Volatile organic compounds as behavioural modifiers in Hypera nigrirostris reproductive ecology

The lesser clover leaf weevil (Hypera nigrirostris) is a persistent pest of red clover (Trifolium pratense) seed production. Current management strategies rely heavily on insecticides, which can negatively affect beneficial arthropods, including pollinators and natural enemies. This research explores a sustainable alternative by developing a volatile-based integrated pest management strategy for H. nigrirostris. The objective is to disrupt reproduction by exploiting volatile organic compounds (VOCs) involved in mating and host-plant location. Using olfactometer bioassays, insect responses to red clover plant structures and conspecific volatiles will be quantified. VOCs responsible for behavioural attraction will be extracted via headspace solid-phase microextraction and identified using gas chromatography-mass spectrometry (GC-MS). Candidate compounds will be acquired and tested individually and in blends using olfactometry and electroantennographic detection (GC-EAD) to assess physiological relevance and dose sensitivity. Compounds eliciting strong behavioural and antennal responses will be formulated into synthetic lures for field trials, where their ability to reduce H. nigrirostris populations will be compared to standard insecticide treatments. This research aims to deliver a selective, non-destructive control method that preserves beneficial insect communities and aligns with the increasing demand for environmentally sustainable agricultural practices. Field-scale implementation of pheromone trapping could offer a scalable pest management solution applicable in other red clover seed-producing regions globally. The outcomes will support more targeted pest control while reducing reliance on broad-spectrum chemicals in forage seed systems.