Nález kolonie mravence lužního na dubu na hrázi rybníka Vrkoč posouvá hranici recentního výskytu tohoto druhu o 15 km severozápadním směrem. Podle dosavadních terénních šetření jde o izolovanou kolonii, jejíž původ je nejasný. Obývaná lokalita se přitom velmi liší od preferovaného biotopu v podobě lesních porostů, protože jde o solitérní strom. Solitérní stromy či aleje přitom podle starších výzkumů využívá pouze 7 % kolonií tohoto druhu., A new colony of the ant species Liometopum microcephalum was found on the solitary oak tree growing on the dam of the pond Vrkoč near Pohořelice (southern Moravia). This discovery extends its recent distribution in the Czech Republic about 15 km to the north-west. The new colony is isolated and unusual in respect that only 7 % of south Moravian colonies are living on solitary trees or on trees in alleys., Antonín Krása., and Obsahuje seznam literatury
Článek se věnuje nově popsanému rodu Oreojuncus Záveská Drábková et Kirschner, který zahrnuje dva druhy - Oreojuncus trifidus a Oreojuncus monanthos. V České republice se vyskytuje pouze O. trifidus, sítina horská trojklanná, které je věnována větší pozornost. Rod Oreojuncus byl tradičně zařazován mezi sítiny (Juncus) sekce Steirochloa, avšak na základě komplexního výzkumu zahrnujícího fylogenetickou analýzu molekulárních dat a revizi morfologie byl vyčleněn jako samostatný, osmý rod čeledi sítinovitých (Juncaceae)., The new genus Oreojuncus Záveská Drábková et Kirschner has been described, with two species - O. trifidus and O. monanthos. Attention is given to the first species, which occurs in the Czech Republic. The genus Oreojuncus has been traditionally included in the Juncus sect. Steirochloa; however, complex research based on phylogenetic analysis of the molecular data and morphological revision revealed the necessity to establish this eighth genus in the Juncaceae family., and Lenka Záveská Drábková.
The mechanism of sex determination is common for all honeybee species (Apis spp.) by the complementary sex determination (csd) gene. The csd gene has been studied in the Western honey bee (Apis mellifera L.), the Eastern honey bee (Apis cerana F.) and the giant honey bee (Apis dorsata F.), whereas no studies had been conducted on the high altitude Himalayan or black giant honey bee, Apis laboriosa Smith. In the present study, we cloned the genomic exon 6 to exon 9 region of the A. laboriosa csd gene, and identified 13 csd haplotypes. The data was analyzed and compared with the other aforementioned three honeybee species. The results showed that, as with the other three Apis species, region 3 of the csd gene contains an RS domain at the N terminal, a proline-rich domain at the C terminal, and a hypervariable region in the middle. A phylogenetic tree showed that the csd haplotypes from A. laboriosa fell into one clade with those from A. dorsata, and were separated from those from the other two species, A. mellifera and A. cerana. The network map also showed that the csd haplotypes from A. laboriosa and A. dorsata are well mixed among each other, and do not form two separate branches. Pairwise Fst analysis revealed that the value between A. laboriosa and A. dorsata was very low (0.098), confirming a close relationship to exist between them., Huan Wang ... [et al.]., and Obsahuje seznam literatury
Ovsenka skalní (Chondrina avenacea) je plicnatý plž, který žije celoročně na holých vápencových skalách, kde dochází k drastickým denním i sezonním změnám ozáření, teploty, vlhkosti a také dostupnosti potravy. V článku popisujeme fyziologické a biochemické adaptivní mechanismy, které umožňují ovsenkám přežít na jejich extrémním stanovišti., Chondrina avenacea is a pulmonate snail dwelling on exposed rock walls where it experiences drastic daily and seasonal fluctuations of abiotic conditions and food availability. In this paper, we describe the physiological and biochemical adaptive mechanisms that allow the snails to survive in their extreme microhabitat., Vladimír Košťál, Jan Rozsypal, Pavel Pech., and Obsahuje seznam literatury
Endosymbiotic organisms are known to manipulate the reproductive biology of their hosts. Incomplete prevalence of endosymbiont inducing thelytokous parthenogenesis results in the coexistence of sexual and asexual individuals, and could account for the maintenance of sexual reproduction in certain populations or species. In the parasitoid Venturia canescens, arrhenotokous ("sexual") and thelytokous ("asexual") individuals occur sympatrically. We aimed to determine whether endosymbionts are implicated in the thelytoky of V. canescens. After screening females of the two reproductive modes for several reproductive parasites: bacteria (Wolbachia, Rickettsia, Bacteroidetes, Spiroplasma, Arsenophonus) and Microsporidia, we concluded that thelytoky in V. canescens is not induced by any of these parasites and confirmed its suitability as a biological model for solving the evolutionary enigma of the maintenance of sexual reproduction., Vincent Foray ... [et al.]., and Obsahuje seznam literatury
The Multicoloured Asian Ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is known to thrive principally in shrubby and arboreal habitats. This study focuses on the occurrence of this exotic species and its seasonal abundance in various field crops. The abundance of adults, larvae and pupae of H. axyridis was evaluated over a three-year period, from 2009 to 2011, in four important agronomical crops (wheat, corn, broad bean and potato) in Belgium. From May to September, 48 1-m² quadrats were visually inspected in each of the fields sampled on several farms every seven days. H. axyridis colonized and reproduced in all of the four crops studied, with the largest numbers recorded in corn and broad bean crops. Larvae and adults of H. axyridis were recorded mainly in corn and to a much less extent in wheat and potato crops. From 2009 to 2011, the mean weekly abundance of H. ayxridis remained constant except in corn crops, where the recorded densities of all the immature stages and adults were higher in 2011 than in 2009. The population dynamics of aphids and H. axyridis are well described by a symmetric logistic function (S-shape) of cumulative population size. H. axyridis was not always recorded where aphids were abundant, e.g. aphids were abundant on wheat where no H. axyridis were recorded. H. axyridis start reproducing after the peak in aphid population, suggesting that H. axyridis is able to complete its development by feeding on alternative prey such as larvae and pupae of the same and other species of ladybird and other aphidophagous species. H. axyridis is often considered to be bivoltine but it only completes one generation per year in field crops. The second generation generally develops late in the season in other habitats., Axel Vandereycken ... [et al.]., and Obsahuje seznam literatury
Ovaries of Puto superbus and Ceroputo pilosellae are composed of numerous short telotrophic ovarioles that are arranged around the distal part of the lateral oviduct. An individual ovariole consists of a distal trophic chamber (= tropharium) and proximal vitellarium. The tropharia enclose individual trophocytes (= nurse cells) and early previtellogenic oocytes termed arrested oocytes. A single oocyte develops in each vitellarium. Analysis of serial sections has shown that ovarioles of P. superbus contain from 16 to 51 germ cells (13–43 trophocytes, 2–7 arrested oocytes, 1 developing oocyte) while those of C. pilosellae from only 8 to 10 germ cells (5–7 trophocytes, 0–2 arrested oocytes, 1 developing oocyte). The classification and phylogeny of scale insects are discussed taking into consideration the results of this study., Anna Michalik ... [et al.]., and Obsahuje seznam literatury