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Effect of global climate change on areal and phenology shifts of dragoflies species
Perthen, Ervín ; Černý, Martin (advisor) ; Bílková, Eva (referee)
Climate change in recent decades affects the distribution and phenology of dragonflies. The main factor causing these changes is the increase in the average global temperature, but other factors, such as loss of habitats or changes in precipitation regime, also play a role. As a result of climate change, phenological processes are accelerating. We can therefore observe a faster egg development rates, an earlier emergence of adults, a longer flight period and also a shift in voltinism towards a greater number of generations per year. Good dispersal abilities allow dragonflies to respond to changing environmental conditions also by shifting their distribution. The ranges of most species are currently expanding towards the poles. Generalists and species capable of using temporary waters expand their ranges the most, while specialized species with a narrow niche are the most threatened by climate change. Shifts are also visible in the altitudinal distribution, increasing temperatures allow warm- adapted species to expand their ranges to higher altitudes. Keywords: climate change, dragonflies, distribution, phenology, temperature, altitudinal shift
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Visual orientation of dragonflies - using polarized light
Kalavská, Tereza ; Černý, Martin (advisor) ; Kolář, Vojtěch (referee)
Polarized light is a physical phenomenon that is quite common in the nature. It has been known for a long time that some animals use such kind of light for various purposes in their lives. This group also includes dragonflies, which use horizontally polarized light to detect areas of water where mating and egg-laying takes place. The aim of this bachelor's thesis is to summarize the current knowledge of the visual orientation of dragonflies in space using polarized light. In my thesis, I focus on habitat selection and in which spectrum range dragonflies can perceive polarized light. Furthermore, I focus on the area of perception of polarized light by dragonfly larvae in the aquatic environment, which has not been properly researched yet as there are very few studies. Key words: orientation, insects, dragonflies, visual, polarized light, habitat selection
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Habitat selection by dragonflies - effect of littoral and riparian vegetation
Bonková, Anita ; Černý, Martin (advisor) ; Waldhauser, Martin (referee)
Dragonflies form one of the important pillars of most aquatic ecosystems and play an important role in maintaining their balance. The main goal of this bachelor's thesis is to summarize current knowledge about the habitat preferences of members of the order Odonata, with a focus on the effect of littoral and riparian vegetation, which are critical components of aquatic biotopes and significantly influence the distribution, abundance and reproductive success of dragonflies. In my work, I focus on all developmental stages, from larvae to adults. These findings are important for the maintenance and revitalization of freshwater ecosystems, in which it is necessary to pay attention to the composition of littoral and riparian vegetation to support the diverse needs of this unique insect order. Key words: habitat preference, dragonflies, Odonata, riparian vegetation, littoral vegetation
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Crypsis at dragonflies
Záhorová, Kristýna ; Černý, Martin (advisor) ; Hadrava, Jiří (referee)
Crypsis is one of the defens mechanisms used by animals to hide from predators. It is a form of coloring that allows prey to blend in with their surroundings or makes difficult for predators to see them due to disruptive coloration. Dragonflies utilize crypsis across different families and sometimes even within individual species in various types of environments, ranging from savannas to tropical rainforests. Crypsis also serves as a defense mechanism not only against predators, but also against members of their own species, where females avoid sexual harassment from males and young males avoid fighting with adult males. This is related to changes in coloration during ontogenetic development, as well as the sometimes pronounced sexual dimorphism that is relatively common in dragonflies. Additionally, larvae of dragonflies are often cryptically colored. This study focuses on cryptically colored dragonflies from around the world and in various types of environments. Rather unexpectedly there are not many studies focing on this phenomena at otherwise throroughly studied group of insects. Key words: dragonflies, crypsis, cryptic coloration, sexual dimorphism, dragonflies larvae
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Dragonflies (Odonata) of selected localities around Benešov
ŘÍHOVÁ, Radka
This bachelor thesis aimed to map the presence of dragonflies (Odonata) in selected locations around the municipalities of Heřmaničky, Velké Heřmanice, and Mrákotice in Benešovsko. This Bachelor thesis is based on pre-conducted field research (dragonfly capture and observation). Another aim of this bachelor thesis was to investigate the natural conditions at eight pre-selected locations in Benešovsko, compare the sites with each other based on environmental characteristics, and find out the presence of dragonfly communities. It has made the suggestion even about didactic use in primary school teaching.
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Dragonflies (Odonata) of selected localities around Borovany, South Bohemia
VOTRUBOVÁ, Daniela
This bachelor thesis focuses on research of the occurrence of Odonata (dragonflies) in the surrounding area Borovany. The research was motivated by a lack of information on the occurrence of Odonata species in this area, which is part of mapping square 7153b. The detection of Odonata communities was carried out through field research. Larvae and imagos were collected at nine pre-selected sites. Larvae and imagos were collected from June to September in 2021, and in the winter months, individual samples were determined in a laboratory. Laboratory equipment and determination keys according to known literature were used to determine individual species of larvae and imagos. The Canoco program (DCA, CCA) and other summary statistical analysis were used to present the results. This work demonstrated the surprising occurrence of Aeshna affinis, Lestes dryas, Sympecma fusca, Coenagrion pulchellum, Coenagrion hastulatum and Gomphus vulgatissimus.
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Dragonflies (Odonata) of selected localities around České Budějovice, South Bohemia
SVYSTUNOVA, Valérie
SVYSTUNOVA, Valérie. Dragonflies (Odonata) of selected localities around České Budějovice, South Bohemia. Bachelor thesis. Faculty of education, University od South Bohemia in České Budějovice. Department od Biology, 42 pages. The bachelor's thesis deals with field research of selected localities around České Budějovice. This is a survey of dragonfly communities in six localities. The aim of the work is to obtain basic faunistic information about the order Odonata and about the natural conditions of the studied areas, to obtain an orientation overview of the character of odonatofauna in selected localities and their mutual comparison, but also with published results of other authors and a proposal for the possible didactic use of the rules in primary school teaching.
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Local dispersal of Golden-ringed dragonfly Cordulegaster boltonii
Hančíková, Barbora ; Černý, Martin (advisor) ; Dolný, Aleš (referee)
We carried out a pilot study of local dispersion and patterns of movement of Golden- ringed dragonfly Cordulegaster boltonii (Odonata: Cordulegasteridae). Cordulegasteridae is a family with many primitive traits present and rather restricted geographical distribution ranges (at least among European species). Their migration seems to be limited despite the body size that predetermines them to high mobility over large spatial scale. Linear habitat (upper parts of narrow forest streams) specialisation along with behavioural ecology (peculiar premating habit of scanning streams for females) is a unique life history, which bring lot of questions. We collected mark-release-recapture data during two adult flight seasons in year 2010 and 2011. We were simultaneously capturing patrolling males along three separate streams (Dračice, Koštěnický and Struha) in total length of 9.9 km in, located in the Natural park Česká Kanada, in the Southern Czech Republic. We captured and marked 440 individuals and recorded 113 recapture events (26 % recapture rate) in year 2010 and 355 individuals were marked, 171 recapture events made (48 % recapture rate) in 2011. Our data suggested high level of stream fidelity (only 10 inter stream dispersal events, 2.8 % dispersal rate). What was as well reflected in a closeness of...
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Spatial orientation in Odonata
Hupková, Lenka ; Černý, Martin (advisor) ; Sacherová, Veronika (referee)
The aim of this review is to evaluate and sum up an existing knowledge about spatial orientation of dragonflies, particularly at small and medium spatial scales. I deal mostly with orientation by horizontally polarized light, which belongs among the most explored field of orientation of Odonata; beside that I explore an orientation of dragonflies during the habitat selection and within their home ranges / territories. Regarding the latter, I pay an attention namely to the function of spatial landmarks, which has not been yet fully explored and offers a lot of opportunities for further research (like many other orientation topics of Odonata). I also briefly discuss an orientation of dragonflies during migrations. Besides the visual orientation I mention the orientation by olfactory sense, tough Odonata was concerned anosmic for a long time. Key words: spatial orientation, visual orientation, dragonflies, Odonata, landmarks
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Factors affecting dragonfly species composition in newly created pools and assessment of invertebrate predation on pools zooplankton
Dobiáš, Jakub ; Černý, Martin (advisor) ; Harabiš, Filip (referee)
To identify and quantify the influence of physico-chemical, biotic and geographic factors on the population of dragonflies (Odonata) is an essential tool for research of their ecology. The aim of this study was to 1) assess how these factors influence species richness, diversity and spatial distribution of dragonflies in 42 newly constructed or renewed pools located in the Kokořínsko Protected Landscape Area, which is characterized by two valleys of Liběchovka and Pšovka creeks, low human impact, and a great diversity of small water bodies and 2) use laboratory experiments in order to estimate the relationship between large predatory invertebrates of these pools (Aeshna cyanea, Coenagrion puella, Chaoborus crystallinus and Notonecta glauca) and their common prey (Daphnia curvirostris) in an artificial environment with or without aquatic macrophytes. The pools were monitored and sampled between years 2005 and 2006. In total, 23 dragonflies species were found inhabiting these lentic habitats, comprising 11 species belonging to the suborder Zygoptera and 12 species belonging to the suborder Anisoptera, including a rare species Sympetrum depressiusculum (larvae). Most variability in the dragonfly species richness was explained by the size of the water surface area, followed by the location of the pools (inside...
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