Biologie dekompozitorů byla vždy tak trochu na druhé koleji širšího vědeckého i veřejného zájmu. Není se trochu čemu divit – než se přehrabovat v něčem nevábném, je pohodlnější pozorovat zvířata na rostlinách či jejich predátory. Nicméně dekompozitoři si naši pozornost zaslouží už jen tím, že po nás uklízejí, ať jde o kontinuální úklid koprofágů, tak o jednorázový úklid, který po nás provedou nekrofágové, a tím pomáhají udržovat to krásné a přitažlivé v chodu a stabilitě. Z koprofágů se již od věků pyramid těší jisté pozornosti koprofágní brouci, nicméně za poslední léta o nich v naší literatuře mnoho slyšet nebylo. Cílem tohoto článku je tedy představit širší veřejnosti tyto koprofágní brouky s jejich osobitou a zajímavou ekologií, která zajímavě ovlivnila jednu lidskou kulturou., Dung beetles are introduced as an important and interesting ecological group. Their ecology, what they eat and their impact on human culture and society are reviewed. Although they are no longer considered to be a deity, dung beetles still prove to be highly beneficial for both nature and human society, thanks to their degradation of dung., and František Xaver Jiří Sládeček.
We investigated the variation in body colour and its thermoregulatory function in Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae), a parasitoid wasp of Spodoptera and other free-living lepidopteran larvae. We show that the body colour of adult wasps darkens when cocoons are kept at low temperatures. The range in the variation in colour, however, differs for different parts of the body and among uniparental (thelytokous) strains. This melanism enables these wasps to attain a body temperature in sunshine up to 2°C. Moreover, this small gain in body temperature can markedly increase the flight activity of wasps at low ambient temperatures. We conclude that the variation in body colour that resulted from rearing the cocoons at different temperatures enable the wasps to adapt to changing thermal environments. The ecological significance of the difference in the degree of melanism of the different strains is discussed., Yosuke Abe, Takuma Nishimura, Kaoru Maeto., and Seznam literatury
Although the effects of host plant quality on the performance of polyphagous herbivores are largely uniform across insect taxa, there are various exceptions to this rule. In particular, there are scattered reports of cases in which the relative quality of different hosts differs among larval instars of a single insect species. Such cases are explained either in terms of differences in the susceptibility of different aged larvae to plant defences or, alternatively, age-specific nutritional demands. Here we report the results of experiments that show that young larvae of the polyphagous common heath moth Ematurga atomaria (Lepidoptera: Geometridae) consistently attain higher weights on common heather Calluna vulgaris than bilberry Vaccinium myrtillus, whereas the rank order of these host plants is reversed in the final larval instar. Phytochemical analyses showed that differences in nutrient content of these plants are not likely to explain the observed pattern. Instead, the results are more consistent with the idea that the greater chemical defence of bilberry has a relatively stronger influence on young than old larvae., Helen Vellau, Siiri-Lii Sandre, Toomas Tammaru., and Seznam literatury