Follow up question to Earthworm report

[NiceGuyJack]

http://www.straightdope.com/mailbag/mwormsna.html

If the 30 varieties were virtually identical, wouldn’t that indicate that they could interbreed creating new hybrid species? If they are virtually identical, how can you tell if they haven’t already?

Jack

[sford]

> If the 30 varieties were virtually identical…

He didn’t say “varieties”. He said:

> If you live in the East, you’re just going
> to have to learn to recognize 30 virtually
> identical species if you want to know for sure.

(emphasis mine)

By definition, species can’t interbreed. I assumme he meant that they were visually almost identical. There would be genetic differences significant enough to prevent the production of fertile offspring of a cross-breed. (Actually, I think there are exceptions to this rule, but I don’t know what they are.)

More importantly, even though we humans have a hard time telling one worm from another, that doesn’t mean that the worms have a hard time. There could be chemical or behavioral cues that make all the difference.

[C_K_Dexter_Haven]

One of the problem of courtship amongst the earthworms is not only that they have a hard time telling one earthworm from another, they have a hard time figuring out which END of the other worm they’re dealing with. This can lead to embarrassment, as you might imagine.

[Duck_Duck_Goose]

Thank you, Doug, for ushering us into the wonderful world of earthworm taxonomy.

http://www.microsoil.com/earthworm.htm

Ten thousand years ago, immediately after the last ice age,the lumbricid earthworms were to be found only in certain restricted areas of the planet, such as in the valleys of three great civilizations - the Indus, the Euphrates, and the Nile - where crops grew almost without cultivation in a soil of immensely fruitful richness.

< snip >

In the northern part of North America the last ice age so stripped the country bare of earthworms that in very few areas of what is now the United States were agricultural lands rich enough to support even moderately large populations of native American Indians. As Minnich says: “Before European contact, the only lumbricids native to the United States were some lacy species of Bismatus and Eisenia, essentially worthless as soil builders.”

But wedged in the shoes of the colonists’ horses were tiny lumbricid egg capsules, and in the root balls of European plants immigrant earthworms arrived to remedy the situation. In no time a rich but dormant soil was transformed into one of high fertility. The lush meadows of New England, the vast farmlands of the upper Midwest, the great wheat fields of Canada are all attributed to the introduction of the earthworm.

Not to mention this.

http://idid.essortment.com/whatareearthwo_rsyf.htm

During the last Ice Age, some 10,000-50,000 years ago, the worm population was almost entirely wiped out. As a result, many birds that relied on worms as food, also began to perish. As settlers moved from Europe, they tucked worms into their plants, having already heard of the worm’s plight. After arriving in the New World, settlers began to stuff worms into the soil and within a few years, the worm population had returned.

And this.

http://www.compost-bin.com/column.htm

The most common garden earthworm, the nightcrawler (lumbricus terristris) is not native to North America and was in fact brought,over in potted plants by Europeans. Most of the native North American earthworms were killed during the last Ice Age 10 to 15 thousand years ago. This is one case of where the accidental introduction of a foreign species has been beneficial.

A Google search for “earthworm Ice Age” brought up 2,030 websites where people are repeating this factoid. So, what you’re saying is, this is a crock?

[sub]Duh. Like the entire North American ecosystem was saved only because some white Europeans happened to arrive with worm eggs?[/sub]