The Relation between Flower Traits of Bitter Vetch Landraces and Potential Insect Pollinators’ Visitation

Plant–pollinator interactions research can assist in the development of more ecologically friendly crop breeding methods, leading to enhanced global food security. In the present study, we have aimed to assess fifteen floral traits as insect attractancies of six bitter vetch (Vicia ervilia (L.) Willd.) landraces, a neglected crop. Four traits related to seed yield were also measured. Abundance and foraging behavior of potential insect pollinators on bitter vetch flowers were recorded, and their species were identified. Differences among landraces regarding floral and yield traits were statistically significant in most cases. A total number of four insect species were recorded as positively visiting flowers and constituting potential pollinators of bitter vetch. At a landrace level, there was a positive correlation between potential insect pollinators’ foraging activity and the number of open flowers, especially for the landrace ERV65-Kastania, Korinthia (p ≤ 0.01). Floral tube length, as well as standard petal length, was also positively correlated with potential insect pollinator species abundance and their visitation frequency. A positive correlation was also recorded between seed yield-related traits, which varied among landraces, and potential insect pollinators’ foraging activity. The results showed that bitter vetch flowers can attract and receive positive visits from insects, despite their mainly self-pollination reproductive system. Bitter vetch flower traits, such as the number of open flowers, floral tube length, and standard petal length, could, therefore, be useful as breeding tools, aiming to develop varieties with insect pollinator-friendly traits that could lead to enhanced seed yield production and help to conserve wild insect species biodiversity in the context of sustainable agriculture.