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Vyhodnocení plodnosti raka signálního včetně post-ovulačního stavu vaječníků
FOJT, Martin
The theoretical part of diploma thesis is aimed at breeding, growth and molting events in crayfish. Thesis is also aimed at life cycle and reproduction of three indigenous crayfish species (Astacus astacus, Austropotamobius torrentium, Pontastacus leptodactylus) and two introduced crayfish species (Faxonius limosus, Pacifastacus leniusculus). The results show apparent linear dependence between female size (POCL), abdomen surface (1M: y = -1061,2 + 65,4*x; r2 = 0,9829; p10-5; 2M: y = -1160,4 + 68,7*x; r2 = 0,8732; p < 10-5) and fertility (1M: y = -194,4 + 12,8*x; r2 = 0,4104 p = 0,0042; y = -330.9 + 15,9*x; r2 = 0.4372; p < 10-4) in once (1M) and twice (2M) molted females. As the length of carapax increase, the area of the abdomen increase and fertility increase in both groups of females. Furthermore, the differences in fertility, carapax length, abdomen surface, and weights in once and twice molted females of signal crayfish. In group of once molted females fertility (t-test, t = -3.12, p = 0.003), carapax length (t-test, t = -3.17, p = 0.003) = -3.24; p = 0.002) and the weight (t-test, t = -3.35; p = 0.002) was higher than in twice molted group of female. Consequentially evaluation of egg size of females. The size of the eggs did not differ between groups of females (1M and 2M) (t-test, t = -0.975, p = 0.335). The mean egg size for both groups of females was 2.71 ? 0.18 mm. Evaluation of post-ovulation conditions of the ovary, including visible signs of females that resorbed unovulated oocytes. Evaluating how much unovulated oocytes were found in the ovaries. Only in 46.4% of the total number of females were ovaries completely empty. In once and twice molted females were found in average 2.2 ? 3.8 and 1.9 ? 2.6. unovulated oocytes, respectively. In once molted, three females didn't lay eggs, two females lost the clutch of eggs. In twice molted females, six females did not lay the eggs and four females lost the clutch.
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Embryonic and postembryonic development of marbled crayfish in different temperatures
FOJT, Martin
The aim of this bachelor thesis was to characterise the life cycle by parthenogenetic reproduction of marbled crayfishProcambarus fallax f. virginalis and to focus on the effects of its life cycle at different temperatures. The theoretical part of this thesis is focused on the reproductive biology of crayfish, with emphasis on embryonic and postembryonic development of marbled crayfish. It also acquaints us with the reproduction of indigenous crayfish and introduced crayfish species occurring in the territory of the Czech Republic. The practical part acquaints us with the conditions that need to be adhered during the experiment, changes in embryo development and assessing embryo development at different temperatures. Our experiment confirmed that the postembryonic stages of marbled crayfish were able to survive at low temperature (10 °C). Individuals were able to undergo the first postembryonic stadium at the lower temperature, but they developed slowly. Individuals develop without problems at 15 °C. The duration of postembryonic development was a little bit longer than in warmer temperature. There were expectations that the highest survival rate would be at higher temperatures, but our experiment showed that our predictions were false. Temperature of 20 °C was shown as the lowest survival rate, but we suspect that this poor result wasn't caused by the effect of water temperature, but rather by other physical-chemical water parameters which were not controlled. The highest survival rate of embryos in our experiment was at 15 °C. This thesis deals with the prediction of survival rates of marbled crayfish in the Czech Republic as written in the scientific literature and the obtained results refer to the ability in hatched individuals of marbled crayfish to tolerate the natural conditions of low temperatures in the Czech Republic.
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