A phylogenetic framework for wing pattern evolution in the mimetic Mocker Swallowtail Papilio dardanus.

Area of Science:

• Evolutionary biology
• Genetics
• Zoology

Background:

• The swallowtail butterfly Papilio dardanus displays significant wing color polymorphism, crucial for Batesian mimicry.
• Understanding the evolutionary history of these morphs requires detailed phylogenetic and genetic analyses.

Purpose of the Study:

• To establish a phylogenetic framework for studying the evolutionary origins of Papilio dardanus wing color morphs.
• To investigate the genetic basis and geographic structuring of mimicry-related genes.
• To correlate the evolution of P. dardanus morphs with the introduction of mimicry models in Africa.

Main Methods:

• DNA sequencing of mitochondrial genes and the nuclear internal transcribed spacer marker.
• Analysis of genetic markers linked to the mimicry locus H, including the invected gene and amplified fragment length polymorphisms.
• Examination of variation in the unlinked wingless gene.

Main Results:

• Deeply separated eastern and western African mainland lineages, with distinct lineages on Madagascar and Grande Comore, were identified using mitochondrial and ITS markers.
• Markers linked to the mimicry locus H exhibited high nucleotide diversity but lacked geographic structure, unlike mitochondrial DNA.
• The timing of P. dardanus divergence from P. phorcas predates the arrival of the mimicry model Danaus chrysippus in Africa, but mimicry morphs likely arose early in P. dardanus evolution.

Conclusions:

• Widespread mimicry morphs in Papilio dardanus appear to have originated early in the lineage's evolution, potentially before recent population differentiation.
• The nuclear genome's lack of geographic structure suggests a different evolutionary history compared to mitochondrial DNA.
• The current distribution and population structure of P. dardanus are likely linked to the historical spread of its mimicry models across Africa.