Quantifying inherent predictability and spatial synchrony in the aphid vector Myzus persicae: field-scale patterns of abundance and regional forecasting error in the UK

Background

Sugar beet is threatened by virus yellows, a disease complex vectored by aphids that reduces sugar content. We present an analysis of Myzus persicae population dynamics with and without neonicotinoid seed treatment. We use 6 years' yellow water trap and field-collected aphid data and two decades of 12.2 m suction-trap aphid migration data. We investigate both spatial synchrony and forecasting error to understand the structure and spatial scale of field counts and why forecasting aphid migrants lacks accuracy. Our aim is to derive statistical parameters to inform regionwide pest management strategies.

Results

Spatial synchrony, indicating the coincident change in counts across the region over time, is rarely present and is best described as stochastic. Uniquely, early season field populations in 2019 did show spatial synchrony to 90 km compared to the overall average weekly correlation length of 23 km. However, 70% of the time series were spatially heterogenous, indicating patchy between-field dynamics. Field counts lacked the same seasonal trend and did not peak in the same week. Forecasts tended to under-predict mid-season log₁₀ counts. A strongly negative correlation between forecasting error and the proportion of zeros was shown.

Conclusion

Field populations are unpredictable and stochastic, regardless of neonicotinoid seed treatment. This outcome presents a problem for decision-support that cannot usefully provide a single regionwide solution. Weighted permutation entropy inferred that M. persicae 12.2 m suction-trap time series had moderate to low intrinsic predictability. Early warning using a migration model tended to predict counts at lower levels than observed. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Gill epithelial cells kinetics in a freshwater teleost,Oncorhynchus mykiss during adaptation to ion-poor water and hormonal treatments

The aim of this work was to determine the kinetics of the dramatic development of the gill chloride cells (CCs) during adaptation of the salmonid Oncorhynchus mykiss to an ion-poor environment. To monitor cell division, the incorporation in the mitotic cell DNA of bromo-deoxyuridine (BrdUrd) was visualized with a monoclonal antibody. The density of labelled nuclei was used as an index of cellular division (proliferation), concomitantly with morphometry of phenotypic changes monitored with SEM. In the filament epithelium, a phase of CC differentiation occurred within 12h after the transfer, followed by a delayed phase of cell proliferation (48h). In the lamellar epithelium, the present study demonstrates the absence of cell proliferation after ion-poor water transfer. The conclusion is that proliferation (mitosis) is important in the primary filament whereas differentiation and migration (from the filament) is the main mechanism for the appearance of CCs on the secondary lamellae. The present study suggests that cortisol promoted differentiation, but not division, of cells. CCs, presumably premature, were stained by anti-cortisol monoclonal antibody indicating the presence of cortisol. No mature CCs were stained. Growth hormone (oGH, ratGH) increased the rate of cell division both in lamellar and filament epithelium.     

Earthquake impacts on a protected pinniped in New Zealand

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Comparison of a computed tomographic pulmonary trunk to aorta diameter ratio with echocardiographic indices of pulmonary hypertension in dogs

There are limited criteria for the detection of pulmonary hypertension in dogs undergoing computed tomography (CT) for pulmonary disease. This retrospective analytical exploratory study compared a CT pulmonary trunk to aorta ratio with echocardiographic estimates of pulmonary hypertension. Dogs having both a contrast thoracic CT and echocardiogram were selected and maximal pulmonary trunk and descending aorta diameters were measured by two observers on a single transverse CT image. Computed tomographic diameter ratios were compared with the echocardiographic parameters of tricuspid regurgitation gradient, right ventricular acceleration time‐to‐ejection time ratio, pulmonary insufficiency gradient, and pulmonary artery to aorta diameter. A total of 78 dogs were sampled, with 44 dogs having one or more finding suggestive of pulmonary hypertension. A moderate positive correlation was shown between tricuspid regurgitation gradient and CT pulmonary trunk to aorta ratio (r = 0.61, P‐value < 0.0001). Mean CT pulmonary trunk to aorta ratio of dogs with moderate (P = 0.0132) and severe (P < 0.0003) pulmonary hypertension were significantly higher than normal dogs. There was no significant difference in mean CT pulmonary trunk to aorta ratio between normal and mild pulmonary hypertension dogs (P = 0.4244). The intraclass correlation coefficient (0.72) showed good reproducibility of the ratio. Findings indicated that CT pulmonary trunk to aorta ratio is a reproducible and potentially useful method to predict moderate and severe pulmonary hypertension in dogs, but not mild pulmonary hypertension. In dogs undergoing thoracic CT for pulmonary disease, an increased ratio should prompt follow up echocardiography.     

The Effect of Temperature on Feed Consumption and Nutrient Absorption in Procambarus clarkii and Procambarus zonangulus

Feeding characteristics of acclimated red swamp crayfish Procambarus clarkii and white river crayfish Procambarus zonangulus were determined at 8, 14, 20, 26, and 32 C. Food consumption rates of crayfish were directly related to temperature. Feeding was minimal at 8 C. At 14 CP. zonangulus consumed significantly more feed (5.5% body weight (BW/d) than P. clarkii (1.8% BW/d). At 32 C P. clarkii consumed significantly more feed (23% BW/d) than P. zonangulus (10% BW /d), reflecting species-specific thermal optimums for feeding. Differences in food consumption rates correspond to differences in the geographical distributions of these two species. Dry matter absorption rates ranged from 55% to 75% for both species without significant temperature effect. Patterns of protein and carbohydrate absorption were similar in P. clarkii and P. zonangulus. Protein absorption efficiency decreased from 45% to 10% as temperature increased from 8 C to 32 C. The total amount of protein absorbed increased seven- to ten-fold as temperature increased. Soluble carbohydrate absorption efficiency was reduced at low temperatures. However, absorption efficiency increased approximately five-fold as temperature increased from 14 C to 20 C, but did not change substantially as temperature was increased to 32 C. The total amount of carbohydrate absorbed increased approximately 15- to 26-fold as temperature increased. The protein to carbohydrate utilization ratio was similar between species, but varied dramatically with temperature. Both species absorbed between 2.5 and four-times more protein than carbohydrate at low temperatures (8 C and 14 C). At 32 C both species utilized approximately three times more carbohydrate than protein. In spite of reduced consumption at lower temperatures, crayfish absorbed a greater protein portion. At these low temperatures it appears that crayfish maximize the efficiency of protein absorption, presumably for maintenance and growth requirements. At high temperatures it appears that crayfish maximize energy intake, presumably to sustain higher metabolic rates due to increased activity levels. These apparent temperature-dependent nutrient requirements may influence natural foraging strategies or, for species in aquaculture, the effectiveness of commercial feed preparations. At high temperatures P. clarkii was more effective in consuming nutrients than P. zonangulus and may be more successful than P. zonangulus at these temperatures.     

Predicting cumulative risk of bovine respiratory disease complex (BRDC) using feedlot arrival data and daily morbidity and mortality counts

Although bovine respiratory disease complex (BRDC) is common in post-weaning cattle, BRDC prediction models are seldom analyzed. The objectives of this study were to assess the ability to predict cumulative cohort-level BRDC morbidity using on-arrival risk factors and to evaluate whether or not adding BRDC risk classification and daily BRDC morbidity and mortality data to the models enhanced their predictive ability. Retrospective cohort-level and individual animal health data were used to create mixed negative binomial regression (MNBR) models for predicting cumulative risk of BRDC morbidity. Logistic regression models were used to illustrate that the percentage of correctly (within |5%| of actual) classified cohorts increased across days, but the effect of day was modified by arrival weight, arrival month, and feedlot. Cattle arriving in April had the highest (77%) number of lots correctly classified at arrival and cattle arriving in December had the lowest (28%). Classification accuracy at arrival varied according to initial weight, ranging from 17% (< 182 kg) to 91% (> 409 kg). Predictive accuracy of the models improved from 64% at arrival to 74% at 8 days on feed (DOF) when risk code was known compared to 56% accuracy at arrival and 69% at 8 DOF when risk classification was not known. The results of this study demonstrate how the predictive ability of models can be improved by utilizing more refined data on the prior history of cohorts, thus making these models more useful to operators of commercial feedlots.     

Sorghum extrusion increases bioavailability of catechins in weanling pigs

Catechins and procyanidins are beneficial for human health; however, their bioavailability is low. The effect of food processing on catechin bioavailability from sources containing predominantly procyanidins has not been studied. The sumac sorghum mixture (50% whole grain+50% bran) used in this study contained catechins, procyanidins dimers, and polymers at 0.08, 0.6, and 26.4 mg/g, respectively. Extrusion decreased the polymeric procyanidins by 48% to 22 mg/g while increasing catechins (50%) and dimers (64%) to 0.12 and 1.0 mg/g, respectively. Six weanling pigs (8.9+/-1.1 kg) received a single dose by gavage of the sorghum mixture (7 g/kg0.75), the sorghum mixture extrudate, or white sorghum (50% whole grain+50% bran) in a randomized crossover design. Treatments were separated by a 7-day washout period. Blood was drawn at 0, 1, 2, and 4 h. Plasma catechin, 3'-O-methylcatechin, 4'-O-methylcatechin, epicatechin, 3'-O-methylepicatechin, and 4'-O-methylepicatechin peaked at 1 h and were 18, 43, 1, 0.7, 0.7, and 0.3 nmol/L for pigs receiving sorghum, respectively. Plasma levels in pigs receiving extruded sorghum were 66, 110, 2, 16, 8, and 11 nmol/L, respectively. Plasma levels of catechin, 3'-O-methylcatechin, and the total catechins were higher in pigs fed extruded sorghum at 1, 2, and 4 h postdose (P相似文献   

Greater coverage of the phylum Nematoda in SSU rDNA studies

The small subunit ribosomal gene (SSU rDNA) is used in both environmental and phylogenetic studies of nematodes. However, currently described SSU rDNA primers near to the 5′ end of the gene show mismatches with a number of different nematode sequences. Here a new SSU rDNA 5′ forward primer, Nem_SSU_F74, is designed from existing database sequences and its performance compared with a previously described forward primer, SSU_F04, by sequencing from nematode assemblage DNA, in combination with a previously described reverse primer. DNA was extracted from three nematode assemblages isolated from arable soil and, in total, six clone libraries were created: three amplified with established forward primer SSU_F04 and three with the novel primer Nem_SSU_F74. Ninety six clones were sequenced from each library. Nem_SSU_F74 libraries yielded a higher number of nematode sequences than SSU_F04 libraries, and a greater number of nematode taxa were found using the novel forward primer. The most abundant sequences were common to libraries created with either forward primer. Data from a morphological survey of the same samples revealed that biomass was more closely related to molecular analysis than simple counts of nematodes. For all but one nematode order (Aphelenchida), percentage assemblage composition was not significantly different between biomass and sequences obtained with the novel forward primer Nem_SSU_F74.     

Innovation Processes in Forest-related Recreation Services: The Role of Public and Private Resources in Different Institutional Backgrounds

This article examines innovation processes in forest recreational services on the basis of case studies in five European countries with differing institutional backgrounds of forest ownership and access rights. The analysis reveals that forest-related recreation services are developed under varying institutional conditions and on public as well as private land. Ideas for innovations in recreational services may come from within but often outside the forestry sector. Financing is provided from public and private sources. Both public and private spheres have important roles in providing natural, human and financial resources and usually a network of public and private actors are involved in innovation processes. Of particular importance are cross-sectoral interactions between forestry and tourism. Greater institutional support is needed for the development of forest-related recreation services because the field is at an early stage of development. It is concluded that support should focus on providing ideas and financial resources for product development and on facilitating cross-sectoral interaction between forestry and tourism actors. A particular need is seen for development of models for durable interaction between land owners and tourism operators on a regional scale.     

Effects of stem girdling on cone yield and endogenous phytohormones and metabolites in developing long shoots of Douglas-fir (Pseudotsuga menziesii)

Stem-girdling treatments were applied in early spring to stimulate cone formation in two genotypes of interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco). After girdling treatments, male cone yield increased significantly in the next growing season. The increase was 14-fold in genotype 9137. In genotype 9550, more than 8,700 male cones were induced from each tree whereas no male cones were found in controls. Female cone yield was zero in controls and low for girdled trees in both genotypes. Multiple phytohormone-related compounds, including gibberellins (GAs), cytokinins, indole-3-acetic acid (IAA), abscisic acid (ABA) and their selected metabolites, were analyzed in developing long shoots after girdling treatments by high performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC?CESI?CMS/MS) in multiple reaction monitoring mode. Concentrations of GA₄ were slightly higher at week 2 following girdling treatment, whereas at week 8 lower GA₄ concentrations were found in girdled samples. Stem girdling did not affect concentrations of IAA and major cytokinins, such as zeatin riboside and isopentenyl adenosine. Concentrations of ABA differed two-fold between the genotypes. Although girdling treatment did not cause differences in ABA concentrations, it generally resulted in higher concentrations of ABA glucose ester. Concentration increase of 7??-hydroxy ABA by girdling was only found in genotype 9550 at week 8. Girdling caused little change in concentrations of phaseic acid in both genotypes.