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Reproductive behaviour of wolf spiders of the genus Alopecosa (Araneae: Lycosidae)
Just, Pavel ; Dolejš, Petr (advisor) ; Hajer, Jaromír (referee)
In my master's thesis, I deal with reproduction of central European wolf spiders of the genus Alopecosa. Here I present patterns and duration of courtship behaviour and copulation of 15 members of the genus Alopecosa. Such information were never published before. I recognized 17 courtship elements, six of them are described here for the first time. Duration of copulation, number of palpal insertions and number of hematodochal expansions of 15 species were examined. The obtained data were analyzed, courtship and copulations among species and species groups are discussed. Courtship behaviour of two sibling species, A. striatipes and A. mariae, is compared, as well as differences in reproduction of Czech and Italian populations of A. accentuata. Based on courtship behaviour, I propose placing Alopecosa psammophila in a striatipes group. Stridulatory apparatus on male pedipalps was not detected, however, some pegs on vetral side of the abdomen in males of Alopecosa pinteroum were found. These pegs could serve as a source of vibratory signals. The thesis provides some new remarks on ecology of members of the genus Alopecosa and contains faunistical information, including those on the recent occurrence of some of the rarest Czech spiders.
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Study on dynamics of spinning apparatus of some wolf spiders (Araneae: Lycosidae) during their life cycle
Dolejš, Petr
Current knowledge of the spinning apparatus comes namely from studies on orb web spiders and their relatives, whereas that of wolf spiders were more or less neglected. Therefore, developmental changes of the spinning apparatus of four wolf spiders were studied throughout their life cycles. Each of these lycosids possesses stenochronous life cycle with similar number of instars (7-10) but of different length (1-3 years). There is only one period of reproduction in spring/summer in all four species. Sperms are being formed just after the final moult; diplotene in some species is peculiar. The courtship behaviour reflects the microhabitat occupied by the concrete spider species; the copulations are species specific. Ontogeny of the spinning apparatus of developing spiderlings was observed: The spinning apparatus initiate its function in the first instar. Secondary ampullate, all piriform and all but four aciniform glands are tartipore-accommodated; they do not moult in situ. The tartipores, vestigial structures corresponding to spigots of the previous instar, appear on the spinning field starting with the second instar. Tartipore-accommodated glands play roles also during proecdysis and their evolution corresponds with the way how do the spiders secure themselves when moulting. Hence, the not yet...
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Study on dynamics of spinning apparatus of some wolf spiders (Araneae: Lycosidae) during their life cycle
Dolejš, Petr ; Smrž, Jaroslav (advisor) ; Žďárek, Jan (referee) ; Hajer, Jaromír (referee)
Current knowledge of the spinning apparatus comes namely from studies on orb web spiders and their relatives, whereas that of wolf spiders were more or less neglected. Therefore, developmental changes of the spinning apparatus of four wolf spiders were studied throughout their life cycles. Each of these lycosids possesses stenochronous life cycle with similar number of instars (7-10) but of different length (1-3 years). There is only one period of reproduction in spring/summer in all four species. Sperms are being formed just after the final moult; diplotene in some species is peculiar. The courtship behaviour reflects the microhabitat occupied by the concrete spider species; the copulations are species specific. Ontogeny of the spinning apparatus of developing spiderlings was observed: The spinning apparatus initiate its function in the first instar. Secondary ampullate, all piriform and all but four aciniform glands are tartipore-accommodated; they do not moult in situ. The tartipores, vestigial structures corresponding to spigots of the previous instar, appear on the spinning field starting with the second instar. Tartipore-accommodated glands play roles also during proecdysis and their evolution corresponds with the way how do the spiders secure themselves when moulting. Hence, the not yet...
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Arachnophobia and the cause of fear of spiders
Říha, Roman ; Dolejš, Petr (advisor) ; Vlček, Kamil (referee)
Fear of spiders is largely widespread, and in some cases may even grow into a phobia. Negative attitude towards spiders can be found already in the mythology of some peoples. This attitude is often in the Western culture. It is interesting that this fear persists even though there are very few spiders which are able to endanger human life. There are more possible causes of arachnophobia, including classical conditioning, information transmission and impact of disgust emotions. Right the disgust seems to be the probable explanation of spider phobia. Relevance fear is documented by a list of dangerous spiders to humans. Some spiders are in fact able to endanger human health by toxins contained in their venom. Basic questions to deal with are validity of human fear of spiders and possible causes of this negative relationship.
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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
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