Several workers have brought attention to the fact that elaborated characters that ought to be costly in one way or another for their bearers (e.g., the tails of some species of Xiphophorus fish) do not always appear to have a cost in terms of energetics, performance or even survival.
En varios traballos prestouse atención ao feito de que os elaborados caracteres que deberían ser costosos dun modo ou outro para os que os levan (por exemplo, as colas dalgunhas especies de peixes Xiphophorus) non sempre parecen ter un custo en termos enerxéticos, en rendemento ou mesmo en supervivencia.