Complete Germination Failure of Alcea rosea L. Caused by Rhopalapion longirostre (Olivier, 1807) (Coleoptera: Apionidae): First Experimental Evidence and a New Locality Record from Türkiye

This study provides the first experimental evidence on the effect of seed damage by Rhopalapion longirostre (Olivier, 1807) on the germination success of Alcea rosea L. and reports a new locality record for the species in Isparta (Western Mediterranean region of Türkiye). A total of 68 adult individuals were collected from A. rosea populations and identified based on current taxonomic keys. Seeds obtained from infested plants were separated into damaged and undamaged groups and subjected to controlled germination experiments under laboratory conditions. Thirty seeds per treatment were sown in ten replicate pots and monitored daily. Germination success was evaluated at the pot level to avoid pseudoreplication, and differences between treatments were analysed using Fisher’s Exact Test. No germination was observed in pots containing insect-damaged seeds, whereas germination occurred in 70% of pots with undamaged seeds. The difference between treatments was statistically significant (Fisher’s Exact Test, p < 0.01). These results demonstrate that seed damage caused by R. longirostre can completely suppress germination under controlled conditions, indicating a strong potential impact on host plant regeneration. Although the present findings are based on a single population and experimental setting, they provide quantitative evidence that this monophagous weevil may influence population dynamics of A. rosea. The record from Isparta City Center, extends the known distribution of R. longirostre in Türkiye and suggests a continuing range expansion. The ecological implications of this interaction and its possible relevance for plant population management are discussed. This study provides one of the clear experimental demonstrations that a specialized seed-feeding weevil can entirely suppress host plant germination under controlled conditions.