MATCHING THE SHAPE OF TIME-INTENSITY CURVES1

Time-Intensity Curves are often summarized by average curves. From these curves TI-parameters are inferred. In this paper a different method is proposed in which the shape of the curves is the central concept. Isotropic scaling factors are computed for each curve. These factors can be tabled and inspected. Often a large number of scaling factors will be computed, which makes it hard to study them in a table. In such cases they can be represented in a plot, for which in this paper PCA is suggested. In this plot a structure in the scaling factors for the different TI-curves may become visible. It is also possible to make a plot in which the homogeneity of the panel of subjects can be studied.     

Development of imaginal competence to adipokinetic hormone in Locusta: lipid and carbohydrate levels, and glycogen phosphorylase activity in precocene-induced adultiforms

Abstract. Adipokinetic responses to injection of synthetic adipokinetic hormone I (sAKH) were investigated in precocene-induced fifth-instar adultiforms and in chemically allatectomized but morphogenetically normal adults of Locusta migratoria (L.). The results were compared with data on normal fifth (=last)-instar nymphs and normal adults. Chemical allatectomy did not affect the resting level of lipid in the haemolymph, nor the slight decrease of haemolymph carbohydrate concentration induced by sAKH. The effects of chemical allatectomy on sAKH-induced hyperlipaemia, the resting level of haemolymph carbohydrate, total glycogen phosphorylase specific activity, as well as sAKH-induced phosphorylase activation in the fat body, were mostly minor and probably indirect. The concentrations of lipid and carbohydrate in the haemolymph, and sAKH-induced activation of fat body glycogen phosphorylase were more or less similar in normal fifth-instar nymphs, normal adults and fifth-instar adultiforms. Thus, precocious metamorphosis did not affect markedly those parameters which show no or slight changes during normal metamorphosis. In contrast, parameters which change substantially during normal metamorphosis (sAKH-induced hyperlipaemia, sAKH-induced changes in haemolymph carbohydrate level and total glycogen phosphorylase activity) showed similar changes in the course of precocious metamorphosis; the values for fifth-instar adultiforms were similar to those obtained for normal adults, but differed markedly from those found in normal fifth-instar nymphs. Thus, accelerated (precocious) morphological adult development is strongly correlated with accelerated imaginal target competence to AKH and with relevant physiological development.     

Principal climatic and edaphic determinants of Culicoides biting midge abundance during the 2007–2008 bluetongue epidemic in the Netherlands,based on OVI light trap data

Palaearctic Culicoides midges (Diptera: Ceratopogonidae) represent a vital link in the northward advance of certain arboviral pathogens of livestock such as that caused by bluetongue virus. The effects of relevant ecological factors on weekly Culicoides vector abundances during the bluetongue virus serotype 8 epidemics in the Netherlands in 2007 and 2008 were quantified within a hurdle modelling framework. The relative role of meteorological parameters showed a broadly consistent association across species, with larger catches linked to temperature‐related variables and lower wind speed. Moreover, vector abundance was found to be influenced by edaphic factors, likely related to species‐specific breeding habitat preferences that differed markedly amongst some species. This is the first study on Culicoides vector species in the Netherlands identified during an entomological surveillance programme, in which an attempt is made to pinpoint the factors that influence midge abundance levels. In addition to providing key inputs into risk‐mitigating tools for midge‐borne pathogens and disease transmission models, the adoption of methods that explicitly address certain features of abundance datasets (frequent zero‐count observations and over‐dispersion) helped enhance the robustness of the ecological analysis.