The parthenogenetic Marmorkrebs (marbled crayfish) produces genetically uniform offspring

Genetically identical animals are very much in demand as laboratory objects because they allow conclusions about environmental and epigenetic effects on development, structures, and behavior. Furthermore, questions about the relative fitness of various genotypes can be addressed. However, genetically identical animals are relatively rare, in particular, organisms that combine a high reproduction rate and a complex organization. Based on its exclusively parthenogenetic reproduction mode, it has been suggested that the Marmorkrebs (Crustacea, Decapoda, Astacida), a recently discovered crayfish, is an excellent candidate for research addressing the aforementioned questions. However, until now, a study using molecular markers that clearly proves the genetic uniformity of the offspring has been lacking. Here, with this first molecular study, we show that this crayfish indeed produces genetically uniform clones. We tested this with 19 related individuals of various generations of a Marmorkrebs population by means of six different microsatellite markers. We found that all examined specimens were identical in their allelic composition. Furthermore, half of the analyzed loci were heterozygous. These results and the absence of meioses in previous histological studies of the ovaries lead us to conclude the Marmorkrebs propagates apomictically. Thus, a genetically uniform organism with complex morphology, development, and behavior is now available for various laboratory studies.     

The influence of shade trees on coffee quality in small holder coffee agroforestry systems in Southern Colombia

Production of coffee, especially by small holders, is often associated with various forms of shade management. To analyse the effects of shade on physical coffee quality and on sensorial cup quality of Coffea arabica L. cv. Caturra KMC, a study was carried out with 94 plots on 16 farms in two municipalities, Timaná and Oporapa, located at elevations from 1272 to 1730 masl. in Huila, Colombia. The study was designed with emphasis on shade cover variation within each of the two study areas, while minimizing the variability of environment, agronomic management other than shade, and post-harvest processing. 46 samples of shade coffee and 46 samples of sun coffee were evaluated for physical and sensorial attributes using three professional coffee cuppers (assessors). A principal component analysis including all quality and environmental variables showed that sensory attributes were influenced negatively by shade, and that physical attributes were influenced positively by altitude. A mixed linear model, with coffee cupper and farm as random variables, revealed different shade effects on coffee quality in the two areas. In Oporapa, situated at high altitudes, shade had a negative effect on fragrance, acidity, body, sweetness and preference of the beverage, while no effect was found on the physical quality. In Timaná, situated at lower altitudes, shade did not have a significant effect on sensorial attributes, but significantly reduced the number of small beans. At high altitudes with low temperatures and no nutrient or water deficits, shade trees may thus have a partly adverse effect on C. arabica cv. Caturra resulting in reduced sensory quality. The occurrence of berry borer (Hypothenemus hampei) was lower at high altitudes and higher under shade. Future studies on shade and coffee quality should focus on the interaction between physical and chemical characteristics of beans.     

Sheepfolds as “hotspots” of nitric oxide (NO) emission in an Inner Mongolian steppe

We investigated nitric oxide (NO) fluxes at a summer and a winter sheepfold in the Baiyinxile livestock farm, near Xilinhot, Inner Mongolia, which are a typical feature of the regional husbandry. Using a manual static opaque chamber/chemiluminescence measuring system, we intermittently observed fluxes in the summer sheepfold between May 28th and September 26th 2005 and in both winter and summer sheepfolds between March 8th and October 18th 2006. During these periods, mean NO emissions (±S.E., in terms of mass of nitrogen) were 124.0 ± 28.7, 134.6 ± 23.3 (summer sheepfold) and 214.4 ± 79.6 μg NO–N m⁻² h⁻¹ (winter sheepfold), respectively, and thus, three magnitudes higher than observed steppe NO emissions in the same region. The NO fluxes were not significantly different between the 2 years, but in summer they were much higher than in spring (p < 0.05). Temperature and moisture of the faeces layer significantly regulated the NO fluxes (p < 0.01). The direct NO emission factor (EF) for faeces and urine excreted in the sheepfolds was 0.7 g NO–N_emitted kg⁻¹ N_excreted, which was almost 37 times lower than a recently reported N₂O EF. We estimated the total NO emission from the sheepfolds of the Baiyinxile livestock farm to be 1.82 ± 0.43 tons NO–N year⁻¹, which accounts to approximately 12.3% of the total NO emission from this steppe region. With the rapid increase of livestock numbers, sheepfold NO emissions may further increase and contribute to high N deposition in confined areas around sheepfolds.     

Costing reproduction: effects of mating opportunity on mating success in male Bicyclus anynana butterflies

It is frequently assumed that males have an almost unlimited reproductive capacity, while access to receptive females is typically limiting. Consequently, sexual selection is expected to favor vigorous courtship behavior in males. If such behavior is associated with non-trivial costs, ample current mating opportunities should be accompanied by a reduction in future mating vigor. To test this hypothesis, three treatments differing in sex ratio were established using the tropical butterfly Bicyclus anynana: 50 males each were housed either with 0, 25, or 50 females. Mating trials involving the competition among males from each treatment for a single virgin female were carried out on days 3, 9, and 15 after allocation to treatments. While there was no difference on day 3, prior mating opportunity clearly reduced mating success on days 9 and 15, being lowest if identical numbers of males and females were housed together. This finding suggests accumulating costs associated with high courtship and/or mating activity. Further, older males were more active and initiated copulation earlier than the younger ones, consistent with the residual reproductive value hypothesis. We found no evidence for a survival or fertility cost of mating.     

Male mating history: effects on female sexual responsiveness and reproductive success in the parasitoid wasp Spalangia endius

Males frequently mate multiply, but are there negative fitness consequences for their later mates? Potential costs include less sperm and less nutrition. In most hymenopterans, daughters, but not sons, are produced sexually. This mean that effects of being a later mate on sperm received versus on nutrients received should be distinguishable. If later mates receive less sperm, it should manifest as a reduction in daughter production, whereas a reduction in nutrients should affect production of both sexes. Any cost to being a later mate may in turn select for polyandry or for female choice of virgin males. Males of the parasitoid wasp Spalangia endius were presented with up to five females in succession. Offspring production was compared among first, third, and fifth females; and it did not differ. However, about half of fifth females had begun producing only sons by their tenth day, whereas first and third females rarely had. Despite the reduction in daughter production, even fifth females rarely remated. However, females tended to mate with virgin males rather than mated males when given a choice. This tendency was dependent on male, not female, behavior, but should benefit the female nevertheless. Sex ratios in this species are one male for every one and a half to three females. Thus, the number of times that males could mate before daughter production was reduced coincided roughly with the mean number of times that males likely mate in this species. Nevertheless, some females are likely to experience the cost of being a fifth female because of skewed mating success among males.     

Participatory scenario planning to facilitate human–wildlife coexistence

Fostering human–wildlife coexistence requires transdisciplinary approaches that integrate multiple sectors, account for complexity and uncertainty, and ensure stakeholder participation. One such approach is participatory scenario planning, but to date, this approach has not been used in human–wildlife contexts. We devised a template for how participatory scenario planning can be applied to identify potential avenues for improving human–wildlife coexistence. We drew on 3 conceptual building blocks, namely the SEEDS framework, the notion of critical uncertainties, and the three-horizons technique. To illustrate the application of the proposed template, we conducted a case study in the Zambezi region of Namibia. We held 5 multistakeholder workshops that involved local people as well as numerous nongovernment and government stakeholders. We identified 14 important wildlife species that generated multiple services and disservices. The subsequent benefits and burdens, in turn, were inequitably distributed among stakeholders. Government actors played particularly influential roles in shaping social-ecological outcomes. We identified 2 critical uncertainties for the future: the nature of governance (fragmented vs. collaborative) and the type of wildlife economy (hunting vs. photography based). Considering these uncertainties resulted in 4 plausible scenarios describing future human–wildlife coexistence. Stakeholders did not agree on a single preferred scenario, but nevertheless agreed on several high-priority strategies. Bridging the remaining gaps among actors will require ongoing deliberation among stakeholders. Navigating the complex challenges posed by living with wildlife requires moving beyond disciplinary approaches. To that end, our template could prove useful in many landscapes around the world.     

Improved degradation of azo dyes by lignin peroxidase following mutagenesis at two sites near the catalytic pocket and the application of peroxidase-coated yeast cell walls

• Mutations in Lignin peroxidase Trp171 environment improved azo dyes degradation. • Expression on yeast cell surface and cell lysis allowed reusability of biocatalyst. • Aga2-LiP chimeric variants were characterized. The enzymatic degradation of azo dyes is a promising alternative to ineffective chemical and physical remediation methods. Lignin peroxidase (LiP) from Phanerochaete chrysosporium is a heme-containing lignin-degrading oxidoreductase that catalyzes the peroxide-dependent oxidation of diverse molecules, including industrial dyes. This enzyme is therefore ideal as a starting point for protein engineering. Accordingly, we subjected two positions (165 and 264) in the environment of the catalytic Trp171 residue to saturation mutagenesis, and the resulting library of 10⁴ independent clones was expressed on the surface of yeast cells. This yeast display library was used for the selection of variants with the ability to break down structurally-distinct azo dyes more efficiently. We identified mutants with up to 10-fold greater affinity than wild-type LiP for three diverse azo dyes (Evans blue, amido black 10B and Guinea green) and up to 13-fold higher catalytic activity. Additionally, cell wall fragments displaying mutant LiP enzymes were prepared by toluene-induced cell lysis, achieving significant increases in both enzyme activity and stability compared to a whole-cell biocatalyst. LiP-coated cell wall fragments retained their initial dye degradation activity after 10 reaction cycles each lasting 8 h. The best-performing mutants removed up to 2.5-fold more of each dye than the wild-type LiP in multiple reaction cycles.     

Dawn chorusing in guereza colobus monkeys

Dawn chorusing by guereza black-and-white colobus monkeys is one of the most impressive spectacles of African rainforests. This vocal behaviour is highly contagious, travelling from one neighbouring group to the next, until a wide forest area is covered by calling monkeys. Chorusing usually occurs up to 2 h before dawn, sometimes more than once, unless the preceding night was cold and wet. We conducted a series of playback experiments, which showed that guerezas’ chorusing was difficult to elicit experimentally, suggesting that callers took several variables into account before responding to other monkeys’ predawn calls. Acoustic analyses showed that morning calls were individually distinct, but we found no evidence that callers took individual identity into account in their decision to participate in chorusing. The only way to reliably elicit chorusing in our study area was to broadcast recordings of morning choruses for longer than 30 s and at a time when a chorus simultaneously emerged in a distant part of the forest.     

15N Metabolic test for the determination of phytotoxic effects of chemicals and contaminated environmental samples

A stable isotope¹⁵N-nitrogen test (ESIMA = Ecotoxicological Stable Isotope Metabolic Assay) was developed to assess biological effects and the potential toxicological hazard of chemicals and contaminated environmental samples on plant metabolism. The assay measures the effect of toxicants on the incorporation of a¹⁵N labelled tracer into the total nitrogen fraction (both the nonprotein and protein fraction) of plants. Segments ofPisum arvense epicotyls are used as test substrates because of their high metabolic activity. The plant material is incubated under standardised conditions for two hours; subsequently¹⁵N incorporation is analysed by determining the¹⁵N abundance (¹⁵N atom-%) in the epicotyl segments. The effects of toxicants are evaluated by comparing the¹⁵N incorporation rates of control tissue and epicotyl segments exposed to individual chemicals or complex environmental samples. The specificity and sensitivity of effects as indicated by ESIMA were compared with effects as measured by two established ecotoxicological bioassays, the pollen tube growth test using pollen ofNicotiana sylvestris and the bacterial luminescence inhibition test using pollen ofPhotobacterium phosphoreum. The results of the study clearly indicate the suitability of ESIMA for assessing toxic impacts on plant nitrogen metabolism. Prof. Dr. habil. Hans Faust dedicated to his 70^th birthday.     

Verteilungskoeffizienten chlorierter Kohlenwasserstoffe zwischen Muskulatur und Leber bei Fischen

Measured partition coefficients (KL_M/L) related to lipid-concentrations between the muscle (C_ML) and liver (C_LL) tissue of two fish species (Abramis brama, Zoarces viviparus) exhibit nominal values of unity according the relationship KL_M/L=C_ML/C_LL=1 for persistent compounds such as highly chlorinated PCB and values above one for degradable compounds for example chlorinated cyclohexanes or DDT. The corresponding theory is presented. The relationship holds for samples for single fish as well as for pooled samples.