Dietary restriction induces persistent multigenerational phenotypic effects in Phytoseiulus persimilis

Transgenerational phenotypic plasticity (TGP) allows environmental effects to persist across generations, yet the extent of diet-induced TGP remains incompletely resolved. Prey availability is a key determinant of predator performance in both mass-rearing and field environments, potentially influencing the reliability of pest suppression. Here, we examined how ancestral dietary restriction affects life-history traits in the predatory mite Phytoseiulus persimilis, a widely used biological control agent of the two-spotted spider mite Tetranychus urticae.

Founding (F₀) and first-generation (F₁) individuals were reared under low- or high-prey diets, followed by three generations (F₂-F₄) under abundant prey to simulate recovery. In F₄, individuals from high-prey ancestral lineages exhibited higher survival and larger body size, although size effects were restricted to females. In a second experiment, F₅ offspring from crosses manipulating maternal and paternal ancestral diet histories and paternal mating history showed that maternal diet consistently influenced egg size, female developmental duration, and size at maturity. Paternal effects were context-dependent, interacting with maternal lineage and mating history to affect offspring traits.

Poor ancestral diet can exert persistent, sex-specific effects on predator performance even after multiple generations of favorable conditions, with maternal influences generally stronger than paternal effects. These findings highlight the complexity of TGP and the importance of considering multigenerational dietary legacies in mass-rearing and field deployment of predatory mites. Optimizing diet during rearing and accounting for ancestral nutritional history may enhance the consistency and effectiveness of biological control programs. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.