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
Slunéčka (Coccinellidae) se brání jedovatými alkaloidy v hemolymfě. Zároveň inzerují svoji jedovatost rozmanitým výstražným zbarvením. V laboratorním pokusu se sýkorou koňadrou (Parus major) jsme ukázali, že odmítání slunéček hmyzožravými ptáky je alespoň zčásti naučené. Důležité je červené zbarvení, méně tečkovaný vzor., Ladybirds (Coccinellidae) possess poisonous defensive alkaloids in their haemolymph. They also employ variable warning colouration. In a laboratory experiment with an avian predator – the Great Tit (Parus major) – we have shown that avoidance of ladybirds was at least partly learned. The red colour itself is most important, the spotted pattern less important for the decision., and Oldřich Nedvěd, Petr Veselý.
Recent efforts to catalogue global biodiversity using genetic techniques have uncovered a number of "cryptic" species within morphologically similar populations that had previously been identified as single species. Chlosyne lacinia (Lepidoptera: Nymphalidae), with a range extending from the Southwest U.S. to South America, is one of the most phenotypically variable and broadly distributed butterfly species in the New World. We sampled populations of C. lacinia in two temperate locations (California and Arizona) and one tropical location (El Salvador) to determine if cryptic species were present at this scale (temperate vs. tropical). We examined mtDNA sequence variation in COI, COII, the intervening tRNA (Leucine-2), 16S, 12S and an additional intervening tRNA (Valine), accounting for approximately 20% of the mitochondrial genome (3479 bp). Among all C. lacinia individuals, sequence divergence did not exceed 0.0084 compared to a 0.06 estimated divergence between C. lacinia and congener C. leanira. We also found subclade structure which did not clearly correspond to geography or subspecific designation. Though the mitochondrial phylogeny suggests a complex evolutionary history and biogeography, we demonstrate that one C. lacinia species is distributed throughout North and Central America spanning a diverse set of temperate and tropical habitats. and Timothy C. Bonebrake, Ward B. Watt, Alejandro Perez, Carol L. Boggs.
Microscope images of scales from the wings of the male butterfly Apatura ilia of two forms (ilia and clytie) show parallel fibres with tiny transverse grooves. These can cause (due to the light interference) violet or blue iridescence on the wings, which normally have brown pigmentation. We examined the dependence of the sudden color changes on variable illumination and observation angles. and George O. Krizek a kol.
Abandoned military training ranges are important biodiversity refuges in the modern landscape. We surveyed 41 such areas across the Czech Republic in order to establish butterfly diversity and abundances. We found exceptionally high species richness, including many nationally-threatened rarities like Phengaris arion, Polyommatus dorylas and Zygaena punctum. We conclude that the high conservational value of these areas was maintained by the former army activities, which encouraged high habitat heterogeneity. and Pavel Vrba a kol.