Národní úložiště šedé literatury Nalezeno 70 záznamů.  1 - 10dalšíkonec  přejít na záznam: Hledání trvalo 0.01 vteřin. 
Butterfly thermoregulation across habitats and climates
LAIRD-HOPKINS, Benita Carmen
Global warming, through rising temperatures and changing precipitation patterns, is placing major stress on species and ecosystems. Understanding how species respond to temperature and the mechanisms underpinning thermoregulation can help us predict which species are most vulnerable in the face of warming. In this thesis, I explore how butterflies across different habitats and climates thermoregulate and the mechanisms, including morphology and behaviour, underlaying thermoregulatory ability. Firstly, when comparing the buffering ability of neotropical and temperate butterflies I found that tropical butterflies were able to maintain more stable body temperatures than temperate butterflies, and this was likely driven by their morphology. I also found that temperate butterflies used postural means to raise their body temperature more than neotropical species, likely an adaptation to the cooler air temperatures they experience. Secondly, I showed the importance of butterflies' thermoregulatory abilities at the community level, by comparing thermoregulation of European butterflies across geographic regions and climatic zones. This study highlighted that behavioural thermoregulation, including the use of microclimates and postural means, drives regional differences in butterflies' thermoregulatory abilities. Finally, I utilised the Müllerian mimicry exhibited in Heliconius butterflies to untangle the contributions of morphology and phylogeny in butterfly thermoregulation, investigating thermal traits, including buffering ability, take-off temperature and heating rate. I found that morphology, not phylogeny, was the main driver of thermoregulation in these butterflies. Further, I investigated differences in the thermoregulatory ability of Heliconius butterflies from different habitats. I found that species from colder habitats were able to maintain a more stable body temperature and took off at a lower temperature than those from hotter habitats, suggesting there is local adaptation or acclimation in thermal traits. Overall, this work highlights that species have their own unique thermoregulatory abilities, as a result of the thermal environment they experience, and that thermoregulation is driven by morphology, behaviour and physiology. My findings have important consequences for predicting the impacts of climate change on ectotherms, by highlighting variation in thermal ability which makes some populations and species more vulnerable, while others more resilient. This thesis lays the groundwork for future studies comparing species' thermal traits across climates and habitats, increasing our understanding of how species cope with climate and land-use change.
W chromosomes in Lepidoptera: evolution, diversity and molecular features
HEJNÍČKOVÁ, Martina
Sex chromosome evolution is a fascinating and very dynamic process, which is best to be studied on diverse groups of organisms. Moths and butterflies (Lepidoptera) are known for their species diversity and female heterogamety, which makes them an ideal research model. Most species of Lepidoptera have a WZ/ZZ (female/male) system, although some species lack the W chromosome. The first part of this thesis discusses possible mechanisms and points of its origin in terms of phylogeny. Specifically, it focuses on the lack of W chromosome in the group of bagworms (Psychidae), supporting recent theory about the independent origin of W chromosomes in Lepidoptera. The second part of the thesis provides valuable information about the W chromosome variability and molecular content within the group of loopers (Geometridae). Finally, the third part describes the accumulation of retrotransposons on the W chromosome in Peribatodes rhomboidaria and emphasizes their importance in the process of sex chromosome differentiation.
Drivers of karyotype evolution in Lepidoptera
PROVAZNÍKOVÁ, Irena
Research of lepidopteran karyotypes and their evolution has been challenging for decades due to their many peculiar characteristics. However, this field has advanced thanks to modern cytogenetic techniques and sequencing technologies. We combined explored possibilities how to detect chromosomal rearrangements, and cytogenetic and genomic approaches to explore evolutionary forces shaping karyotypes of non-model Lepidoptera including representatives of early diverging species. Results obtained in the present thesis point to a possible role of satellite DNA and sexual antagonistic selection in mobilisation of rDNA and sex chromosome turnover, respectively.
Vývoj molekulárních markerů pro chromozom W u modráska \kur{Polyommatus icarus}
HRUBÁ, Monika
Tato diplomová práce se zabývá vývojem molekulárních markerů pro chromozom W u modráska Polyommatus icarus, u kterého byly nalezeny karyotypové rasy lišící se konstitucí neo-pohlavních chromozomů. Vyvinuté markery byly použity pro určení pohlaví pomocí PCR u čerstvě vylíhlých housenek, ze kterých byla izolována celková RNA, která bude dále použita pro testování role pohlavně antagonistické selekce ve fixaci neo-pohlavních chromozomů.
Obchodované druhy živočichů: srovnání IUCN a CITES
KORCH, Martin
Legální a nelegální obchod s volně žijícími druhy a planě rostoucími rostlinami stále roste a vytváří tak neustálý tlak na celé ekosystémy. Existuje však mnoho organizací, které se snaží tomuto problému zabránit a mezinárodní obchod regulovat. Mezi takové organizace se řadí IUCN a mezinárodní úmluva CITES. Bohužel kvůli nedostatečné koordinaci se počet obchodních záznamů neustále zvyšuje a může to vést k rychlému vymírání druhů. Cílem práce bylo zjistit překryv mezi kriticky ohroženými, ohroženými, zranitelnými a zároveň mezinárodně obchodovanými druhy pavouků (Araneae), stonožek (Chilopoda), paryb (Chondrichthyes), ryb (třídy: Actinopterygii, Dipneusti a Coelacanthii) a šelem (Carnivora) uvedených v Červeného seznamu druhů s druhy uvedenými v přílohách I, II či III mezinárodní úmluvy CITES. Z analýzy bylo zjištěno, že z 1 585 mezinárodně obchodovaných druhů dle IUCN není úmluvou CITES chráněno 42%. To je téměř polovina druhů, které jsou přehlíženy a potencionálně potřebují regulaci mezinárodního obchodu. Mezi nejvíce ohrožené druhy patří vodní organismy (41%) a pouze jedno procento tvoři organismy terestrické.
PREDATION PRESSURE ON ARTIFICIAL CATERPILLARS INDICATES ENEMY-REDUCED TIME AND SPACE
SEIFERT, Carlo Lutz
This thesis explores patterns of predation on artificial caterpillars in two neotropical lowland rainforest ecosystems. The specific aim was to test if enemy-reduced time and space does exist for physical undefended caterpillars. Our results indicated that larval Lepidoptera are capable to lower predation risk by nocturnal foraging and by avoiding habitats of high light irradiance. Thus, habitat-specific host plant choice by adult females and a timely scheduled foraging behaviour of the caterpillars could remarkably increase the survival rate of immature stages.
Analýza repetic v genomech vybraných druhů modrásků rodů \kur{Polyommatus} a \kur{Lysandra}
HRUBÁ, Monika
Tato bakalářská práce se zabývá studiem mobilních elementů, které by mohly mít vliv na fragmentaci karyotypu u řádů Polyommatus a Lysandra (Lepidoptera). Přítomnost vybraných repetic v genomech 15 vybraných druhů modrásků byla testována metodou PCR. Stejná metoda byla také použita k detekci studovaných elementů u 13 vybraných druhů mravenců, protože mezi mravenci a myrmekofilními modrásky by mohlo docházet k horizontálnímu přenosu genů. Vybrané mobilní elementy byly lokalizovány na pachytenních jádrech pomocí fluorescenční in situ hybridizace. Výsledky této práce naznačují mozaikovitou distribuci repetic v rámci fylogenetických vztahů zkoumaných modrásků, která by mohla být částečně vysvětlena šířením mobilních elementů mezidruhovým křížením a horizontálním přenosem mezi studovanými rody Polyommatus a Lysandra.
Reconstruction of the evolution of multiple sex chromosomes in \kur{Leptidea} wood white butterflies
POSPÍŠILOVÁ, Kristýna
Having a crucial role in many evolutionary processes, such as sex determination, speciation and adaptation, sex chromosomes tend to be highly conserved. Rapidly evolving sex chromosome systems offer a special opportunity to study the evolution of the sex chromosomes in miraculous resolution. Butterflies of genus Leptidea possess a unique species-specific sex chromosome system with 3-4 W and 3-4 Z chromosomes. Using novel genomic tools established for L. juvernica, namely transcriptome-based microarray for comparative genomic hybridization (array-CGH) and a library of bacterial artificial chromosome (BAC) clones, we assembled the physical maps of Z chromosomes in three cryptic Leptidea species (L. juvernica, L. sinapis, and L. reali) by fluorescence in situ hybridization (FISH) of BAC clones containing orthologs of Bombyx mori genes. In all three species, we identified the 'ancestral' Z chromosome and synteny segments of autosomal origin and reconstructed the step-by-step evolution of multiple sex chromosomes. We propose that the multiple sex chromosome system originated in the common ancestor of Leptidea species by means of multiple chromosomal rearrangements, especially translocations, fusions and fissions, between the sex chromosomes and autosomes. Thus, the turnover of neo-sex chromosomes could not be the main engine driving speciation in this genus. Instead, we propose that subsequent differentiation of the sex chromosome multiples in each species together with enlarged number of Z-linked genes could play a crucial role in accumulation of genetic incompatibilities facilitating subsequent divergence and speciation in Leptidea wood white butterflies.
Analýza chromosomu W u skvrnopásníka lískového, \kur{Lomaspilis marginata}
DEMKOVÁ, Miriam
The aim of this master thesis was to analyse variability of sex chromosomes in Lomaspilis marginata (Geometridae). Several families of this species were tested for the presence of sex chromatin and also for their variability in the W chromosome composition using comparative genomic hybridization. My results of this study indicated existence of at least three different types of the W chromosome in the investigated species.
Ecological factors affecting the structure, diversity, and specialisation of caterpillar communities in forest ecosystems
SEIFERT, Carlo Lutz
The aim of the thesis was to explore how caterpillar assemblages are spatially, functionally, and taxonomically structured in temperate and tropical forest ecosystems. Firstly, we investigated to what extent caterpillar assemblages are vertically structured in a temperate forest in eastern North America. By using a comprehensive dataset of temperate forest sites across three continents, we further examined if distance metrics derived from plant phylogeny can be used to predict structural changes in caterpillar assemblages among co-occurring plants. We further studied if folivorous caterpillars associated with bamboo in an Ecuadorian montane rainforest can be considered as 'classical' herbivores (sensu stricto). In the last chapter, we introduce and compare plot-based sampling approaches to study interaction networks in forest ecosystems and provide comprehensive guidelines for replication in future studies.

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