Caring for Pollinators - Bundesamt für Naturschutz

Hamm Fact sheet pollinators: Hymenoptera
POLLINATOR GROUP:
HYMENOPTERA
Author: ANDRÉE HAMM
Species number
Worldwide: nearly 100.000
Distribution
Virtually in all terrestrial habitats
worldwide. Across from arid
deserts to swamps and from
sub arctic tundra to tropical
rain forests.
Hymenopterans and pollination
Celonites abbreviatus eating pollen from Satyreya thymbra out of
her front tarsus after wiping over her cortex. (Photo: V. Mauss)
The order Hymenoptera (bees, wasps and ants) is characterized by a large number of species
and high diversity regarding biological organisation and behaviour. Hymenopterans diversified
to occupy many terrestrial and semi-terrestrial habitats and also display both diurnal
and nocturnal activity. They use a seemingly endless variety of resources as food. Hymenopterans
can be phytophagous or carnivorous and perhaps most are parasitic and live within
their host during part of the life cycle. Multiple specializations also exist, for example by
adults that visit flowers and also are parasites of other insects.
Many phytophagous species have a narrowly defined relationship to specific plants. They
feed on nectar and pollen or lay their eggs in specific plant parts. During their “residence” in
or on the flowers Hymenopterans often act as pollinators. That partly resulted in complex
adaptations involving not only morphological and behavioural features, but precise responses
to host odors or chemicals. A long history of coevolution between plants, arising
during the Cretaceous, typifies many Hymenoptera. Some examples are the fig trees of the
genus Ficus which depend on one or two figs-wasps (Agaonidae) for pollination. Other examples
are the pollen-wasps (Masarinae) which use pollen for feeding their larvae.
Ants, because of their small body size and smooth integument, lacking hairs that might
transport pollen, only rarely achieve plant pollination. Therefore ants usually are nectar
thieves. Anyway some ants do form a mutualistic relationship with plants and provide for
pollination in an indirect way: they guard flowers and discourage nectar and pollen consumers
that are not pollinators, and also keep the plant free from herbivores.
Bees – with 20.000 or 30.000 species worldwide – contrast greatly with ants: Many are hairy
and have other adaptations for acquiring the pollen they use as food. They are the most important
pollinator group. To a large degree bees are responsible for the preservation of biodiversity
in terrestrial ecosystems (see fact sheet bees).
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