Transgenerational Plasticity in the Context of Predator-Prey Interactions

Abstract

Almost all animal species are engaged in predator-prey interactions. These interactions, variable in time and space, favor the emergence and evolution of phenotypic plasticity, which allows prey to fine-tune their phenotype to the current risk of predation. A famous example is the induction of defensive neck-teeth, spines or helmets in some water fleas when they detect cues of predator presence. In general, the response may involve different types of traits (behavioral, morphological, physiological, and life-history traits), alone or in combination. The induced traits may be adaptive anti-predator defenses or reflect more general stress-based responses. Recently, it has been found that predator-induced plasticity occurs not only within but also across generations (transgenerational plasticity), i.e., the phenotype of a generation is influenced by the detection of predator-cues in previous generation(s), even if the current generation is not itself exposed to these cues. In this paper, we aim to review this accumulating literature and propose a current state of key aspects of predator-induced transgenerational plasticity in metazoans. In particular, we review whether patterns of predator-induced transgenerational plasticity depend on the type of traits. We analyze the adaptive value of predator-induced transgenerational plasticity and explore the evidence for its evolution and underlying mechanisms. We also consider its temporal dynamics: what are the time windows during which predator-cues must be detected to be transmitted across generations? Are transgenerational responses in offspring stage-dependent? How many generations does transgenerational plasticity persist? Finally, we discuss other factors highlighted in the literature that influence predator-induced transgenerational plasticity: what are the relative contributions of maternal and paternal exposure to predator-cues in generating transgenerational plasticity? Do transgenerational responses depend on offspring sex? Do they scale with the perceived level of predation risk? This review shows that we are only at the beginning of understanding the processes of predatorinduced transgenerational plasticity, and it encourages future research to fill the lack of knowledge highlighted here.

Feedbacks between size and density determine rapid eco-phenotypic dynamics

“…While previous studies found that phenotypic change often lags behind ecological rates of change (e.g., )), our results clearly show that phenotypic change not only occurs well within ecological timescales, but may even precede-and causally influence-those dynamics (Fig 2c). Our results thus emphasize the need to further study and understand the ecological consequences of rapid plastic phenotypic change (Yamamichi, Yoshida & Sasaki 2011;Tariel, Plénet & Luquet 2020), as plasticity may play a crucial role in determining the fate of networks of species interactions in a warming world (Barbour & Gibert 2021;Jacob & Legrand 2021).…”

Combining information from parental and personal experiences: Simple processes generate diverse outcomes

“…situations in which exposure to cues for parents have different effects on the trait values of their offspring, depending on the age at which those exposures occurred in the parents, or the age at which the offspring received the information from their parents (e.g. [31,33,43]). However, at this point it is unclear how sensitive periods of parents, offspring or both might interact to affect offspring estimates of conditions in the external environment.…”

“…However, this assumption is often violated in experimental studies of TWP. For instance, of the 13 experimental studies of TWP in response to cues from predators listed in a recent review [ 31 ], the duration of exposure to the cues for parents and for their offspring differed in 11 of them. Hence, one important question is whether and how different durations of exposure to the same cues in parents and offspring might contribute to differences among the offspring in their information-states at the end of experimental studies of TWP.…”

How basic components of information-updating interact to encourage variation in the results of empirical studies of within and transgenerational plasticity

“…situations in which exposure to cues for parents have different effects on the trait values of their offspring, depending on the age at which those exposures occurred in the parents, or the age at which the offspring received the information from their parents [e.g. 26,30,41]. However, at this point it is unclear how sensitive periods of parents, offspring or both would interact to affect offspring estimates of conditions in the external environment.…”

“…This assumption is frequently violated in experimental studies of TWP. For instance, of the 13 experimental studies of TWP in response to cues from predators listed in a recent review [26], the duration of exposure to the cues for parents and for their offspring differed in 11 of them. Hence, one important question is whether and how different durations of exposure to the same cues in parents and offspring might contribute to differences among the offspring in TWP experiments in their information states at the end of these experiments.…”