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Golden-ringed Dragonfly (Cordulegaster boltonii): Effect of individual male characteristics on their epigamic behavior
Rohlíková, Barbora ; Černý, Martin (advisor) ; Holuša, Otakar (referee)
My study researches the individual male characteristics of Cordulegaster boltonii in relation to their epigamic behavior. The first part of this study analyzes the relations of the measured characteristics (length and height of the wing, wings area, body weight, age), in the second part I assess their possible effect on the epigamic behavior of males of Cordulegaster boltonii, specifically how they affect the intensity of searching for females. Males of this species perform distinctive scanning flights over a stream to find an ovipositing female to mate with her. I used individually marked males to quantify their performance which can be interpreted as reproductive success because more active males are more likely to meet and mate females. My work includes 3 methods of evaluating activity. The first is based on the actual number of flights, the second on the average daily order of the males (based on the number of flights in days when the males have been seen). The third method combines the average daily order with number of days when the males could be seen. In the second part of the study I evaluate the effect of the above-mentioned individual characteristics on the flight activity of males. The outcome of the GLM indicates that the only characteristic with significant effect is the age of the...
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Individual fitness in Odonata: effect of phenotypic traits
Rohlíková, Barbora ; Černý, Martin (advisor) ; Harabiš, Filip (referee)
My study summarizes current knowledge of the aspects influencing reproductive success of dragonflies (Odonata). As with other organisms, the reproductive success (fitness) differs on the individual level, and it is influenced mainly by factors related to body structures. The body characteristics of individuals dragonflies affect their totally physical performance. The most studied factors include size, pigmentation and fat reserves; the individual performance is influenced also by the weight, fluctuating asymmetry, age etc. Some of these factors apply during larval development. However, the precopulatory phase (epigamic behaviour) is the most explored, since during that, males gain control and defend territory or perform courtship behaviour. At this phase, beside physical capabilities, there are other important factors such as ornamentation (pigmentation) or fluctuating asymmetry; some damselflies have developed various strategies which, at some species (namely within Calopterygidae), may evolve into colourful dimorphism of males. Next, the copulation in dragonflies is very specific, besides usual sperm transfer it often involves removal of sperm of predecessors to ensure paternity. At many species, the copulation is followed by the postcopulatory phase, during which the males secure their...
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