Urania is a large genus of tropical insects inhabiting the territory of the tropics of South and Central America and North America’s southern zones. The majority of this taxon’s representatives can be found in Brazil, Suriname, Guiana, Colombia, Venezuela, Ecuador, Peru, Mexico, Cuba, Barbados, Dominica, and Jamaica. At the same time, out of more than thirteen species, only Chrysiridia is an endemic population inhabiting the territory of Madagascar and coastal zones. Thus, the biogeographic study’s first question should be related to the search for the mechanism of dispersal of butterflies so that one of the subspecies turned out to be geographically isolated.
Apparently, at the time of Pangea, a single population of butterflies existed on a rather limited range, but this group remained entirely on Gondwana at the time of division. This assumption agrees well with Urania’s current dispersal since, as has been said, the butterflies predominantly occupy the southern regions of the planet. Over time, however, presumably 88 million years ago, when Gondwana has been already divided, a fragment, called in modern geography the island of Madagascar, was broken away from it. The Urania population may have historically remained directly on this island, has changed over time into Chrysiridia. This hypothesis can be confirmed by conducting an additional phylogenetic study and estimating the age of divergence of butterflies. According to this analysis, it was determined that Chrysiridia is indeed a distant relative for modern Urania, from which it follows that the assumption of dispersal was correct. However, it is also worth noting that even if continentally forced dispersal was not the cause of separation, human activity, namely the active settlement of the island, may have been a factor in introducing the invasive species to Madagascar and further isolation.
Nevertheless, in all probability, anthropogenic activity (or even the natural migration of butterflies through the waters of the Indian Ocean) was not the cause of the settlement of Madagascar’s territories. Logical confirmation of this question may be found in the study of the ecological peculiarities of the species. Thus, plants of the genus Omphalea, evolutionarily related to butterflies’ life activity, are distributed over a much wider area, and among them, active colonization is represented in Madagascar. In other words, assuming that Chrysiridia was introduced artificially, then the toxic Omphalea plants must also have entered the island. Therefore, it is more likely that this dispersal of the butterfly is due to natural geographical modifications of the continents, which caused the close symbiotic proximity with Omphalea. This study requires additional phylogenetic analysis of Omphalea from South America and Madagascar’s territories to clarify the degree of similarity.
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