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© Garden Cottage Nursery, 2011
Plants & Their Insect Pollinators
A Mutually Beneficial Relationship
Insects are the most important biotic pollinators of flowering plants.
Plants have their flowers fertilised, insects get a pollen or nectar reward.
Different animals are sensitive to different wavelengths of light, most insects are able to see well beyond the frequencies of visible light (to
humans) into the Ultra Violet. It is light at these higher frequencies that attract insects most, as such the colours in the visible spectrum are
not hard indicators of likely pollinators but they can still help indicate pollinator types.
So as not to exclude potential pollinators most plants take a generalist approach to attracting pollinators, not specialising too much in
morphology so as to allow as many different potential pollinators access to their flowers. Many others have some degree of adaptation
which may favour certain types of pollinator over others. A few, particularly among orchids, go all out via natural selection & can become
commited to even a single species of pollinator.
Perhaps the most frequently cited example of pollinator specialisation is the Madagascan orchid Angraecum sesquipedale which possesses
incredibly long narrow spurs to the flower at the bottom of which resides the nectar. In 1862 Charles Darwin published a work on orchid
specialisation for pollinators in which he examined this flower, after much experimentation he concluded that to effect pollination of the
flower & for the pollinator to get its nectar reward it would require a moth with a 35cm long proboscis. Many dismissed this as fanciful at the
time but in 1903 the moth which did the job was dually found. You can read more here:
http://en.wikipedia.org/wiki/Angraecum_sesquipedale
Bees
Moths
Butterflies
Flies
Bees respond to generally showy flowers, especially keen on flowers rich in nectar, though
sometimes frequenting those offering a reward of pollen instead of nectar. Yellow & blue
flowers are particularly popular; many have markings guiding the bee like runway lights to
the reward, often this is visible only in Ultra Violet wavelengths of light. Bees are absolutely
vital to our survival in their role as pollinators for many of our food crops. Internationally
bees, both wild types like our familiar bumble bees & commercially bred honey bees are in
drastic decline. There seems to be several factors combining to cause this decline
including disease, parasitism, climate change & insecticide use. By offering as many plants
attractive to bees as possible in your garden you can do your little bit to help your local bee
population. Good bee plants include: Aquilegia, Brunnera, Caltha, Doronicum, Eryngium,
Fuchsia Geranium, Hemerocallis, Iberis, Jasione, Knautia, Lamium, Monarda, Nepeta,
Olearia, Primula, Quercus (oaks, like chestnuts provide pollen rather than nectar),
Rudbeckia (Rhododendron provide tons of nectar for bees but many varieties make the
bees ‘drunk’), Salvia, Thymus, Ulex, Verbascum, Weigela, Xanthorrhoea, Ypsilandra &
Zinnia. An X,Y & Z wasn’t easy to come up with!
Passiflora mollissima the ‘Banana
Passionfruit’ frequented by heavy weight
bumble & honey bees in warmer climates.
Though moths are not major pollinators in the North of Scotland elsewhere they can play
an important role. Hawk moths particularly have quite a lot of flowers evolved to suit them.
Generally flowers for moths are large open, creamy or white, often sweetly or musky
scented in the evening. They are usually pollinated on the wing & are nectar-rich to support
the hawk moths active life-style.
Yucca gloriosa is entirely dependant for
pollination on the yucca moth whose
caterpillar also eats nothing but yucca seeds
Butterflies prefer pink & lavender flowers
often strongly scented with long narrow
tubes to allow the butterflies to get their
long tongues down to the ample nectar.
A few good butterfly plants are: Buddleja,
Calendula, Echinops, Eupatorium,
Echinacea, Hebe, Kniphofia, Lavandula,
Mentha, Sedum & Verbena.
Buddleja 'Lochinch' with its narrow tubed
highly scented nectar-rich flowers has
attracted two red admirals.
There are huge numbers of flies in multitudinous varieties, there a many generalist types that
take advantage of any available food source & this makes them very frequent pollinators of
flowers particularly of non-specialised flowers. Their ubiquity makes them important pollinators
in more extreme environments like alpine regions where there aren’t the range of different
specialised pollinators. Many plants also use trickery to attract to attract pollinators &
particularly flies. Some flowers will produce chemicals that mimic fly pheromones to attract
male flies which will then crawl all over the flower covering themselves in pollen, the plant
hopes the fly will then go to another flower of the same species, falling for the same trick again
& shed some of its pollen on the stigmas of the second flower. Another common method of
duping flies used by plants is to make a flower appear to the fly to be a rotting animal. These
flowers are often red or brown in colour & mottled & put out an irresistible scent of corrupting
meat. A great many aroids (family Araceae) are pollinated by flies, e.g. Arum, Arisaema,
Dracunculus, Lysichiton & the huge & slightly pornographic Amorphophallus titanium. The
worlds largest flower is the Indonesian fly-pollinated parasite Rafflesia arnoldii, it is sometimes
called the ‘corpse plant’.
Sauromatum venosum, the ‘Voodoo Lily’
doing an impersonation of a dead mammal to
fool bluebottles into pollinating it.
Other types of insects act as pollinators in some plant species. Beetles pollinate many Magnolias, amongst the oldest of flowering plants, as
such beetles were amongst the first flower pollinators. European wasps (the normal black & yellow kind people try to swat on sight) adore
Angelica gigas. Figs require certain species of small wasps to pollinate their flowers, there was an excellent BBC Natural World documentary
on the symbiotic relationship between the African sycamore fig & its pollinator wasp Ceratosolen arabicus & their impact on the wider
environment. No doubt will be repeated sometime on the Beeb or on one of innumerable satellite channels.
Arisaema griffithii uses it’s tail-like spadix
appendix to guide flies into inflorescence at
the base of the encircling spathe
© Garden Cottage Nursery, 2011
Plants & Their Insect Pollinators
A Mutually Beneficial Relationship
Insects are the most important biotic pollinators of flowering plants.
Plants have their flowers fertilised, insects get a pollen or nectar reward.
Different animals are sensitive to different wavelengths of light, most insects are able to see well beyond the frequencies of visible light (to
humans) into the Ultra Violet. It is light at these higher frequencies that attract insects most, as such the colours in the visible spectrum are
not hard indicators of likely pollinators but they can still help indicate pollinator types.
So as not to exclude potential pollinators most plants take a generalist approach to attracting pollinators, not specialising too much in
morphology so as to allow as many different potential pollinators access to their flowers. Many others have some degree of adaptation
which may favour certain types of pollinator over others. A few, particularly among orchids, go all out via natural selection & can become
commited to even a single species of pollinator.
Perhaps the most frequently cited example of pollinator specialisation is the Madagascan orchid Angraecum sesquipedale which possesses
incredibly long narrow spurs to the flower at the bottom of which resides the nectar. In 1862 Charles Darwin published a work on orchid
specialisation for pollinators in which he examined this flower, after much experimentation he concluded that to effect pollination of the
flower & for the pollinator to get its nectar reward it would require a moth with a 35cm long proboscis. Many dismissed this as fanciful at the
time but in 1903 the moth which did the job was dually found. You can read more here:
http://en.wikipedia.org/wiki/Angraecum_sesquipedale
Bees
Moths
Butterflies
Flies
Bees respond to generally showy flowers, especially keen on flowers rich in nectar, though
sometimes frequenting those offering a reward of pollen instead of nectar. Yellow & blue
flowers are particularly popular; many have markings guiding the bee like runway lights to
the reward, often this is visible only in Ultra Violet wavelengths of light. Bees are absolutely
vital to our survival in their role as pollinators for many of our food crops. Internationally
bees, both wild types like our familiar bumble bees & commercially bred honey bees are in
drastic decline. There seems to be several factors combining to cause this decline
including disease, parasitism, climate change & insecticide use. By offering as many plants
attractive to bees as possible in your garden you can do your little bit to help your local bee
population. Good bee plants include: Aquilegia, Brunnera, Caltha, Doronicum, Eryngium,
Fuchsia Geranium, Hemerocallis, Iberis, Jasione, Knautia, Lamium, Monarda, Nepeta,
Olearia, Primula, Quercus (oaks, like chestnuts provide pollen rather than nectar),
Rudbeckia (Rhododendron provide tons of nectar for bees but many varieties make the
bees ‘drunk’), Salvia, Thymus, Ulex, Verbascum, Weigela, Xanthorrhoea, Ypsilandra &
Zinnia. An X,Y & Z wasn’t easy to come up with!
Passiflora mollissima the ‘Banana
Passionfruit’ frequented by heavy weight
bumble & honey bees in warmer climates.
Though moths are not major pollinators in the North of Scotland elsewhere they can play
an important role. Hawk moths particularly have quite a lot of flowers evolved to suit them.
Generally flowers for moths are large open, creamy or white, often sweetly or musky
scented in the evening. They are usually pollinated on the wing & are nectar-rich to support
the hawk moths active life-style.
Yucca gloriosa is entirely dependant for
pollination on the yucca moth whose
caterpillar also eats nothing but yucca seeds
Butterflies prefer pink & lavender flowers
often strongly scented with long narrow
tubes to allow the butterflies to get their
long tongues down to the ample nectar.
A few good butterfly plants are: Buddleja,
Calendula, Echinops, Eupatorium,
Echinacea, Hebe, Kniphofia, Lavandula,
Mentha, Sedum & Verbena.
Buddleja 'Lochinch' with its narrow tubed
highly scented nectar-rich flowers has
attracted two red admirals.
There are huge numbers of flies in multitudinous varieties, there a many generalist types that
take advantage of any available food source & this makes them very frequent pollinators of
flowers particularly of non-specialised flowers. Their ubiquity makes them important pollinators
in more extreme environments like alpine regions where there aren’t the range of different
specialised pollinators. Many plants also use trickery to attract to attract pollinators &
particularly flies. Some flowers will produce chemicals that mimic fly pheromones to attract
male flies which will then crawl all over the flower covering themselves in pollen, the plant
hopes the fly will then go to another flower of the same species, falling for the same trick again
& shed some of its pollen on the stigmas of the second flower. Another common method of
duping flies used by plants is to make a flower appear to the fly to be a rotting animal. These
flowers are often red or brown in colour & mottled & put out an irresistible scent of corrupting
meat. A great many aroids (family Araceae) are pollinated by flies, e.g. Arum, Arisaema,
Dracunculus, Lysichiton & the huge & slightly pornographic Amorphophallus titanium. The
worlds largest flower is the Indonesian fly-pollinated parasite Rafflesia arnoldii, it is sometimes
called the ‘corpse plant’.
Sauromatum venosum, the ‘Voodoo Lily’
doing an impersonation of a dead mammal to
fool bluebottles into pollinating it.
Other types of insects act as pollinators in some plant species. Beetles pollinate many Magnolias, amongst the oldest of flowering plants, as
such beetles were amongst the first flower pollinators. European wasps (the normal black & yellow kind people try to swat on sight) adore
Angelica gigas. Figs require certain species of small wasps to pollinate their flowers, there was an excellent BBC Natural World documentary
on the symbiotic relationship between the African sycamore fig & its pollinator wasp Ceratosolen arabicus & their impact on the wider
environment. No doubt will be repeated sometime on the Beeb or on one of innumerable satellite channels.
Arisaema griffithii uses it’s tail-like spadix
appendix to guide flies into inflorescence at
the base of the encircling spathe