A model for studying isolation mechanisms in parasite populations: the genus Lepeophtheirus (Copepoda, Caligidae)

Area of Science:

• Marine biology
• Parasitology
• Ichthyology

Background:

• Lepeophtheirus thompsoni parasitizes Mediterranean turbot.
• Lepeophtheirus europaensis infests brill and flounder in the Mediterranean.

Purpose of the Study:

• To investigate physiological compatibility between Lepeophtheirus copepods and turbot.
• To explore genetic compatibility and reproductive isolation mechanisms between Lepeophtheirus species.

Main Methods:

• Experimental infestation of turbot with L. thompsoni and L.europaensis.
• Observation of parasite development and hybrid formation.

Main Results:

• No physiological incompatibility was observed for turbot infestation by either copepod species.
• Experimental interspecific hybrids were successfully produced.
• Absence of strict genetic barriers between L. thompsoni and L.europaensis.

Conclusions:

• Natural isolation between these parasitic copepod species is likely due to habitat selection, not genetic or physiological barriers.
• The presence of L.europaensis on brill and flounder warrants further investigation into its origin and ecological impact.