Non-consumptive effects of a predatory mite volatile: Dimethyl trisulfide disrupts mating, oviposition, and ovarian development in Phthorimaea operculella.

BACKGROUND

Predator-derived chemical cues suppress pest reproduction through non-consumptive pathways and may be exploitable as semiochemicals in integrated pest management. We evaluated the volatile organic compounds (VOCs) emitted by the predatory mite Pyemotes zhonghuajia, for their inhibitory effects on reproduction in the potato tuber moth (Phthorimaea operculella, PTM).

RESULTS

Screening of 34 mite-associated VOCs identified dimethyl trisulfide (DMTS) as the strongest oviposition suppressor. In dose-response assays, DMTS reduced egg-laying (>80% at 0.9 mg mL-1), shortened the oviposition period (from 5.09 to 1.86 days at 0.9 mg mL-1) and decreased female longevity (from 13.48 to 4.80 days), but did not affect the pre-oviposition period. DMTS exposure also lowered mating frequency without affecting copulation duration, thereby compounding fecundity reduction. Offspring from exposed parents hatched slightly earlier (4.00 versus 4.32 days), showed prolonged larval development (14.44 versus 13.61 days), and exhibited higher food consumption (1.66 versus 0.83 g). Ovarian dissections revealed fewer mature oocytes, consistent with inhibited oocyte maturation.

CONCLUSION

DMTS disrupts PTM reproduction by suppressing oviposition and mating, and inhibiting ovarian maturation, with additional, modest carry-over effects on offspring development. These findings support DMTS as a promising predator-derived semiochemical for sustainable PTM management. © 2026 Society of Chemical Industry.