Knowing the Enemy: Inducible Defences in Freshwater Zooplankton

Abstract

Phenotypic plasticity in defensive traits is an appropriate mechanism to cope with the variable hazard of a frequently changing predator spectrum. In the animal kingdom these so-called inducible defences cover the entire taxonomic range from protozoans to vertebrates. The inducible defensive traits range from behaviour, morphology, and life-history adaptations to the activation of specific immune systems in vertebrates. Inducible defences in prey species play important roles in the dynamics and functioning of food webs. Freshwater zooplankton show the most prominent examples of inducible defences triggered by chemical cues, so-called kairomones, released by predatory invertebrates and fish. The objective of this review is to highlight recent progress in research on inducible defences in freshwater zooplankton concerning behaviour, morphology, and life-history, as well as difficulties of studies conducted in a multipredator set up. Furthermore, we outline costs associated with the defences and discuss difficulties as well as the progress made in characterizing defence-inducing cues. Finally, we aim to indicate further possible routes in this field of research and provide a comprehensive table of inducible defences with respect to both prey and predator species.

Induction and reversibility of Ceriodaphnia cornuta horns under varied intensity of predation risk and their defensive effectiveness against Chaoborus larvae

“…Therefore, the importance of such inducible traits is widely considered in various environments (Huang et al., ,,2016, 2018; Lürling & Scheffer, 2007; Riessen et al., 2012; Weiss et al., 2018; Zhu et al., 2019; Zhu, Wang, et al., 2020). Undoubtedly, the present study developed an effective research model to understand the plasticity patterns of an inducible defence trait, which could also provide further implications for the interaction between predators and prey under various environments (Diel et al., 2020).…”

Predators as Agents of Selection and Diversification

“…This work shows how some predators indirectly affect the evolution of prey traits through other selective agents. Diel et al [62] remind us that predators can induce phenotypic defenses in prey species in remarkable ways. They provide a detailed review of inducible defenses in zooplankton, including morphological, behavioral, and life history shifts completely mediated by the presence or absence of predators.…”

Inducible responses to antagonistic predation risks are not in a dilemma: Evidences from multi-traits and transcriptome of Ceriodaphnia

“…Inducible defenses are common in aquatic organisms, such as phytoplankton (Lürling, 2020), zooplankton (Diel, Kiene, Martin-Creuzburg, & Laforsch, 2020), amphibians (Mitchell, Bairos-Novak, & Ferrari, 2017), and fish (Brönmark & Miner, 1992). Through integration of inducible defense researches, the present study classified the responses against multiple predators into two major categories.…”