Browsing by Subject "Speciation"

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    New species based on the biological species concept within the complex of Lariophagus distinguendus (Hymenoptera, Chalcidoidea, Pteromalidae), a parasitoid of household pests
    (2023) Pollmann, Marie; Kuhn, Denise; König, Christian; Homolka, Irmela; Paschke, Sina; Reinisch, Ronja; Schmidt, Anna; Schwabe, Noa; Weber, Justus; Gottlieb, Yuval; Steidle, Johannes Luitpold Maria
    The pteromalid parasitoid Lariophagus distinguendus (Foerster) belongs to the Hymenoptera, a megadiverse insect order with high cryptic diversity. It attacks stored product pest beetles in human storage facilities. Recently, it has been shown to consist of two separate species. To further study its cryptic diversity, strains were collected to compare their relatedness using barcoding and nuclear genes. Nuclear genes identified two clusters which agree with the known two species, whereas the barcode fragment determined an additional third Clade. Total reproductive isolation (RI) according to the biological species concept (BSC) was investigated in crossing experiments within and between clusters using representative strains. Sexual isolation exists between all studied pairs, increasing from slight to strong with genetic distance. Postzygotic barriers mostly affected hybrid males, pointing to Haldane's rule. Hybrid females were only affected by unidirectional Spiroplasma‐induced cytoplasmic incompatibility and behavioural sterility, each in one specific strain combination. RI was virtually absent between strains separated by up to 2.8% COI difference, but strong or complete in three pairs from one Clade each, separated by at least 7.2%. Apparently, each of these clusters represents one separate species according to the BSC, highlighting cryptic diversity in direct vicinity to humans. In addition, these results challenge the recent ‘turbo‐taxonomy’ practice of using 2% COI differences to delimitate species, especially within parasitic Hymenoptera. The gradual increase in number and strength of reproductive barriers between strains with increasing genetic distance also sheds light on the emergence of barriers during the speciation process in L. distinguendus.
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    Publication
    Phylogenomic approach to integrative taxonomy resolves a century‐old taxonomic puzzle and the evolutionary history of the Acromyrmex octospinosus species complex
    (2024) Mera‐Rodríguez, Daniela; Fernández‐Marín, Hermógenes; Rabeling, Christian; Mera‐Rodríguez, Daniela; Department of Integrative Taxonomy and Biodiversity of Insects, Institute of Biology, University of Hohenheim, Stuttgart, Germany; Fernández‐Marín, Hermógenes; Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología, INDICASAT AIP, Panama City, Panama; Rabeling, Christian; Department of Integrative Taxonomy and Biodiversity of Insects, Institute of Biology, University of Hohenheim, Stuttgart, Germany
    Accurately delimiting species boundaries is essential for understanding biodiversity. Here, we assessed the taxonomy of the leaf‐cutting ants in the Acromyrmex octospinosus (Reich) species complex using an integrative approach incorporating morphological, population genetic, phylogenetic and biogeographical data. We sampled populations across the biogeographic distribution of the species complex and reconstructed their evolutionary relationships using ultraconserved elements (UCEs) as molecular markers. We evaluated traditional morphological characters used to distinguish putative taxa and performed species delimitation analyses to investigate divergence between evolutionary lineages. Our results support the hypothesis that the A. octospinosus species complex consists of two species: the widely distributed and polymorphic species A. octospinosus and its inquiline social parasite A. insinuator Schultz et al. We consider A. echinatior (Forel) syn. nov . and A. volcanus Wheeler syn. nov . as well as the subspecies A. octospinosus cubanus Wheeler syn. nov ., A. octospinosus ekchuah Wheeler syn. nov . and A. octospinosus inti Wheeler syn. nov . as junior synonyms of A. octospinosus . We also investigated the biogeographic history of the species complex and the evolutionary origin of the social parasite A. insinuator . We inferred that A. octospinosus originated during the late Miocene approximately 6.9 Ma ago in the Neotropical rainforest. Acromyrmex insinuator shared a common ancestor with A. octospinosus approximately 3.4 Ma ago, with a crown‐group age of approximately 0.9 Ma. Our phylogeny supports the hypothesis that the inquiline social parasite speciated via the intra‐specific route of social parasite evolution in direct sympatry from its host. Our findings reshape our understanding of the A. octospinosus species complex and provide a foundation for future studies of Acromyrmex leaf‐cutting ants.