This video says about itself:
Platanthera chlorantha is pollinated by night-flying moths. This Treble-bar (Aplocera plagiata, Geometridae) stayed for quite a long time on the same flower spike, inspecting the flowers for nectar. Eventually it retreated with a pollinarium sticking to its proboscis.
Platanthera chlorantha orchids and related species grow, eg, in the southern Netherlands.
Bees are often seen as the main insect pollinators and as they are certainly playing a very important role in pollinating many plants we should not forget all the flies; many of them will visit flowers for pollen and nectar as well: here.