The molecular identification and genetic diversity of economically important wireworm species (Coleoptera: Elateridae) in Canada

Click beetle larvae (wireworms) are significant crop pests in Europe and North America. In Canada, there are ~30 economically important species which are morphologically difficult to identify, but for which sequence data are lacking. Accurate knowledge of damage-causing species and the population genetics and phylogeography of elaterids will provide insight into their sustainable management. Here, we use interspecific variation in mitochondrial 16S rRNA as a robust method of identification, consider the intra- and interspecific genetic variation of some important Canadian wireworm pests and assess the genetic structure and isolation by distance for a re-emerging major pest species, Hypnoidus bicolor Eschscholtz. Wireworms were sampled from Canada and the USA, identified as morphospecies, and sequenced at the 16S rRNA region (294–442 bp). Within some species unusually high intraspecific genetic distances between samples suggested the possibility of cryptic wireworm species or misidentifications, though this was <1 % for most species. Phylogenetic analyses gave some indication of the likely identity of these ambiguous samples. There was a significant correlation between genetic and geographic distance and significant genetic structuring within and between H. bicolor populations, which appeared to be composed of two species comprising several haplotypes. These data provide a starting point for determining the distribution of damage-causing species throughout Canada. The inclusion of data from other nuclear and mitochondrial loci, and use of sequence data from known adult samples, would further aid identification and relationships of wireworm species.     

The effect of a seaweed concentrate on the in vitro growth and acclimatization of potato plantlets

Summary The seaweed concentrate ‘Kelpak’ is used commercially in the greenhouse and field to improve plant quality. ‘Kelpak’ was added to the in vitro culture medium of potato cv. ‘BP1’ and also applied as a leaf/soil drench immediately after transplanting. The addition of 0.25% seaweed concentrate to the medium improved plantlet quality and led to better establishment in the greenhouse. No beneficial effect of seaweed concentrate in the tissue culture medium was observed if a second cutting was part of the micropropagation process. Additional application of 0.5% seaweed concentrate in the greenhouse to plantlet cuttings derived from tissue culture was not beneficial.     

Influence of pig substitution on milk yield, litter weights, and milk composition of machine milked sows.

This study was conducted to 1) determine milk yield of sows that were machine milked up to four times daily; 2) determine the effect of pig substitution on milk yield; 3) assess litter weight changes for sows that are milked; and 4) determine milk composition. Eight sows were milked four times daily to d 51 postpartum. Sows either maintained their own litter or had a week-old replacement litter to replace 25-d-old pigs. Individual gland milk yields were obtained on random days throughout lactation, and different diameter and weighted teat cups were rotated so that all glands received all combinations. Composite milk samples were analyzed for fat, protein, and somatic cells. Milk yields peaked at about 19 d postpartum and declined to 45 d postpartum in sows with their own litter, whereas milk yields peaked earlier and had a more dramatic decline after fostering of a younger litter. Litter weights were 17.1 +/- 1.0 kg at farrowing with 13.6 +/- .6 pigs born alive. Final litter weights were 34.4 +/- 11.7 kg for sows with replacement litters and 74.4 +/- 13.5 kg for sows with their own litters, and numbers of pigs weaned were 6.5 +/- 1.3 and 9.7 +/- 1.5, respectively. Milk fat was influenced by route of oxytocin administration (6.53 +/- .12 for i.v. vs 7.21 +/- .19% for i.m. administration; P < .05). Milk fat percentage was highest on d 2 and declined to 13 d postpartum. Milk protein was influenced by time of day of milking (lowest at the fourth milking, 5.57 +/- .11%) and followed a pattern similar to that for milk fat. Milk protein was affected in a linear manner by milk yield, with highest protein associated with lowest milk yields. Somatic cells in milk were influenced by litter replacement (P < .05) and oxytocin administration (P < .01). There was a linear increase in somatic cells from about 8 x 10(6) cells/mL milk at d 2 to more than 12 x 10(6) cells/mL milk at d 51 postpartum. These results show that pig replacement affects the amount of milk obtained. Moreover, milk composition changes throughout lactation. However, milk removal from sows has a severe impact on litter weight gains, and in systems where sow's milk is needed for commercial purposes, pig supplementation is necessary.     

Bleeding of anaesthetized and exhausted Atlantic salmon: body cavity inspection and residual blood in pre‐rigor and smoked fillets as determined by various analytical methods

The bleeding efficiency of anaesthetized and exhausted Atlantic salmon was studied. Unbled fish were used as control groups for both treatments. Several analytical methods (computer vision, Minolta Chroma Meter, transflectance spectroscopy, haemoglobin iron and visual assessment of smoked fillets) were used to evaluate colour or residual blood contents of pre‐rigor and smoked fillets. In all cases, the amount of residual blood in the fillets was modest and blood was not considered a quality problem in terms of fillet appearance. Perimortem stress did not affect residual blood contents of pre‐rigor fillets. Only salting and smoking had a significant effect on filet colour. The low levels of residual blood was partly attributed to filleting shortly after killing allowing washing before the blood had time to coagulate. In addition, a computer vision method was developed for automated blood inspection of the body cavity after gutting and washing. A classifier (‘no blood’ or ‘blood present’) based on linear discriminant analysis was tested and the classification accuracy was over 90% as evaluated with the leave‐one‐out method.     

Repeated monitoring of organic carbon stocks after eight years reveals carbon losses from intensively managed agricultural soils in Western Germany

Past land‐use changes, intensive cropping with large proportions of root crops, and preferred use of mineral fertilizer have been made responsible for proceeding losses of soil organic C (SOC) in the plough layer. We hypothesized that in intensive agriculturally managed regions changes in SOC stocks would be detectable within a decade. To test this hypothesis, we tracked the temporal development of the concentrations and stocks of SOC in 268 arable sites, sampled by horizon down to 60 cm in the Cologne‐Bonn region, W Germany, in 2005 and in 2013. We then related these changes to soil management data and humus balances obtained from farmers' surveys. As we expected that changes in SOC concentrations might at least in part be minor, we fractionated soils from 38 representative sites according to particle size in order to obtain C pools of different stability. We found that SOC concentrations had increased significantly in the topsoil (from 9.4 g kg^?1 in 2005 to 9.8 g kg^?1 in 2013), but had decreased significantly in the subsoil (from 4.1 g kg^?1 in 2005 to 3.5 g kg^?­1 in 2013). Intriguingly, these changes were due to changes in mineral‐bound SOC rather than to changes in sand‐sized organic matter pools. As bulk density decreased, the overall SOC stocks in the upper 60 cm exhibited a SOC loss of nearly 0.6 t C (ha · y)^?1 after correction by the equivalent soil mass method. This loss was most pronounced for sandy soils [?0.73 t SOC (ha · y)^?1], and less pronounced for loamy soils [?0.64 t SOC (ha · y)^?1]; silty soils revealed the smallest reduction in SOC [?0.3 t SOC (ha · y)^?1]. Losses of SOC occurred even with the overall humus balances having increased positively from about 20 kg C (ha · y)^?1 (2003–2005) to about 133 kg C (ha · y)^?1 (2005–2013) due to an improved organic fertilization and intercropping. We conclude that current management may fail to raise overall SOC stocks. In our study area SOC stocks even continued to decline, despite humus conservation practice, likely because past land use conversions (before 2005) still affect SOC dynamics.     

Effect of mitratapide on body composition, body measurements and glucose tolerance in obese Beagles

The objective of this study was to confirm that weight loss after treatment with mitratapide (Yarvitan®) is loss of adipose tissue. Obese dogs were treated with the recommended treatment schedule of mitratapide. Dual-energy X-ray absorptiometry (DEXA) was done before and after the treatment schedule. Body weight, feed consumption and pelvic circumference were recorded and a glucose tolerance test was performed. Dual-energy X-ray absorptiometry measurements showed an impressive loss of fat tissue, corresponding to a mean loss of approximately 41.6% of the body fat mass recorded before treatment. After treatment with mitratapide, the mean body fat percentage had returned within the normal range. At the end of the study, the dogs had lost on average 14.2% of their body weight and 15.2% of their pelvic circumference compared to baseline. The results also suggest that losing weight with mitratapide might help to reverse insulin resistance.