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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2012

Abstract

The aim of this paper is to complete the studies of the genus Stenostola in Northern Europe. Together with previous published studies the characters presented form a better basis for separation of S. ferrea and S. dubia both as imagines and as larvae. The presented paper consists of three parts: Studies of the genitalia, morphological characters for identification of the larvae and DNA barcoding of both Stenostola dubia (Laicharting, 1784) and S. ferrea (Shrank, 1776). Although very similar, the male genitalia have good characters for species separation. The easiest characters to use are the parameres and tips of sclerite 2. The posterior ends of the elongated median sclerites of S. ferrea are irregularly curved or “zigzag” shaped, while the posterior ends of the median sclerites of S. dubia are straight. The genitalia characters presented are not previously published. No single morphological character alone is enough to identify the larvae to species. However, when the characters are used together the mature larvae are usually identifiable. The younger the larvae are, the more difficult they are to identify. Barcoding analysis of mitochondrial COI gene shows that S. ferrea and S. dubia are genetically different. The genetic distance between the species is 10.3 %. These results, in addition to previous findings, show that despite the morphological similarities, they are clearly two different species.

Abstract

Light-emitting diodes (LEDs), high-pressure sodium lamps (HPSLs) and some cladding materials offer possibilities of influencing arthropod integrated pest management in greenhouse crops where light quality, quantity and photoperiod differ from nature. Light intensity, photoperiod and wavelength distribution affect plant functions and quality which, in turn, can be reflected in the performance of herbivores. The attenuation of UV-light in HPSL spectrum and in the natural winter daylight of northern latitudes may make plants more vulnerable to pests, whereas the high ratio of red to far-red of HPSLs may act to compensate for the effects of attenuated UV-levels. High red to far red ratio has been shown to result in increased production of plant phenolics and physical defences such as leaf toughness, which, in turn, can negatively influence the performance of some herbivore guilds on plants. Specific spectra produced by LEDs can influence plant quality and hence herbivore performance, but direct effects on arthropods can be even more pronounced, such as the inability to visually locat host plants in red and blue lights. Other direct effects of artificial light on pests and beneficial organisms include the detrimental effect of UV-C and UV-B on arthropods, diapause prevention by species-specific wavelengths or photoperiods, attraction to yellow-green and polarized light, reduced visibility of host or prey, and changes in take-off behaviour. Other effects include response to light intensity, interactive effects of light quality and photoperiod on fecundity, and species-specific effects of continuous light on the population growth of arthropods and plant-infesting fungi as well as the rhythmic expression of xenobiotic metabolising genes in arthropods. The potential of using the knowledge of photobiology and visual ecology of organisms for plant protection are discussed using whiteflies and fungal diseases of plants as the model species.