Bougainvillea - A Favorite Flower with a French Imperialist Name

 

A Crested Antillean Hummingbird came to collect nectar from a Bougainvillea flower.

During dry times, the Bougainvillea bushes we planted in our yard usually manage to stay colorful and attractive, though this summer has been particularly challenging. They were recommended to us years ago as new homeowners for being both drought-resistance and decorative. I enjoy them also for the birds and insects they bring to the yard when they are flowering.      

 

I soon learned that the colorful parts are not flowers, but are called ‘bracts’. These are specialized leaf structures that assist plants in reproduction. For Bougainvillea plants, the papery bracts surround and protect the small white flowers, while helping to attract birds and insects as pollinators.

 

A Bananaquit stretched precariously past the bracts to reach the tiny white flower. 

 

Once we had a few plants, it was easy to start new ones from cuttings. Over the years, we lost some to hurricane damage and erosion, but others have grown profusely and threaten to obstruct the walkway. One negative is that their stems have hard, sharp thorns and can scratch badly when I try to cut them back.     

 

Although Bougainvillea sap is mildly toxic, a Pearly-eyed Thrasher enjoyed nibbling on its bracts and leaves. 

 

I had read that these plants were named after a French explorer, Louis-Antione de Bougainville. Then this summer his name came up in connection with naval battles during the so-called French and Indian War in North America. From 1756 to 1763, England and France were struggling for control over land and trade in the colonies, and at least one of my ancestors in Maine fought with the British in that war. Meanwhile, some of the Indigenous people fought alongside the French, apparently viewing them as less inclined to remove the native inhabitants from their ancestral lands. 

 

The French were ultimately defeated. They were forced to give up their colonial claims in North America, along with control over the islands of Saint Vincent and the Grenadines, Dominica, Grenada and Tobago in the Caribbean. 

 

Despite the French military failure, during the war Bougainville had an opportunity to develop significant skills in naval navigation. Afterwards, in 1766, King Louis XV agreed to send him on a mission to circumnavigate the globe. Bougainville set off to search for alternative lands for potential colonies in places not yet claimed by another European country. The French were hoping to restore their national pride – and find new sources of wealth. Bougainville did lay claim to several islands in the south Pacific, including Tahiti, in what became known as French Polynesia. 

 

Bougainville’s naval expedition was the first to include an official botanist, Philibert Commerson, with a mandate to search for plants that could become useful for medical and economic advancements.

 

The botanist’s assistant on the voyage was eventually revealed to be a woman that he was involved with, Jeanne Baret. She had been disguised as a man because at that time women were not allowed on ships, in the belief that they brought bad luck. After he became ill, it seems that she was the one who did most of the specimen collecting. 

 

The flower now known as Bougainvillea is native to the tropical forests of South America, and was found near Rio de Janeiro. There is no record of what the people who lived there called it.

 

Bougainvillea flowers are favorites of Long-tailed Skipper butterflies, whose native range includes South America, as well as the Caribbean.

 

One author, Glynis Ridley, suggested that Baret was familiar with medicinal plants in France, and was hoping to find a possible cure for Commerson’s illness when the bright bracts caught her eye. According to the ancient ‘doctrine of signatures’ the shapes and colors of plants can provide signals indicating their potential medicinal uses. Sadly, nothing Baret collected was able to cure Commerson. They left the ship in Mauritius during the return voyage and he died not long afterwards. The plant specimens remained onboard and were brought back to France by Bougainville, who later wrote a report on his travels and discoveries. A number of species ended up carrying his name, but only one became world famous.     

 

Over time, Bougainvillea plants were introduced and cultivated in hot, tropical locations around the world. 

 

The bright Bougainvillea flowers attract Caribbean tailless swallowtail butterflies. 

 

Many other types of plants and trees were also collected and relocated by Europeans during the so-called ‘Age of Discovery’. In the years after Bougainville’s circumnavigation and colonial claims, botanical exploration and long-distance transfers of plants became critical elements of European empire building. Labor-intensive commercial cultivation of plants such as coffee, tea, sugar cane, spices, tobacco and cotton led to the establishment of large-scale plantation systems around the world as the basis for colonial economies. 

 

A European Honeybee delicately probed a Bougainvillea flower. 

 

While the Bougainvillea bracts and flowers have been used in some parts of Asia and Africa to make teas to treat respiratory or digestive problems, the plants seem to have been valued primarily for their looks and drought-resistance. They are mostly sold for ornamental use in gardens, delighting both pollinators and people generally unaware of their links to a global history of imperialism.

 

Native Flowers Cheat Pollinators Out of Rewards

 

Butterfly Orchids are attractive but not so sweet inside.

What if these delicate beauties are really deceitful posers?

 

Stopping for a moment to notice the local flowers always makes me smile, even though I know that they are not really showing off for my benefit. The shapes and colors and fragrances of flowers are mostly meant to attract insects and birds that can transfer pollen from one flower to another, thereby enabling the plants to gain the advantages of cross-pollination. The evolutionary deal is supposed to be a mutually beneficial relationship, with the pollinators getting food in exchange for reproductive services. However, nothing is ever so simple.  

 

Recently I reported on some of the birds and bees that get food from flowers for free by poking holes directly into the nectar sacs, without going inside the flowers and providing pollination services in exchange. 

 

Now I am getting some feedback from pollinators about the cheating behaviors of the flowers themselves. The biggest complaint is that some flowers look good, and smell sweet, but don’t have any nectar inside. 

 

From the plant’s perspective, it takes a lot of effort to produce nectar to feed the pollinators. The chlorophyl-containing cells in their leaves can produce sugars through photosynthesis, absorbing sunlight to provide the energy needed to break down water and carbon dioxide and then synthesize glucose. That’s a complicated procedure, though. 

 

If an energy-conserving plant really needs cross-pollination to reproduce successfully, it might try to save its strength by relying on flashy colors and cheap scents rather than nectar to draw in the pollinators, thereby tricking them into doing the work without any food in exchange. The energy the plants save by not having to make nectar for pollinators can otherwise be spent on plant growth and maintenance, seed production, and other important activities.

 

The no-nectar deception generally works best on young ‘naive’ pollinators, because eventually most hungry pollinators will catch on and avoid those cheating flowers. 

 

One deceitful type of flower in my yard is the delicate Psychilis macconnelliae, which is native only to the Virgin Islands and Puerto Rico. They are variously called Butterfly Orchids, Island Peacock Orchids or Sandy Point Orchids. Their flowers last for months, so I enjoy having them around.  

 

The bright colors and protruding petals of the Psychilis macconnelliae are designed to attract bees and butterflies – but there is no nectar there. As a result, they don’t get very many repeat visitors. 

 

These plants seem to be resigned to the low-pollinator situation. Their energy-saving adaptation is a trade-off that makes it possible for the plants to grow in a dry environment and survive drought conditions. Their flowers, when they come, last a long time. Eventually a naive bee will probably stop by. Then if pollination occurs, the fertilized plant will have enough energy to produce and throw off large numbers of tiny seeds in hopes of expanding its population. 

 

The hanging seed pouch of a Butterfly Orchid can contain 3 to 4 million seeds.

I don’t actually think it’s fair to conclude that the Butterfly Orchids are being lazy or unethical. The no-nectar decision may be critical for their survival under precarious living conditions. Still, you can understand that the pollinators feel cheated and won’t be coming back once they catch on.      

 

Another no-rewards native flower, Tolumnia prionochila, is commonly known as the Dancing Lady Orchid. As epiphytes, they get nutrients and water just from the air. They attach themselves to thin tree branches using hairy, white roots. 

Dancing Lady Orchids are charming deceivers. 

 

These orchids, too, are only found in the Virgin Islands and Puerto Rico. They have small, crinkly upper petals (forming the head and waving arms) and much larger lower petals (the swirling skirts of the dancer). 

 

The bottom petals of the Dancing Lady Orchid flowers also have slits that make them look like face masks. 

 

The deception here involves luring pollinators by impersonating another type of flower. The Dancing Lady flowers look a lot like those of the Stigmaphyllon emarginatum vine (Yellow Wiss, Monarch Amazonvine, or Goat Bush), which has developed a special evolutionary relationship with oil-collecting Centris bees. 

   

Yellow Wiss flowers have petals similar to the Dancing Lady Orchids. 

 

Centris bees are solitary bees that make nests underground. Female Centris bees are attracted to flowers like the Yellow Wiss that produce fatty floral oils instead of nectar, which the bees collect to form energy-rich food for their larvae, and to waterproof their nests. In the process of collecting the oils, the bees pollinate the flowers.  

 

Because of the similar flowers, the bees come to the similar Dancing Lady Orchids as well, and pollinate them while they hunt for oil – but they are wasting their time because they don’t get any oil in return. 

 

Maybe the Dancing Lady Orchids feel challenged as epiphytes, living on air and water, without having roots in the ground like the Yellow Wiss. So because of their precarious circumstances, they might feel justified in tricking the bees and not paying for their pollination. Or they might just do it because they can get away with it. 

 

Meanwhile, it’s not just orchids that practice deception. 

 

Frangipani flowers are alluring but nectar-less. 

The native frangipani trees (Plumeria alba) primarily target nighttime pollinators like sphinx moths. Their fragrance is strongest at night, and their pale petals glow in the moonlight. The large, hairy moths come to investigate, and pick up pollen when they land. They then transfer the pollen to other frangipani flowers as they unsuccessfully search around for the expected nectar. 

 

During the day, bees and butterflies might also be drawn to the scent, and the bright yellow centers, of the frangipani flowers. However, all of the potential pollinators will leave hungry and possibly feeling used.  

 

One type of moth, the female Pseudosphinx tetrio, seems to get back at the no-nectar frangipani tree by laying 50-100 eggs on its leaves. 

 

Frangipani trees serve as hosts for Pseudosphinx moths. 

 

Those eggs grow into huge hungry caterpillars that can end up eating almost all of the leaves on the tree before they change into their chrysalis forms and later emerge as new moths. 

 

 

Frangipani caterpillars are huge, and voracious leaf eaters. 

 

Regrowing all those leaves requires the frangipani tree to expend really a lot of effort. So the frangipani tree is actually paying a very high price for its pollination. That could explain why the tree doesn’t want to give the moths nectar as well.

 

I know it may seem silly to describe these plant-pollinator relationships in terms of intentions, feelings and judgments, since the long-term evolution of flower and insect behavior has been based on a mix of genetic diversity, natural selection and environmental factors.  

 

However, a storytelling approach can be useful for getting people emotionally engaged with the complicated relationships and dramas playing out in the natural world. I find it marvelous that these sweet-looking flowers are actually conducting very complex sexual reproduction maneuvers, including perhaps abusing the goodwill of unwitting third-party insects. Of course, I realize they are not just acting on impulse. Their respective ancestors have had millions of years to work out their mutual survival strategies. Let’s hope they can manage to continue.