<I>Bombus</I>

The rapid decline in bumblebee populations within Europe has been linked to habitat loss through agricultural intensification, and a consequential reduction in the availability of preferred forage plants. The successful introduction of four European Bombus species to the South Island of New Zealand from England (in 1885 and 1906) provides an opportunity to determine how important different forage plants (also introduced from the U.K.) are to two severely threatened European bumblebee species (Bombus ruderatus and B. subterraneus).

Banana passionfruit (Passiflora tripartita var. mollissima) is an invasive vine in New Zealand where it lacks its natural hummingbird pollinator. We investigated the mating system and reproductive traits that facilitate its spread in the Marlborough Sounds. Flower observations revealed that visitors were almost exclusively introduced honeybees and bumblebees, indicating an invasive mutualism.