At the end of Micro, by Crichton, there was an extensive bibliography, from which I made quite a few notes for future reading - this is the first of those books. Agosta does a fine job of explaining in layman's terms (for the most part) some of the incredible complexity of chemical and other interactions between diverse species in the plant and animal kingdoms. While he is careful to attribute all of this wild and crazy stuff to the forces of evolution (no science writer dares to cross the Darwinists, after all), people who regard these things as evidence of God's infinite creativity will enjoy this book, too. I had yellow sticky notes plastered throughout the book, highlighting interesting points, by the time I was through.
The world of chemical interactions among plants, animals and other organisms is far more complex that I ever imagined, and I'm certain that in the decade since this book was published, scientists have discovered even more amazing and wonderful things. I'd always known that ants used chemical scents to mark their trails to food, and to communicate on a very basic level, but I hadn't realized that there are between ten and twenty different antenna-detected chemical signals that keep a colony running smoothly, from trail marking, to reporting the existence of another colony's scouts, and even a special "recruiting" chemical to gather the war party to drive off the invaders.
Even the same chemical compound can be used by different species for different functions. Carbon dioxide is used by ants as an aggregation signal - encouraging them to join their nestmates, used by corn rootworms as a signal leading them towards their food - corn roots, and used by mosquitoes and a few other pests to track their prey.
Agosta tells the story of ant gardens in the forests of southeastern Peru, where arboreal ants gather the seeds of particular plants - only the types that will flourish in their nests - and take them into their nests, which are cemented together by their own glandular secretions. Some of these plants bear moist, pulpy fruits and nectar to feed the ants, in return for their hospitality, and exude anti-fungal compounds to keep fungus from growing in the ant nests. The ants care for the plants, protecting them from herbivores, fertilizing them with vertebrate feces, and covering up their questing roots with new nest material. As scientists began to investigate the selection of particular seeds, they found that a particular chemical was present in all of the seeds selected, and not present in those which are not used in the ants' nest gardens. Non-gardening ants in the same forest find these particular seeds repugnant, and will not gather them for food.
Neat factoid - a single pound of honey represents the nectar from about seventeen thousand foraging trips and entails over seven thousand bee-hours of labor. Appreciate that next dollop in your tea!
In the pollination of fringed orchids of the genus Platanthera, there are only two species of hawk moths that are able to do the job. The orchids store their nectar deep inside a 6 cm tube at one end of the flower, the longest of any North American orchid. Only hawk moths have a proboscis (nose) long enough to reach down to the bottom of the flower to get at the nectar, and the necessary requirements to pollinate the flower, as well. When the moth is in the proper position to gather the nectar, its head touches against two pollen-bearing organs, one on each side, and the pollen is cleanly transferred to the moth's eyes, which are set at precisely the correct width to transfer the pollen. At the next orchid, the pollen is transferred to two receptive structures (if it's a female flower), again spaced just right for the moth's pollen-coated eyes.
There used to be a show on PBS or the History Channel called Connections, I think. They would trace the development of some modern event or invention back to something you would never believe was related. Agosta does the same thing with mosquitoes and the Louisiana Purchase. It seems that in 1802, a yellow fever epidemic caused by mosquitoes caused the French forces occupying Haiti to finally give up. Napoleon ordered a withdrawal, and decided not to seek an American empire any longer, which left France receptive to the young U.S.'s $15 million dollar offer for the territory in 1803. My hometown of Lewiston would certainly not exist if it were not for those mosquitoes.
There is a certain type of insect, the firebrush mite, that lives only on firebrush pollen and nectar in the wild. If a mite ends up on the wrong type of flower, it will have no opportunity to mate with others of its kind. The mites travel from flower to flower in the nasal cavities of hummingbirds. When a hummingbird approaches a particular flower, it will only hover there for a short time, and the mite has to decide whether to rush (at a speed equivalent to that of a cheetah) out of the bird's nose and onto the flower. The mites are blind, so they must use the scent of the flower as it is inhaled by the hummingbird, and make the right decision in a split second. The mites jump to the wrong flowers only 1 time in 200!
"Tiny parasitic wasps...lay their eggs in the larvae of Caribbean fruit flies, which they find by following the strong smell of rotting fruit where the larvae mature. Three simple chemical compounds from the fruit are particularly enticing to the wasps. These chemical markers, themselves products of microbial fermentation, are formed as bacteria and fungi feed on the fruit and decompose it. In this case, then the feeding of one group of organisms (microbes) on another (fruit) yields a chemical signal that leads a third group (wasps) to the location of a fourth (fly larvae). Only with this elaborate assistance are the wasps able to reproduce."
Agosta spends some time in the oceans, too. There is a particular type of dragon fish which lives in the lightless depths that uses blue light to hunt. As all other deep water species can see only red light, and are blind to blue, this is a huge advantage. The blue pigment in its eyes, however, is chlorophyll-based. Chlorophyll is produced by plants, not animals. How did the fish get the chlorophyll?
It turns out that there are species of green sulphur bacteria living in the ocean vents, which are eaten by plankton, which are eaten by tiny crustaceans, which are eaten by larger crustaceans, which are eaten, finally, by the dragon fish. The chlorophyll is sequestered (unused) by all of the organisms in the food chain, until the dragon fish metabolizes it and uses it to produce the blue pigments which give it its hunting advantage. Crazy, huh?
Another thing I found interesting was the magnetic microbes. There are certain bacteria which live in muddy ponds in North America that accumulate magnetite (a magnetic ore) and align the crystals in spikes about 120 nanometers long, just the right length to create a needle-like magnet. The magnet helps them to determine which direction is north and which is up and is down. They always swim to the north and downward so they can remain at the bottom of their murky pools. Similar bacteria living in the southern hemisphere always swim to the South; their compasses are aligned the opposite direction!
Tons of great, crazy discoveries to enjoy in this book. I highly recommend it!