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Food preferences of land snails in a river flood-plain invoved with invasive plants
Ševčíková, Štěpánka ; Juřičková, Lucie (advisor) ; Čejka, Tomáš (referee)
Food preferences to five most widespread invasive plant species from river floodplains: Impatiens glandulifera, Helianthus tuberosus, Fallopia japonica, F. sachalinensis a F.x bohemica and one native species - U. dioica were studied on two common land snail species. Using three different methods I tried to recognize, whether or not these plants serve as a food source to Succinea putris and Urticicola umbrosus. From histological sectionsit was impossible to identify the plants. The majority of plants don`t provide structures usable for identification of plant in the snail maces. I was able to identify only H. tuberosus and U. dioica undoubtedly, thanks to trichomes. According to the results of laboratory tests, the most important factors for snails food preferences are plant species and the condition of plant material. U. umbrosus consumed much less fresh material than S. putris. Consumption of frozen leaves became larger for both species. The most preffered plant species were U. dioica and H. tuberosus. Only frozen I. glandulifera was consumed. Fallopia spp. were rejected both, fresh or frozen.
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Rats of the genus Rattus: their biology and food preferences
Voráčková, Petra ; Frynta, Daniel (advisor) ; Telenský, Petr (referee)
Genus Rattus falls into the most extensive mammalian family Muridae, concretely to subfamily Murinae. The Norway rat (Rattus norvegicus) and black rat (Rattus rattus) are the best known species of genus Rattus. Although the laboratory rat is widely used as model organism, the wild species of genus Rattus cause huge economic losses in agriculture, especially in South East Asia. These commensal rodents are also vectors of zoonotic deseases which can cause human infection. One of the way how to reduce their populations is to study the transmission of food preferences. Well known phenomenon of genus Rattus is the social learning and sharing the experience about food to other individuals. Not only due to this fact is this kind one of the most successful in the animal kingdom.
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Factors affecting food choices by birds in winter
Korencová, Petra ; Klvaňová, Alena (advisor) ; Fuchs, Roman (referee)
I studied food choices of four small passerine species in winter on an artifical source of food, a bird feeder. I did experiments with two different types of food. I proposed that birds would prefer the type of food with higher contain of fat and calories. Food preferences were shown, but independently on calories contain. Greenfinches always selected sunflower seeds. I conclude, this species is affected by tradition, because it is usually fed by sunflower seeds in all bird feeders in vicinity of experimental location. In the second series of experiments I presumed the birds would prefer the food of bigger size because of easier manipulation on a potentially dangerous spot, which bird feeder represents. Again, the choices of greenfinches and field sparrows were not affected by this factor. Great tits did not prefer any food type. Siskins on the other hand prefered smaller food type, apparently because of its better accessibility using their small beaks. In the third series of experiments I tested the effect of presence of a stuffed predator - a sparrowhawk. I presumed it would lower food selectivity in this dangerous situation. The birds visited the bird feeder significantly less fraquently than in the absence of predator, but the food choices were not affected.
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Caterpillars food of Minois dryas on selected area
Hájková Březinová, Kateřina ; Vrabec, Vladimír (advisor) ; Kamil, Kamil (referee)
The dryad Minois dryas, described in 1763 by Giovanni Antonio Scopoli, belogs to our endangered species of butterflies. Its expansion today is restricted to a few localities in Central and Southern Bohemia and Southern Moravia only. Renewal and preservation of appropriate types of biotopes and research of its autecology and bionomy play the key roles in conservation of this species. The intention of my thesis was to identify host plants of Minois dryas caterpillars, to find out which grass is the most preferred one and to verify the correctness of hypothesis that the most preferred plant is also dominant from the range of potential host plants in the chosen area (a meadow in the vicinity of Žehuň in Central Bohemia). In the first part of experiment caterpillars were offered grasses collected in Žehuň. Plants which were eaten by caterpillars, were determined as host plants. According to results of this stage the host plants of caterpillars in the Czech republic are Dactylis glomerata, Bromus erectus, Festuca rubra, Arrhenatherum elatius and Carex acutiformis. In the second part of experiment caterpillars were offered all grasses evaluated in the first part as host plants and frequency of eaten / untouched leaves was recorded. Results identified Bromus erectus as the most desired grass and statistical proved there was a strong dependance among the plants . As Bromus erectus is indeed the most dominant grass in the location (approx. 30 % of all grasses), the hypothesis was confirmed. The experiment contributed with some other knowledge about dryad's bionomy. Observations confirmed that caterpillars pupate at the turn of June and July, primarilly at night. Larvae pupates in or on the ground. I did not notice any silk spinning during the time of pupation which is mentioned by Beneš et al. (2002). The pupal stage lasted 22 -- 23 days. Butterflies hatched in the morning. Imagos chose red watermelon as a food in most cases which proves that adults prefer red colour while deciding on their food (Vrabec et al., 2007).
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A comparison of selected ethological aspects of chosen tortoise species
BLAŽEK, David
In this thesis we studied individuals of 4 species of tortoises, often bred in captivity genus Testudo species T. hermanni, T. graeca, T. horsfieldi and T. marginata, in possession of the ZOO Hluboká nad Vltavou. We studied and analyzed their morphological parameters, size measurements, their weight and biometrical indexes, wheather they follow described sexual dimorphism as it was found out in non-captive populations. We also studied and analyzed their food preferences to find out differences between sexes and between keeping individual animal versus a group, by giving them a choice between 4 types of food (the red cabbage, leaves of dandelion and clover, and carrot roots). Sexual dimorphism displayed by different body proportions was most apparent in Testudo hermanni. In specimen from the ZOO of Testudo horsfieldi a T. graeca was sexual dimorphism less prominent. Measured Testudo females from the ZOO were in lowest, approximate and highest values bigger and heavier than males of the same species, which mirrors data from other studies of non-captive populations. Males are quicker to get to and quicker to start eating food than females. Males preffered red cabbage and carrot while the females clover and dandelion. The amplitude of preference change between individual and group experiment was not correlated by individual´s sex, species or size. We found out no apparent hierarchical enforcement from the side of faster or bigger specimen in the feeding process.
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Preferences of the basic components of food by central European speciens of ants.
NOSKOVÁ, Lenka
This thesis has two parts: the first brings an overview of the role of various foods and nutrients in ants, the second presents the results of an experiment focused on preference of the basic components of food by central European species of ants. In the experiment we provided ants with six different baits (water, 1% sodium chlorid, olive oil, 20% amino acid glutamine, artificial honey [10% sucrose + 10% amino acid] and 20% sucrose). Total, 187 of 690 traps were visited by ants. There were 26 recorded species of ants. Preference of four most abundant species differed. F. polyctena attended most of the offered baits, while other species preferred the sugar components. In general, ants preferred artificial honey and sucrose, regardless of the season and habitats. Additional field tests with different bait concentration of salt and sucrose showed the same preferences regardless of bait type and no additive effects of the amino acid in the sucrose baits. The results of the experiment show a surprisingly consistent and strong preference of central European species of ants for sugars.
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Food preference of the moose (\kur{Alces alces}) at zoological gardens
ŠERÁKOVÁ, Veronika
The thesis deals with food preferences of elk (Alces alces) in Czech zoological gardens and contains observation of food preferences in zoo Hluboká nad Vltavou. The results are compared with food offer and preference in the wilds described in literature. The first part of the thesis is aimed at literary review about elk, its characteristic, categorization, distribution and biology. It is focused mainly on the studies dealing with feeding habits and food preferences of elk in the wilds and captivity. The second part describes observation of food preferences of three elks in zoo Hluboká nad Vltavou, provided during 10 feedings. The food quality and composition of feed ration was also evaluated not only in zoo Hluboká nad Vltavou, but also in zoo Praha and zoo Brno (based on information from local zoo keepers). Analysis of variance showed that there are differences in feeding latency between various types of food. Elks preferred dried herbs, carrot and oak bark. On the contrary, elks did not preferred oat flakes and both granules for giraffes and elks. Recommendation for feed ration improving, including also food preferences of the elk were also suggested.
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Dietary preferences of selected snake species
STARÁ, Zuzana
In this study I investigated the dietary preferences of very familiar snake in our country - grass snake (Natrix natrix). I did the experiments with both adults and young individuals. I used Y-maze apparatus for testing. I selected frog (Rana esculenta) and fish of two sizes (Cyprinus carpio) as a prey items for those experiment. I tested snakes in three experimental settings. In the first the prticular snake can choose between empty branch and small fish at the end of the second branch, in the second two fish of different size were offered, and the third experimental setting investigated the preference between small fish and frog. As a prey I used only the cotton rubbed against the prey item (carp or frog) which I subsequently placed to the plastic box at the end of two branches of Y-maze. The results show that the adult snakes are less choosy in their diet than the young snakes which almost always prefer frog prey against fish.
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Food preferences of small terrestrial mammals and their influence on biodiversity of plant communities in wet orchid meadows
CUDLÍN, Ondřej
Food preference of small rodents to consume the roots of wild plants with the emphasize on their impact to bulbs of orchid Dactylorhiza majalis has been studied on three localities during years 2002 - 2007. There were selected ten couples of plants in each plots, one individual of couple plants was protected by tin triangle. Indicated plants have been measured in the beginning (high, length and wide of the leaves and flower number) and at the end of growing period (number of capsules). Small mammals were snaptrapped for three nights in the autumn. On each locality four rows of 25 snap traps were situated, two rows through orchid plots and two without orchids. In years 2004 {--} 2007 the food preference was ascertained on studied sites. Roots of Daucus carota (as a control in year 2004) and roots of Selinum carvifolia (as control in years 2005 - 2007) and roots of tested plant were put into one rectangle "bait" of size 15 x 6 centimeters from gauze. These 50 "baits" were placed among 100 traps on each locality, every other trap, during snaptrapped of small mammals. Browsing was classified by six number scale. During years 2005 - 2007 food preference of Microtus arvalis under laboratory conditions of Science Faculty of South Bohemia University was achieved with the roots of the same species as we used during food preference on plots. During years 2006 -2007 bulbs of Dactylorhiza majalis from laboratory condition and a few idividuals from endengered meadows by revitalization of pond were added. During yeas 2006 and 2007 the contain of stomach from Microtus arvalis and Microtus agrestis, catched during autumn, was studied. Bulb destruction by small rodents during years 2002 - 2007 was not confirmed. But Microtus arvalis preferred bulbs of Dactylorhiza majalis under laboratory conditions and roots of Selinium carvifolium and Lysimachia vulgaris boths in laboratory and wet meadows. Destruction of orchid bulbs and more preferred roots of wild plants by small rodents could occur probably only in outbreaks of their population cycle. I did not observe this on studied plots. In mount of stomach from Microtus arvalis only 3% underground supply organs of plants; rest of stomach contain was consisted of aboveground green part of plants. This result was expexted, because small rodents prefere during vegetation period green part of plants.
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