genetically programmed to select certain microhabitats, using particular
(but unknown) cues (for a recent study of niche preferences in gill
Monogenea, see also Gutiérrez and Martorelli, 1999).Mating
The role of mating in hermaphroditic parasites
The common occurrence of sexual reproduction in most animal (and
plant) species clearly indicates that it has significant selective advantages,
but there is still debate on what these advantages are. Escape from
parasites and the accelerated evolution of beneficial traits have been174 K. Rohde
Fig. 9.1. Distribution of species of Mallophaga onIbis falcinellus. A.Ibidoecus
bisignatus, feathers of head and neck. B.Menoponplagadis, feathers of chest,
sides and abdomen. C.Esthiopterum rhaphidium, feathers of the dorsum.
D. Species ofColpocephalumandFerribia, feathers of wings and tail. Redrawn
and strongly modified after V.B. Dubinin (in Dogiel, 1962).