Pollination: how to play the game

alternatives.

Some flowering plants have reverted to use of wind. Flowers very minimal

Ultraviolet patterns (right) that insects can see.

Red trumpet shaped flowers designed for hummingbirds.

Tropical Heliconia – flower designed to match hermit (hummingbird) bill shape.

CP51: Perhaps the most striking of all orchid flower mimics are the Ophrys family members that grow in Europe. This specimen from Turkey has flowers whose lips look like the abdomen of a female bee. The male bee's energetic efforts to mate with it scatters the pollen everywhere. The orchid gets pollinated and the frustrated bee gets nothing.

Natural selection has molded the flowers of these orchids (many in the genus Ophyrys) into mimics of the insects that pollinate them. Horny male insects, thinking that the petals are a female, land on them and engage in fruitless attempts to copulate (“pseudocopulation”). During the barren act, the insects’ heads or bodies contact the orchids’ pollen sacs, which break off and attach to the insect. The frustrated insect flies off, but soon tries to copulate with another orchid, which puts the hitchhiking pollen in contact with the new orchid’s stigma. In such a way the bees/wasps serve as “flying penises,” helping the orchids have sex. Here are some specimens:

Ophyrys insectifera (fly orchid), which deceives male digger wasps.

Meat smelling flower – attracts flies as if to carrion – a specialty pollinator.

Human caused problems for plants

• Fire ( frequency)

• Water supply

• lowering of water table in Arizona

• Diseases

• dutch elm disease

• new insects.

• New Competators

Fire: if an area regularly burns, all plants living there have a way of surviving.

- annuals as seeds

- perennials – resistant bark

- underground storage roots.

Number of fires has gone down

But severity of fires has gone up.

Reason: wood is a resource to be protected = prevent fires

Get fuel build up – now fires more severe that before.

Frequent fires keep fuel from building up – get rid of small plants, fire burns on ground and does not crown (get to top of trees)

Natural forest

Widely spaced trees, older trees. Ground fire cannot reach branches.

If fuel buildup – trees burn –

If frequent fires – forest becomes grassland

Local chaparral after fire; everything burns. If too hot, sterilizes the ground.

In deserts, little soil moisture.

Plants must reach ground water for supply. How deep is it??

Ground water use.

No rules about saving any for organisms.

Western U.S.; less rain = more use of ground water, especially in southwest.

Result: streams dry up, ground water is deeper – new seedlings cant reach it.

Desertification.

Result of lowering water table

Winners: annual plants and drought resistant (cactus)

Losers: trees and perennials

So savannas and dry area forests slowly turn into grasslands.

Arizona desert community – lots of perennials, can reach ground water

Arizona grasslands; annuals replace perennials when water table drops

Plant diseases - introduced

• Movement of plants from other continents – brings diseases never seen before by native plants.

• These diseases are in closely related plants and can infect our plants.

Dutch elm disease in the U.S.

A fungus spread by bark beetles.

Even as a kid, there was something about the story of the American Chestnut tree that made me yearn for a past I never knew. The blight first appeared in Brooklyn in 1904, and within 50 years they were gone. Millions of trees stretching from New England to Georgia, along the spine of the Appalachians, spilling across the Great Lakes into Ontario, and along the Ohio Valley, gone. Mere ghost trees, whose trunks still exist, stumps ten foot in diameter, slowly succumbing to rot over generations.

The Passenger Pigeon, once probably the most numerous bird on the planet, made its home in the billion or so acres of primary forest that once covered North America east of the Rocky Mountains. Their flocks, a mile wide and up to 300 miles long, were so dense that they darkened the sky for hours and days as the flock passed overhead. Population estimates from the 19th century ranged from 1 billion to close to 4 billion individuals. Total populations may have reached 5 billion individuals and comprised up to 40% of the total number of birds in North America (Schorger 1995). This may be the only species for which the exact time of extinction is known.

Chestnut blight; killed American chestnut. Chinese resistant.

Another fungus

Red Gum eucalyptus – CMC campus

Lerps = an infectious aphid like organism (psyllid), finally arrived in California from Australia

Lerps suck out plant juice – kill leaves, tree gets sick and less resistant to disease as no leaves for photosynthesis.

Solution: bring in a parasitic wasp from Australia to kill the lerps

Or ignore it. Why?