-PCBs). In animals and plants, this biotransformation of PCBs to OH-PCBs is primarily carried out by cytochrome P-450-dependent monooxygenases. One of the reasons for infrequent detection of lower chlorinated PCBs in serum and other biological matrices is their shorter half-lives, and their metabolic transformation, resulting in OH-PCBs or their conjugates, such as sulfates and glucuronides, or macromolecule adducts. Recent biomonitoring studies have reported the presence of OH-PCBs in human serum. The occurrence of OH-PCBs, the size of this group (there are 837 mono-hydroxyl PCBs alone), and their wide spectra of physical characteristics (pKa’s and log P’s ranging over 5 to 6 orders of magnitude) give rise to a multiplicity of biological effects. Among those are bioactivation to electrophilic metabolites that can form covalent adducts with DNA and other macromolecules, interference with hormonal signaling, inhibition of enzymes that regulate cellular concentrations of active hormones, and interference with the transport of hormones. This new information creates an urgent need for a new perspective on these often overlooked metabolites.     

Authentication of synthetic environmental contaminants and their (bio)transformation products in toxicology: polychlorinated biphenyls as an example

Environmental Science and Pollution Research - Toxicological studies use “specialty chemicals” and, thus, should assess and report both identity and degree of purity (homogeneity) of...