Caring for Pollinators - Bundesamt für Naturschutz

Ssymank & Kearns Flies – Pollinators on two wings
While some flower – pollinator relationships are highly
specialised, many pollinator
interactions are complex systems usually involving several pollinators. Daily and seasonal
changes in pollinator communities are frequent, especially in plants with long flowering
periods. Plant species with large ranges or cultivated in large areas may have a significant
regional or geographical variation in pollinator communities, and the surrounding landscape
with its features and habitat requisites can play an important role. Many pollinator
assemblages are not well understood or even known, a fact not only true for wild plants but
also for many crops and cultivated plant species.
Fig. 26: The flower fly Chrysotoxum “intermedium”
(aggregate) pollinating the flowers of the tree spurge
(Euphorbia dendroides) on the Maltese islands.
6.
Pollinator decline and research needs
47
Fig. 27: A small and black flower fly (Melanogaster
nuda) with a preference for yellow buttercup flowers
eating pollen on Ranunculus repens.
Our understanding of pollination services is considerably hampered by a lack of some very
basic knowledge. Although some types of fly pollinators have been well studied, as a group,
fly pollination deserves far more research. It is striking how large the gaps in species
knowledge are: probably less than 10% of all Diptera species are named worldwide;
considerable gaps exist even in Europe, where the fauna is generally well documented. For
many groups, even the existing knowledge is not easy to use, as identification keys are
missing.
Fig. 28: Monoceromyia is a flower fly genus with
many afrotropical species, mimicking wasps, and
visiting tropical trees.
Pollination services of flies are underestimated
and functional relations poorly understood. In
the past, much pollination research has focused
on bees, leaving a wide opportunity open for
the study of other pollinator assemblages. A
systematic look at ecosystems without bees
(e.g. on some islands, in high mountains, nordic
or arctic environments) could provide insight
into functional replacements, and into the
evolution of plant and fly adaptations. The
review by Klein et al. (2007) makes it apparent