Laboratory mating and biological species concept

Michael Gochfeld gochfeld at
Sat Mar 2 09:00:00 EST 2002

A word of caution regarding testing the biological species concept in the

1. Failure to mate under laboratory conditions may not complete-out
conspecificness, since some species are difficult to breed in the lab under the
best of circumstances.  Consistent production of infertile eggs or aberrant
offspring is better evidence if several pairings are tried.

2. Two different species may be induced, encourage, allowed etc. to mate in a
laboratory that wouldn't do so under natural conditions.  At least that's true
in birds. Ironically, in the field they may choose to mate with another
species......Or at least that's what happened to the last wild Spix's Macaw.

The lone male mated with a female Blue-winged Macaw.  They nested and produced
infertile eggs.  The pair remained mated even when a female Spix's was released
in his territory.  The threesome flew around for some months before the female
Spix disappeared, but the pair heterospecific (and heterosexual) pair bond
remained intact.

3.  The test of the biological species concept, at least as I understood it, was
whether selection operated against the f1, f2,f3,f4 or who knows how many
generations down the line to either strengthen or breakdown pre-mating
isolation.  So even fertile offspring in the lab is not a complete test.

Mike Gochfeld


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