37 research outputs found

    Meat Feeding Restricts Rapid Cold Hardening Response and Increases Thermal Activity Thresholds of Adult Blow Flies, Calliphora vicina (Diptera: Calliphoridae)

    Get PDF
    Virtually all temperate insects survive the winter by entering a physiological state of reduced metabolic activity termed diapause. However, there is increasing evidence that climate change is disrupting the diapause response resulting in non-diapause life stages encountering periods of winter cold. This is a significant problem for adult life stages in particular, as they must remain mobile, periodically feed, and potentially initiate reproductive development at a time when resources should be diverted to enhance stress tolerance. Here we present the first evidence of protein/meat feeding restricting rapid cold hardening (RCH) ability and increasing low temperature activity thresholds. No RCH response was noted in adult female blow flies (Calliphora vicina Robineau-Desvoidy) fed a sugar, water and liver (SWL) diet, while a strong RCH response was seen in females fed a diet of sugar and water (SW) only. The RCH response in SW flies was induced at temperatures as high as 10°C, but was strongest following 3h at 0°C. The CTmin (loss of coordinated movement) and chill coma (final appendage twitch) temperature of SWL females (-0.3 ± 0.5°C and -4.9 ± 0.5°C, respectively) was significantly higher than for SW females (-3.2 ± 0.8°C and -8.5 ± 0.6°C). We confirmed this was not directly the result of altered extracellular K+, as activity thresholds of alanine-fed adults were not significantly different from SW flies. Instead we suggest the loss of cold tolerance is more likely the result of diverting resource allocation to egg development. Between 2009 and 2013 winter air temperatures in Birmingham, UK, fell below the CTmin of SW and SWL flies on 63 and 195 days, respectively, suggesting differential exposure to chill injury depending on whether adults had access to meat or not. We conclude that disruption of diapause could significantly impact on winter survival through loss of synchrony in the timing of active feeding and reproductive development with favourable temperature conditions

    BSC-based evaluation for the factors affecting the performance of wind energy companies

    No full text
    This study aims to identify the significant factors which improve the performance of wind energy companies. For this purpose, a detailed literature review is conducted, and eight different performance evaluation criteria are identified based on four dimensions of balanced scorecard (BSC) approach. In the evaluation process of these factors, fuzzy DEMATEL approach is taken into consideration. The results indicate that internal process and learning and growth are the most important dimensions of BSC regarding the wind energy investment projects. Moreover, it is also concluded that the most important criteria are technological background and research and development. Hence, it is recommended that wind energy companies should mainly pay attention to technological development in order to be successful in such a complex investment which requires high engineering knowledge. In this context, the equipment and information technology software should be effective in these countries. Owing to this issue, the risk of having deficiencies can be minimized. Additionally, high technology can be obtained with a lower cost by making extensive research and development activities
    corecore