Attractiveness of fresh and aged fermented baits for Noctuidae moths and temporal changes in their volatile profiles

Semi-synthetic bisexual lures (SBL) based on the combination of synthetic attractant and red wine are widely used for monitoring noctuid moths because they attract both females and males and provide community-level information. However, their attractiveness is known to decline over time, and the mechanisms underlying lure ageing effects remain poorly understood. Here, we investigated how ageing alters the volatile profile of SBL and how these changes affect trap catches of target noctuids and non-target organisms in field conditions. Field trapping experiments compared fresh and four-week-old SBLs with a fully synthetic lure and unbaited controls during the main summer and autumn flight period. In parallel, the temporal changes in volatile emission were analyzed using gas chromatography – mass spectrometry (GC-MS) and antennal responses of selected noctuid species and a non-target dipteran were explored using gas chromatography electroantennographic detection (GC-EAD). Fresh SBL yielded the highest overall catches of Macroheteroceran moths but also attracted substantial numbers of non-target taxa. Ageing resulted in a marked decline in trap catches, together with pronounced shifts in volatile composition, characterized by the loss of short-chain esters and the relative enrichment of heavier compounds. Despite the reduced attractiveness, aged SBL continued to capture noctuid moths effectively, while non-target attraction was decreased. Community-level analysis showed no difference in Macroheteroceran species composition among lure types, indicating that ageing primarily affected activity levels rather than altering catch composition. Indicative GC-EAD recording revealed large overlapping antennal sensitivity to fermentation-related volatiles among tested noctuid species, suggesting that shared olfactory responses may contribute to the observed patterns. Together, these findings highlight opportunities to optimize bait replacement schedules and to develop more selective synthetic blends that balance trapping efficiency with reduced non-target by-catch.