|
|
Centric fusions in karyotype evolution of spiders
Mlnáříková, Barbora ; Forman, Martin (advisor) ; Nguyen, Petr (referee)
Entelegynae are the most specious group of spiders. Their karyotypes are characterized by the predominance of X1X20 sex chromosome system and exclusively acrocentric morphology of chromosomes. Mono-armed chromosomes can be the substrate for centric fusion, the rearrangement, in which two acrocentric chromosomes fuse at their centromeric regions and form single bi-armed chromosome. In Entelegynae, centric fusion events followed the "all or nothing" rule, where all acrocentric chromosomes fuse during one event or in a very rapid sequence and karyotype is fully saturated by bi-armed chromosomes. Although the cytogenetics of Entelegynae is relatively well studied, so far, "all or nothing" phenomenon has been observed only rarely, namely in 12 species from 5 families. In this thesis, new data about the occurrence of centric fusion in 12 species from 5 unrelated families are reported. In all cases the "all or nothing" rule was confirmed. Strong female meiotic drive is proposed as the main force responsible for changes in chromosomal morphology of Entelegynae. The persisting of bi-armed chromosomes is likely to be rare in Entelegynae. However, in the family Dictynidae, bi-armed chromosomes are fixed. For a better understanding of karyotype dynamics in this unique family, molecular cytogenetic approaches...
|
|
|
Viniční terasy jako refugia pro výskyt xerotermních druhů pavouků (Araneae) a jejich bioindikační využití v hodnocení kvality životního prostředí a úrovně biodiverzity
Košulič, Ondřej
The large-scale decline of traditionally managed early-successional habitats caused by the joint effects of agricultural intensification and abandonment of marginal lands has resulted in a critical reduction of xerophilous arthopods throughout Europe. The question is whether newly generated early-successional sites of human-made habitats (in this case vineyard terraces) may partially compensate this habitat loss. My research, therefore, focusses on spiders as model organisms to determine the potential importance of xeric slopes of vineyard terraces for biodiversity conservation in agricultural landscapes. I analyzed species density, abundances, rareness degree and conservation value among vineyard terraces with two habitat types of different succession stages (sparse and dense grass turf) placed in in landscapes with varying proportions of surrounding potential source areas (steppe -- foresteppes) and different surrounding habitats (habitat structure) around studied terraces. During 2011 were collected by different methods 6040 adult specimens of spiders belonging to 171 species, 69 genus and 24 families. From this representation were calculated high proportion of rare xeric specialist (40 %) and red-listed threatened species (15 %). From the statistical analyses, overall species density and abundance of spiders did not differ significantly between the terraces with sparse and dense vegetation cover, however species density was significantly influenced by presence of xeric grasslands around vineyards. The occurence of rare and endangered epigeic was significantly associated with the type of successional stage (for epigeic and epiphytic species), as well as rareness degree, conservation value and abundances significantly increased with presence of adjacent steppe grasslands. The results indicate that artificial habitats, such as vineyard terraces, are important refuges for wide spectra of xerothermophilous spiders. To prevent losses of rare and endangered xeric species, I suggest some small scale management methods that maintain important microhabitat mosaic structures under the different succession stages.
|
|
|
Traded animal species: comparison between IUCN and CITES
KORCH, Martin
The legal and illegal trade in wild animals and plants is still growing and creates constant pressure on entire ecosystems. There are many organizations that try to prevent this problem and regulate the international trade. Such organizations include the IUCN and the international convetion CITES. Due to a lack of coordination, the number of business records is constantly increasing and it can lead to rapid extinction of species. The aim of the work is to find out the overlap between critically endangered, endangered, vulnerable and internationally traded species: Araneae, Chilopoda, Lepidoptera, Chondrichthyes, Actinopterygii, Dipneusti, Coelacanthii and Carnivora listed by IUCN and the species included in appendices I, II or III to the international convention CITES. The analysis revealed that of 1 585 internationally traded species listed by IUCN is 42% (1 585 species) unprotected by CITES. That is almost half of the species that are overlooked and potentially in need of international trade regulation. Aquatic organisms are among the most endangered species (41%) and only one percent includes terrestrial organism.
|
|
|
Ecology and courtship behaviour of the wolf spider genus Alopecosa (Araneae: Lycosidae)
Just, Pavel ; Dolejš, Petr (advisor) ; Žďárek, Jan (referee)
In my bachelor thesis, Czech members of the wolf spider genus Alopecosa are discussed. Literature review summarizes our knowledge in ecology of wolf spiders, their life histories, phenology and habitat preference. I concentrated on reproduction of wolf spiders of the genus Alopecosa, especially on their courtship behavior. Recently, spider courtship is studied with focus on multimodal signalling. The review also contains remarks about spiders life cycles, copulation and parental care. Research of courtship of the genus Alopecosa is sligthly neglected, especially when we consider achievements gained by study of the American wolf spiders of the genus Schizocosa. It is necessary to know the taxonomy of the genus Alopecosa, thus some taxonomical remarks about current systematics and phylogeny of family Lycosidae are outlined
|
|
|
Vývoj epigeické arachnoentomofauny borových porostů v požářišti revíru Bzenec - Moravská Sahara (LS Strážnice)
Prágr, Jakub
Successional changes occurring in the structure and composition of communities of epigeic fauna in the first three (Coleoptera: Carabidae), or two (Araneae) years after the pine stands fire have been studied since 2013 in the territory of the Moravian Sahara (Bzenec, Czech Republic). 11 permanent research plots were established in order to evaluate the response of epigeic fauna and habitat changes after the fire. These included areas deforested after the fire, pine stands severely affected by the fire (27 years) left to natural successional development and pine stands (94 years) with ongoing salvage cutting. Qualitatively equal stands undisturbed by the fire (29 and 78 years) were simultaneously studied. Pitfall traps were used (5 pcs/area) to determine the state of the epigeic fauna. A total of 90 kinds of Carabid species and 151 spider species were caught and determined. The structure and composition of ground beetle and spider communities in locations disturbed and undisturbed by fire differed throughout the observation period. Ground beetle and spider communities of biotopes undisturbed by the fire showed a stable structure and community composition, while in pine stands disturbed by the fire, a gradual increase in species dominance and diversity of heliophilous and xerophilous groups took place. A significant decline in the species diversity of spiders in pine stands disturbed by fire was recorded between 2013 and 2014. Ground beetle communities showed the opposite trend. Ground beetle and spider communities in the surveyed area demonstrated a sensitive link to a change in the microclimatic conditions of the studied habitats; on the basis of changes in their composition, it was therefore possible to infer changes taking place also in the stands, where the effects of fire were not apparent at first glance.
|
|
|
Vliv intenzity pasečného hospodaření v dubových porostech na epigeickou faunu pavouků (Arachnida, Araneae)
Staněk, Luboš
The objective of the present study was to investigate the impact of intensity glade economy at oak forests on epigeic fauna of spiders. Specifically, there were two types of glade economy - mechanical and non-mechanical. The main target of was compare two types. Finding of the species richness, abundance and degree of rareness of spiders The spiders were cought in an individual way. Collect was held in six locations (3 mechanical and 3 non-mechanical) near cities Pasohlávky, Ivaň, Pouzdřany and Vranovice. Repeated five times, from May 2016 to September 2016, once a month. A total number 6915 individual spiders and 120 spider species. The research revealed a statistically significant difference in the species richness between mechanical and non-mechanical locations, where there was a significantly higher diversity on non-mechanical locations. Activit density was bigger on the mechanical locations. Non-mechanical locations a significantly higher incidence of rare and endangered species of spiders and overall, the arachnofauna in these locations was significantly more diverse. The results indicate the inappropriateness of large-scale milling of stump in forest management. The results can also serve as a basis for arboriculture practice in the care of scattered and public greenery.
|
|
|
Struktura a distribuce společenstev pavouků (Araneae) v závislosti na ochranářském managementu přírodní památky Pláně
Hamřík, Tomáš
Until the second half of the 20th century, the Czech landscape was traditionally maintained by traditional farming and grazing that produced a heterogeneous mosaic of microhabitats. However, the abandonment of traditional farming caused the areas with early stages of succession to overgrow and become homogeneous, resulting in the serious loss of arthropod biodiversity. This traditional farming therefore needs to be replaced by an active conservation management method. This Master thesis studies the effect of conservation management on the arachnofauna of the steppe biotopes Pláně Nature Monument. Specifically, the influence of disturbance, mowing, prescribed burning, and non-intervention on abundance, species richness, occurrence of rare and endangered species and species and functional composition of spiders was investigated. Spider sampling was carried out using pitfall traps and sweeping during the whole season in 2017 and 2018. The treatments were applied on the patches (4 x 5 m) and replicated at three sites. A total of 154 species with 11,634 specimens including many rare and endangered spider species were captured. Management had no significant effect on the abundance and species richness of epigeic spiders. Herb-dwelling spiders had high abundance and high species richness in control and burned patches. Burned patches had high values of conservation indicators, where the significant proportion of xerothermic species and hunting guilds were represented. Intensive disturbance had rather a negative effect on the overall arachnofauna. Prescribed burning had positive results for most of the studied indicators. The results show that interventions performed on a small area can significantly support the valuable arachnofauna of steppe habitats. To support habitat heterogeneity and the diversity of organisms that depend on it, the interventions should be combined and performed in such a scale that would avoid extensive habitat disturbance.
|
|
|
Druhová diverzita, početnost a význam pavouků (Arachnida, Araneae) na listnatých dřevinách v arboretu Mendelovy univerzity v Brně
Bernatová, Martina
The aim of my work was to find out the species diversity and the number of spiders in the arboretum of Mendel University in Brno and also to deduce their significance and last but not least to assess the importance of arboretums, parks and other urban greenery as areas of biological diversity in urban areas. Within the research fifteen deciduous trees were selected, located in different parts of the arboretum. The spiders were collect by using two capture methods, a shaking off method and a selection of cardboard belts method. Shaking off took place within the research four times, namely 11.5.2017, 14.6.2017, 1.8.2017 and 18.9.2017. A selection of cardboard belts took place twice, 28.6.2017 and 19.10.2017. In both methods, a total of 303 adult specimens of spiders belonging to 45 species, 36 genera and 14 families were obtained and determined. The most frequently represented was the species of Philodromus cespitum, which accounted for more than a third of the captured material (over 33%). This species belongs to species capable of living even in disturbed biotopes of urbanized areas, so its considerable representation is expectable. Within the research, however, several threatened species were acquired, species that occur only in a natural, undisturbed environment. From this fact, it can be concluded that the environment of the arboretum is at least partially a natural environment for the occurrence of different species, from which it can be deduced that arboretums, parks and similar greenery in cities are indeed a place of biodiversity. This conclusion is important also for arboristic practices, as well as the fact that spiders are important invertebrate predators and can therefore be used for biological protection in cities (where it is inappropriate to use chemical preparations for plant protection) and also outside them. Endangered and rare species that have been identified in the arboretum within the research can also be used to bioindicate the quality of the environment in the arboretum and similarly spiders can be used for the bioindication in urban parks and other urban greenery as well as in open landscapes.
|
|
|
Rozdíly v druhové diverzitě a abundanci pavouků na hlavách révy vinné na terasovaných a klasických vinicích v závislosti na typu hospodaření
Havlová, Lucie
Spiders belong to one of the most important natural pest antagonists in many agroecosystems. The species diversity and abundance of spiders, hence their biocontrol potential, is directly related and is often increased by the presence of non-agricultural, non-productive areas in the landscape directly surrounded with agroecosystems. My research was focused on spiders related to the vine plats trunks, first of all as organisms reflecting the function of vineyard terraces in relation to increasing their heterogeneity, which in turn reflects on the resulting biodiversity of the landscape, and secondly as pest antagonists in vineyards, which can effectively and nature-friendly contribute to the sustainability of agricultural units. Research areas in the South Moravian Region were selected and species diversity and spider abundance were analyzed. Two vineyards at each site have been selected: classic - plain vineyards and terraced vineyards which were lined with non-productive slopes. From November 2013 to October 2014, 727 adult spiders belonging to 21 species and 7 families were recorded. Concerning the vulnerability of each species, 12 abundant species were found, 4 species were almost threatened, 3 were endangered species, 1 species was strongly endangered, and 1 species was critically endangered. According to the results, we can state that the species spectrum of spiders found on vine plant trunks may in the future function as a biocontrolling agent and may have an interesting influence on vine pests.
|
|
|
Robertsonian translocations and their involvement into genome evolution
Mlnáříková, Barbora ; Forman, Martin (advisor) ; Sember, Alexandr (referee)
Chromosome aberrations play an important role in human pathologenesis as well as in evolution of many organisms. Robertsonian translocation or centric fusion are the most frequent chromosomal rearrangements in mammals. The most investigated model for their research is house mouse Mus musculus. The standard karyotype of a mouse consists from 40 acrocentric chromosomes, notably there are more than one hundred wild populations that are characterized by various combination of metacentrics, formed by centric fusion of different acrocentrics. Several models have been proposed for the formation of metacentrics, taking account of the sequential structure of their centromeres and short arms in mouse. Segregation distortion in favor of metacentrics is present in female and/or male meiosis, such as meiotic drive can positively affect the degree of fixation of metacentric chromosomes in certain population. Centric fusions have been also presented in evolution of other organisms. Cytogenetic data in spiders indicate the possibility of similar phenomena in the most diversified group of spiders, Entelegynae. Spiders are notable for their unusual sex chromosome systems. Centric fusions also play an important role in the evolution of sex chromosomes and the formation of neo-sex chromosome systems. So far, there is...
|
guest ::
