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Importance of UV perception for dragonflies (Odonata)
Jačmeněv, Vjačeslav ; Černý, Martin (advisor) ; Stella, David (referee)
It has long been known that some animals are able to perceive radiation at other wavelengths than perceive we humans. In dragonflies, UV sensitivity has been demonstrated in the 1974, however a recent study has unveiled an extraordinary diversity of genes of specific photoreceptor proteins known as opsins, including UV-sensitive opsin. In addition some dragonflies have coloration on their body and wings, which can reflect UV radiation at unchanged wavelength - UV reflectance. Very little is known about the use of UV in dragonfly life. My thesis summarizes the current knowledge of the importance of UV for dragonflies, focusing on interspecific and intraspecific communication.
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Functions of myrmecomorphy in the arthropods and its occurrence and potential functions in true bugs
Hrebiková, Tereza ; Exnerová, Alice (advisor) ; Pipek, Pavel (referee)
Myrmecomorphy (ant mimicry) is structural and chromatic (sometimes also chemical and behavioural) resemblance to ants. Ant-mimicking species can be found in many arthropod taxa particularly in spiders and true bugs. Myrmecomorphy may serve several functions, protecting the mimics either from the ants themselves or from predators. Mechanisms of ant mimicry have been studied mostly in spiders and some insect taxa (e.g. beetles). In true bugs (Hemiptera: Heteroptera), ant mimicry exists in many species belonging to several families, and it is present in both larvae and adults. Notwithstanding its frequent occurrence, the literature about ant mimicry in true bugs is limited only to several incomplete lists of myrmecomorphic species, hypotheses on mimicry functions, and a few experimental studies. This thesis aims to review (1) experimental studies focused on function of ant mimicry in spiders and insects and (2) occurrence, form and potential function of ant mimicry in true bugs (Heteroptera). Key words: Myrmecomorphy, function, Arthropoda, spiders, insects, Heteroptera
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Determination of basic nutritional parameters in edible insects
Korček, Jakub ; Štursa, Václav (referee) ; Diviš, Pavel (advisor)
In this bachelor thesis is dicussed nutritional value of chosen insect species. Analysed samples consisted of worms, crickets and locusts. Analysed parameters were: total nitrogen, crude protein, total lipids and content of chosen elements. Total lipids were, after homogenization, determined by Soxhlet method, using diethyl ether as a solvent. Prior to protein and element determination, samples did undergo Kjehldal digestion process, using sulfuric acid. Weiniger catalyst was only added to samples digested for protein measurement. Element content was determined by optical emission spectrometry with inductively coupled plasma (ICP-OES). Crude protein was determined by Kjeldahl method. The highest protein content was determined in crickets. (75 ± 5) %. Locusts contained the highest lipid content (33 ± 2) %. We also found out, that samples were rich in calcium, potassium, manganese and zinc, which are all important elements for the proper functioning of our body. The results of this thesis prove, that insects can present nutritionally important food.
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Population genetics and speciation in Stylops (Strepsiptera)
Kodejš, Karel ; Straka, Jakub (advisor) ; Černá, Kateřina (referee)
This thesis is focused to population genetics of selected species of genus Stylops in Europe. Within this genus, five species was analysed by usage of two approaches - microsatellite analysis in Stylops ater and analysis of mitochondrial DNA in all five species. Mitochondrial gene for cytochome c oxidase (1st subunit) was used. For microsatellite analysis was performed bayesian clustering analysis and ABC approach (Aproximate Bayesian Computation). Mitochondrial markers were processed by making haplotype networks and demography analysis by computing Bayesian skyline plots. For Stylops ater, surprisingly low lewel of population subdivision was detected, yet with clearly differentiated population clusters from Scandinavia and baltic coast of Europe, which may imply period of isolation of these populations or relativelly recent population expansion and genetic differentiation due to lower population sizes. Next, hypotesis of possible temporal segregation of subpopulations of Stylops nevinsoni based on different aktivity period of their host species groups, was supported. In other three species, population subdivision was observed to be related either due to host specialisation (Stylops mellitae) or geographic consequences (S.nassonowi, S.spreta). Interesting finding is also detection of population...
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Hormonal regulation of behavioral manipulation in insects caused by parasites
Janů, Hana ; Jůzová, Kateřina (advisor) ; Žďárek, Jan (referee)
Number of scientific publications describing how parasites alter their host's behaviour providing them successful reproduction or transmission to other hosts has significantly increased during the last few decades. In recent years, more and more researchers are not only describing changes in the host organisms, but also trying to figure out mechanisms beyond these parasitic manipulations. Parasites can manipulate the host through neural and endocrine system using neuromodulators, immunomodulators, neurotransmitters and hormones. Either increase or decrease of hormone levels may cause changes of the infected hosts development, metabolism, reproduction and behaviour. Hosts, whose behaviour is altered via hormonal pathways are mostly developmentally arrested and their feeding and locomotion is terminated. Observed behavioral changes like hole digging or termination of participation in group work in insects demonstrably increase parazite's fitness. This thesis is a summary of behavioral manipulations of insects caused by changes in hormone levels.
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Ecology of pollination networks
Hadrava, Jiří ; Janšta, Petr (advisor) ; Novotný, Vojtěch (referee)
In communities, plants and pollinators are organized into complex network of relations. Description of structure in this network can contribute to understanding of community dynamics and persistence of biodiversity. Better understanding of patterns in assemblages of plants and pollinators may also help in their protection. The aim of this work is to review recent methodological principles in the pollination network analyses and to show potential problems in concept of ecological networks. Graph theory is breefly summarized and applied to the description of pollination networks. As an example, results on comparison of communities from different geographical sites are given.
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Porovnání účinnosti peletovaného krmiva s obsahem hmyzu a směsi s běžným složením při odchovu okouna říčního (Perca fluviatilis) v poloprovozních podmínkách
NOVOTNÝ, Martin
This thesis deals with the possibility of using insects as a potential source of proteins in artificial feed for Eurasian perch. In conventional feed, 25 % of fish meal was replaced by meal from adult Acheta domestica and Zophobas morio. There were performed two 12-week long experiments, the first one in the Experimental Fishery Workplace at the Faculty of Fisheries and Water Protection of the University of South Bohemia in Vodňany and the second one in the commercial operation of Anapartners s.r.o. Company in Prague Horní Počernice. The production indicators of the breed were evaluated and the fat and fatty acids in the fish muscles were analyzed as an important indicator of its nutritional value. At the end of both experiments, fish fed by experimental feeds showed lower length and weight gains and worse feed conversion, compared to fish fed by control diet. During the experiment and after its completion, the feed effect on fish survival were not noticed. Furthermore, there were not found any changes in fat content in fish muscles, but changes in the content of individual fatty acids were noticed. In fish fed with experimental feed, the content of linoleic acid (C18: 2n-6) increased as well as the total content of n-6 fatty acids, on the contrary, the content of n-3 fatty acids in the fish muscle decreased more than in fish fed by control diet. This also affected the resulting ratio of the n-6 fatty acid to n-3 fatty acid ratio, while this ratio increased significantly in the experimental fish group. Changes in fatty acids content in fish muscle were small and did not affect its nutritional value from the perspective of human consumption. In other experiments dealing with this topic, it is necessary to focus on testing of other insect species or to modify the quantity of substituted fishmeal.
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Digestive proteases of termites
Čermáková, Markéta ; Konvalinka, Jan (advisor) ; Ryšlavá, Helena (referee)
Digestive proteolysis in termites has not been studied yet. In this diploma thesis, proteolytic enzymes of the digestive tract of two significant pest species Reticulitermes santonensis and Coptotermes formosanus (Rhinotermitidae) were analyzed. Proteases were identified and quantified in gut compartments using a panel of specific substrates and inhibitors. Major proteases were localized in the midgut and were classified as endogenous serine proteases of trypsin type. Minor cysteine proteases were detected in the paunch and were most likely produced by symbionts. The trypsin protease from R. santonensis was chromatographically isolated and its N-terminal sequence was identified. The physiological importance of the digestive trypsin proteases was demonstrated using selective inhibitors tested in vivo with C. formosanus. Based on the analysis of proteases from additional 12 termite species, a general scheme of digestive proteolysis in the order Isoptera was proposed. (In Czech)
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Insects as human food
Augustinová, Šárka ; Pivnička, Karel (referee) ; Frouz, Jan (advisor)
Insects as a traditional source of food widespread in tropical and subtropical regions offer significant nutritional, economical and ecological gains not only to rural communities. Western bias against insects led to gradual reduction of usage of insects as food without any compensation for lost sources of nutrition and other benefits. Current efforts of the Western world to prevent starvation of population and undo the consequences of inconsiderate human interventions into the environment are often futile and ineffective. One of possible answers to these global problems could be reestablishment of insects as a food source for the native population. Insects offer a renewable source of protein with nutritional values as high as 3186kJ per 100g of solids which exceeds the values of most species traditionally cultivated. The protein content varies throughout the various insect species from 30% in wood-worms to 81% in wasps of the genus Polybia. Moreover, the quality of these proteins is very high and the high values of the amino acids contained outperform the FAO recommended designs. Many species contain important minerals such as calcium, sulfur, iron, phosphor, magnesium and zinc and are as well rich in B vitamins, niacin, riboflavin and thiamin, which are often not incorporated enough into standard meal...
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