In temperate climates, bumblebee colonies typically persist for a single season, with their life span averaging 3 to 6 months depending on the species. However, certain bumblebee species exhibit bivoltinism, producing two generations within one season. This study investigates the seasonal food availability and its impact on the number of Bombus terrestris generations on Lesvos Island. Data were collected across 16 locations, categorized into forests, olive groves, abandoned fields, and coastal areas, conducted over nine weeks in winter (October 2020 to January 2021) and nine weeks in spring (March to May 2021). The emergence of the queens at early October and at the end of March indicates the presence of two distinct generations annually. The winter generation is sustained mainly by Arbutus unedo flowering in forested areas, which exhibited significantly higher bumblebee activity compared to other habitats. Also a correlation test showed that there is no significant correlation between temperature and bumblebee activity. This study highlights the ecological flexibility of B. terrestris and its potential adaptation to Mediterranean conditions.

Bivoltinism, Bombus terrestris, ecological flexibility, Lesvos Island, Mediterranean, pollinators, seasonal food availability