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Sperm competition in frogs in relation to the reproductive strategy
Malečková, Vendulka ; Šandera, Martin (advisor) ; Hortová, Kateřina (referee)
2 Abstract This bachelor thesis focuses the comparison of the various reproductive strategies of frogs and the degree of sperm competition. Frogs are ecologically important group inhabiting all continents except Antarctica and northern polar regions. Frogs have species-specific reproductive strategies. Most frogs have external fertilization, but there are exceptions (eg. Ascaphidae) with internal fertilization. Before mating occurs, male grips female - this is called amplexus. Amplexus is divided into several types according to the place of gripping the female, and there are exceptions that do not use amplexus. Even for them there is a complex behavior, in which the male directs the female to the eggs laying spot. Mating mostly occurs in water. Frogs are polyandrous, meaning that one female mates with multiple males. Such a system encourages the male-male competition, as well as the sperm-competition. Breeding of frogs can be classified as explosive or prolonged. Clutches of eggs are being laid by females into water or foam nests. In some cases the male takes part in taking care of the clutch, nest building, or they steal other clutches. In conclusion, it is discussed whether there is a connection between specific reproductive strategies and levels of sperm competition. Key words: amplexus, clutch-piracy,...
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Sperm competition in frogs in relation to the reproductive strategy
Malečková, Vendulka ; Šandera, Martin (advisor) ; Hortová, Kateřina (referee)
This bachelor thesis focuses the comparison of the various reproductive strategies of frogs and the degree of sperm competition. Frogs are ecologically important group inhabiting all continents except Antarctica and northern polar regions. Frogs have species-specific reproductive strategies. Most frogs have external fertilization, but there are exceptions (eg. Ascaphidae) with internal fertilization. Before mating occurs, male grips female - this is called amplexus. Amplexus is divided into several types according to the place of gripping the female, and there are exceptions that do not use amplexus. Even for them there is a complex behavior, in which the male directs the female to the eggs laying spot. Mating mostly occurs in water. Frogs are polyandrous, meaning that one female mates with multiple males. Such a system encourages the male-male competition, as well as the sperm-competition. Breeding of frogs can be classified as explosive or prolonged. Clutches of eggs are being laid by females into water or foam nests. In some cases the male takes part in taking care of the clutch, nest building, or they steal other clutches. In conclusion, it is discussed whether there is a connection between specific reproductive strategies and levels of sperm competition. Key words: amplexus, clutch-piracy,...
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