@article{BuellesbachVetterSchmitt2018,
  author    = {Buellesbach, Jan and Vetter, Sebastian G. and Schmitt, Thomas},
  title     = {Differences in the reliance on cuticular hydrocarbons as sexual signaling and species discrimination cues in parasitoid wasps},
  series = {Frontiers in Zoology},
  volume    = {15},
  journal   = {Frontiers in Zoology},
  doi       = {10.1186/s12983-018-0263-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-221702},
  year      = {2018},
  abstract  = {Background Cuticular hydrocarbons (CHC) have been documented to play crucial roles as species- and sex-specific cues in the chemical communication systems of a wide variety of insects. However, whether they are sufficient by themselves as the sole cue triggering sexual behavior as well as preference of con- over heterospecific mating partners is rarely assessed. We conducted behavioral assays in three representative species of parasitoid wasps (Hymenoptera: Pteromalidae) to determine their reliance on CHC as species-specific sexual signaling cues. Results We found a surprising degree of either unspecific or insufficient sexual signaling when CHC are singled out as recognition cues. Most strikingly, the cosmopolitan species Nasonia vitripennis, expected to experience enhanced selection pressure to discriminate against other co-occurring parasitoids, did not discriminate against CHC of a partially sympatric species from another genus, Trichomalopsis sarcophagae. Focusing on the latter species, in turn, it became apparent that CHC are even insufficient as the sole cue triggering conspecific sexual behavior, hinting at the requirement of additional, synergistic sexual cues particularly important in this species. Finally, in the phylogenetically and chemically most divergent species Muscidifurax uniraptor, we intriguingly found both CHC-based sexual signaling as well as species discrimination behavior intact although this species is naturally parthenogenetic with sexual reproduction only occurring under laboratory conditions. Conclusions Our findings implicate a discrepancy in the reliance on and specificity of CHC as sexual cues in our tested parasitioid wasps. CHC profiles were not sufficient for unambiguous discrimination and preference behavior, as demonstrated by clear cross-attraction between some of our tested wasp genera. Moreover, we could show that only in T. sarcophagae, additional behavioral cues need to be present for triggering natural mating behavior, hinting at an interesting shift in signaling hierarchy in this particular species. This demonstrates the importance of integrating multiple, potentially complementary signaling modalities in future studies for a better understanding of their individual contributions to natural sexual communication behavior.},
  language  = {en}
}
@article{DiaoMoussetHorsburghetal.2016,
  author    = {Diao, Wenwen and Mousset, Mathilde and Horsburgh, Gavin J. and Vermeulen, Cornelis J. and Johannes, Frank and van de Zande, Louis and Ritchie, Michael G. and Schmitt, Thomas and Beukeboom, Leo W.},
  title     = {Quantitative Trait Locus Analysis of Mating Behavior and Male Sex Pheromones in Nasonia Wasps},
  series = {G3: Genes Genomes Genetics},
  volume    = {6},
  journal   = {G3: Genes Genomes Genetics},
  number    = {6},
  doi       = {10.1534/g3.116.029074},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-165412},
  pages     = {1549-1562},
  year      = {2016},
  abstract  = {A major focus in speciation genetics is to identify the chromosomal regions and genes that reduce hybridization and gene flow. We investigated the genetic architecture of mating behavior in the parasitoid wasp species pair Nasonia giraulti and Nasonia oneida that exhibit strong prezygotic isolation. Behavioral analysis showed that N. oneida females had consistently higher latency times, and broke off the mating sequence more often in the mounting stage when confronted with N. giraulti males compared with males of their own species. N. oneida males produce a lower quantity of the long-range male sex pheromone (4R,5S)-5-hydroxy-4-decanolide (RS-HDL). Crosses between the two species yielded hybrid males with various pheromone quantities, and these males were used in mating trials with females of either species to measure female mate discrimination rates. A quantitative trait locus (QTL) analysis involving 475 recombinant hybrid males (F2), 2148 reciprocally backcrossed females (F3), and a linkage map of 52 equally spaced neutral single nucleotide polymorphism (SNP) markers plus SNPs in 40 candidate mating behavior genes revealed four QTL for male pheromone amount, depending on partner species. Our results demonstrate that the RS-HDL pheromone plays a role in the mating system of N. giraulti and N. oneida, but also that additional communication cues are involved in mate choice. No QTL were found for female mate discrimination, which points at a polygenic architecture of female choice with strong environmental influences.},
  language  = {en}
}
@article{HartkeSprengerSahmetal.2019,
  author    = {Hartke, Juliane and Sprenger, Philipp P. and Sahm, Jacqueline and Winterberg, Helena and Orivel, J{\´e}r{\^o}me and Baur, Hannes and Beuerle, Till and Schmitt, Thomas and Feldmeyer, Barbara and Menzel, Florian},
  title     = {Cuticular hydrocarbons as potential mediators of cryptic species divergence in a mutualistic ant association},
  series = {Ecology and Evolution},
  volume    = {9},
  journal   = {Ecology and Evolution},
  doi       = {10.1002/ece3.5464},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227857},
  pages     = {9160-9176},
  year      = {2019},
  abstract  = {Upon advances in sequencing techniques, more and more morphologically identical organisms are identified as cryptic species. Often, mutualistic interactions are proposed as drivers of diversification. Species of the neotropical parabiotic ant association between Crematogaster levior and Camponotus femoratus are known for highly diverse cuticular hydrocarbon (CHC) profiles, which in insects serve as desiccation barrier but also as communication cues. In the present study, we investigated the association of the ants' CHC profiles with genotypes and morphological traits, and discovered cryptic species pairs in both genera. To assess putative niche differentiation between the cryptic species, we conducted an environmental association study that included various climate variables, canopy cover, and mutualistic plant species. Although mostly sympatric, the two Camponotus species seem to prefer different climate niches. However in the two Crematogaster species, we could not detect any differences in niche preference. The strong differentiation in the CHC profiles may thus suggest a possible role during speciation itself either by inducing assortative mating or by reinforcing sexual selection after the speciation event. We did not detect any further niche differences in the environmental parameters tested. Thus, it remains open how the cryptic species avoid competitive exclusion, with scope for further investigations.},
  language  = {en}
}
@article{KoenigZundelKrimmeretal.2019,
  author    = {K{\"o}nig, Kerstin and Zundel, Petra and Krimmer, Elena and K{\"o}nig, Christian and Pollmann, Marie and Gottlieb, Yuval and Steidle, Johannes L. M.},
  title     = {Reproductive isolation due to prezygotic isolation and postzygotic cytoplasmic incompatibility in parasitoid wasps},
  series = {Ecology and Evolution},
  volume    = {9},
  journal   = {Ecology and Evolution},
  doi       = {10.1002/ece3.5588},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-222796},
  pages     = {10694-10706},
  year      = {2019},
  abstract  = {The reproductive barriers that prevent gene flow between closely related species are a major topic in evolutionary research. Insect clades with parasitoid lifestyle are among the most species-rich insects and new species are constantly described, indicating that speciation occurs frequently in this group. However, there are only very few studies on speciation in parasitoids. We studied reproductive barriers in two lineages of Lariophagus distinguendus (Chalcidoidea: Hymenoptera), a parasitoid wasp of pest beetle larvae that occur in human environments. One of the two lineages occurs in households preferably attacking larvae of the drugstore beetle Stegobium paniceum ("DB-lineage"), the other in grain stores with larvae of the granary weevil Sitophilus granarius as main host ("GW-lineage"). Between two populations of the DB-lineage, we identified slight sexual isolation as intraspecific barrier. Between populations from both lineages, we found almost complete sexual isolation caused by female mate choice, and postzygotic isolation, which is partially caused by cytoplasmic incompatibility induced by so far undescribed endosymbionts which are not Wolbachia or Cardinium. Because separation between the two lineages is almost complete, they should be considered as separate species according to the biological species concept. This demonstrates that cryptic species within parasitoid Hymenoptera also occur in Central Europe in close contact to humans.},
  language  = {en}
}