WHAT FLOWERS ARE FOR
By Carll Goodpasture and Gro Heining
The beauty of flowers so admired by poets isn’t for us
- its for the birds and the bees that pollinate them.
When you think of a flower, what first comes to mind? A painter might visualize color, a poet natural harmony. In our dreams it is said that the Lilly symbolizes purity and the rose feminine beauty. We use flowers as metaphors to declare love and to represent life after death. Looking beyond the poetic and aesthetic attributes of flowers, there is an entirely practical form of life: the flowers’ biological purpose is the survival and the evolution of its species. Perhaps, at least in our mythology, we have failed to appreciate fully the significance of a flower.
The Significance of Pollination
Pollination is a fundamental ecological process. It accomplishes plant reproduction producing fruit, seed, and fiber for mankind. While some flowers are engineered for pollination by the wind, others are designed to be attractive to animal pollinators. The pollination of flowering plants by insects is an example of the integrated and interdependent community of organisms that comprise an ecosystem. Although green plants are the primary producers at the base of the food chain, animals such as bats, hummingbirds, and the insects are the pollinators that make possible the existence of most plants. Pollinating insects are as essential to an ecosystem as the telephone is to a teenager. About 80 percent of flowering plants are dependant upon insects to transport their pollen from the male to the female parts of the same or another flower. Without pollinator services people wouldn’t have sweet fruits such as apples and melons or addictive seeds such as coffee and cacao.
As anyone knows who has harvested seed, a flower is a bundle of reproductive organs. Within the flower, sexual organs produce the gametes or sex cells that correspond to the eggs and the sperm of animals. When gametes fuse an embryo develops which in plants resides within the seed. Unlike animals and primitive plants whose sperm are motile, flowering plants use grains of pollen to produce and to transport the male’s gamete.
Even the best-dressed flower’s reproduction is not assured unless it can
attract the humble bee
Flowers are sexual beacons, not just to humans but to insects. Yet beauty and attraction are only skin deep. To understand flowers, we must appreciate their need of pollinator services. Flowers are only coincidentally appealing to the eyes of humans – to the insects their alluring qualities are advertisements with directions to a source of food. In turn the insects are important to flowering plants because these profoundly rooted lifeforms need someone (usually an insect) or something (often the wind) to transport their pollen. Because plants are sessile, they need help to carry the encapsulated male gamete to the stigma.
Despite our fascination with its showiness, the flowers raison d’ être is clearly to help the plant to reproduce. But the reson d’ être of the pollinator is also reproduction. Perhaps the need for pollination can explain how flowers have come to invest do heavily in the advertising business. Could it be that pollinators are in scarce supply so that flowers must compete for gamete transportation services?
The very fact that flowers are gaudy and conspicuous suggests that there is an ancient competition for scarce pollinator resources in the environment. What is happening between flowers and their visitors is a trade off: food in exchange for pollen transportation. The clever flower advertises its seductive presence while offering an irresistible reward to its most faithful customers. As flowers evolved their kaleidoscopic variety of form, color, texture, and scent to guide insects searching for nectar and pollen, so the insects evolved special structures, behavior, and complex abilities to enable them to exploit the flower’s reproductive needs. From a plant point of view, it paid to be distinguishable from all other occupants of the same habitat, thus to aid pollinators to carry the right pollen to the right pistil. From the insects perspective it was important to be at the right place at just the right time to better utilize the floral resource to which it adapted. The result of this coevolution – more than one hundred million years in the making – is a poetic display of mutual interdependence no less than miraculous.
As gardeners and nature lovers with an eye and an ear to ecological issues, we find that there is worldwide recognition in the scientific community of a decline in native pollinator populations. In our neighborhood, we are alarmed to notice each year fewer and fewer species of native bees in our garden. In a recent book from The States (The Forgotten Pollinators by Stephen Buchmann and Gary Nabham, Island Press, 1977) it is suggested that pollinator population changes are human-induced, caused by overuse of chemical pesticides, unbridled development, and conversion of natural areas into monocultural cropland. Probably the best documented example of pollinator decline in Europe in the bumblebee situation in
Britain: there were once many species but only a few survive today with their distributions greatly reduced. Pollination ecologists believe that the viability of crops and wildflowers is threatened and that understanding and managing pollination systems is becoming a practical necessity. Key to the preservation of pollinator biodiversity will be a public appreciation of the pollinator’s need for living space: if people need sweet foods and wild flowers, they need pollinators.
Engaging life in the garden
Pollination is the miracle of nature that attracts us to the garden. As artist and scientist, we are fascinated by what we see and what we feel about nature. Using the camera and the paintbrush as our gardening tools, we hope to bring life to the hidden relationship between the plants and animals they depend on for reproduction, perhaps shedding light on a human society, which affects and is affected by those relationships. Like the poet we see beauty in nature but only through direct experience of plants, butterflies, bees and other creatures, will we grow to know intimately the life forms we depend on for food and spiritual substance.
But our new love affair with the managerie of pollinators inhabiting our backyard involves more than gardening, photography, and bug watching activities: we are realizing that every garden, waste place, and roadside is a potential pollinator reserve. There are others of like mind, as the popularity of butterfly gardening in England attests. We suggest that an awareness of the key role that pollinators play in maintaining the integrity of ecosystems, both natural and man made, will lead to widespread intentional planting of floral gardens with diverse nectar-producing and pollen-source plants to attract and sustain a diversity of pollinators. Perhaps the real beauty in the garden is our experience, not just of its flowers as poets metaphor, but of ourselves engaged in a plant/animal relationship that the beauty and grace of pollinators and their flowers represent.