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Abstract

This diploma thesis focuses on the freshwater cyclopoid copepod Macrocyclops albidus. Since not much is known about potential mating preferences in this species, first of all I investigated whether any of the sexes exhibits mating preferences towards the other sex. As body size is a signal used by many animals of both sexes to assess the quality of a potential mate, this trait was used as an indicator for male and female quality in mating contests, in which mate choice and mate competition could interact. When a single female was put together with two males of different body size, then the femal mated in significantly more trials with the larger male. When a single male was put together with two females of different body size, then the males mated same often with the large and the small female. In further experiments the effect of body size and carotenoid content of males on female mate choice were studied. Females preferred larger males as well as males that contained a higher carotenoid amount. As females mate only once and males can mated several times there might be strong selection on females to maximise their benefits on each reproductive attempt, and one way to do this is to exert mate choice preferences.