Analyzing historical plant-pollinator interactions by conducting pollen metabarcoding on museum specimens of German bumblebee species

点击翻译按钮获取中文摘要

More than 35 nonparasitic pollen collecting bumblebee species occur in Germany, 20 percent of which are important pollinators and 16 are rare or threatened with extinction. Many bumblebee species populations have dramatically declined in recent decades primarily due to land use changes and changes in agricultural practices. Historical analyses of host plant use from natural history collections by microscopic identification of pollen contained on the bodies of wild bees from the Netherlands, Belgium and Britain revealed the decline of preferred host plant species to be the main driver for wild bee decline (Kleijn and Raemakers 2008, Scheper et al. 2014). DNA metabarcoding analyses currently allows for enhancing the pollen identification process with higher resolution and in more depths (Pornon et al. 2016). Our aim is to make efficient novel use of this by using and optimizing DNA-metabarcoding technologies for pollen identification on all German bumblebee species across three time periods (before 1950, between 1950-1980, after 1980, indicative of major shifts in agricultural practices). An interdisciplinary project involving zoologists, botanists and ecologists will (i) enhance the current software used for pollen DNA-metabarcoding to reduce method-related biases (ii) improve accuracy of taxonomic assignments through multiple marker usage, (iii) analyze foraging preferences of common and rare German bumblebee species in a retrospective manner by sampling from natural history collections, and (iv) evaluate if plant availability is the potential driver of twentieth century bumblebee population trends and could serve as an explanation of current species rarities or abundances.