Pozorování zajímavého a neobvyklého chování vosíka Polistes dominula – schopnost dosednutí na hladině vodní nádrže při sání vody, aniž by došlo ke smočení chodidel. and Watching the remarkable and unusual behavior of the European Paper Wasp (Polistes dominula), i.e. its ability to sit down on the water surface of a water reservoir when sucking up the water without drenching its soles.
Merule mrkvová (Trioza apicalis) patří mezi hmyz, o němž existují podrobné studie o životě na mrkvi, kdy se projevuje jako zemědělský škůdce. O životě merule mimo porosty mrkve, což představuje větší část sezony, jsou poznatky jen útržkovité. Autor se věnuje některým sporným otázkám z této fáze života tohoto druhu. and The Carrot Psyliid (Trioza apicalis) is an insect which has been studied because it is a serious pest in agriculture. Moreover, its life outside carrot growths, which actually lasts most of the season, has only been known to some extent. The author pays special attention to some disputable aspects in the latter phase of the Carrot Psyliid’s life cycle.
A review of all known descriptions of immature stages of the species of the genera Scaeva Fabricius, 1805, Ischiodon Sack, 1913 and Simosyrphus Bigot, 1882 is presented using SEM illustrations. The third instar larval and/or pupal morphology of Scaeva dignota (Rondani, 1857), Scaeva mecogramma (Bigot, 1860) and Simosyrphus grandicornis (Macquart, 1842) are newly described. All species of the genera studied in this paper are very similar for all the studied characters of their immature stages, including the chaetotaxy. Molecular characters of the mitochondrial cox1 gene (1128bp) were used for inferring relationships of the studied taxa. The nuclear internal transcribed spacer 2 (ITS2) was additionally applied for species delimitation of the closely related species Scaeva selenitica and S. dignota. The Palaearctic Scaeva species could be split into two groups based on the analysis of morphology of posterior respiratory process. These groups were previously diagnosed as S. selenitica-group [i.e., S. selenitica (Meigen, 1822), S. dignota (Rondani, 1857), S. mecogramma (Bigot, 1860)] and S. pyrastri-group [i.e., S. pyrastri (Linnaeus, 1758), S. albomaculata (Macquart, 1842), S. latimaculata (Brunetti, 1923)]. Semiscaeva Kuznetzov, 1985 and Scaeva Fabricius, 1805 are the available names for these two natural groups that should be classified as subgenera; the former name is proposed for S. selenitica-group and the latter for S. pyrastri-group. Mecoscaeva Kuznetzov, 1985 syn. n. is transferred as a junior synonym of the subgenus Semiscaeva Kuznetzov, 1985 according to the principle of the first reviser. Based on the analysis of immature stages, the generic name Ischiodon Sack, 1913 syn. n. is proposed as a junior synonym of the genus Simosyrphus Bigot, 1882. The similarity of immature stages between Scaeva s. str. and Simosyrphus grandicornis Macquart, 1842, Simosyrphus aegyptius (Wiedemann, 1830) comb. n. and Simosyrphus scutellaris (Fabricius, 1805) comb. n. is discussed. All the proposed subgeneric and generic taxa based on morphological studies received high support employing molecular characters.