{"id":5326,"date":"2019-12-04T10:57:09","date_gmt":"2019-12-04T10:57:09","guid":{"rendered":"https:\/\/www.naturepl.com\/blog\/?p=5326"},"modified":"2019-12-05T10:35:19","modified_gmt":"2019-12-05T10:35:19","slug":"pollination-partnerships","status":"publish","type":"post","link":"https:\/\/www.naturepl.com\/blog\/2019\/12\/04\/pollination-partnerships\/","title":{"rendered":"Pollination Partnerships"},"content":{"rendered":"

Pollination Partnerships by Heather Angel<\/h3>\n

Heather Angel has spent much of her long career in professional photography investigating and documenting the fascinating adaptations of both animals and plants. Tim Harris asked Heather to tell us more about her fascination with the subject of plant pollination. Heather also reveals the stories behind some of her favourite pollination images, many of them revealing intriguing pollination partnerships. A wider selection of her work can be viewed in our new gallery of her pollination images<\/a>.<\/p>\n\"\"\n

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Not all plant visitors are pollinators<\/h4>\n

Spotting an insect (or any animal) feeding on a flower does not prove they are pollinators; for instance a butterfly with outstretched wings could be sunbathing. It helps if an image captures which part of the body picks up pollen, so the camera angle is crucial.<\/p>\n

Bee-flies often hover as they feed on nectar. Viewed head-on a large bee-fly (Bombilius major<\/em>) withdraws its pollen-laden proboscis from an honesty flower. Unlike butterflies, bee-flies fly with the proboscis outstretched, so much of the pollen is transferred to the next flower it visits.<\/p>\n

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Day gecko lapping nectar<\/h4>\n

A day gecko (Phelsuma<\/em> sp.) laps up nectar from a crown of thorns (Euphorbia<\/em> sp.) in Madagascar. I spotted it outside a restaurant but it scuttled round to the back of the flower. After each course, I nipped out, with no luck after the starter and main course. Finally, I was rewarded after my dessert, capturing the gecko with its the red tongue feasting on nectar!<\/p>\n

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Pollen pick-up on butterfly wings<\/h4>\n

A Chinese peacock butterfly (Papilio bianor<\/em>) sips nectar from a hibiscus flower in Yunnan, China. The position is maintained by flapping the wings, which pick up pollen on the underside from the stamens placed on the end of a long column.\u00a0 Butterflies that visit flowers with a narrow tube to access the nectar may pick up pollen on their proboscis. A green praying mantid lurks on the right…<\/p>\n

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Drone fly upside down on snowdrop<\/h4>\n\"\"\n

Winter flowers with rewards \u2013 including snowdrops \u2013 are visited by pollinators, but only on fine days with little wind and temperatures above 0\u00b0C.\u00a0 Insect visitors include drone flies (shown here), honeybees and bumblebees, which hang on upside-down. When the proboscis or a leg touches the open end of any of the six anthers, orange pollen falls onto their undersides.<\/p>\n

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SPP – Secondary pollen presentation<\/h4>\n

Exposed pollen on the petal edges of a newly opened St Helena ebony (Trochetiopsis ebenus<\/em>) is a surprising sight. Known as secondary pollen presentation (SPP), it occurs when pollen from the anthers is transferred to another part of the flower in the bud stage. Here, the anthers face outwards and release pollen onto the petal margins before the bud opens. This makes it more accessible to small insects alighting on open flowers. Once the flower opens the pollen does not last long, especially if wind buffets the flower around. SPP is not uncommon in the Campanulaceae family.<\/p>\n\"\"\n

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Rare red nectar<\/h4>\n

Red nectar is not commonly seen in flowers. I first saw it in Hawaii, when I upturned the bell of a Mauritian bloody bellflower (Nesocodon mauritianus<\/em>)<\/span>. Back in the 1970s a single population of the bellflower was discovered on a cliff beside a waterfall. Some years later, the species was propagated from seed at the Royal Botanic Gardens Kew. The natural pollinator is a native gecko (Phelsuma ornata<\/em>) that lives in the cliffs nearby.<\/p>\n

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Dual-tasking bees<\/h4>\n

The Californian tree poppy (Romneya<\/em> coulteri<\/em>) has large white petals and a huge cluster of stamens.\u00a0 Female leaf cutter bees (Megachile centuncularis<\/em>) have special pollen-collecting hairs (scopa) on the underside of their abdomen.\u00a0 This bee is dual-tasking by collecting pollen and pollinating the flower as it perches atop the stigmatic disc.\u00a0 In the foreground, a dead head hoverfly (Myathropa<\/em> florea<\/em>) also feeds on pollen.<\/p>\n

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Some flowers use deceitful mimicry<\/h4>\n

Some flowers are deceitful by mimicking a reward that does not exist.\u00a0 Small begonias (Begonia semperflorens<\/em>), common as bedding plants, have stigmas in female flowers that look like a mass of yellow pollen-laden stamens. But they are fake.\u00a0 Nonetheless, they lure pollinators which, if carrying pollen, land on them and effectively pollinate the flowers. However, they are unlikely to pay a return visit once they realise they have been duped!<\/p>\n

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The embrace of the hoverfly<\/h4>\n

A marmalade hoverfly (Episyrphus balteatus<\/em>) steadies its body by resting all six legs on the stamens of viper’s bugloss (Echium vulgare<\/em>) in the Italian Dolomites. It then wraps the proboscis round an anther to feed on the blue pollen.<\/p>\n

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Cyclamen buzz-pollination<\/h4>\n

Cyclamen flowers are buzz-pollinated by bumblebees. Here, high speed flash in a studio captures pollen release from a pore at each anther tip, triggered by mechanical vibration, which replicates sonication by a bumblebee. The upside-down flower, with upswept petals and the opening at the base, protects the pollen from rain damage.<\/p>\n

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Nocturnal pollinators<\/h4>\n

Photographing pollinators at night is more difficult than by day.\u00a0 A head torch with an optional red light for finding and focusing on insects is preferable to white light, which disturbs many moths.\u00a0 The camera angle is key, preferably showing a moth\u2019s proboscis inserted into the flower. A macro flash lighting set-up is ideal.\u00a0 Here, an angle shades moth (Phlogophora meticulosa<\/em>) is nectaring on snowberry (Symphoricarpos<\/em> x chenaultii<\/em>).<\/p>\n

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How foxgloves and bees work together<\/h4>\n

As a female wool carder bee (Anthidium manicatum<\/em>) enters a rusty foxglove (Digitalis ferruginea<\/em>) flower in a Surrey garden, pollen transfers to the head from anthers, just beneath the upper lip of the flower. Male bees often cruise around these flowers looking for a potential mate, sometimes landing on a female and knocking her off onto the ground.<\/p>\n

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Honeybee feeding frenzy<\/h4>\n

A feeding frenzy of honeybees pull stamens free to access pollen from Magnolia grandiflora<\/em> flowers. In the USA the pollinators of this tree are beetles and the magnolia controls when the insects enter and leave the flowers. They open at dusk when a sticky lemony secretion amongst receptive stigmas attracts the beetles; pollen from incoming insects is deposited on the stigmas. \u00a0The flowers then close, trapping the beetles inside. \u00a0During the night, the anthers start releasing pollen. In the morning the flowers open, so the beetles escape carrying a fresh pollen load on their sticky bodies. In Surrey, honeybees converge on the fallen stamens and collect pollen without aiding pollination.<\/p>\n\"\"\n

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Wasp with pollen load<\/h4>\n

The purple stamens of Spanish love-in-the mist (Nigella hispanica<\/em>) mature before the stigmas. When the flowers open, both stamens and styles are upright.\u00a0 Gradually, the stamens bend down, so the anthers lie in a horizontal plane. Honeybees and wasps circumnavigate to sip nectar from the ring of turquoise and white nectaries. Their bodies just fit below the anthers that swipe across their back, depositing pollen on their hairy bodies. A few days later, the stigmas bend down sequentially, ready to pick up pollen from bee or wasp bodies.<\/p>\n

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Ultraviolet light shows slipper flower’s pollination strategy<\/h4>\n

Darwin’s slipper flower (Calceolaria uniflora<\/em>) occurs in Tierra del Fuego, Chile. Instead of pollen or nectar as a reward, this flower has a sweet fleshy white lip. The pollinator is the least seedsnipe. As a bird walks to a flower and bends to pluck off the sweet lip, pollen transfers from the two stubby stamens onto the bird\u2019s head.\u00a0 In UV light, the focus stack clearly shows the lower lip and two stamens with exposed pollen that both reflect UV, with the rest absorbing UV. This highlights the position of the lip very clearly.<\/p>\n\"\"\n\"\"\n

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Many of Heather’s pollination images feature in her book Pollination Power<\/em>,\u00a0 published by Chicago University Press with Royal Botanic Gardens Kew. We’ve created a new gallery featuring\u00a0 many bookplate images<\/a> and illustrating pollinations partnerships, as well as some brand new material. Here is a taster of some of the bird pollinators illustrated:<\/p>\n