Caring for Pollinators - Bundesamt für Naturschutz

Ssymank & Kearns Flies – Pollinators on two wings
Other flies visit flowers to lay eggs, and the larvae feed on the flower heads or the
developing fruits and seeds. Plants with carrion flowers deceive flies into visiting and
effecting pollination by providing a scent and appearance that mimics the carcasses where
these types of flies normally lay their eggs.
In cold, arctic and alpine habitats, some flowers attract flies by providing a warm shelter.
Flies bask in the warmth, which can be more than 5 degrees C warmer than the ambient
temperature (Luzar and Gottsberger 2001). This keeps their flight muscles warm, and allows
them to fly at temperatures that would thwart most bees. Their movement between flowers
results in pollination.
Flowers can also serve as rendezvous sites for mating. Large numbers of flies will
congregate at a particular type of flower, and the byproduct of their behavior can be
pollination.
Fig. 12: Stapelia hirsuta, carrion
flower
3. Cultivated plants pollinated by flies
Fig. 13: Plecia nearctica, Bibionidae
– “love bug” flies on Solidagoflowers.
Fig. 14: Muscoid fly on Linum
lewisii
More than 100 cultivated crops are regularly
visited by flies and depend largely on fly
pollination for abundant fruit set and seed production (Ssymank et al. 2008). In addition a
large number of wild relatives of food plants, numerous medicinal plants and cultivated
garden plants benefit from fly pollination. Klein et al. (2007) reviewed the literature for crop
pollination and concluded that 87 out of 115 leading global food crops are dependent on
animal pollination. They present a table of pollinators for those crops where this information
is known. For thirty crop species flies are listed as pollinators and visitors (with 14 cases
referring to flower flies, Syrphidae).
This result certainly underestimates the importance of fly pollination for two major reasons:
first pollination studies focus mainly on bee pollination, second the literature and data on fly
pollination are much more dispersed and often published in smaller journals with less
complete indexing. From just my own non-systematic field data (Ssymank) we could add at
least 12 crop species which are visited or partly pollinated by flower flies, such as Fagopyron
esculentum (18), Mangifera indica (6), Prunus spinosa (35), and Sambucus nigra (24;
number of fly species known to visit in brackets).
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