Tuesday, May 12, 2009
Sunday, May 10, 2009
Those Clever Ants, Part 2
I’ve been looking here at the extraordinary capabilities of ants, that stem primarily from their social nature. Ants have an elaborate communication system, which they use to attract one another, raise an alarm, recruit new members, control group activities, and groom one another; especially the queen. Any outsider who does not smell like a colony mate will get warded off or attacked. Yet some sneaky and cunning solitary critters—beetles, mites, wasps—are able to crack the colony’s communication code and live as a pampered member, getting workers to groom and feed them as they do the queen.
Most residents of a colony are female workers, who live a predominantly altruistic life. Biologists do not agree on referring to the actions of sterile workers as altruism, since it seems to contradict the “selfish gene” theory, which describes the activities of most critters as being dominated by a drive to propagate one’s own genes downstream. If so, why would a worker ant devote her life to the continuation of another’s life, another’s genes—specifically the queen? But workers do lavish extraordinary care on the queen and zealously guard and tend her eggs and offspring, forgoing any chance at having kid ants of their own. Let’s call it altruism. It still manages to do a superb job of sending the group’s genes into the future.
Ants exhibit their swarm intelligence in scores of ways—depending on their local habitat. To begin with, the size of a colony is wisely maintained—growing when conditions are favorable and stabilizing (or even shrinking) when times get lean. Some ants form symbiotic relationships with plants—weeding and pruning their environs, to promote the health of the plants they use. One clever species of ant lives unharmed on pitcher plants. As other bugs fall in, to become digested by the plant, ants get a safe home (no ant predator would dare invade) and the plant gets protection from ant-sized herbivores. Some ant species even farm—carrying preferred seeds into the colony, planting them in rich ant detritus, and later harvesting nutritious fruit.
Leafcutter ants cut pieces of vegetation (sometimes stripping human gardens in the process), carry them to the colony, and grow a fungus which they feed upon. Weaver ants create nesting enclosures by forming long chains with their bodies to curl leaves up, and then binding the edges together with larval silk. Some ants tend aphids and mealy bugs as cattle, which they milk (by tenderly stroking them) for a source of nutritious honeydew. Some species of ants coevolved with seed-producing plants—trading nectar for pollination and seed dispersal. And the list goes on.
I may have failed in absorbing most of the voluminous book Ants, but I got enough to significantly increase my appreciation, even if I still don’t revere those little black pests who insist on trying to set up their colony in my kitchen. I guess I should be grateful that army ants aren’t indigenous to these woods.
Most residents of a colony are female workers, who live a predominantly altruistic life. Biologists do not agree on referring to the actions of sterile workers as altruism, since it seems to contradict the “selfish gene” theory, which describes the activities of most critters as being dominated by a drive to propagate one’s own genes downstream. If so, why would a worker ant devote her life to the continuation of another’s life, another’s genes—specifically the queen? But workers do lavish extraordinary care on the queen and zealously guard and tend her eggs and offspring, forgoing any chance at having kid ants of their own. Let’s call it altruism. It still manages to do a superb job of sending the group’s genes into the future.
Ants exhibit their swarm intelligence in scores of ways—depending on their local habitat. To begin with, the size of a colony is wisely maintained—growing when conditions are favorable and stabilizing (or even shrinking) when times get lean. Some ants form symbiotic relationships with plants—weeding and pruning their environs, to promote the health of the plants they use. One clever species of ant lives unharmed on pitcher plants. As other bugs fall in, to become digested by the plant, ants get a safe home (no ant predator would dare invade) and the plant gets protection from ant-sized herbivores. Some ant species even farm—carrying preferred seeds into the colony, planting them in rich ant detritus, and later harvesting nutritious fruit.
Leafcutter ants cut pieces of vegetation (sometimes stripping human gardens in the process), carry them to the colony, and grow a fungus which they feed upon. Weaver ants create nesting enclosures by forming long chains with their bodies to curl leaves up, and then binding the edges together with larval silk. Some ants tend aphids and mealy bugs as cattle, which they milk (by tenderly stroking them) for a source of nutritious honeydew. Some species of ants coevolved with seed-producing plants—trading nectar for pollination and seed dispersal. And the list goes on.
I may have failed in absorbing most of the voluminous book Ants, but I got enough to significantly increase my appreciation, even if I still don’t revere those little black pests who insist on trying to set up their colony in my kitchen. I guess I should be grateful that army ants aren’t indigenous to these woods.
Saturday, May 9, 2009
Thursday, May 7, 2009
Those Clever Ants, Part 1
I recently attempted to tackle a weighty book (7 ½ pounds, 732 pages, letter page size) by Burt Hölldobler and E.O. Wilson. Titled simply Ants, it got the best of me… just a little too heavy a read. But I wanted to try, and I did get a major boost to my appreciation of this social insect of the order Hymenoptera, family Formicidae, subfamily Myrmicinae. (All those 25-cent words is one reason why the book was more than I could handle.)
Ants are the pinnacle of insect evolution, and that’s a lot to say, given that insects are the most copious of critters. Ants' extreme success and longevity can be attributed to their highly developed social lives. Social critters generally seem to thrive better than solitary animals do. Life is a struggle. There are numerous threats to endure, such as competitors, predators, and natural catastrophes. When animals band together cooperatively, their chance of survival increases. (Consider Homo sapiens!)
Thus ants are both robust and plentiful. There are some 8800 known species. They make up some 10-15% of animal biomass in most areas where they live; in the rainforest, as much as 75%. Think of that: such tiny creatures outweighing most all other animals in their vicinity—even elephants and giraffes! They turn and enrich more soil than earthworms. They’ve been around far longer than many extant creatures. They first appeared about 100 million years ago and were unfazed by the disaster that drove the dinosaurs to extinction. Most species last, on a gross average, about one million years. Ants have pushed that much further. Pretty dazzling feats for such a little critter!
I wanted to try to understand ants better, partly because most of my impressions were formed years ago, when I learned to regard them mostly as pests. I came to think that the only thing rivaling a termite or cockroach infestation is to see a line of ants parading across the kitchen counter. But I sensed that, like all the works of Mother Nature, there must be something to appreciate about them, and even revere; so I decided to take a closer look, try to drop my prejudice, and seek to understand them.
I have written here before about my fascination with watching ants (6/9/08) and a bit on their intelligent behavior due to something referred to as swarm intelligence (1/25/09). My ant appetite had become whetted and Ants was a book to try.
Crucial to ants’ success is their caste system: an effective division of labor that gets many sophisticated jobs done. But even though they have a strict hierarchy of tasks, any one ant is free to communicate (mostly chemically, via pheromones) with any other member of the colony. This democratic feature is a major aid in helping the group to be successful—in contrast (the authors of Ants point out) to the rigid hierarchies in the human military and factories, where communication goes from the top down only. In some ways ants are smarter than we are!
Next time, more on ant intelligence and skills.
Ants are the pinnacle of insect evolution, and that’s a lot to say, given that insects are the most copious of critters. Ants' extreme success and longevity can be attributed to their highly developed social lives. Social critters generally seem to thrive better than solitary animals do. Life is a struggle. There are numerous threats to endure, such as competitors, predators, and natural catastrophes. When animals band together cooperatively, their chance of survival increases. (Consider Homo sapiens!)
Thus ants are both robust and plentiful. There are some 8800 known species. They make up some 10-15% of animal biomass in most areas where they live; in the rainforest, as much as 75%. Think of that: such tiny creatures outweighing most all other animals in their vicinity—even elephants and giraffes! They turn and enrich more soil than earthworms. They’ve been around far longer than many extant creatures. They first appeared about 100 million years ago and were unfazed by the disaster that drove the dinosaurs to extinction. Most species last, on a gross average, about one million years. Ants have pushed that much further. Pretty dazzling feats for such a little critter!
I wanted to try to understand ants better, partly because most of my impressions were formed years ago, when I learned to regard them mostly as pests. I came to think that the only thing rivaling a termite or cockroach infestation is to see a line of ants parading across the kitchen counter. But I sensed that, like all the works of Mother Nature, there must be something to appreciate about them, and even revere; so I decided to take a closer look, try to drop my prejudice, and seek to understand them.
I have written here before about my fascination with watching ants (6/9/08) and a bit on their intelligent behavior due to something referred to as swarm intelligence (1/25/09). My ant appetite had become whetted and Ants was a book to try.
Crucial to ants’ success is their caste system: an effective division of labor that gets many sophisticated jobs done. But even though they have a strict hierarchy of tasks, any one ant is free to communicate (mostly chemically, via pheromones) with any other member of the colony. This democratic feature is a major aid in helping the group to be successful—in contrast (the authors of Ants point out) to the rigid hierarchies in the human military and factories, where communication goes from the top down only. In some ways ants are smarter than we are!
Next time, more on ant intelligence and skills.
Tuesday, May 5, 2009
Sunday, May 3, 2009
Bird Experiences, Part 2: Visual
I started these two entries grouping bird experiences as being of two kinds: visual and aural. This posting will look at how birds delight our visual senses. The other three senses—taste, touch, and smell—may become involved at Thanksgiving, but thankfully they’re of little concern for songbird experiences.
Our foremost sense is visual. And there is something about birds that fascinates the eye. Few other spectator sports induce their practitioners to lay out oodles of money for binoculars, pour over birding lists, and fly halfway across the globe just to get a fleeting glance of an exotic species in the forests of Costa Rica or Borneo.
And of the visual appeal of birds, nothing captures our attention like a bird in flight. We are drawn to follow the action. Noting differences in flight styles can be a help in identifying a bird. Look up in the sky around here and see a bird gliding lazily, and it’ll surely be a hawk or a buzzard. (They can be distinguished by their underside. A hawk is nearly white, a buzzard is dark.) If a bird is in power flight with constant wing pumps, it may be a crow far overhead. Most songbirds have a bouncy or undulating flight—in which they’ll pump furiously for a moment (causing it to rise) and then fold their wings momentarily (causing it to dip). That style of action keeps lactic acid from building up in the muscles. Some birds will exhibit more than one kind of flight pattern—depending on their energy level, flight distance, their load, and wind conditions.
I love to watch birds at the feeder—their antics are fascinating. The pecking order is on display then—both within and between species. Sweet little chickadees are at the bottom rank and the red-bellied woodpecker is the current king of the feeder. Nuthatches intimidate titmice. Cardinals tyrannize nuthatches, etc.
Various types of sunflower seed-cracking techniques are also fun to watch. Birds with short, pointed beaks (chickadees, titmice) grab a seed, fly to a nearby branch, wedge the seed under a foot, and bang away at it until they’ve penetrated the shell; then they pick out the meat. Birds with strong beaks (finches, cardinals) just sit on the feeder, pick up a seed and crush it with their bill, spitting out the shell pieces. Ground feeders (juncos, doves) hop around under the feeder, pecking for bits dropped by the spitting finches.
Finally, it’s fascinating to watch how songbirds flock cooperatively around the feeder during winter, but then pair up and face off in the spring. Any pretense of collaboration evaporates, as males begin showing off to prospective mates—calling boldly, as previous buddies square off against each other.
I’m hooked. The more I watch birds, the more I learn, the more I watch. I’m caught in a charming bird whirlpool, but this hermit has no plans to fly to Costa Rica any time soon.
Our foremost sense is visual. And there is something about birds that fascinates the eye. Few other spectator sports induce their practitioners to lay out oodles of money for binoculars, pour over birding lists, and fly halfway across the globe just to get a fleeting glance of an exotic species in the forests of Costa Rica or Borneo.
And of the visual appeal of birds, nothing captures our attention like a bird in flight. We are drawn to follow the action. Noting differences in flight styles can be a help in identifying a bird. Look up in the sky around here and see a bird gliding lazily, and it’ll surely be a hawk or a buzzard. (They can be distinguished by their underside. A hawk is nearly white, a buzzard is dark.) If a bird is in power flight with constant wing pumps, it may be a crow far overhead. Most songbirds have a bouncy or undulating flight—in which they’ll pump furiously for a moment (causing it to rise) and then fold their wings momentarily (causing it to dip). That style of action keeps lactic acid from building up in the muscles. Some birds will exhibit more than one kind of flight pattern—depending on their energy level, flight distance, their load, and wind conditions.
I love to watch birds at the feeder—their antics are fascinating. The pecking order is on display then—both within and between species. Sweet little chickadees are at the bottom rank and the red-bellied woodpecker is the current king of the feeder. Nuthatches intimidate titmice. Cardinals tyrannize nuthatches, etc.
Various types of sunflower seed-cracking techniques are also fun to watch. Birds with short, pointed beaks (chickadees, titmice) grab a seed, fly to a nearby branch, wedge the seed under a foot, and bang away at it until they’ve penetrated the shell; then they pick out the meat. Birds with strong beaks (finches, cardinals) just sit on the feeder, pick up a seed and crush it with their bill, spitting out the shell pieces. Ground feeders (juncos, doves) hop around under the feeder, pecking for bits dropped by the spitting finches.
Finally, it’s fascinating to watch how songbirds flock cooperatively around the feeder during winter, but then pair up and face off in the spring. Any pretense of collaboration evaporates, as males begin showing off to prospective mates—calling boldly, as previous buddies square off against each other.
I’m hooked. The more I watch birds, the more I learn, the more I watch. I’m caught in a charming bird whirlpool, but this hermit has no plans to fly to Costa Rica any time soon.
Friday, May 1, 2009
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