Reproductive behaviour and the effects of substrate on the reproduction of annual killifish ( Hypsolebias flagellatus )

Abstract

This work aimed to evaluate two types of substrate for egg production by annual killifish (Hypsolebias flagellatus) and to describe the reproductive behaviour of males and females. Experiment I, with two phases, tested two types of substrates: coconut shell powder (CP) and brown 100% acrylic wool (AW), with five male–female pairs in each treatment. In Phase 1, reproduction was monitored for 45 days. In Phase 2, AW nests were replaced by CP nests and reproduction monitored for another 45 days. Experiment II, with three phases, involved installing a camera and inserting a CP nest in each of five aquariums with one pair in each. Phase 1 began after 5 days of adaptation and involved observing the pairs for 4 days. Phase 2 began on the fifth day with the removal of nests followed by observation for 48 h. In Phase 3, the nests were returned and the pairs were observed for another 4 days. Phase 1 of Experiment I found higher egg production with CP substrate (p < 0.05). In Phase 2, egg production did not differ significantly between treatments (p > 0.05) after AW substrate was replaced by CP. Phase 2 of Experiment II found almost no interaction between the sexes. Both sexes spending most of their time close to the nest (p < 0.05). The frequency of nest entry and exit was higher for males than for females in both Phase 1 and Phase 3 (p < 0.05). The CP substrate showed better results for the reproduction of H. flagellatus than did the AW substrate.