Oviposition,adult longevity and temperature effects on the eggs of Tetanocera elata (Fab.) (Diptera: Sciomyzidae): a potential biocontrol agent for slugs

Pestiferous slugs in organic and conventional farming systems damage crops, reduce yield and quality, and reduce profits; however, no biological control agent that is both efficacious and inexpensive has yet been developed. One potential biological control agent is the slug‐feeding Tetanocera elata (Fab.), for which scant scientific data are currently available regarding optimum growing conditions. This study examined the effect of constant temperatures (14, 17, 20, 23 and 26°C) and ambient outdoor and laboratory temperatures on the duration of the egg stage of T. elata. In general, mean and median duration of incubation decreased as temperatures increased, with the highest (52%) and lowest (20%) hatch rates occurring at 14 and 26°C, respectively. Longevity and oviposition rates for T. elata are discussed in the context of mass biocontrol production systems, and possible reasons for low hatch rates for eggs stored at 2–3°C are discussed in the context of the phenology of the species.     

Larval feeding behaviour of Tetanocera elata (Diptera: Sciomyzidae): potential biocontrol agent of pestiferous slugs

Examining predatory behaviour is useful for determining the potential of novel biocontrol agents. We investigated the predatory behaviour of Tetanocera elata (Fabricius) larvae on the pestiferous slug Deroceras reticulatum (Müller). Results indicate three prey-finding strategies, including the predator reaching its prey without previous contact with it or its mucus trail.     

Turlough ground beetle communities: the influence of hydrology and grazing in a complex ecological matrix

Turloughs are groundwater dependent grazed wetlands of conservation importance that occur in limestone depressions in the karst landscape, mostly in the west of Ireland. Data on Carabidae, hydrological regime, soils and management (using grazing exclosures) were collected to assess the effects of both hydrological regime and grazing management on ground beetles of Skealoghan turlough. Distinct ground beetle communities have been found associated with different hydrological regimes with carabid beetle community composition sensitive to both changes in hydrological regime and vegetation structure. The hydrological regime is the primary factor controlling the carabid species composition of this grazed wetland. Grazing, particularly selective grazing by animals plays an important but subordinate role to hydrology in providing suitable habitat conditions for many species of conservation importance. This paper provides a detailed assessment of species responses to wetland management and demonstrates the need to maintain a range of hydrological and grazing regimes.     

Factors affecting Sciomyzidae (Diptera) across a transect at Skealoghan Turlough (Co. Mayo,Ireland)

Sciomyzid flies, which have potential as bio-indicators, were sampled by sweep-net surveys at a turlough in the west of Ireland. Turloughs are ephemeral wetlands (unique to Ireland), which flood from groundwater in winter and empty in the summer, during that time, they are frequently grazed. The weekly survey consisted of ten linear sweeps (5 m × 1 m) in each of six homogeneous and contiguous vegetation zones throughout the summer of 2004. The fauna was dominated by univoltine species with Ilione albiseta being particularly abundant, though species displaying a range of phenologies and life histories were also present. Species richness and total abundance were significantly higher in the two zones with the highest hydroperiods. Mantel tests showed that the species matrix was significantly co-structured with permanent features of the physical environment, but not with stochastic sampling variables related to weather conditions. Mantel correllograms displayed typical patterns of autocorrelation for hydroperiod, soil moisture and soil pH in each zone and vegetation height, vegetation length and Ellenberg moisture index (weighted for vegetation composition) in each sweep-path. No patterns of autocorrelation were evident for distance among zones, area of patch of vegetation zone sampled, area of the vegetation zone on the whole turlough, soil mass-loss-on-ignition and Ellenberg N and reaction indices. These results provide strong evidence for high microhabitat specificity in Sciomyzidae at this site and indicate a major influence of vegetation structure and hydrological regime on their ecology.

A study of factors influencing hydration of sodium hyaluronate from compressibility and high-precision densimetric measurements.

A study of the factors influencing the hydration of the biopolymer hyaluronic acid was made by compressibility and density measurements. The factors investigated were the hydration changes on glycosidic bond formation, and also the influence of counterion type, solution ionic strength and temperature. The results indicate that, with this biopolymer, the hydration of the glucuronate residue is significantly more than that of the N-acetylglucosamine residue, and further that the biopolymer is less hydrated than the sum of its component monosaccharide residues. Change of the counterion salt form of this polyelectrolyte from univalent to bivalent counterion type (Na+ to Ca2+) leads to a small though significant increase in the total hydration sheath surrounding the polymer. An increase in the background ionic strength of the solvent leads to a quantifiable lowering of the hydration of the polymer at physiological ionic strength compared with its value in salt-free aqueous solution. A decrease in hydration with increase in temperature in the range 20-50 degrees C is the opposite of previous reports, and was observed when the polymer was dissolved both in pure water and in 0.15 M-NaCl.     

Spatiotemporal variation of Diptera changes how we evaluate High Nature Value (HNV) wet grasslands

Proposed strategies to protect biodiversity within agricultural systems are often based on botanical criteria with plant species richness generally considered the prime indicator of conservation potential. While wet grasslands dominated by rushes (Juncus spp.) are commonly considered to be of lesser ecological value than those which are more botanically diverse (e.g. Carex dominated wet grasslands), their value for invertebrates such as Diptera has not yet been fully explored. Data from two Diptera families (Sciomyzidae and Syrphidae) were examined at spatial, temporal and spatiotemporal scales to determine the contribution of two different (Juncus and Carex dominated) wet grassland habitats towards the maintenance of Diptera diversity. The two habitats were significantly different in terms of community structure for both families and temporal variation was a significant component of dipteran diversity. Spatiotemporal analysis showed that species turnover between habitats at different times made the most significant contribution to overall Diptera diversity. Temporal variation of both families suggests that the relative importance of each habitat type to overall diversity fluctuates depending on sampling period, with both habitats supporting diversity at different times. Our results indicate that lowland wet grasslands characterised by Juncus cover need to be recognised as ecologically important for the maintenance of dipteran diversity. We discuss the possible implications for the diversity of Diptera in wet grasslands if these commonly perceived marginal areas (both agriculturally and ecologically) are ignored in conservation strategies. The necessity of recognising spatiotemporal variation when evaluating habitats using invertebrates as indicators is also discussed.     

The use of GIS techniques to quantify the hydrological regime of a karst wetland (Skealoghan turlough) in Ireland

Question: Can GIS and GPS technology be used to quantify the hydrological regime of different plant communities on turloughs (groundwater dependent calcareous wetlands)? Location: Skealoghan turlough, County Mayo, Ireland. Methods: Plant communities were mapped and digitised with GIS software and a digital elevation model of the site was constructed from differential GPS data. Together with records of water level fluctuations on the site from May 2001 to May 2004, these data were used to calculate hydrological variables for each plant community. Hierarchical cluster analysis was used to identify groups of plant communities with similar hydrological regimes. Results: 15 plant communities were mapped at Skea loghan, with the Cirsio‐Molinietum and Ranunculo‐Potentilletum anserinae being the dominant phytosociological associations. Skealoghan is subject to large temporal and spatial variation in its hydrological regime and fluctuations in water level are intrinsically linked to rainfall. The spatial variation in flooding can be linked to the vegetation zones. Conclusions: GIS and DGPS technology can be used to quantify the hydrological regime of different plant communities on turloughs. Since the hydrological regime is a major environmental factor controlling the vegetation composition of the site, the maintenance of natural flooding regimes is a vital component for the conservation and management of the diverse vegetation mosaic at Skealoghan turlough.     

Binge Eating Disorder Affects Outcome of Comprehensive Very-Low-Calorie Diet Treatment

To determine the effects of binge eating disorder (BED) on weight loss and maintenance in women undergoing treatment for obesity, we studied the weight changes of 38 women (body mass index >30 kg/m²), 21 of whom met proposed criteria for BED and 17 of whom reported few problems with binge eating, during and after a 26-week comprehensive very-low-calorie diet (VLCD) treatment program. All 17 subjects without and 16/21 subjects with BED returned for four follow-up visits over 12 months (p=0.05). While a similar proportion of subjects with and without BED reported absolute adherence to both the modified fast and refeeding, those with BED showed a significantly different distribution in energy intake from those without BED, with fewer small and more large lapses among those who deviated from the diet (p<0.05). There was no significant difference in mean weight loss over the 26 weeks of treatment, but subjects with BED showed significantly diminished weight loss during the middle third of treatment (p<0.05). Black subjects, regardless of the presence of BED, lost significantly less weight during treatment than white subjects (p<0.005). Although there was no significant difference in mean weight loss at any of the four follow-up visits between subjects with and without BED, 25% of subjects with BED had regained >50% of their lost weight by three-month follow-up, vs. no subjects without the disorder (p<0.05). One year after completing treatment, approximately half of BED (+) and BED (-) subjects had a good outcome, maintaining a weight loss ≥10% of initial body weight. However, 35% of subjects with BED, and none of the subjects without BED, had a poor outcome (p<0.05). We conclude that many individuals with BED will respond well to a medically supervised comprehensive VLCD program, attaining medically significant weight loss. However, this subgroup appears to be at risk for early major regain of lost weight and for poor outcome one year following weight-loss treatment.     

Sexual dimorphism and the impact of temperature on the pupal and adult stages of Sepedon spinipes spinipes, a potential biological control agent of fascioliasis

The malacophagous feeding behaviour of larvae of members of the family Sciomyzidae makes the group ideal for the selection of potential biological control agents of snail hosts of trematode diseases. The aim of this study was to investigate the effects of temperature (14 °C, 17 °C, 20 °C, 23 °C, and 26 °C) on the pupal and adult stages of Sepedon spinipes spinipes (Scopoli) (Diptera: Sciomyzidae). Larval prey density effects on the pupal stage and the extent of sexual dimorphism within the species are also assessed. Optimum growth conditions for the pupal stage and pre‐oviposition/oviposition periods, and female fecundity are identified for mass culturing purposes. The tendency of mature third instar larvae to engage in wandering behaviour is highlighted, and the biological control implications of such behaviour are discussed. Female puparia were significantly (P<0.001) heavier than males for both larval prey densities. Such sexual dimorphism would enable the prediction of adult sex from puparial weight prior to eclosion, thereby facilitating culture establishment. The effect of three food types [honey/yeast mixture only, crushed Radix balthica (L.) (Gastropoda: Pulmonata: Lymnaeidae) only, and honey/yeast mixture plus a crushed snail] on adult longevity (laboratory conditions) was also determined and the results suggest that adults live longest when provided with a crushed snail and a honey/yeast mixture.     

Enhanced iron availability by protein glycation may explain higher infection rates in diabetics

Serum proteins exist in a state of higher glycation among individuals with poor glycemic control, notably diabetics. These non-enzymatic modifications via the Maillard reaction have far reaching effects on metabolism and regulation, and may be responsible for increased infection rates within this population. Here we explore the effects of glycation on iron metabolism and innate immunity by investigating the interaction between siderophores and bovine serum albumin (BSA). Using a quartz crystal microbalance with dissipation monitoring to quantify association rates, glycated BSA exhibited a significantly reduced affinity for apo and holo enterobactin compared to a non-glycated BSA standard. Bacterial growth assays in the presence of BSA and under iron-limited conditions indicated the growth rate of enterobactin-producing E. coli increased significantly when the BSA was in a glycated form. The results, in addition to data in the literature, support the hypothesis that glycation of serum proteins may effectively increase the available free iron pool for bacteria in blood serum and weaken our innate immunity. This phenomenon may be partially responsible for higher infection rates in some diabetics, especially those with poor glycemic control.