Clade Distributions of <i>Leptotes</i> Butterflies (Lepidoptera: Lycaenidae): Invisible Pieces of the Puzzle in Butterfly Biogeography

ABSTRACT Biogeographic allopatry is easy to miss when clades are not mapped because the patterns are made invisible. This invisibility occurs when ancestral area programs analyse the relationships of artificially constructed areas that have no direct relationship with the distributions of taxa. This problem is illustrated with reference to Leptotes clades, where ancestral areas analysis generates ambiguous results over the role of vicariance and chance dispersal for Madagascar and America. Examination of clade distributions as visible patterns shows that three principal clades are reciprocally allopatric, other than for one widespread African species. The principal allopatric groups are America‐Canary Islands, Africa‐Europe‐Middle East, southern and eastern Asia‐eastern Australia. Each clade comprises two allopatric subclades (excluding one widespread species), which is consistent with allopatric divergence of a widespread ‘pantropical’ ancestor in the Mesozoic. The vicariance pattern of Leptotes clades is repeated by similar patterns in Vanessa (Nymphalidae), Biblidini (Nymphalidae) and Leptocircini (Papilionidae) butterflies. Concordant allopatry requires chance dispersal to generate the same or similar results, time and again in different taxa, whereas a vicariance process implies past tectonic, geological or ecological disruption of entire biotas. The presence of endemic Leptotes on oceanic islands (Galapagos, Canary Islands, Mauritius, Príncipe and São Tomé) does not necessitate chance dispersal, as tectonic studies indicate that the history of these locations involved former geological connections and relationships with other regions. These events could mediate widespread ancestral Leptotes distributions followed by isolation and local survival from Mesozoic time to the present through sequential metapopulation persistence. The biogeography of Leptotes suggests its distribution is an integral part of the global fabric of life rather than the result of waifs and strays disconnected from life in general.