@article{MayrKellerPetersetal.2021, author = {Mayr, Antonia V. and Keller, Alexander and Peters, Marcell K. and Grimmer, Gudrun and Krischke, Beate and Geyer, Mareen and Schmitt, Thomas and Steffan-Dewenter, Ingolf}, title = {Cryptic species and hidden ecological interactions of halictine bees along an elevational gradient}, series = {Ecology and Evolution}, volume = {11}, journal = {Ecology and Evolution}, number = {12}, doi = {10.1002/ece3.7605}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-238853}, pages = {7700 -- 7712}, year = {2021}, abstract = {Changes of abiotic and biotic conditions along elevational gradients represent serious challenges to organisms which may promote the turnover of species, traits and biotic interaction partners. Here, we used molecular methods to study cuticular hydrocarbon (CHC) profiles, biotic interactions and phylogenetic relationships of halictid bees of the genus Lasioglossum along a 2,900 m elevational gradient at Mt. Kilimanjaro, Tanzania. We detected a strong species turnover of morphologically indistinguishable taxa with phylogenetically clustered cryptic species at high elevations, changes in CHC profiles, pollen resource diversity, and a turnover in the gut and body surface microbiome of bees. At high elevations, increased proportions of saturated compounds in CHC profiles indicate physiological adaptations to prevent desiccation. More specialized diets with higher proportions of low-quality Asteraceae pollen imply constraints in the availability of food resources. Interactive effects of climatic conditions on gut and surface microbiomes, CHC profiles, and pollen diet suggest complex feedbacks among abiotic conditions, ecological interactions, physiological adaptations, and phylogenetic constraints as drivers of halictid bee communities at Mt. Kilimanjaro.}, language = {en} } @article{MorisChristmannWirtgenetal.2021, author = {Moris, Victoria C. and Christmann, Katharina and Wirtgen, Aline and Belokobylskij, Sergey A. and Berg, Alexander and Liebig, Wolf-Harald and Soon, Villu and Baur, Hannes and Schmitt, Thomas and Niehuis, Oliver}, title = {Cuticular hydrocarbons on old museum specimens of the spiny mason wasp, Odynerus spinipes (Hymenoptera: Vespidae: Eumeninae), shed light on the distribution and on regional frequencies of distinct chemotypes}, series = {Chemoecology}, volume = {31}, journal = {Chemoecology}, number = {5}, issn = {0937-7409}, doi = {10.1007/s00049-021-00350-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-306999}, pages = {311-322}, year = {2021}, abstract = {The mason wasp Odynerus spinipes shows an exceptional case of intrasexual cuticular hydrocarbon (CHC) profile dimorphism. Females of this species display one of two CHC profiles (chemotypes) that differ qualitatively and quantitatively from each other. The ratio of the two chemotypes was previously shown to be close to 1:1 at three sites in Southern Germany, which might not be representative given the Palearctic distribution of the species. To infer the frequency of the two chemotypes across the entire distributional range of the species, we analyzed with GC-MS the CHC profile of 1042 dry-mounted specimens stored in private and museum collections. We complemented our sampling by including 324 samples collected and preserved specifically for studying their CHCs. We were capable of reliably identifying the chemotypes in 91\% of dry-mounted samples, some of which collected almost 200 years ago. We found both chemotypes to occur in the Far East, the presumed glacial refuge of the species, and their frequency to differ considerably between sites and geographic regions. The geographic structure in the chemotype frequencies could be the result of differential selection regimes and/or different dispersal routes during the colonization of the Western Palearctic. The presented data pave the route for disentangling these factors by providing information where to geographically sample O. spinipes for population genetic analyses. They also form the much-needed basis for future studies aiming to understand the evolutionary and geographic origin as well as the genetics of the astounding CHC profile dimorphism that O. spinipes females exhibit.}, language = {en} } @article{SprengerMuesseHartkeetal.2021, author = {Sprenger, Philipp P. and M{\"u}sse, Christian and Hartke, Juliane and Feldmeyer, Barbara and Schmitt, Thomas and Gebauer, Gerhard and Menzel, Florian}, title = {Dinner with the roommates: trophic niche differentiation and competition in a mutualistic ant-ant association}, series = {Ecological Entomology}, volume = {46}, journal = {Ecological Entomology}, number = {3}, doi = {10.1111/een.13002}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228215}, pages = {562 -- 572}, year = {2021}, abstract = {1. The potential for competition is highest among species in close association. Despite net benefits for both parties, mutualisms can involve costs, including food competition. This might be true for the two neotropical ants Camponotus femoratus and Crematogaster levior, which share the same nest in a presumably mutualistic association (parabiosis). 2. While each nest involves one Crematogaster and one Camponotus partner, both taxa were recently found to comprise two cryptic species that show no partner preferences and seem ecologically similar. Since these cryptic species often occur in close sympatry, they might need to partition their niches to avoid competitive exclusion. 3. Here, we investigated first, is there interference competition between parabiotic Camponotus and Crematogaster, and do they prefer different food sources under competition? And second, is there trophic niche partitioning between the cryptic species of either genus? 4. Using cafeteria experiments, neutral lipid fatty acid and stable isotope analyses, we found evidence for interference competition, but also trophic niche partitioning between Camponotus and Crematogaster. Both preferred protein- and carbohydrate-rich baits, but at protein-rich baits Ca. femoratus displaced Cr. levior over time, suggesting a potential discovery-dominance trade-off between parabiotic partners. Only limited evidence was found for trophic differentiation between the cryptic species of each genus. 5. Although we cannot exclude differentiation in other niche dimensions, we argue that neutral dynamics might mediate the coexistence of cryptic species. This model system is highly suitable for further studies of the maintenance of species diversity and the role of mutualisms in promoting species coexistence.}, language = {en} } @article{HartkeWaldvogelSprengeretal.2021, author = {Hartke, Juliane and Waldvogel, Ann-Marie and Sprenger, Philipp P. and Schmitt, Thomas and Menzel, Florian and Pfenninger, Markus and Feldmeyer, Barbara}, title = {Little parallelism in genomic signatures of local adaptation in two sympatric, cryptic sister species}, series = {Journal of Evolutionary Biology}, volume = {34}, journal = {Journal of Evolutionary Biology}, number = {6}, doi = {10.1111/jeb.13742}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228355}, pages = {937 -- 952}, year = {2021}, abstract = {Species living in sympatry and sharing a similar niche often express parallel phenotypes as a response to similar selection pressures. The degree of parallelism within underlying genomic levels is often unexplored, but can give insight into the mechanisms of natural selection and adaptation. Here, we use multi-dimensional genomic associations to assess the basis of local and climate adaptation in two sympatric, cryptic Crematogaster levior ant species along a climate gradient. Additionally, we investigate the genomic basis of chemical communication in both species. Communication in insects is mainly mediated by cuticular hydrocarbons (CHCs), which also protect against water loss and, hence, are subject to changes via environmental acclimation or adaptation. The combination of environmental and chemical association analyses based on genome-wide Pool-Seq data allowed us to identify single nucleotide polymorphisms (SNPs) associated with climate and with chemical differences. Within species, CHC changes as a response to climate seem to be driven by phenotypic plasticity, since there is no overlap between climate- and CHC-associated SNPs. The only exception is the odorant receptor OR22c, which may be a candidate for population-specific CHC recognition in one of the species. Within both species, climate is significantly correlated with CHC differences, as well as to allele frequency differences. However, associated candidate SNPs, genes and functions are largely species-specific and we find evidence for minimal parallel evolution only on the level of genomic regions (J = 0.04). This highlights that even closely related species may follow divergent evolutionary trajectories when expressing similar adaptive phenotypes.}, language = {en} }