Let’s Do It

When the little bluebirdWho has never said a wordStarts to sing Spring. When the little bluebellAt the bottom of the dellStarts to ring Ding dong Ding dong. When the little blue clerkIn the middle of his workStarts a tune to the moon up above. It is nature that is allSimply telling us to fall in love And that’s why birds do it, bees do it,Even educated fleas do it.Let’s do it, let’s fall in love... -Cole Porter- Let’s Do It

Pollination Biology

Help me! I am rooted and I cannot move! • Plants are stationary (usually) and thus depend on external forces to bring their gametes together. • As a result, plant sex is extraordinarily varied and competitive. • Some plants species may be specialized for one pollinator. • Some plants may be served by a wide range of pollinators. Such plant species are called generalists. • Me thinks that a generalist might be a wise thing to be! What thinks you?

Pollination as a science… • The study of pollination brings together many disciplines, such as botany, horticulture, entomology, zoology, and ecology. The pollination process as an interaction between flower and vector was first addressed in the 18th century by Christian Konrad Sprengel in his work Das entdeckte Geheimnis der Natur im Bau und in der Befruchtung der Blumen (Berlin 1793).

Christian Konrad Sprengel(1750-1816) • One of the founders of pollination ecology as a scientific discipline. Together with one of his predecessors, Josef G. Köhlreuter, he is still the classic author in this field. • During his lifetime, his work was neglected, not only because it seemed to many of his contemporaries as obscene that flowers had something to do with sexual functions, but also because the immanent importance of his findings on the aspects of selection and evolution was not recognized. • Until C. Darwin’s book On the various contrivances by which British and foreign orchids are fertilised by insects, and on the good effects of intercrossing. (London 1862), floral ecology was not considered a 'proper science'.

Plant Pollination • The greatest percentage of all plant pollination is biotic in nature (animal assisted). • Only 10% (some say 20%) of flowering plants are pollinated without animal assistance (sometimes called abiotic pollination).

Abiotic Pollination • The most common form, anemophily, is pollination by wind. This form of pollination is predominant in grasses, most conifers, and many deciduous trees. • Hydrophily is pollination by water and occurs in aquatic plants which release their pollen directly into the surrounding water.

We already know or will know… • Sperm of seed plants are packaged in pollen grains for transport to ovules or stigmas (aka pollination). • Conifer pollination occurs largely by wind. • Most flowering plants are pollinated by animals (insects included here). • Wind pollination predominates in the grasses and other ecologically dominant families. • Water pollination is rare.

Those observant Babylonians • 1500 BC is when Babylonians first noted that the yellow pollen of date palms must be applied to the flowers of fruit-bearing trees in order for the trees to produce fruit. • So Babylonian date farmers started spreading the yellow pollen on date flowers by hand to increase fruit production.

Today, somewhere in the world… • I wonder if this man is thinking…”I need to thank a Babylonian for this exciting job”?

No Pollination No People • Pollination remains essential to human welfare today. • Most human food comes from cereal grains (Poaceae) and legumes (Fabaceae) all of which result from pollination. • Nearly all edible fruits would not exist without pollination.

Those Voluptuous Flowers • Be us prurient or puritanical, we all know that bright blooms are just inviting, irresistible advertisements for ‘falling in love’. • Flowers are adaptations for pollination. How they ‘get’ it is how they bloom.

Whilst in Madagascar, Darwin speculated… • There had to be a some type of animal pollinator with a VERY long tongue because there was an orchid species there whose flowers had a 30 cm long spur to reach the flower nectary. He predicted there was a moth with a tongue long enough.

Floral Pollination Syndromes (syn FPS) • The link between floral color, scent, time of flowering, structure, and rewards on the plant’s side and animal pollinator sensory capacity, behavior, and diet on the other is the basis for FPS. • The link may be strong enough that a plant and a pollinator adapt to each other, to coevolve so to speak.

Yucca and FPS • The yuccas comprise the genus Yucca of 40-50 species of perennials, shrubs, and trees in the agave family Agavaceae, notable for their rosettes of evergreen, tough, sword-shaped leaves and large terminal clusters of white or whitish flowers. They are native to the hot and dry (arid) parts of North America, Central America, and the West Indies.

Yucca and FPS continued… • Yucca pollination seldom occurs without the aid of females of several species of yucca moths, especially Pronuba yuccasella and Prodoxus quinquepunctellus. • These moths purposefully transfer the pollen from the stamens of one plant to the stigma of another, and at the same time lay eggs in the flower; the moth larva then feeds on some of the developing seeds, but far from all.

Yucca and FPS continued yet again… • The relationship between yucca plants and yucca moths is one of the classic examples of an obligate pollination/seed predation mutualism.

And again… (Yucca and FPS) • The moth makes sure not to lay too many eggs in each flower to prevent the larva from eating all of the yucca seeds. • Pollination of soapweed yucca is dependent upon the yucca moth (Pronuba yuccasella) or other pollinating insects such as small flies (Pseudocalliope spp.)

Yucca FPS Research Results… • In a study to determine the relationship between soapweed yucca and the yucca moth, 124 plants with a mean of 291 ovules per plant had 138 viable seeds after consumption by (adult?) and larval yucca moths. The maximum number of larvae per fruit was 19. In Colorado, the number of surviving seeds increased with elevation despite fewer fruits. This was likely due to decreased predation by the yucca moth, which prefers the warmer temperatures of the Great Plains over those experienced at higher elevations

Yucca glauca Nutt. • Great Plains yucca,Spanish bayonet,needle and thread, beargrass,small soapweed,soapweed yucca,yucca. • Montana native • Look for one in your neighborhood.

Wind Pollination(aka anemophily) • Wind pollinated flowering plants are characterized by the production of large amounts of pollen that is readily transported by the wind (small and light). • In many wind-pollinated angiosperms, each flower has only a few ovules, and often only one of them produces a seed. • Wind pollination is unusual in the tropics, especially in lowland rain forests.

Wind Pollination(aka anemophily) • Temperate forests, in contrast, are dominated by wind-pollinated trees such as oaks, beeches, hickories, walnuts, birches, and many conifers in our Northern Hemisphere. • Pollen shed in wind-pollinated temperate species occurs at the beginning of the growing season, before or as leaves develop as a leafless forest has fewer obstacles to interrupt pollen flow.

Wind Pollination(aka anemophily) • Pollen shed is also timed to avoid high humidity (moisture weighs pollen down and reduces its buoyancy). • Pollen shed is also timed to avoid periods of seasonal rain (which carries pollen down out of the air currents.)

Wind Pollination(aka anemophily) • Corn (Family Poaceae) illustrates another common feature of wind-pollination: unisexual flowers. • Corn pollen in borne is staminate flowers in the tassel at the top of the plant and the ‘female’ stigmas are the “silk” that emerge from the top of what will become the ear of corn.

Anemophily, You, and Ah-Chew! • For those of you (not me fortunately!) that suffer from ‘hay fever’, your symptoms of watering eyes to sneezing might be caused from an allergic reaction to proteins in the outer pollen wall of some wind-pollinated species such as ragweed (Ambrosia spp.), Carolus L.’s ‘food of the gods!’

'Safe Sex in the Garden'Sticking to Female Plants May Help Reduce Allergies, Book Says • More than 35 million Americans suffer from seasonal allergies, according to the American Academy of Allergy, Asthma and Immunology. Part of the problem, says horticulturist Thomas Leo Ogren, is rooted in the types of plants commonly used in landscaping.

'Safe Sex in the Garden'Sticking to Female Plants May Help Reduce Allergies, Book Says • For about 50 years, commercial and residential landscapers have been planting single-sex male trees and shrubs almost exclusively. Males don't litter the ground with seeds, fruits or pods but they do emit high quantities of pollen into the air and up our noses. • Cities like Billings forbid the intentional planting of cottonwood trees unless they are ‘cottonless’ (aka male…)

'Safe Sex in the Garden'Sticking to Female Plants May Help Reduce Allergies, Book Says • The solution, Ogren suggest, may lie in a form of gardening girl power. In his book, Safe Sex in the Garden, Ogren argues that boosting the use of female plants, which absorb pollen in the air, could help dramatically reduce the suffering of those affected by pollen allergies. • Believe it or not.

Water Pollination(aka hydrophily) • Water pollination is limited to about 150 angiosperm species in 31 genera and 11 families. • Almost half of these species are marine or grow in brackish water. • Nine of the eleven families are monocots.

Water Pollination(aka hydrophily) • Pollen may be transported above, on, or below the water surface. • Plants that pollinate under water often have filamentous, or eel-shaped pollen borne in mucilaginous strands.

Animal Pollination(aka biotic pollination) • Thought to be an important factor in the evolutionary success of angiosperms. • Animals are often more efficient transporters of pollen than wind, and they can be found where there is little wind (dense tropical forests). • Animals promote cross-pollination (thus plant vigor) by moving between plants.

Animal Pollination(aka biotic pollination) • Animal pollination has driven diversification in many plant groups. • Evolution associated with animal pollination is nowhere more evident than in the Orchidaceae. Many species in the large family are separated by floral structure reproductive isolation (whilst in Madagascar, Darwin speculated…) • This may or may not be such a good thing…

Animals and FPS • Flowers attract their pollinators with color: • Bees – blue, yellow, purple. • Butterflies – bright, often red. • Moths – white or pale colors (see them at night) • Birds – bright, often red • Bats – white (see them at night)

Animals and FPS • Flowers open and emit scents when their pollinators are active: • Bees – fresh, strong scented flowers open during the day. • Moths – sweet, strong smelling flowers opening at dusk and throughout the night. • Bats – musky, strong flowers opening at night. • Birds – are not attracted by scent but by color and thus utilize flowers during the day.

Animals and FPS • About 60 species of non-flying mammals have been documented as pollinators of about 100 plant species. • Flowers pollinated by non-flying mammals have a broad range of floral characteristics due to differences in morphology and foraging behavior of the three groups of pollinating mammals.

Animals and FPS • Primates – flowers pollinated by primates tend to be unscented and very large to accommodate the large size of the animals. • Marsupials – flowers pollinated by marsupials are usually located in the forest canopy. • Rodents – flowers pollinated by rodents tend to be close to the ground and have a yeasty odor.

Animals and FPS • Flowers are built to fit their pollinators physically and to provide them with an appropriate reward. • In some cases, pollinators are not rewarded, but rather are deceived into pollinating a flower.

Deception in the plant world… • Of the 19,500 species of orchids, about 8,000 offer no food reward to their pollinators. • Instead they deceive or provide them with nonnutritive rewards such as fragrant chemicals • Drug pusher/addict relationship perhaps? Sounds kind of like co-dependency to me!

Oh, those fraudulent orchids… • Some orchids mimic female insects, luring males with odors of potential mates ready for loving. • Some orchids have textures stimulating male insects into ‘pseudo-copulation’. The insects may be duped, but the orchid gets what it wants! • Some orchids flutter their flowers in the breeze making them look like male bees. This provokes other male bees in the neighborhood to attack one impersonating flower after another, thus pollinating them. Exploiting machismo perhaps???

We know rotting flesh attracts flies… • So, if I am a flower that emits the scent of rotting meat, I can deceive a fly into investigating my interior and pollinating me.

I smell good… • “I just love the way the fragrant chemicals (pheremones?) in those New World orchids make my hind tibiae smell. All the girl euglossines really come a flying when I wear that cologne, and the orchids really seem to appreciate me too!!!” • -Calvin Klein aka male euglossine bee-

Self-Pollination • Some plants are self-fertile or and can pollinate themselves. • Self-pollination (autogamy): pollen moves to the female part of the same flower, or to another flower on the same individual plant.

Avoiding Self-pollination • It has long been known that many plants avoid self-pollination and thus the possible harmful consequences of inbreeding. • Avoiding self-pollination my be achieved by separating male and female gametes in space or in time. • Can you think of examples of this???

Cross-pollination • Some plants have chemical or physical barriers to self-pollination and need to be cross-pollinated. • Cross-pollination (syngamy): pollen is delivered to a flower of a different plant. Plants adapted to cross-pollination often have taller stamens than carpels to better spread pollen to other flowers.

Examples from the continuum… • Peaches are considered self-fertile because a commercial crop can be produced without cross-pollination, though cross-pollination usually gives a better crop. • Apples are considered self-incompatible, because a commercial crop must be cross-pollinated. If all of the trees in the orchard are clones (ie Red Delicious) you need to introduce pollen from another variety of apple or you won’t get any Red Delicious to sell.

To Bee or Not to Bee

Pollination Management • A branch of agriculture that seeks to protect and enhance present pollinators and often involves the culture and addition of pollinators in monoculture situations, such as commercial fruit orchards. • The largest managed pollination event in the world is in California almond orchards, where nearly half of the US honey bees are trucked to the almond orchards each spring.

Pollination Management • The ecological and financial importance of natural pollination by insects to agricultural crops, improving their quality and quantity, is becoming more and more appreciated and has given rise to new financial opportunities.

Pollination Management • Agricultural monocultures require great concentrations of pollinators at bloom time yet deem vast areas forage poor for the rest of the season. • Pollinator populations are declining due to pesticide misuse, new diseases and parasites of bees, decline of beekeeping, suburban development, habitat destruction, and public paranoia about bees. • Widespread aerial spraying for mosquitoes due to West Nile fears is causing an acceleration of the loss of pollinators.

Pollination Management • The vicinity of a forest or wild grasslands with native pollinators near agricultural crops can improve their yield by about 20%. The benefits of native pollinators may result in forest owners demanding payment for their contribution in the improved crop results - a simple example of the economic value of ecological services.

Let’s Do It

Let’s Do It

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