Taxonomy of the genus Scathophaga Meigen (Diptera: Scathophagidae) in Korea

Three species of the genus Scathophaga–S. mellipes (Coquillet), S. scybalaria (Linnaeus) and S. stercoraria (Linnaeus) – are treated in this study. Of these, S. scybalaria (Linnaeus) is reported for the first time from Korea. A key to the Korean species, their domestic localities and some illustrations are given.     

Leaf cuticular n-alkanes as markers in the chemotaxonomy of the eggplant (Solanum melongena L.) and related species

The complex of species formed by eggplant (Solanum melongena L.) and its wild and weedy relatives (mainly S. incanum L. and S. insanum L.) is characterised by an extreme morphological divergence that is not always associated with genetic variation. The taxonomy of so‐called ‘spiny Solanum’ species (subgenus Leptostemonum) is therefore extremely unclear. Cultivated eggplant lacks resistance to pests that frequently occur among the wild forms and species. As these wild plants are a potential gene pool for improvement of eggplant cultivars, knowledge of the characteristics of taxonomic relations between plants of different origin is crucial. We suggest using the leaf cuticular n‐alkane chain length distribution pattern as an alternative taxonomic marker for eggplant and related species. The results are in good agreement with current knowledge of the systematics of these plants; at the same time, the method developed here is useful for verifying plant identification based on morphological traits. Analysis of 13 eggplant cultivars, five accessions of S. incanum and two lines of S. macrocarpon enabled the intraspecific variation within eggplant to be assessed as low. There was wide variability among S. incanum accessions, probably because plants described as S. incanum are members of a number of different species. Some Asian accessions (sometimes described as S. insanum) were found to be almost identical to S. melongena, while a truly wild African S. incanum plant showed extensive similarity. The usefulness of the chemotaxonomic approach in dealing with the S. melongena–S. incanum complex is discussed.     

Fourier transform infrared characterization of the Middle Devonian non‐vascular plant Spongiophyton

Spectroscopy information (functional groups and semiquantitative data) by Fourier transform infrared (FTIR) spectroscopy of Spongiophyton Kräusel emend. Chaloner et al. is reported for the first time, in an attempt to identify spectroscopic patterns that would differentiate species of these taxa. A total of 33 specimens identified as S. lenticularis, S. nanum and S. minutissimum and preserved as compressions were analysed. They come from the same fossiliferous horizon of one outcrop situated in the uppermost Middle Devonian São Domingos Formation of the Paraná Basin in southern Brazil. The results reveal that functional groups in the 3000–2800 and 1800–700 cm^?1 wavenumber regions are present in all specimens. Infrared‐derived ratios (CH₂/CH₃, Al/Ox, Ox1/Ox2, C=O cont., C=C cont., Al2 and Ar/Al) and types of kerogen led to a comparison of the morphological characteristics of the studied material and indicate that compressions of S. lenticularis, S. nanum and S. minutissimum contain different organic compounds. S. nanum and S. minutissimum show higher oxidation and lower aromaticity of its organic matter than S. lenticularis. Additionally, S. lenticularis shows low A‐factor values, suggesting a composition similar to type III kerogen, while S. nanum and S. minutissimum showed intermediate to high A‐factor values, suggesting a composition similar to type II kerogen. In conclusion, the chemical‐analytical techniques and statistical analysis (using PCA technique) reveal a closer taxonomic relationship between S. nanum and S. minutissimum than either has with S. lenticularis, supporting their taxonomic separation, previously proposed in the literature on the basis of morphological features. Lastly, the chemical signatures support the hypothesis that links these enigmatic fossils to a type of lichen or other early inland plant.     

Efficacy and safety of Saccharomyces boulardii in the 14-day triple anti-Helicobacter pylori therapy: a prospective randomized placebo-controlled double-blind study

Background: Recent studies indicate a potential role of Saccharomyces boulardii in the prevention of Helicobacter pylori treatment‐related side‐effects and also in improvement of eradication rate. Our aim is to investigate the efficacy and safety of S. boulardii in the prevention of side‐effects related to H. pylori eradication. The secondary aim of the study was to define the effect of S. boulardii on the eradication success of anti‐H. pylori therapy. Materials and methods: One hundred and twenty‐four patients with H. pylori infection (male/female: 44/80, mean age: 48 ± 14.25 year) receiving 14 days of triple therapy (clarithromycin 500 mg b.i.d., amoxicillin 1000 mg b.i.d., and lansoprazole 30 mg b.i.d.) were randomly assigned to S. boulardii or placebo. Dyspeptic symptoms were recorded by using modified Glasgow Dyspepsia Questionnaire (GDQ). Side‐effect profile and tolerability were assessed using a symptom‐based questionnaire. H. pylori status was rechecked after 6 weeks after completion of eradication therapy. Results: H. pylori eradication rate, although higher in the treatment group, was statistically similar in treatment and control groups: 71% (44/62) versus 59.7% (37/62), respectively (p > .05). Nine (14.5%) patients in the treatment group and 19 (30.6%) patients in the placebo group experienced diarrhea (p < .05). Epigastric discomfort was more frequent in the control group [9 (14.5%) versus 27 (43.5%), respectively (p < .01)]. Diffuse abdominal pain, abdominal gas, taste disturbance, urticaria, nausea symptoms were similar in both groups. GDQ scores after treatment were significantly better for treatment group (mean ± SD, range: 1.38 ± 1.25 (0–5) vs. 2.22 ± 1.44 (0–6), respectively; p < .01). Conclusion: S. boulardii improved anti‐H. pylori antibiotherapy‐associated diarrhea, epigastric discomfort, and treatment tolerability. In addition, S. boulardii supplement decreased post‐treatment dyspepsia symptoms independent of H. pylori status. However, S. boulardii had no significant affect on the rate of H. pylori eradication.     

The effects of Symbiodinium (Pyrrhophyta) identity on growth,survivorship, and thermal tolerance of newly settled coral recruits

For many coral species, the obligate association with phylogenetically diverse algal endosymbiont species is dynamic in time and space. Here, we used controlled laboratory inoculations of newly settled, aposymbiotic corals (Orbicella faveolata) with two cultured species of algal symbiont (Symbiodinium microadriaticum and S. minutum) to examine the role of symbiont identity on growth, survivorship, and thermal tolerance of the coral holobiont. We evaluated these data in the context of Symbiodinium photophysiology for 9 months post‐settlement and also during a 5‐d period of elevated temperatures Our data show that recruits that were inoculated with S. minutum grew significantly slower than those inoculated with S. microadriaticum (occasionally co‐occurring with S. minutum), but that there was no difference in survivorship of O. faveolata polyps infected with Symbiodinium. However, photophysiological metrics (?Fv/F′m, the efficiency with which available light is used to drive photosynthesis and α, the maximum light utilization coefficient) were higher in those slower growing recruits containing S. minutum. These findings suggest that light use (i.e., photophysiology) and carbon acquisition by the coral host (i.e., host growth) are decoupled, but did not distinguish the source of this difference. Neither Symbiodinium treatment demonstrated a significant negative effect of a 5‐d exposure to temperatures as high as 32°C under low light conditions similar to those measured at settlement habitats.     

Length–weight relationships,sex ratio and growth estimates for five sympatric sillaginids (Pisces) from the northern Arabian Sea coast

Five species were collected (n = sample sizes in parentheses): Sillago arabica (8), S. attenuata (26), S. indica (971), S. sihama (77) and Sillaginopodys chondropus (18) from the northern Arabian Sea coast of Pakistan. Specimens were caught with gill nets (mesh size 2.5 cm knot‐to‐knot) by medium‐sized commercial fishing vessels from September 2015 to April 2016. The parameter slope (b) in the length–weight relationships ranged from 2.44?3.21 for sexes grouped. Sex ratios were male‐biased in all species and deviated from an ideal 1:1 sex ratio. Applying the von Bertalanffy function growth coefficient, reasonable growth (K = 0.890 year^?1) was estimated for Sillago sihama, whereas this was slower in S. attenuata (0.24 year^?1). Goodness of fit range was R_n = 0.32–1.0. This study provides a new reference for LWRs in three of the species (S. arabica, S. attenuata, and S. chondropus), with a new maximum total length for S. indica to add to FishBase. The data presented here on the five sillaginid species can be useful for local management and conservation of these species.     

Ecophysiological responses of six coastal dune species along the eastern seaboard of South Africa

Ecophysiological responses of six co‐occurring dune species were investigated in a field study to determine whether they exhibit similar functional traits in response to environmental stressors. The species included Brachylaena discolor DC, Chrysanthemoides monilifera (L.), Scaevola plumieri (L.) Vahl, Canavalia maritima (Aubl.) Thouars, Gazania rigens (L.) Gaertn. and Cyperus esculentis L. Carbon dioxide exchange was saturated at 1,800 μmol m^?2 s^?1 in S. plumieri and at 1,000–1,300 μmol m^?2 s^?1 in the others. Maximal CO₂ exchange occurred during mid‐morning. Midday stomatal closure occurred in S. plumieri, C. monilifera and B. discolor, while stomatal regulation was achieved by maintaining low conductance. Photoinhibition was minimized by efficient mechanisms for light dissipation. Species such as S. plumieri, C. maritima and B. discolor exhibited sclerophylly, a trait for survival in saline and nutrient‐ and water‐deficient environments. Concentrations of Na⁺ and Cl^?1 were high in C. monilifera, G. rigens, B. discolor and S. plumieri, while the high C:N ratio in S. plumieri and C. esculentis suggested nitrogen deficiency. The responses of the six species to environmental stressors in terms of light use, gas exchange, ion and water relations and degree of sclerophylly suggest similar strategies for survival in the dune environment.     

Predicted range expansion of the invasive fire ant, Solenopsis invicta, in the eastern United States based on the VEMAP global warming scenario

The red imported fire ant, Solenopsis invicta Buren, is an invasive pest from South America that currently occupies much of the south‐eastern USA. Global warming is likely to allow range expansion of many invasive species, including S. invicta. We used a dynamic, ecophysiological model of fire ant colony growth coupled with models simulating climate change to predict the potential range expansion of S. invicta in the eastern USA over the next century. The climate change scenario predicted by the Vegetation–Ecosystem Modelling and Analysis Project (VEMAP) was used in our analyses. Our predictions indicate that the habitable area for S. invicta may increase by c. 5% over the next 40–50 years (a northward expansion of 33 ± 35 km). As the pace of global warming is expected to quicken in the latter half of the century, however, the habitable area for S. invicta in 2100 is predicted to be > 21% greater than it currently is (a northward expansion of 133 ± 68 km). Because the black imported fire ant, S. richteri Forel, occupies higher latitudes than S. invicta, the overall area of the eastern USA infested with invasive Solenopsis species could be greater than that estimated here.     

Broad-range antagonistic rhizobacteria Pseudomonas fluorescens and Serratia plymuthica suppress Agrobacterium crown gall tumours on tomato plants

Aim: To examine the biocontrol activity of broad‐range antagonists Serratia plymuthica IC1270, Pseudomonas fluorescens Q8r1‐96 and P. fluorescens B‐4117 against tumourigenic strains of Agrobacterium tumefaciens and A. vitis. Methods and Results: Under greenhouse conditions, the antagonists, applied via root soak prior to injecting Agrobacterium strains into the wounded stems, significantly suppressed tumour development on tomato seedlings. A derivative of P. fluorescens Q8r1‐96 tagged with a gfp reporter, as well as P. fluorescens B‐4117 and S. plymuthica IC1270 marked with rifampicin resistance, stably persisted in tomato tissues for at least 1 month. Mutants of P. fluorescens Q8r1‐96 and S. plymuthica IC1270 deficient in 2,4‐diacetylphloroglucinol or pyrrolnitrin production, respectively, also proficiently suppressed the tumour development, indicating that these antibiotics are not responsible for the observed biocontrol effect on crown gall disease. The volatile organic compounds (VOCs) produced by the tested P. fluorescens and S. plymuthica strains inhibited the growth of A. tumefaciens and A. vitis strains in vitro. Solid‐phase microextraction‐gas chromatography‐mass spectrometry analysis revealed dimethyl disulfide (DMDS) as the major headspace volatile produced by S. plymuthica IC1270; it strongly suppressed Agrobacterium growth in vitro and was emitted by tomato plants treated with S. plymuthica IC1270. 1‐Undecene was the main volatile emitted by the examined P. fluorescens strains, with other volatiles, including DMDS, being detected in only relatively low quantities. Conclusions: S. plymuthica IC1270, P. fluorescens B‐4117 and P. fluorescens Q8r1‐96 can be used as novel biocontrol agents of pathogenic Agrobacterium. VOCs, and specifically DMDS, might be involved in the suppression of oncogenicity in tomato plants. However, the role of specific volatiles in the biocontrol activity remains to be elucidated. Significance and Impact of the Study: The advantage of applying these antagonists lies in their multiple activities against a number of plant pathogens, including Agrobacterium.     

Immunization with attenuated Salmonella typhimurium producing catalase in protection against gastric Helicobacter pylori infection in mice

Aim. To evaluate the protective effect of live attenuated Salmonella typhimurium expressing catalase against gastric Helicobacter pylori infection in mice, and to explore the underlying mechanisms of the protective immune reaction. Materials and Methods The H. pylori catalase gene was introduced into attenuated S. typhimurium strain SL3261. C₅₇BL/6 mice were orally immunized with the SL3261 vaccine strain expressing catalase or with SL3261 alone or phosphate‐buffered saline (PBS). Mice were sacrificed 4 weeks after immunization and 5 weeks after H. pylori challenge, respectively. Results. All PBS control mice were infected. Eight of 13 (61.5%) mice immunized with the SL3261 vaccine strain and three of 14 (21%) mice immunized with SL3261 alone showed protection against H. pylori infection. Serum anti‐H. pylori IgG2a levels of S. typhimurium‐immunized mice were higher than those of PBS controls, both before and after H. pylori challenge, while there were no differences for IgG1 and IgA. Similarly, mRNA expression of interleukin (IL)‐2, IL‐12 and interferon‐γ in the gastric mucosa of S. typhimurium‐immunized mice was significantly higher than that of PBS controls both before and after challenge. Moreover, S. typhimurium‐immunized mice were characterized by marked infiltration of lymphocyte and mononuclear cells in the gastric mucosa after challenge. IL‐4 and IL‐10 were not detected in any of the three groups. IL‐6 expression was increased in the PBS group compared with the S. typhimurium‐immunized groups after challenge. Conclusions. This study demonstrates that oral immunization of mice with catalase delivered by an attenuated S. typhimurium strain offers protection against H. pylori infection. This protective immunity was mediated through a predominantly Th1‐type response and was associated with post‐immunization gastritis.     

Length–weight relationships of two Nemacheilid fish species [Schistura fasciata Lokeshwor and Vishwanath, 2011 and Schistura reticulofasciata (Singh and Bănărescu, 1982)] from Simsang River,Meghalaya, India

Length–weight relationships (LWRs) are presented for two fish species: Schistura fasciata Lokeshwor and Vishwanath, 2011 and Schistura reticulofasciata (Singh and B?n?rescu, 1982), sampled from the Simsang River in Meghalaya, India. Fishes were caught seasonally from January to December 2015, with cast nets (10–15 mm mesh size) and electrofishing devices. The b values in the LWRs were determined as 3.09 for S. fasciata and 3.318 for S. reticulofasciata.     

Reproduction,growth and mortality of the exploited sillaginid,Sillago ciliata Cuvier, 1829

The goal of this study was to examine the age and size composition, growth, reproductive biology and mortality of Sillago ciliata Cuvier, 1829 in one of the largest estuarine commercial fisheries in south‐eastern Australia. The study also aimed to present a qualitative comparison of latitudinal variations in some of these characteristics along the eastern Australian coastline. The sampled population contained fish aged up to 10 years with a maximum size of 39.2 cm fork length (L_F), and was dominated by 1–5 year olds. Sexual divergence in both the age and size structure of the population was recorded. Female S. ciliata grew slightly faster and attained a greater maximum size (L_∞ = 33.79 cm L_F, k = 0.50 year^?1 and t₀ = ?0.57 years) than males (L_∞ = 29.73 cm L_F, k = 0.49 year^?1 and t₀ = ?0.67 years). Females also matured at a significantly larger size (19.13 cm) and older age (1.63 years) than males (size: 17.07 cm, age: 1.10 years). Reproductive activity was highest between September and March. There were no differences between males and females in terms of mortality rate; the estimated total population, natural and fishing mortality rates were Z = 0.64, M = 0.42 and F = 0.22, respectively. Although these mortality rates suggest that S. ciliata in the Clarence River are relatively resilient to current rates of exploitation, regular monitoring of their commercial and recreational catch as well as their population structure is recommended in order to maintain sustainable fisheries. Potential latitudinal shifts in the spawning period, age structure and growth of S. ciliata along eastern Australia were also revealed.     

Intraguild predation of parasitoids by Solenopsis invicta: a non-disruptive interaction

The outcome of intraguild predation among natural enemies can have significant ramifications for herbivore suppression and biological control. Manipulating habitat complexity may alter the strength of intraguild predation, since changes in habitat complexity are often associated with concomitant changes in natural enemy abundance. Using a combination of greenhouse and field experiments, we determined if asymmetric intraguild predation by a pervasive generalist predator, the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), disrupts important parasitoids in a collard, Brassica oleracea L. (Brassicaceae), agroecosystem. The effect of habitat complexity on this interaction was assessed by conducting field experiments in a simple, collard monocrop and a more complex, collard‐white clover intercrop. Neither the density of adult parasitoids nor the percentage parasitism of caterpillars was affected when S. invicta abundance was manipulated. Solenopsis invicta reduced the survival of the diamondback moth larvae, Plutella xylostella (L.) (Lepidoptera: Plutellidae) by 26% and 42% in greenhouse and field experiments, respectively, but there was no preference of S. invicta for parasitized or unparasitized caterpillars. An increase in habitat complexity significantly affected the abundance of both S. invicta and parasitoids, but had no overall effect on their interaction. The results of this study suggest that although S. invicta is an intraguild predator of parasitoids because it preys upon parasitized caterpillars, the action of S. invicta may not compromise overall biological control. This study's findings are important, because they suggest that the presence and conservation of multiple natural enemies may result in sustained pest suppression in agroecosystems, even complex systems containing many species of natural enemies including strong intraguild predators such as S. invicta.     

Exotic Spartina alterniflora invasion alters ecosystem–atmosphere exchange of CH4 and N2O and carbon sequestration in a coastal salt marsh in China

Coastal salt marshes are sensitive to global climate change and may play an important role in mitigating global warming. To evaluate the impacts of Spartina alterniflora invasion on global warming potential (GWP) in Chinese coastal areas, we measured CH₄ and N₂O fluxes and soil organic carbon sequestration rates along a transect of coastal wetlands in Jiangsu province, China, including open water; bare tidal flat; and invasive S. alterniflora, native Suaeda salsa, and Phragmites australis marshes. Annual CH₄ emissions were estimated as 2.81, 4.16, 4.88, 10.79, and 16.98 kg CH₄ ha^?1 for open water, bare tidal flat, and P. australis, S. salsa, and S. alterniflora marshes, respectively, indicating that S. alterniflora invasion increased CH₄ emissions by 57–505%. In contrast, negative N₂O fluxes were found to be significantly and negatively correlated (P < 0.001) with net ecosystem CO₂ exchange during the growing season in S. alterniflora and P. australis marshes. Annual N₂O emissions were 0.24, 0.38, and 0.56 kg N₂O ha^?1 in open water, bare tidal flat and S. salsa marsh, respectively, compared with ‐0.51 kg N₂O ha^?1 for S. alterniflora marsh and ?0.25 kg N₂O ha^?1 for P. australis marsh. The carbon sequestration rate of S. alterniflora marsh amounted to 3.16 Mg C ha^?1 yr^?1 in the top 100 cm soil profile, a value that was 2.63‐ to 8.78‐fold higher than in native plant marshes. The estimated GWP was 1.78, ?0.60, ?4.09, and ?1.14 Mg CO₂eq ha^?1 yr^?1 in open water, bare tidal flat, P. australis marsh and S. salsa marsh, respectively, but dropped to ?11.30 Mg CO₂eq ha^?1 yr^?1 in S. alterniflora marsh. Our results indicate that although S. alterniflora invasion stimulates CH₄ emissions, it can efficiently mitigate increases in atmospheric CO₂ and N₂O along the coast of China.     

Isotopic discrimination and kinetic parameters of RubisCO from the marine bloom‐forming diatom,Skeletonema costatum

The cosmopolitan, bloom‐forming diatom, Skeletonema costatum, is a prominent primary producer in coastal oceans, fixing CO₂ with ribulose 1,5‐bisphosphate carboxylase/oxygenase (RubisCO) that is phylogenetically distinct from terrestrial plant RubisCO. RubisCOs are subdivided into groups based on sequence similarity of their large subunits (IA–ID, II, and III). ID is present in several major oceanic primary producers, including diatoms such as S. costatum, coccolithophores, and some dinoflagellates, and differs substantially in amino acid sequence from the well‐studied IB enzymes present in most cyanobacteria and in green algae and plants. Despite this sequence divergence, and differences in isotopic discrimination apparent in other RubisCO enzymes, stable carbon isotope compositions of diatoms and other marine phytoplankton are generally interpreted assuming enzymatic isotopic discrimination similar to spinach RubisCO (IB). To interpret phytoplankton δ¹³C values, S. costatum RubisCO was characterized via sequence analysis, and measurement of its K_CO2 and V_max, and degree of isotopic discrimination. The sequence of this enzyme placed it among other diatom ID RubisCOs. Michaelis‐Menten parameters were similar to other ID enzymes (K_CO2 = 48.9 ± 2.8 μm ; V_max = 165.1 ± 6.3 nmol min^?1 mg^?1). However, isotopic discrimination (ε = [¹²k/¹³k ? 1] × 1000) was low (18.5‰; 17.0–19.9, 95% CI) when compared to IA and IB RubisCOs (22–29‰), though not as low as ID from coccolithophore, Emiliania huxleyi (11.1‰). Variability in ε‐values among RubisCOs from primary producers is likely reflected in δ¹³C values of oceanic biomass. Currently, δ¹³C variability is ascribed to physical or chemical factors (e.g. illumination, nutrient availability) and physiological responses to these factors (e.g. carbon‐concentrating mechanisms). Estimating the importance of these factors from δ¹³C measurements requires an accurate ε‐value, and a mass‐balance model using the ε‐value for S. costatum RubisCO is presented. Clearly, appropriate ε‐values must be included in interpreting δ¹³C values of environmental samples.     

Behavioural responses of the Colorado potato beetle to trichomes and leaf surface chemicals of Solanum tarijense

Wild Solanum species constitute a source of resistance to several pests and diseases of potato. Several species of wild tuber‐bearing potato have been identified as resistant to the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), including Solanum tarijense Hawkes (Solanaceae). Our objective was to determine the mechanism of resistance of S. tarijense to the Colorado potato beetle and, because the resistance is limited to the adult stage of the insect, to study the host selection behaviour on resistant plants. In the field, Colorado potato beetles demonstrated a unique behaviour when in contact with S. tarijense, abandoning the plant by falling to the ground after a few minutes. The abundant trichomes on the leaves of S. tarijense induced the falling behaviour. However, on S. tarijense feeding remained low even after the trichomes were mechanically removed. Observations demonstrated that the normal sequence of behaviour leading to feeding was interrupted before adult beetles fed on S. tarijense leaves. Feeding experiments using volatile and non‐volatile fractions of leaf surface extracts identified a phagodeterrent effect of the volatile fraction. Our results contrast with a similar evaluation of the mode of resistance of Solanum berthaultii Hawkes, a close relative of S. tarijense, on which some feeding occurred and adults did not show falling behaviour. This study presents information on S. tarijense as a new source of resistance to the Colorado potato beetle that can be used for potato breeding.     

Characterization of a Bacillus thuringiensis strain with a broad spectrum of activity against lepidopteran insects

The insect pathogen Bacillus thuringiensis is suitable for use in biological control, and certain strains have been developed as commercial bioinsecticides. The molecular and biological characterization of a Bacillus thuringiensis subsp. aizawai strain, named HU4‐2, revealed its potential as a bioinsecticide. The strain was found to contain eight different cry genes: cry1Ab, cry1Ad, cry1C, cry1D, cry1F, cry2, cry9Ea1, and a novel cry1I‐type gene. Purified parasporal crystals from strain HU4‐2 comprised three major proteins of 130–145 kDa, which were tested for their insecticidal potency to four species of Lepidoptera (Helicoverpa armigera, Spodoptera exigua, S. littoralis, and S. frugiperda) and three species of mosquito (Culex pipiens pipiens, Aedes aegypti, and Anopheles stephensi). The crystal proteins were highly toxic against all the species of Lepidoptera tested, moderately toxic against two of the mosquito species (C. pipiens and Ae. aegypti), but no toxicity was observed against a third species of mosquito (An. stephensi) at the concentrations used in our study. The LC₅₀ values of the HU4‐2 Bt strain against H. armigera larvae (5.11 µg/ml) was similar to that of HD‐1 Bt strain (2.35 µg/ml), the active ingredient of the commercial product Dipel®. Additionally, the LC₅₀ values of the HU4‐2 Bt strain against S. littoralis, S. frugiperda, and S. exigua (2.64, 2.22, and 3.38 µg/ml, respectively) were also similar to that of the Bt strain isolated from the commercial product Xentari® for the same three species of Spodoptera (1.94, 1.34, and 2.19 µg/ml, respectively). Since Xentari® is significantly more toxic to Spodoptera spp. than Dipel® and, reciprocally, Dipel® is significantly more toxic against H. armigera than Xentari®, we discuss the potential of the HU4‐2 strain to control all these important lepidopteran pests.     

Antimycin A-producing nonphytopathogenic Streptomyces turgidiscabies from potato

Aim:  To detect if substances with mammalian cell toxicity are produced by Streptomyces turgidiscabies and Streptomyces scabiei isolated from potato scab lesions. Methods and Results:  In vitro cultures of phytopathogenic and nonphytopathogenic strains of S. scabiei and S. turgidiscabies, isolated from scab lesions of potato tubers originating from nine different cultivars from Finland and Sweden, were tested for toxicity using the rapid spermatozoan motility inhibition assay, previously shown useful in the detection of many different Streptomyces toxins and antimicrobial compounds. Purified toxins were used as reference. Three nonphytopathogenic strains of S. turgidiscabies were found to produce antimycin A when cultured on solid medium. Conclusions:  Boar sperm-motility-inhibiting substances are produced by strains of S. turgidiscabies and S. scabiei. The most powerful inhibitory substance, produced by three nonphytopathogenic S. turgidiscabies strains, was identified as antimycin A. The phytotoxic compounds thaxtomin A and concanamycin A did not inhibit sperm motility even at high doses. Significance and Impact of the Study:  The presence of antimycin A-producing Streptomyces strains, nonpathogenic to potato, was unexpected but important, considering the high mammalian toxicity of this cytochrome bc-blocking antibiotic.     

A hierarchical theory of macroecology

The relationships of local population density (N) with body size (M) and distribution (D) have been extensively studied because they reveal how ecological and historical factors structure species communities; however, a unifying model explaining their joint behaviour, has not been developed. Here, I propose a theory that explores these relationships hierarchically and predicts that: (1) at a metacommunity level, niche breadth, population density and regional distribution are all related and size‐dependent and (2) at a community level, the exponents b and d of the relationships N ~ M  ^b and N ~ D  ^d are functions (f) of the environment and, consequently, species richness (S), allowing the following reformulation of the power laws: N ~ M  ^f(S) and N ~ D ^f(S) . Using this framework and continental data on stream environment, diatoms, invertebrates and fish, I address the following fundamental, but unresolved ecological questions: how do species partition their resources across environments, is energetic equivalence among them possible, are generalists more common than specialists, why are locally abundant species also regionally prevalent, and, do microbes have different biogeography than macroorganisms? The discovery that community scaling behaviour is environmentally constrained calls for better integration of macroecology and environmental science.     

Age and growth characteristics of Schizopygopsis younghusbandi Regan, 1905 in the Yarlung Tsangpo River in Tibet,China

To better understand the biology of Schizopygopsis younghusbandi Regan, 1905 and its relationship with management considerations, this study describes the relationships between otolith size and fish length and age, verifies annual periodicity of otolith annulus formation, and estimates the S. younghusbandi growth parameters. These age and growth characteristics were studied using 694 specimens collected from August 2008 to August 2009. Otoliths grew asymmetrically throughout the range of standard length (SL) studied, showing a clear pattern of alternating translucent and opaque bands. Marginal increment ration (MIR) analysis of specimens up to 6 years of age indicated that one opaque band and one translucent band were laid down each year. Maximum observed age was 17 years, corresponding to a female of 35.8 cm SL and 589.1 g body weight (BW). The SL‐BW relationship was described as BW = 1.122 × 10^?5 SL^3.030 for sexes combined. The von Bertalanffy growth function was used to model back‐calculated lengths as L_t = 338.4 (1?e^{?0.233 (t + 0.403)}) for males, and L_t = 433.9 (1?e^{?0.194 (t + 0.397)}) for females. Growth performance of S. younghusbandi was relatively higher than those of other Schizothoracinaes inhabiting the same river.