The induction and reversibility of horns of Ceriodaphnia cornuta under varied intensities of predation risks and their defensive effectiveness against Chaoborus larvae

Inducible defenses are widespread, while, fully understanding the expression and reversion patterns of inducible traits in the fluctuation of predators is still a challenge. By focusing on the inducible horns of <i>Ceriodaphnia cornuta</i>, the present study tested the induction and reversibility of horns under varied predation density. Additionally, we measured the defensive effectiveness of induced horn formation. Our results revealed horns of <i>Ceriodaphnia</i> could be an effective inducible defensive trait against <i>Chaoborus</i> larvae predation. Furthermore, the responsive time, rate, and intensity during the induction and reversion were well acclimated to increasing predation risks. The present study will contribute to our understanding of the relationship between predators and prey in heterogeneous aquatic environments.