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Evolution of host specifity in cuckoo bees of the genus Sphecodes (Hymenoptera)
Habermannová, Jana ; Straka, Jakub (advisor) ; Kratochvíl, Lukáš (referee)
Cuckoo bees behave similarly to the well-known birds, cuckoos - they lay eggs in the nests of other bees. Proposed thesis charts the evolution of host specialization within the strictly cuckoo genus Sphecodes. According to the classical view based on the Red Queen hypothesis, parasites should gradually specialize during evolution to keep pace in the "arms race" with their hosts. Specialization is also perceived as an evolutionary dead end - narrow adaptation prevents change of host. To test these hypotheses phylogeny of tribus Sphecodini based on the partial sequences of five genes was constructed. For each ancestor has been by two methods of mapping ancestral characters (Bayesian method, Maximum Parsimony) specified, whether it was specialist or generalist and which kind of host or hosts it had. The results show that the original strategy of genus Sphecodes is specialization and generalists originated from specialized ancestors only recently. The results also show that the jumps between the hosts are common. These findings are inconsistent with the Red Queen hypothesis as well as with the view that specialization is an evolutionary dead end. Falsity of these hypotheses within the genus Sphecodes established also likelihood ratio test, in which the likelihood of model allowing two-way transition...
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Biology of solitary bees of various families (Hymenoptera: Apoidea). A comarative study.
Žáková, Zdislava ; Straka, Jakub (advisor) ; Bogusch, Petr (referee)
The diploma thesis deals nesting behavior of the solitary bees Colletidae, Megachilidae, Mellitidae, Halictidae. The bees were monitored in their natural environment in the years 2009 - 2010. Course of their daily activities, number of nests per female, lenght of stay in the nest, length of life, active days and other species characteristics were monitored. By comparing the different nesting behavior patterns of the monitored species were found and pointed out the ones that are common and the unique ones. A nest uzurpation occurred (at all colonies) regardless the species. The (research) literature does not adress the issue of nest uzurpation in detail. Key words: nesting behavior, uzurpation, agression, bees, Hymenoptera
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Nesting biology and alternative reproductive strategies in bees of the genus Anthophora (Hymenoptera)
Macháčková, Lenka ; Straka, Jakub (advisor) ; Tropek, Robert (referee)
My thesis is focused on the nesting behaviour and reproductive strategies of solitary bee Anthophora plumipes, which nests in colonies and builds the nests in the ground. During behavioral observation in seasons 2009 and 2010 the basic demographic characteristics of studied species were described and all the observed behavioral patterns were described in ethogram. Existence of intraspecific cleptoparasitism in form of usurpations was proved. From field usurpations were 22-33 % assessed as a real usurpations and 66-67 % were cases of use of an empty nests. Number of usurpation was constant throughout the season. There was increase in cases of use of empty nests at the end of the season. The underground nests were marked by lanthanides. This way the interactions between females could bee observed. In this way the intraspecific cleptoparasitism could be found out. 25-32 % samples were positive from 152 samples, that were measured on ICP. It suggests relatively low effectivity of marking. The mark losses reach up to 42 % during processing.
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Cyclic development of social communities in insects
Mikát, Michael ; Straka, Jakub (advisor) ; Zrzavý, Jan (referee)
A lot of animal species forms societies - groups of regularly interacting individuals. Societies vary in social structure and relations among their members. Societies with reproductive division of labour are the most complex. Origin of reproductive division of labour is one of main themes of evolutionary biology. In this thesis classification of societies according actual composition is summarized and modified. Societies very changed during colony cycle in taxons which forms eusocial levels societies. For these taxons is describing of society cycle very valuable for comprehension of social strategy. In this thesis cycles of societies are classified and selection pressures which may change society cycle are summarized.
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Host specialization and species diversity in Strepsiptera of the genus Stylops
Jůzová, Kateřina ; Straka, Jakub (advisor) ; Malenovský, Igor (referee)
The twisted-wing parasites (Strepsiptera) are entomophagous insect order with cosmopolitan distribution. There are about 600 known species up to date. In spite of this, they have very broad host spectrum. Strepsiptera parasites in seven insect groups (Thysanura, Blattodea, Mantodea, Orthoptera, Hemiptera, Diptera, Hymenoptera). The mutual relationship between genera or even between species are not known, except for the species list and the host specification. Moreover, there is an anambiguous use of their species concept. Some authors consider Strepsiptera as the specialists and they match almost every host species with one separate strepsipteran parasite. The opposite concept is to consider strepsiptera as the generalists. The presence of the crypctic species also affect our understanding of the diversity of Strepsiptera. Therefore, the knowledge of Strepsiptera phylogeny provide us the important information about species diversity of studied group as well as about their coevolution with their hosts. On the basis of molecular analyses of three genes constructed the phylogeny genus Stylops. This genus has the wider spetrum of the host species from other strepsipterans of Stylopidae, It is obvious, that strepsipterans of genus Stylops are mainly specialised on their host subgenus. There was detected two...
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Nesting behaviour and alternative reproductive tactics in solitary bees (Hymenoptera: Apoidea)
Rezková, Kateřina ; Straka, Jakub (advisor) ; Konvička, Martin (referee)
Proposed thesis describes nesting behaviour of gregarious solitary bee species Andrena vaga. The knowledge of behaviour in solitary bees can be very important, because solitarity might represent the initial point in the evolution of eusociality and obligate cleptoparasitism. A population of the studied species was observed continuously for two nesting seasons, which enabled me to describe basic demographic characteristics of studied species such as lenght of bee season, longevity, density of population, number of nests per female life, etc. All the observed behavioural patterns were described in ethogram and their exact position in provisioning cycle was determined. This information helped me to compile average daily activity of studied species. I found out major differences in bee behaviour in both years and between nonparasitized and stylopized (parasitized by Stylops) bees. I proved the existence of intraspecific cleptoparasitism in form of usurpations. Because it is crucial to link female to the provisioned cell for the detection of intraspecific cuckoo-like behaviour, I tested two new methods of underground cell marking - protein marking and fluorescent dye marking. Powered by TCPDF (www.tcpdf.org)
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