Data from: One fly to rule them all—muscid flies are the key pollinators in the Arctic

Global change is causing drastic changes in the pollinator communities of
the Arctic. While arctic flowers are visited by a wide range of insects,
flies in family Muscidae have been proposed as a pollinator group of
particular importance. To understand the functional outcome of current
changes in pollinator community composition, we examined the role of
muscids in the pollination of a key plant species, the mountain avens
(Dryas). We monitored the seed set of Dryas across 15 sites at Zackenberg,
northeast Greenland, and used sticky flower mimics and DNA barcoding to
describe the flower-visiting community at each site. To evaluate the
consequences of shifts in pollinator phenology under climate change, we
compared the flower visitors between the early and the late season. Our
approach revealed a diverse community of insects visiting Dryas, including
two-thirds of all insect species known from the area. Even against this
diverse background, the abundance of muscid flies emerged as a key
predictor for seed set in Dryas, whereas overall insect abundance and
species richness had little or no effect. With muscid flies as the main
drivers of the pollinating function in the High Arctic, a recently
observed decline in their abundances offers cause for concern.