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Fossil clown beetles (Coleoptera: Histeridae): early evolution of "beetle tanks"
Simon Pražák, Jan ; Prokop, Jakub (advisor) ; Růžička, Jan (referee)
Clown beetles (Histeridae) represent a diverse (>4500 described species) group of beetles with worldwide distribution (except Antarctica) and with exceptional diversity of occupied habitats. Specialisation on environments such as subcortical space, dung and carrion, tunnels of wood- boring insects, caves, sand deserts, beaches, rodent burrows or ant colonies, has led to remarkable adaptations of morphology and even radical changes of entire body shape. To understand evolutionary paths of this extraordinary group of beetles, fossils are of vital importance. In this study, I examined eight undescribed species of fossil Histeridae from mid-Cretaceous Burmese and Hkamti ambers. I provide morphological descriptions and discuss possible taxonomical position of these species based on morphological characters. I further tested the phylogenetic position of all Cretaceous Histeridae genera via a topology-constrained maximum parsimony analysis based on a set of 69 characters. Among the studied species, representatives of Abraeini and Paromalini are reported for the first time from the Cretaceous. I discuss evolutionary implications based on the new as well as other Histeridae fossils. Subcortical strategy was likely common in the Cretaceous histerids, now reported in three separate lineages. It is also...
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Distribution, ecology and conservation of critically endangered Alcon Blue (Phengaris alcon f. alcon) in the Czech Republic
Kupková, Barbora ; Sedláček, Ondřej (advisor) ; Pech, Pavel (referee)
The state of the populations of many insects is critical in the Czech Republic, other species have already extinct. Among the species balancing at the limit of survival is myrmecophilus Alcon Blue (Phengaris alcon), especially its ecological form (P. alcon f. alcon), which is associated with the Marsh Gentian (Gentiana pneumonanthe) during the early larval stages. The general aim of my work was to evaluate the current distribution of the Alcon Blue butterfly (P. alcon f. alcon) in the Czech Republic, to estimate the size of the remaining populations and to propose a practical action plan for conservation of the species in the Czech Republic. The analysis of the databases showed that the species survives theoretically in 11 localities. The field survey in 2016 revealed, however, that at five other sites a species in the recent past was extinct. The remaining 6 localities are concentrated in Southwestern Bohemia on a total area of only 20 hectares. Two population is however close to extinction. The cause of local extinction of Alcon Blues was the extinction of host plants. The main factors influencing the size of butterfly populations in the last localities were the abundace and vitality of host plants (number of fertile shoots, height). Part of my work was an attempt to reintroduce Alcon Blue to a...
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Integration of myrmecophiles into the host colonies
Bažilová, Jana ; Šobotník, Jan (advisor) ; Pech, Pavel (referee)
Although the research on myrmecophilous insects is dated back to the 19th century, certain aspects of fascinating relationship between hosts and their social parasites are not satisfactorily understood. The latest studies focus mostly on the systematics of myrmecophilous taxa, and bionomy remains neglected. Most of the myrmecophilous insect can be found among beetles (Coleoptera). These myrmecophiles reveal a broad spectrum of adaptations that allow them to live in close association with their host ants. These adaptations significantly differ among the well-integrated species on one hand and poorly integrated or non-integrated species of myrmecophilous beetles on the other. This study focuses at the comparison of behaviour in two species of myrmecophilous beetles, Claviger testaceus (Staphylinidae: Pselaphinae) as the member of integrated myrmecophiles, and Pella spp. (Staphylinidae: Aleocharinae) as poorly integrated or non-integrated beetle. My work shows significant differences in behaviour taking place after encounter of a beetle and an ant. Ants are more aggressive towards the non-integrated species, and at the same time, these beetles are well-adapted for aggressive behaviour from the ants. On the other hand, the integrated beetles do not possess many behavioural adaptations for the...
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Biology of myrmecophilous beetles
Bažilová, Jana ; Šobotník, Jan (advisor) ; Klimeš, Petr (referee)
Ants represent an insect group with a great ecological importance, and they are also a valuable source of food for a wide range of predators, parasitoids and social parasites. Myrmecophilous beetles make a significant part of these organisms. According to the specific selection pressures, myrmecophiles reveal a lot of adaptations, such as modifications of the body shape, functions of their extremities and new exocrine glands. These adaptations vary among species differing by the degree of their integration into an ant colony. Non-integrated species live near ant nests as predators and the hosts' behaviour towards them is always hostile. They are protected by thick and sclerotized cuticle, defensive substances and strategic behaviour. Integrated species are adopted by the host colony based on the imitation of hosts' recognition factors. These species have access to the hosts' nests, where they feed on ant larvae and pupae or they are fed directly by the ants. This thesis describes specific adaptations for life associated with ants, which are exploited by various myrmecophilous species. In several chapters it characterizes myrmecophilous organisms, their morphological adaptations, chemical mimicry and behavioural strategies used during interactions with the host. Keywords: myrmecophily, inkvilinism,...
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The evolution of the social parasitism of Phengaris (Maculinea)
PECH, Pavel
The presented thesis deals with the evolution of the social parasitism of Phengaris (Maculinea) butterflies. It consists of three related problems: I) The phylogeny of Glaucopsyche section (Lepidoptera: Lycaenidae: Polyommatinae) {--} the social parasitism occured only once in the Glaucopsyche section. II) The conditions in which the social parasitism of Phengaris evolved {--} the process was probably facilitated by unique species composition of the myrmecofauna of the biotopes inhabited by the ancestor of Phengaris. III) The host specificity of Phengaris {--} today{\crq}s view on the host specificity of Phengaris is poorly supported.
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