Severoameričtí raci (např. rak pruhovaný a rak signální vyskytující se i v ČR) jsou příkladem invazních živočichů, jejichž invazní potenciál je zesílen přenosem onemocnění nebezpečného pro příbuzné druhy z jiných geografických oblastí. Původcem nemoci, tzv. račího moru, je Aphanomyces astaci ze skupiny Oomycetes způsobující úhyny celých populací evropských raků. Račí mor se v Evropě vyskytuje už od 19. století a i v současnosti zůstává přes intenzívní výzkum jedním z nejvýznamnějších faktorů ohrožujících původní raky (u nás jde o raka říčního a raka kamenáče, u nichž bylo jen od roku 2004 zaznamenáno deset případů zdecimování populací touto nemocí)., North American crayfish species such as the Spiny-cheek Crayfish and the Signal Crayfish are examples of invasive animals with an ability to carry and transmit a disease lethal to their relatives from other parts of the world. The disease called the crayfish plague and caused by Aphanomyces astaci (Oomycetes) may eradicate whole populations of the indigenous European crayfish. The disease is known in Europe from the 19th century and despite intensive research it is still one of the main factors endangering indigenous crayfish., and Eva Kozubíková-Balcarová.
The conifer needle scale, Nuculaspis abietis (Schrank) emerged as an important pest of conifers in the Kelardasht region of Mazandaran province, Iran, in the late 1990's. This pest feeds on conifer needles and twigs causing needle drop and branch desiccation. Its discovery in Kelardasht in Mazandaran Province necessitated a local quarantine of conifers in the genera Picea, Abies, and Pinus. We studied the life history and ecology of this scale on Norway spruce, Picea abies, under laboratory and natural field conditions. The complete life cycle of females required 206.4 ± 5.7 days in the laboratory (25 ± 1°C, 65-75% RH, 14L : 10D) and 315.7 ± 9.3 days under field conditions. In Kelardasht, numbers of adult males and females peaked in mid-June and early May, respectively, and numbers of first and second instar nymphs in mid-July and early September. Lifetime fecundity was estimated to be 57.3 ± 5.1 eggs and 54.0 ± 4.4 nymphs per female under laboratory conditions. The sex ratio ranged from 59% female for second instar nymphs to 71% female for adults. Aspidiotiphagus citrinus (Crawford) (Hymenoptera: Aphelinidae) was found naturally parasitizing the scale and overwintering in the larval stage on second instar nymphs. First generation adult wasps emerged in spring from overwintered second instar nymphs to parasitize 64.75% of first instar scales. Second generation wasps emerged from early September to mid-October and parasitized 19.75% of second instar scales, for a cumulative parasitism rate of 84.5%. and Arash RASEKH, J.P. MICHAUD, Hassan BARIMANI VARANDI.
A global decline in pollinator abundance and diversity has demanded increased research attention to the ecology and genetics of bumblebees. However, as progressively more restrictions are placed on sampling for insects, researchers are increasingly obliged to use archival specimens collected for purposes other than genetic analyses. In this study we assessed the suitability, for population genetic studies, of popular, low-cost methods for preservation and storage of bumblebee specimens. Specimens of Bombus terrestris L. were held under six storage regimes for up to two years. DNA was extracted from the samples using three extraction protocols and the quality of the DNA was examined using PCR amplification of a mitochondrial and a nuclear gene. All extraction and storage methods provided sufficient DNA for successful PCR amplification. However, samples preserved in acetone or at freezing temperatures yielded the highest DNA concentrations. DNA yields from pinned specimens at room temperature declined over time, particularly when using standard extraction techniques. DNA concentrations were significantly lower from specimens preserved in 70% ethanol compared to all other extraction techniques and declined linearly over the two years of storage. These results indicate that two of the most popular insect storage methods (pinning and storage in ethanol) should be avoided for the long-term preservation of genetic material for future studies. We suggest that optimal insect preservation methods should be incorporated into research protocols in order to best capitalise on limited collection opportunities., António S. Moreira ... []., and Obsahuje seznam literatury