The False Apollo butterfly, distributed from northeastern Greece and the eastern Aegean islands to Turkey, Syria, and the Levant, has long been a subject of taxonomic interest due to its extensive regional variability. Historically, numerous subspecies and forms were described to account for these differences, but many have since been synonymized. Recent reviews recognized between four and six valid subspecies, with the Levantine populations often classified under the subspecific name A. apollinus bellargus. However, earlier genetic studies reported a deep divergence in mitochondrial DNA sequences between Turkish/Greek populations and those in Israel, suggesting the presence of cryptic diversity that had not been fully explored until now.

To investigate this potential diversity, the research team examined 260 butterfly specimens from private collections, documenting their dorsal and ventral surfaces under standardized lighting conditions. They also conducted genitalia dissections to assess morphological differences and compared field photos of larvae from various populations in Syria, Turkey, and the Levant. By combining these morphological and biological data with molecular analysis, the researchers aimed to determine whether the Levantine and Turkish/Greek populations were specifically distinct and to clarify the relationships of central Anatolian populations to either group.

The molecular analysis involved sequencing the mitochondrial COI gene, commonly used for DNA barcoding, along with five other gene regions to strengthen the phylogenetic backbone. The dataset included sequences from various populations of A. apollinus, as well as its congeners A. apollinaris and A. bostanchii, and outgroups from the sister genus Luehdorfia. Using maximum likelihood and Bayesian phylogenetic methods, the researchers constructed trees that revealed two highly divergent lineages within the species. One lineage was confined to western Turkey, northeastern Greece, and the eastern Aegean islands, while the other was found in central Anatolia and the Levant.

Phenotypic differences between the two lineages were substantial and supported their distinct status. Adults from the Levantine lineage exhibited large, deep black submarginal spots on their hindwings with intense blue coloring, whereas western Turkish adults had less developed spots and banding. The flight periods also differed, with Levantine butterflies flying partially in early winter, a trait not observed in the western populations. Furthermore, the caterpillars of the Levantine lineage were velvety black with orange-red spots, while those from western and central Turkey had additional white or greenish-white spots. The pupae also showed clear differences in color and shape, with Levantine pupae being fawn-brown with a light dot pattern, contrasting with the uniform reddish-black of western Turkish pupae.

Despite the clear phenotypic and genetic separation of the Levantine populations, the central Anatolian populations presented a puzzling case. Genetically, these populations clustered with the Levantine lineage, but their morphological and biological traits, including larval host plants and pupal characteristics, closely resembled those of the western Turkish A. apollinus. This discordance between gene trees and species trees is a classic example of incomplete lineage sorting or genetic introgression, where ancestral polymorphisms or hybridization can obscure the true evolutionary history. The researchers noted that the central Anatolian populations likely represent a transitional zone where the two lineages interacted, leading to a mix of genetic and phenotypic traits.

The phylogenetic analysis suggested that the initial split between the western and central/Levantine lineages occurred in the Miocene, around 9.5 million years ago, driven by sea level oscillations and changes in coastal geography. A second isolating event in the Pleistocene separated the Levantine populations from the central Anatolian group, likely due to drier climatic conditions and shifts in larval host plants. These geological and climatic factors played a crucial role in shaping the distribution and evolution of the False Apollo butterfly, highlighting the impact of environmental changes on biodiversity.

Additionally, the study revealed potential hybridization between A. bellargus and A. apollinaris in the Tunceli region of Turkey. Two samples of A. apollinaris from this area yielded COI sequences matching those of A. bellargus amasina, suggesting that these populations may be hybrids resulting from secondary contact and interbreeding. This finding adds another layer of complexity to the evolutionary history of the genus Archon and emphasizes the need for further research to fully understand the interactions between these species.

The recognition of Archon bellargus as a distinct species and the identification of genetic discordance in central Anatolian populations have significant implications for conservation and taxonomy. By clarifying the species boundaries, the study provides a more accurate framework for assessing the diversity and distribution of these butterflies. It also highlights the limitations of relying solely on morphological traits for species identification, advocating for a multi-disciplinary approach that incorporates genetic data. As climate change continues to alter habitats and species ranges, understanding the evolutionary history and genetic structure of species like the False Apollo butterfly will be essential for predicting their responses to environmental changes and implementing effective conservation strategies.

In conclusion, this study sheds light on the complex evolutionary history of the False Apollo butterfly, revealing hidden diversity and the intricate interplay between genetics, morphology, and environment. The recognition of Archon bellargus as a separate species and the identification of gene tree/species tree discordance in central Anatolia contribute to a deeper understanding of speciation processes in Lepidoptera. Future research should focus on expanding genetic sampling and investigating the mechanisms behind the observed discordance, as well as exploring the potential for hybridization in other regions. These efforts will not only refine our taxonomic understanding but also inform conservation efforts for these ecologically and evolutionarily significant butterflies.

Subject of Research: Evolutionary history and taxonomic revision of the False Apollo butterfly (Archon apollinus)

Article Title: Discordance between biological and genetic traits highlights complex evolutionary history in the False Apollo, Archon apollinus (Herbst, 1798) ( Lepidoptera , Papilionidae , Parnassiinae )

Article References: von Stetten, M., & Nazari, V. (2025). Discordance between biological and genetic traits highlights complex evolutionary history in the False Apollo, Archon apollinus (Herbst, 1798) (Lepidoptera, Papilionidae, Parnassiinae). Deutsche Entomologische Zeitschrift, 72(1), 119-131. https://doi.org/10.3897/dez.72.152069

Image Credits: AI Generated

DOI: 10.3897/dez.72.152069

Keywords: Lepidoptera, Papilionidae, Parnassiinae, Archon apollinus, Archon bellargus, Phylogenetics, DNA barcoding, Speciation, Taxonomy, Morphology, Genetic discordance, Mediterranean biodiversity