Ana Belén Abelaira, María del Carmen Reche, Amador Rodríguez-Gómez, Virginia Balanza, Pablo Bielza
BACKGROUND: The performance of biological control agents (BCAs) is strongly influenced by environmental factors, particularly temperature. In protected crops, Orius laevigatus is widely used to control Frankliniella occidentalis, yet its establishment is often limited by suboptimal temperatures in early-season greenhouse conditions. In this study, we explored the potential of artificial selection to improve cold tolerance in O. laevigatus by exploiting natural genetic variation in early fecundity among 29 wild and commercial populations. RESULTS: Two selection lines (Cold I and Cold II) were developed by selecting females with the highest fecundity at 17 °C and rearing them for multiple generations at 15 °C. Both selected lines showed a significant increase in reproductive performance at low temperature, nearly doubling their mean daily fecundity compared to the commercial strain Agrobio. In addition, the selected lines demonstrated improved survival and shorter development time at both low (15 °C) and high (35 °C) temperatures, indicating enhanced thermal tolerance at both extremes. Interestingly, selection for cold tolerance also resulted in increased adult body size in both sexes, a trait linked to higher fecundity and predation efficiency. These correlated improvements suggest a possible physiological link between thermal tolerance and overall fitness. CONCLUSION: Our results demonstrate that artificial selection is a viable strategy to enhance key adaptive traits in BCAs. The cold-selected O. laevigatus lines offer promising advantages for augmentative biological control, particularly under challenging temperature conditions that limit the efficacy of standard commercial strains. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.