One of the mysteries of the English language finally explained.
Definition of remigrant in English:
remigrant
noun
1Entomology. In aphids and other plant lice: a female of a winged parthenogenetic generation (sexuparae) that returns to the primary plant host in the autumn.
2Zoology. In vertebrates, especially sea turtles: an individual that migrates back to a site where it has bred in previous seasons.
Origin
Early 20th century; earliest use found in Proceedings of the American Philosophical Society. From re- + migrant, originally after scientific Latin remigrantes, plural. In later use probably partly also after remigrate.