ALIEN PARASITES CO-INTRODUCED WITH INVASIVE BUMBLEBEES, AS A POTENTIAL CAUSE OF THE ECOLOGICAL REPLACEMENT OF BOMBUS DAHLBOMII IN PATAGONIA, ARGENTINA

MARINA PAULA ARBETMAN; CAROLINA LAURA MORALES; MARCELO ADRIÁN AIZEN

Quintay

Conferencia; The Rufford Small Grant Conference South America Chile 2015; 2015

Costa Humboldt/The Rufford Foundation/ Universidad Andres Bello

Invasive species and emerging diseases are major threats to biodiversity. Since the introduction of European bumblebees Bombus ruderatus and B.terrestris into Chile last century, a strong decline of B.dahlbomii is perceived. This is the only native bumblebee species of the temperate forests of southern Argentina and Chile, where plays a key role in the pollination of native flora. We investigated the transmission of parasites from invasive to native bumblebees as a possible cause of this aparent ecological replacement. We recorded during 20 years the abundance of these three species in a forest of NW Patagonia Argentina dominated by Alstroemeria aurea, endemic herb pollinated by bumblebees. In 2011 we recorded the abundance of bumblebees in 33 sites along 1200km on the eastern slope of the Andes, covering the entire latitudinal range of B.dahlbomii in Argentina. We determined the presence of internal parasites by PCR and their molecular identity. We document a substantial reduction of the historic range of B.dahlbomii in Argentina simultaneously with the advance of the invasive bumblebees. We detected a highly pathogenic parasite (Apicystis bombi) in B.dahlbomii that was not detected in Patagonia prior to the arrival of B.terrestris, and which shares a common origin with European variants.This suggests that the invasion of bumblebees have induced the collapse ofpopulations of B.dahlbomii and proposes the transmission of pathogenic parasitesas one of the potential underlying mechanisms. We strongly recommend avoidingthe introduction of non-native species of bumblebees.