<Emphasis Type="Italic">Drosophila suzukii</Emphasis> flight performance reduced by starvation but not affected by humidity

Drosophila suzukii is widely studied because of its status as a global pest of berries and soft fruits. Environmental conditions and access to food resources impact the physiology and fitness of D. suzukii; these factors could also affect dispersal. Flight mills are a convenient tool for measuring and comparing the flight performance of insects. In this study, two experiments examined the effects of diet and humidity on D. suzukii flight performance using custom-built flight mills, and a third experiment compared the energy reserves of D. suzukii flown or not flown on flight mills. Over all flight assays, the median flight distance and duration were 27.16 m and 2.37 min, respectively, and the mean flight velocity was 0.18 m/s. The maximum flight distance and duration by an individual were 1.75 km and 2.35 h, respectively. Drosophila suzukii provisioned with blossoms, fruits, or standard laboratory diets flew farther distances and longer durations than starved flies. While starvation was associated with reduced flight performance, there were no observed differences between diet types. It remains unclear whether D. suzukii consistently use lipids, glycogen, sugar, or another energy source for flight because tethered individuals may not have flown enough to deplete energy reserves. Humidity did not affect flight performance of D. suzukii within a?~?2 h test period. These data indicate that most D. suzukii are likely to remain within limited area (e.g., within a field) but that some individuals can disperse long distances (field to field spread).     

Pentatomid host suitability and the discovery of introduced populations of <Emphasis Type="Italic">Trissolcus japonicus</Emphasis> in Oregon

Trissolcus japonicus is an egg parasitoid of Halyomorpha halys, brown marmorated stink bug, a severe agricultural pest in the USA. T. japonicus is being evaluated in quarantine as a classical biological control agent to manage H. halys populations in the USA. To determine T. japonicus’ potential for successful management of the pest, we performed a series of no-choice and paired-host-range tests, evaluating parasitism and host recognition in ten nontarget insects. In laboratory no-choice tests, T. japonicus successfully parasitized egg masses of seven Pentatomidae native to Oregon in addition to H. halys. Mean parasitism proportions of egg masses were greater than 40% in two species, B. dimidiata and H. abbreviatus, and were statistically similar to parasitism of H. halys. However, paired-host tests identified higher proportions of parasitized H. halys egg masses compared to four other pentatomids. T. japonicus was equally attracted to volatiles produced by H. halys and other pentatomids but demonstrated significantly longer arrestment response time on surfaces with H. halys contact kairomones. Although host acceptance patterns were similar between stink bug species, our results suggest a greater potential for parasitoid development in H. halys eggs compared to the native pentatomids. During host-range testing, we detected field populations of T. japonicus at 11 sites in Portland, OR, indicating an unintentional introduction and establishment. Further work is needed to characterize its nontarget activity and dispersal patterns in areas where H. halys causes economic damage in Oregon.     

First laboratory confirmation of Xylophilus ampelinus in Slovenia*

Bacterial blight of grapevine is caused by a slow‐growing bacterium Xylophilus ampelinus. It has been suspected to occur in Slovenia on the basis of visual observation of characteristic symptoms in the 1960s. In the present study, symptoms were recorded in an infected vineyard during three consecutive years (2002/2004). Samples from this vineyard were tested by nested‐PCR and isolation of bacteria on media was attempted. In the first year, angular lesions on leaves were highly expressed and an isolate morphologically similar to X. ampelinus was obtained from one sample. It was purified and identified as X. ampelinus using biochemical and nutritional tests, fatty acid analysis, immuno‐fluorescence, nested PCR and partial sequencing of the 16S rRNA gene. The 16S rDNA sequence showed 99–100% homology to known sequences of X. ampelinus strains, including the type strain. Pathogenicity of the isolate was confirmed in tissue‐cultured and potted grapevine plants. In the following two years, symptoms of bacterial blight were only faintly expressed. Using isolation on media and nested‐PCR, 23 and 17 extracts prepared from 10 and 8 grapevines, respectively, were analysed. In 2003, no positive sample was found, but X. ampelinus was again isolated and identified by colony morphology and nested‐PCR in 2004.     

内蒙古自治区生态福利绩效评估及其驱动效应分解

为探究内蒙古地区经济发展与资源环境的可持续性关系,基于1998—2019年内蒙古地区12个盟市面板数据,通过计算生态福利绩效(Eco-welfare performance,EWP),将其分解为经济增长的福利效应和经济增长的生态效率2个驱动效应,并采用弹性系数脱钩指数和数据包络分析法分别对影响各盟市经济增长的福利效应和生态效率进行分析和测算。结果表明:内蒙古各盟市的人类发展水平大幅度提高,且在空间上表现为自东向西上升的趋势,EWP总体上随时间呈下降趋势;内蒙古地区各盟市人类福祉增长与经济增长总体处于相对脱钩状态,全要素生产率(Total factor productivity,TFP)和绿色全要素生产率(Green total factor productivity,GTFP)不同程度提高,但后者一直低于前者,表明研究区经济增长质量在一定程度上受所消耗生态资本量的影响;此外,分析TFP和GTFP各分项指数时发现,技术进步指数在各分项指数中对经济增长的贡献最高,表明影响内蒙古地区经济增长的首要驱动力为技术进步。本研究可为内蒙古地区高质量绿色发展政策制定提供参考。     

Case–control study on risk factors associated with Brucella Melitensis in goat farms in Peninsular Malaysia

Caprine brucellosis is a bacterial zoonotic infection affecting goats especially in developing countries all over the world. In Malaysia, the risk factors associated with this infection in farms have not been studied. A case–control study was carried out in goat farms in four states of Malaysia to elucidate the risk factors associated with the infection on the farms using structured questionnaires and face-to-face interviews. Results indicate that the introduction of new animals (OR?=?5.25; 90 % CI?=?1.46, 18.88), younger age category of farms (OR?=?5.53; 90 % CI?=?1.09, 21.66), and farms with single breed of goats (OR?=?8.50; 90 % CI?=?1.27, 41.97) were significant risk factors for brucellosis. In order to control brucellosis or possibly eradicate it in goat farms, these factors need to be dealt with. Enforcing stringent importation protocols or complete ban of goat importation from brucellosis endemic countries will help reduce risk of introducing new infection into the country.     

Quantitative analysis of ruminal methanogenic microbial populations in beef cattle divergent in phenotypic residual feed intake (RFI) offered contrasting diets

Background

Methane (CH₄) emissions in cattle are an undesirable end product of rumen methanogenic fermentative activity as they are associated not only with negative environmental impacts but also with reduced host feed efficiency. The aim of this study was to quantify total and specific rumen microbial methanogenic populations in beef cattle divergently selected for residual feed intake (RFI) while offered (i) a low energy high forage (HF) diet followed by (ii) a high energy low forage (LF) diet. Ruminal fluid was collected from 14 high (H) and 14 low (L) RFI animals across both dietary periods. Quantitative real time PCR (qRT-PCR) analysis was conducted to quantify the abundance of total and specific rumen methanogenic microbes. Spearman correlation analysis was used to investigate the association between the relative abundance of methanogens and animal performance, rumen fermentation variables and diet digestibility.

Results

Abundance of methanogens, did not differ between RFI phenotypes. However, relative abundance of total and specific methanogen species was affected (P < 0.05) by diet type, with greater abundance observed while animals were offered the LF compared to the HF diet.

Conclusions

These findings suggest that differences in abundance of specific rumen methanogen species may not contribute to variation in CH₄ emissions between efficient and inefficient animals, however dietary manipulation can influence the abundance of total and specific methanogen species.     

Reverse methanogenesis: testing the hypothesis with environmental genomics

Microbial methane consumption in anoxic sediments significantly impacts the global environment by reducing the flux of greenhouse gases from ocean to atmosphere. Despite its significance, the biological mechanisms controlling anaerobic methane oxidation are not well characterized. One current model suggests that relatives of methane-producing Archaea developed the capacity to reverse methanogenesis and thereby to consume methane to produce cellular carbon and energy. We report here a test of the "reverse-methanogenesis" hypothesis by genomic analyses of methane-oxidizing Archaea from deep-sea sediments. Our results show that nearly all genes typically associated with methane production are present in one specific group of archaeal methanotrophs. These genome-based observations support previous hypotheses and provide an informed foundation for metabolic modeling of anaerobic methane oxidation.