Maternal effects and parent-offspring conflict.

Maternal effects can provide offspring with reliable information about the environment they are likely to experience, but also offer scope for maternal manipulation of young when interests diverge between parents and offspring. To predict the impact of parent-offspring conflict, we model the evolution of maternal effects on local adaptation of young. We find that parent-offspring conflict strongly influences the stability of maternal effects; moreover, the nature of the disagreement between parents and young predicts how conflict is resolved: when mothers favor less extreme mixtures of phenotypes relative to offspring (i.e., when mothers stand to gain by hedging their bets), mothers win the conflict by providing offspring with limited amounts of information. When offspring favor overproduction of one and the same phenotype across all environments compared to mothers (e.g., when offspring favor a larger body size), neither side wins the conflict and signaling breaks down. Only when offspring favor less extreme mixtures relative to their mothers (something no current model predicts), offspring win the conflict and obtain full information about the environment. We conclude that a partial or complete breakdown of informative maternal effects will be the norm rather than the exception in the presence of parent-offspring conflict.