Overspecialized diets and evolution (Talk.Origins)

Claim CB952:

An important element in an animal's struggle for existence is adaptability to a varied diet. If, say, a bird depended for its existence on a diet of one particular gnat, and that gnat disappeared, then the species of bird would die of starvation. But evolution proposes that an ancestral wasp with a varied diet evolved into species with very particular diets. Such evolution would not be advantageous.

Source:
 * Fabre, J. Henri. 1921. A dig at evolutionists. In: Alexander Teixeira de Mattos (transl.), More Hunting Wasps, New York: Dodd, Mead and Company, pp. 203-213.

CreationWiki response:

While Talk Origins does make a good point here, this claim seems to be unique to the cited source.

Dietas demasiado especializadas y la evolución (Talk.Origins) Dietas superespecializadas e evolução (Talk.Origins)