Correlated changes in breeding status and polyunsaturated cuticular hydrocarbons: the chemical basis of nestmate recognition in the burying beetle <Emphasis Type="Italic">Nicrophorus vespilloides</Emphasis>?

Nestmate recognition in eusocial insects has received a lot of attention in the last decades. Recognition in subsocial species, in contrast, has been ignored almost completely and consequently, and little is known about proximate mechanisms of recognition in subsocial systems. We studied one subsocial species, the biparental brood caring burying beetle Nicrophorus vespilloides, an interesting model organism for studies of recognition because of its ability to discriminate between breeding partners and conspecific competitors. Recognition appears to be based on a chemical cue closely linked to the breeding status of individuals. Breeding and non-breeding beetles consistently differ in their relative proportions of polyunsaturated cuticular hydrocarbons. To investigate the function of these polyenes in the burying beetles’ recognition system, we quantified their concentration on the cuticle during the early state of a breeding attempt and tested the response of breeding beetles in corresponding behavioural experiments. We observed a rapid increase in the proportion of polyunsaturated hydrocarbons of both males and females after they were provided with a carcass suitable for reproduction. Furthermore, we found that the relative amount of polyenes on an individual’s surface was closely correlated with its chance of being accepted as breeding partner. Our results support the idea that polyunsaturated hydrocarbons are involved in breeding partner recognition in N. vespilloides, functioning as a signal that conveys information about the individual’s breeding status. Breeding females have greater amount of polyenes than breeding males, and females ingest more carrion during the first days on the carcass, which supports our hypothesis that precursors for the respective polyenes are derived from ingested carrion.     

Maintenance of variance in sperm transfer rates in a scorpionfly: food availability,genetic basis,and heritability

Variation in traits closely related to fitness is expected to be low. This is because these traits are under directional selection and the best genotype should prevail. However, there have been a number of studies demonstrating the existence of considerable variance in sexually selected traits, which is generally known as the lek paradox. Accordingly, earlier studies found substantial variation in sperm transfer rates in Panorpa vulgaris. Aiming at finding the mechanism that maintains this variation, we analyzed the condition dependence and the narrow sense heritability of sperm transfer rates. Food deprivation in the larval/adult phase caused a decrease in the males’ capability of saliva secretion resulting in shorter copulations and a reduced number of transferred sperm. There was a positive correlation between mean sperm transfer rates and mean body mass. Additionally, intermale variation in sperm transfer rates decreased with increasing food availability. Hence, we suggest that sperm transfer rates in P. vulgaris are influenced by adult feeding history. Heritability analyses of sperm transfer rates did not provide significant results, which is consistent with the general hypothesis that additive genetic variance in traits closely related to fitness is small. Since a trait’s potential to respond to selection is proportional to the amount of contained additive genetic variance, the ascertained small heritability provides a satisfying explanation for the maintenance of substantial variation in sperm transfer rates.     

Ablagerung toxischer Chemieabfälle im August 2006 in Abidjan, Republik Côte d’Ivoire: Versuch einer Rekonstruktion

Background

Globally, every year several hundred million tons of problematic, e.g. chemical, wastes are generated stemming to more than 90% from the 25 OECD countries. Due to their partly considerable toxicity special and often expensive measures are required for their disposal. According to the Secretary of the ‘Basel Convention on the Control of Transboundary Movements of Hazardous Waste and Their Disposal’ annually at least 8.5 million tons of wastes are transboundarily traded. Although the ‘Basel Convention’ has set up rules how to handle international waste streams, certain waste amounts are illegally transported from the OECD countries to developing countries — basically for reasons of expenses. Often an environmental safe treatment of toxic waste is not ensured or even not possible in the receiving countries. As set forth in a report of the European Network for the Implementation and Enforcement of Environmental Law (IMPEL) published in 2006, the illegal trade with toxic waste has steadily increased. 3000 shipping documents of 17 European seaports were examined and 258 cargo holds were inspected showing that 68 of 140 waste shippings were illegal. Preventing illegal transports of waste meets with various obstacles. Controlling measures require considerable personal, technical, and logistic resources that are not sufficiently available in each country concerned. Missing or ineffective administrative structures hamper fast actions to stop illegal waste disposal. Partly, the political will to take the necessary steps is lacking. An additional problem is the fact that waste that is obtained from the regular shipping business is not subject to the Basel Convention but to the ‘International Convention for the Prevention of Pollution from Ships’. The implementing statures are summarized in the document MARPOL 73/78; the International Maritime Organization (IMO) is responsible. Identifying the origin of waste and thus defining the responsibility occasionally raises difficulties. This background provides a basis to try to reconstruct the course of events concerning the disposal of chemical waste in Abidjan.

Methods

Several information sources were utilized to reconstruct the course of events at Abidjan in August 2006; e.g. public press, declarations of international governmental organizations, especially of the UN and of its subsidiary organizations, communiqués of the Secretary of the Basel Convention, and statements of several NGOs. Nevertheless a complete reconstruction of the incident is impossible, since a detailed and reliable historical report is not available. Furthermore the responsible politicians have not undertaken significant efforts to shed light upon the incident. Additionally relevant documents of the participating companies are not available to the public.

Conclusions

The analyzed incident makes obvious that the control mechanisms of the Basel Convention can be circumvented. It remains unclear who has to take the political responsibility for the death of 10 people and for the health defects of thousands of humans. Possible civil and criminal consequences are not foreseeable for the actors and company owners involved in the illegal waste dumping. The people of Abidijan are confronted with unresolved questions regarding the occurrence of chronic diseases and possible long-term effects of remaining waste portions.

Recommendations and Perspectives

The incident demonstrates that the control of the transboundary transport and disposal of hazardous waste needs to be enforced and legal grey areas should be eliminated. It should be a task of the OECD countries and of all other economically and technically developed countries and organizations to support the developing countries’ efforts to build up the personal, technical, and infrastructural capacities for an efficient control of waste imports.     

Bees’ subtle colour preferences: how bees respond to small changes in pigment concentration

Variability in flower colour of animal-pollinated plants is common and caused, inter alia, by inter-individual differences in pigment concentrations. If and how pollinators, especially bees, respond to these small differences in pigment concentration is not known, but it is likely that flower colour variability impacts the choice behaviour of all flower visitors that exhibit innate and learned colour preferences. In behavioural experiments, we simulated varying pigment concentrations and studied its impact on the colour choices of bumblebees and honeybees. Individual bees were trained to artificial flowers having a specific concentration of a pigment, i.e. Acridine Orange or Aniline Blue, and then given the simultaneous choice between three test colours including the training colour, one colour of lower and one colour of higher pigment concentration. For each pigment, two set-ups were provided, covering the range of low to middle and the range of middle to high pigment concentrations. Despite the small bee-subjective perceptual contrasts between the tested stimuli and regardless of training towards medium concentrations, bees preferred neither the training stimuli nor the stimuli offering the highest pigment concentration but more often chose those stimuli offering the highest spectral purity and the highest chromatic contrast against the background. Overall, this study suggests that bees choose an intermediate pigment concentration due to its optimal conspicuousness. It is concluded that the spontaneous preferences of bees for flower colours of high spectral purity might exert selective pressure on the evolution of floral colours and of flower pigmentation.     

Job requirements for control room jobs in nuclear power plants

Together with other variables, human factors play a central role in the safety of highly complex technical systems such as nuclear power plants. However, despite the unquestionable importance of human factors, little information is available about relevant ability requirements for control room jobs in nuclear power plants. The purpose of this study was to close this gap, to provide specific information about ability requirements for such jobs, and to evaluate how several hypothesized factors (ability domain, type of job, and operating condition) contribute to ability requirements. We found that high levels of cognitive as well as social/interpersonal abilities are needed for control room jobs, and that ability requirements increase with the hierarchical job level for these two domains but decrease for psychomotor/physical abilities and for sensory/perceptual abilities. Furthermore, specifically concerning jobs with a leadership function, we found some differences between incidents and normal operations regarding requirements for social/interpersonal abilities, indicating that the former require a different leadership style than the latter.     

TNT in Komposten und Flüssigkultur

The formation of aromatic amines was investigated using a summarized test (NEDA-test) during the composting of 2,4,6-trinitrotoluene (TNT) contaminated soil. In this test, the aromatic amines were diazolated and then coupled to N-1-Naphthyl-ethylenediamine-dihydrochloride (NEDA) to yield an azo dye which can be monitored photometrically. The test was calibrated for known TNT-metabolites with an active amine-group. Liquid samples from composting- and liquid-culture-experiments were analyzed by HPLC for these known metabolites. Moreover, the samples were monitored by the NEDA-test and the expected extinction of the TNT-metabolites found with amine function were extrapolated with the help of calibration curves. It was shown that substantial differences are obvious between the monitored and extrapolated values. After separation into polar and non-polar aromatic amines, it became clear that these differences are made by the polar aromatic amines. Polar aromatic amines, which are not detectable by presently available analytical tests, were generated during the composting of TNT-contaminated soils. Contaminated stagnant water, which was generated during anaerobization of a compost prephase, was treated aerobically for 70 days in a biofermenter. During this treatment TNT and its known metabolites were eliminated almost entirely. Simultaneously, the toxicity in the Lumis Tox-test decreased drastically. In striking contrast, the sum of aromatic amines decreased only to a minor extent. Moreover, the percentage of polar compounds from total amount of aromatic amines increased drastically from 48% to more than 95%. At present, the chemical identification of these polar compounds is still missing and is the object for further research.