This study describes the reproductive behaviour of silver bream, Blicca bjoerkna, in an aquarium environment with hormonal injection, constant temperature and natural photoperiod conditions. The results revealed that the reproductive behaviour of silver bream was polyandrous with courting tactics including a high level of tactile stimulation and following behaviour developed by the males, but without territorial or aggressive acts. The individual participation of males in mating acts showed a significant positive correlation with the individual participation of males in following a female. A successful spawning act included trembling movements and violent splashing while eggs and sperm were released on plants. The female mated with one to five males without an active inter- and intra-sexual selection.
The effects of temperatures of 15, 20, 25 and 30°C on the duration of premating and preoviposition periods of Harmonia axyridis reared on the aphid Aphis fabae, were compared in the laboratory. The course of oviposition was monitored at 25°C in females reared on Aphis fabae and the peak of egg laying was recorded at the age of 15 to 45 days. The size of egg groups (batch size), as well as daily and total fecundity was recorded. Half of the total number of eggs was laid in batches of 10-30 eggs. The mean daily and total fecundity reached a maximum of 42 and 1,641.6 eggs, respectively. Adult females oviposited for almost their entire life.