Thermal requirements for flight in butterflies is determined by a combination of external factors, behaviour and physical constraints. Thorax temperature of 152 butterflies was monitored with an infra-red thermometer in controlled laboratory conditions. The temperature at take-off varied from 13.4°C, for a female Heteronympha merope to 46.3°C, for a female Junonia villida. Heteronympha merope, an understorey species, had the lowest recorded take-off temperatures, with females flying at a much lower thorax temperatures than males. Among the tested butterfly species, warming-up rate was positively correlated with take-off temperature and negatively with body mass. Wing loading is a major variable in determining the thorax flight temperature. Butterflies with the highest wing-loadings experienced the highest thorax temperatures at take-off. A notable exception to this rule is Trapezites symmomus, the only Hesperiidae of our data set, which had thorax flight temperatures of 31.5°C and 34.5°C, well within the range of the observed butterflies, despite a wing load ca. five times higher. The high thorax temperature recorded in J. villida is probably linked to its high flight speed. The results highlight the importance of physical constraints such as body size on the thermal requirements for flight across a range of butterfly species., Gabriel Nève, Casey Hall., and Obsahuje bibliografii
Although there is a considerable amount of information on the ecology, genetics and physiology of life-history traits there is little information on the morphological variations associated with flight ability within species. In this paper, the morphology and ultrastructure of certain organelles in the flight muscles of Gryllus firmus are recorded using transmission electron microscopy. The ultrastructure of the flight muscles of 7-day-old female adults reveals that the ratio of thick to thin filaments is 1 : 3. Each thick filament is surrounded by 6 thin filaments in a hexagonal arrangement. The length of the sarcomere of each myofibril is significantly shorter and diameter of the myofibrils significantly smaller in long-winged than in short-winged morphs. However, the thick filaments in the long-winged morph are denser than those in the short-winged morph. Furthermore, in the long winged morph there are a greater number of mitochondria than in the short-winged morph. These differences correspond with the fact that long-winged crickets are stronger fliers than short-winged crickets., Cheng-Ji Jiang ... [et al.]., and Obsahuje seznam literatury
During the last 12 years, 23 mollusc species were recorded in the Czech Republic for the first time. With the exception of several introduced and invasive species, some of these molluscs are native, rare and even endangered, including Pagodulina pagodula. This rare woodland snail of Alpine origin was found in spring 2012 in the Mutenská obora Nature Reserve, which includes the forested slopes above the Moravská Dyje River in South Moravia. This is another occurrence of the species outside its Alpine range, in addition to one site in Poland, two in Slovakia, and a few sites in Hungary and the Balkan Peninsula. The species was also recorded in the Czech Republic in several interglacial sediments of the Pleistocene and also in one profile of Holocene origin (Atlantic period), not far away from the recent site. and Adam Lacina, Michal Horsák.
Soutěžní přehlídka Věda je krásná vznikla v r. 2009 jako interní fotografická soutěž Přírodovědecké fakulty Univerzity Karlovy v Praze. Od třetího ročníku je přístupná všem zaměstnancům a studentům Univerzity Karlovy a ve čtvrtém ročníku se v nové objevitelské kategorii otevřela mimofakultní veřejnosti, která se jí může účastnit prostřednictvím popularizačního projektu Přírodovědci.cz. Cíl projektu je velmi jednoduchý - oslavit českou fotografii a ilustraci s přírodovědnou tematikou a upozornit na krásu skrytou běžnému pohledu, tedy na půvab vědeckých objektů a vědy samotné, protože zůstávají často přístupné jen úzkému okruhu badatelů nebo nadšenců., This competition run by the Faculty of Science at Charles University in Prague and its supportive web www.prirodovedci.cz aims to show the beauty and aesthetics revealed by scientific research, either via photography, illustrations or computerized visualizations of natural phenomena., and Alena Ječmíková.
Velemyši, dříve nazývané krysy obláčkové, jsou největší myšovití hlodavci žijící endemicky na Filipínách. Velemyš dinagatskou (Crateromys australis), považovanou za potenciálně vyhynulou, se nám podařilo znovuobjevit 37 let od jejího posledního (a zároveň prvního) nálezu a vědeckého popisu. To bylo také impulzem k návrhu nového českého jména velemyši pro celou skupinu obláčkových krys. Velemyš dinagatská byla nalezena na severu ostrova Dinagat. Nyní je řazena mezi kriticky ohrožené druhy. Ohrožené jsou také ostatní druhy této skupiny, a to zejména kvůli masivní těžbě dřeva a nerostných surovin a tím ničením jejich přirozeného prostředí. Proto je cílená ochrana je nezbytná k přežití tohoto i ostatních druhů velemyší., Cloud rats are the largest murid rodents endemic to the Philippines. The Dinagat Cloud Rat (Crateromys australis), considered to be potentially extinct, was rediscovered in the north of Dinagat Island after 37 years from its first discovery and scientific description. We have also proposed a new Czech name. The species is now listed as critically endangered. All cloud rats are threatened by the destruction of their natural habitats by logging and mining. Targeted protection is therefore essential for their survival., and Milada Řeháková, Václav Řehák.
The great capricorn beetle or Cerambyx longicorn (Cerambyx cerdo, Linnaeus, 1758) is an internationally protected umbrella species representing the highly diverse and endangered fauna associated with senescent oaks. For the conservation and monitoring of populations of C. cerdo it is important to have a good knowledge of its microhabitat requirements. We investigated determinants and patterns of C. cerdo distribution within individual old, open-grown oaks. Trees inhabited by this species were climbed, and the number of exit holes and environmental variables recorded at two sites in the Czech Republic. Distribution of exit holes in relation to height above the ground, trunk shading by branches, orientation in terms of the four cardinal directions, diameter, surface and volume of inhabited tree parts were investigated. This study revealed that the number of exit holes in the trunks of large open-grown oaks was positively associated with the diameter of the trunk and openness and negatively with height above the ground, and the effects of diameter and openness changed with height. The number of exit holes in the surface of a trunk was also associated with the cardinal orientation of the surface. Approximately half of both C. cerdo populations studied developed less than 4 m and approximately a third less than 2 m above the ground. This indicates that most C. cerdo develop near the ground. Active management that prevents canopy closure is thus crucial for the survival of C. cerdo and searching for exit holes is an effective method of detecting sites inhabited by this species., Jan Albert, Michal Platek, Lukas Cizek., and Obsahuje seznam literatury
V této práci sumarizujeme data o výskytu invazních druhů řas a sinic v České republice a mapujeme reálná či potenciální rizika jejich rozšíření. Seznam invazních druhů v ČR obsahuje 10 druhů sinic, 9 rozsivek, 1 obrněnku, 1 zástupce třídy Ulvophyceae, 2 zelené řasy třídy Chlorophyceae a jednu krásivku., This paper summarizes data on alien species of algae and cyanobacteria in the Czech Republic; we identified actual or potential risks resulting from their spread. The list of aliens contains 10 species of Cyanobacteria (Cyanophyta), 10 species of Bacillariophyceae, one species of Dinophyta, one species of Ulvophyceae, two species of Chlorophyceae, and one species of Desmidiales., and Jan Kaštovský ... [et al.].
Caterpillars of the poplar lutestring moth, Tethea or, construct leaf shelters that they defend against intruding conspecifics using a combination of vibratory signals and physical aggression. Staged interactions between a resident caterpillar and introduced conspecific were recorded with a video camera and laser vibrometer. Residents crawl towards the intruder and perform three behaviours: lateral hitting, pushing, and mandible scraping. Vibrations caused by mandible scraping result from the caterpillar repeatedly scraping opened mandibles laterally against the leaf surface in bouts lasting 1.16 ± 0.39 s, with an average of 4 ± 1 scrapes per bout. We propose that these scrapes function in leaf shelter defense against conspecifics for the following reasons: Mandible scrapes are produced only by residents; they are generated when a resident is approached by an intruder; the rate of scraping increases as the intruder approaches the shelter; and residents in all trials retain their shelters, with the intruder leaving the leaf within 127.9 ±104.3s from the beginning of the trial. The function and evolutionary origins of vibration-mediated territoriality in caterpillars are discussed. and Jaclyn L. Scott, Jayne E. Yack.
V článku se autor zabývá vlivem záplavových vod v nivě Dyje na jižní Moravě, a to na populace tří druhů: motýla Zerynthia polyxena a brouků Cylindera germanica a Akimerus schaefferi schaefferi. U pestrokřídlce podražcového (Z. polyxena) tu postihují povodně všechna nedospělá vývojová stadia hlavně nejblíže koryta Dyje, takže lužní populace se po silnější záplavě obnovuje z kolonií z vyvýšených písečnatých poloh luhu. U svižníka německého (C. germanica) šlo o několikaletý masový výskyt tohoto na prostředí luhu neadaptovaného druhu, proto celou jeho zdejší populaci zničila beze zbytku následná silná povodeň. Určité zvláštnosti ve výskytu tesaříka Schäfferova (A. schaefferi schaefferi) se potvrdily i zde při mnohaletém pozorování, především schopnost nedospělých stadii přežít i delší zaplavení bez zjevné úhony. Přesto se ani zde nepodařilo objasnit příčiny jeho periodicity výskytu, jak se tak projevuje na řadě dalších lokalit., This article deals with the effects of floodwater in the Dyje alluvial plain on the populations of three invertebrate species. Floods affect all immature developmental stages of the butterfly Zerynthia polyxena particularly those close to the river - after a heavy flood, the meadow population is restored from the higher sandy reaches. Once large population of the tiger beetle Cylindera germanica (not adapted to this environment) was wiped out by a heavy flood. Unique features of the occurrence of the capricorn beetle Akimerus schaefferi schaefferi are described, and the ability of immature stages to survive subsequent floods without apparent harm is shown., and Mladen Kaděra.