Induction and termination of diapause in Orius predatory bugs

Abstract

AbstractPhotoperiodic induction of reproductive diapause at 18 °C was investigated in four Orius [Heteroptera: Anthocoridae] species. Orius insidiosus (Say) displayed a long‐day response with a critical photoperiod between L11:D13 and L12:D12. Diapause in this species was terminated rapidly when the temperature and/or the daylength were increased. Orius majusculus (Reuter) also displayed a long‐day response. The critical photoperiod fell between L14:D10 and L16:D8. Diapause in this species was not terminated within 14 days when both temperature and daylength were increased. In Orius albidipennis (Reuter) no diapause could be induced at photoperiods varying from L8:D16 to L16:D8. In Orius tristicolor (White) a high proportion of diapause was found at all photoperiods tested.The effect of temperature on photoperiodic induction of diapause was studied in O. insidiosus at L10:D14. Diapause occurred at 18 °C, 21 °C and 25 °C, but not at 30 °C. Again, diapause was terminated rapidly after transfer to 25 °C/L16:D8. Exposing only the nymphal instars 1–5 to short daylength was not enough to induce diapause in the whole population of O. majusculus. Orius predatory bugs are used as biocontrol agents against western flower thrips, Frankliniella occidentalis (Pergande) [Thysanoptera: Thripidael, in greenhouses. The consequences of photoperiodic induction of diapause for the success of early season releases of Orius are discussed.