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Food neophobia and food preference in rodents (Rodentia) and its interaction with social learning.
Rudolfová, Veronika ; Landová, Eva (advisor) ; Telenský, Petr (referee)
Neophobia (fear of novelty) is first protection from ingesting potentially dangerous food in rodents. After overcoming the fear an animal begins to sample the food (take small parts). The animal then forms an aversion to dangerous food and preference for safe and nutritionally favourable food on the grounds of its experience with its ingestion. These mechanisms of behaviour towards food can be learned individually but an individual's behaviour is also influenced by other animals, especially in social animals. Whether an individual will act on its own experiences and therefore learn or if it will learn from others, depends on the situation and the environment in which the animal currently is. Key words: food neophobia, food preferences, social learning, individual learning, Rodentia, Rattus
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Food preferences and foraging mode in lizards (Squamata: Sauria)
Křivánek, Jan ; Gregorovičová, Martina (advisor) ; Kubička, Lukáš (referee)
In terms of food-foraging, lizards usually occupy one of two possible strategies ("foraging mode"). The first one is called "sit and wait" and it is defined by waiting on one position for a long time with a minimum movements and attack is based on visual cues on prey which gets to a certain distance. The second one is the "active foraging" in which the predator moves through terrain and it detects with help of chemical cues by nasal olfactoric system or vomeronasal system, with which is able to find a prey. Sometimes the third mode is also presented as a transition - "saltatory foraging" or a continuum between two these extreme strategies. Specific variables, which reflects the activity of a predator, are used to determine the "foraging mode" - MPM, PTM, PAM and AD. Within these predators a whole set of sensory adaptations ( such as enlarged olfactory lobes, a large abundance of taste buds, two fovea centralis in macula), morphological adaptations (e.g.shortening of the jaw, slender body morphology, forked tongue) and food adaptations (yellow color preference, ontogenetic shift to herbivory) are presented. Powered by TCPDF (www.tcpdf.org)
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Status of the flatworm Crenobia alpina in the food network of a spring
Reslová, Marie ; Simon, Ondřej (advisor) ; Černý, Martin (referee)
This work focuses on food preferences of freshwater triclad Crenobia alpina and its position in spring food web. It explores the ability of C. alpina to capture living prey, considers ability of C. alpina and to survive feeding on several types of food. Furthermore it gives view on its occurence and ecological preferences in context of other spring species. One chapter is concerned with taxonomy, anatomy and ecology of Tricladida and C. alpina itself. Short term food-preference experiments show the ability of C. alpina to capture living Lumriculidae and larvae of Ephemeroptera. We don't confirm feeding of C. alpina on living Gammarus, although their occurence in our springs and ecological preferences are similar. C. alpina feeds significantly more on damaged prey without substantial afinity to any species. A year-long experiment on C. alpina in lab conditions finds that this flatworm is able to survive and even breed with nothing but filtred water. This fact connected with the observation of huge densities of flatworms in spring source, opens up a question whether C. alpina can be considered a real predator. Key words: Crenobia alpina, triclad flatworms, food preferences, spring
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Foraging strategies of invertebrate predators in mountain lakes
Hrdličková, Jana ; Sacherová, Veronika (advisor) ; Hořická, Zuzana (referee)
In mountain lakes, which were affected by acidification in the past or in the present, invertebrate species have become top predators and they influence the whole community. This thesis deals with foraging strategies of three of these predators, Cyclops abyssorum and Heterocope saliens (Crustacea: Copepoda) and Glaenocorisa propinqua (Insecta: Heteroptera) in the model localities Černé lake, Plešné lake and Prášilské lake. The main aim was the determination of food composition and food preferences of these predators. The quality and quantity of consumed food I investigated with a microscope using a method which has not been published yet. To make a microscope preparation I used Potassium hydroxide or Lactic acid in order to dissolve soft organic matter, so that the chitinous particles were well visible. The found food of animal origin was subsequently compared with the prey availability with the use of Jacobs' index. In addition to this research, a feeding experiment with G. propinqua was carried out. The food of all the invertebrate predators was dependent on food availability or eventually on the season of the year. G. propinqua mostly preferred as a prey members of Daphniidae family and then the species Polyphemus pediculus (Cladocera), if they were available (Prášilské lake). In Plešné lake,...
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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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