As populations differentiate across geographic or host-association barriers, interpopulation fertility is often a measure of the extent of incipient speciation. The bed bug, Cimex lectularius L., was recently found to form two host-associated lineages within Europe: one found with humans (human-associated, HA) and the other found with bats (bat-associated, BA). No unequivocal evidence of contemporary gene flow between these lineages has been found; however, it is unclear whether this is due to an inability to produce viable "hybrid" offspring. To address this question and determine the extent of compatibility between host-associated lineages, we set up mating crosses among populations of bed bugs based on both their host association (human-HA vs. bat-BA) and geographic origin (North America vs. Europe). Within-population fecundity was significantly higher for all HA populations (>1.7 eggs/day) than for BA populations (<1 egg/day). However, all within-population crosses, regardless of host association, had >92% egg hatch rates. Contrary to previous reports, in all interlineage crosses, successful matings occurred, fertile eggs were oviposited, and the F1 "hybrid" generation was found to be reproductively viable. In addition, we evaluated interpopulation genetic variation in Wolbachia among host-associated lineages. We did not find any clear patterns related to host association, nor did we observe a homogenization of Wolbachia lineages across populations that might explain a breakdown of reproductive incompatibility. These results indicate that while the HA and BA populations of C. lectularius represent genetically differentiated host-associated lineages, possibly undergoing sympatric speciation, this is in its incipient stage as they remain reproductively compatible. Other behavioral, physiological, and/or ecological factors likely maintain host-associated differentiation.

Center for Human Health and the Environment North Carolina State University Raleigh NC USA

Department of Biological Science The University of Tulsa Tulsa OK USA

Department of Botany and Zoology Masaryk University Brno Czech Republic

Department of Ecology Faculty of Environmental Sciences Czech University of Life Sciences Prague Czech Republic

Department of Entomology and Plant Pathology North Carolina State University Raleigh NC USA

Department of Entomology University of Kentucky Lexington KY USA

Ecology and Evolutionary Biology Princeton University Princeton NJ USA

W M Keck Center for Behavioral Biology North Carolina State University Raleigh NC USA

Zobrazit více v PubMed

Balvín, O. , Bartonička, T. , Pilařová, K. , DeVries, Z. , & Schal, C. (2017). Discrimination between lineage‐specific shelters by bat‐and human‐associated bed bugs does not constitute a stable reproductive barrier. Parasitology Research, 116, 237–242. 10.1007/s00436-016-5284-y PubMed DOI

Balvín, O. , & Booth, W. (2018). Distribution and frequency of pyrethroid resistance‐associated mutations in host lineages of the bed bug (Hemiptera: Cimicidae) across Europe. Journal of Medical Entomology, 55, 923–928. 10.1093/jme/tjy023 PubMed DOI

Balvín, O. , Munclinger, P. , Kratochvíl, L. , & Vilímová, J. (2012). Mitochondrial DNA and morphology show independent evolutionary histories of bedbug Cimex lectularius (Heteroptera: Cimicidae) on bats and humans. Parasitology Research, 111, 457–469. 10.1007/s00436-012-2862-5 PubMed DOI

Barbarin, A. M. , Barbu, C. M. , Gebhardtsbauer, R. , & Rajotte, E. G. (2014). Survival and fecundity of two strains of Cimex lectularius (Hemiptera: Heteroptera). Journal of Medical Entomology, 51, 925–931. PubMed

Barbarin, A. M. , Gebhardtsbauer, R. , & Rajotte, E. G. (2013). Evaluation of blood regimen on the survival of Cimex lectularius L. using life table parameters. Insects, 4, 273–286. 10.3390/insects4020273 PubMed DOI PMC

Benoit, J. B. , Adelman, Z. N. , Reinhardt, K. , Dolan, A. , Poelchau, M. , Jennings, E. C. , … Richards, S. (2016). Unique features of a global human ectoparasite identified through sequencing of the bed bug genome. Nature Communications, 7, 10165 10.1038/ncomms10165 PubMed DOI PMC

Booth, W. , Balvín, O. , Vargo, E. L. , Vilímová, J. , & Schal, C. (2015). Host association drives genetic divergence in the bed bug, Cimex lectularius . Molecular Ecology, 24, 980–992. PubMed

Bush, G. L. (1969). Sympatric host race formation and speciation in frugivorous flies of the genus Rhagoletis (Diptera, Tephritidae). Evolution, 23, 237–251. 10.2307/2406788 PubMed DOI

Clement, M. , Posada, D. , & Crandall, K. A. (2000). TCS: A computer program to estimate gene genealogies. Molecular Ecology, 9, 1657–1659. 10.1046/j.1365-294x.2000.01020.x PubMed DOI

Dambroski, H. R. , Linn, C. , Berlocher, S. H. , Forbes, A. A. , Roelofs, W. , & Feder, J. L. (2005). The genetic basis for fruit odor discrimination in Rhagoletis flies and its significance for sympatric host shifts. Evolution, 59, 1953–1964. 10.1111/j.0014-3820.2005.tb01065.x PubMed DOI

DeVries, Z. , Mick, R. , Balvín, O. , & Schal, C. (2017). Aggregation behavior and reproductive compatibility in the family Cimicidae. Scientific Reports, 7, 13163 10.1038/s41598-017-12735-3 PubMed DOI PMC

DeVries, Z. C. , Saveer, A. M. , Mick, R. , & Schal, C. (2019). Bed bug (Hemiptera: Cimicidae) attraction to human odors: Validation of a two‐choice olfactometer. Journal of Medical Entomology, 56, 362–367. PubMed PMC

Drès, M. , & Mallet, J. (2002). Host races in plant–feeding insects and their importance in sympatric speciation. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 357, 471–492. 10.1098/rstb.2002.1059 PubMed DOI PMC

Feder, J. L. , Chilcote, C. A. , & Bush, G. L. (1988). Genetic differentiation between sympatric host races of the apple maggot fly Rhagoletis pomonella . Nature, 336, 61–64. 10.1038/336061a0 DOI

Gordon, J. R. , Potter, M. F. , & Haynes, K. F. (2015). Insecticide resistance in the bed bug comes with a cost. Scientific Reports, 5, 10807 10.1038/srep10807 PubMed DOI PMC

Gries, R. , Britton, R. , Holmes, M. , Zhai, H. , Draper, J. , & Gries, G. (2015). Bed bug aggregation pheromone finally identified. Angewandte Chemie, 127, 1151–1154. 10.1002/ange.201409890 PubMed DOI

Hajibabaei, M. , Janzen, D. H. , Burns, J. M. , Hallwachs, W. , & Hebert, P. D. (2006). DNA barcodes distinguish species of tropical Lepidoptera. Proceedings of the National Academy of Sciences of the United States of America, 103, 968–971. 10.1073/pnas.0510466103 PubMed DOI PMC

Harraca, V. , Ryne, C. , Birgersson, G. , & Ignell, R. (2012). Smelling your way to food: Can bed bugs use our odour? Journal of Experimental Biology, 215, 623–629. 10.1242/jeb.065748 PubMed DOI

Hebert, P. D. , Ratnasingham, S. , & De Waard, J. R. (2003). Barcoding animal life: Cytochrome c oxidase subunit 1 divergences among closely related species. Proceedings of the Royal Society of London. Series B: Biological Sciences, 270, S96–S99. PubMed PMC

Hosokawa, T. , Koga, R. , Kikuchi, Y. , Meng, X.‐Y. , & Fukatsu, T. (2010). Wolbachia as a bacteriocyte‐associated nutritional mutualist. Proceedings of the National Academy of Sciences of the United States of America, 107, 769–774. 10.1073/pnas.0911476107 PubMed DOI PMC

Karowe, D. N. (1989). Facultative monophagy as a consequence of prior feeding experience: Behavioral and physiological specialization in Colias philodice larvae. Oecologia, 78, 106–111. 10.1007/BF00377204 PubMed DOI

Lawerence, C. (2018). The bed bug, Cimex lectularius: A model system for the study of mitochondrial and endosymbiont genome evolution. M.S., The University of Tulsa, OK.

Linn, C. E. , Dambroski, H. R. , Feder, J. L. , Berlocher, S. H. , Nojima, S. , & Roelofs, W. L. (2004). Postzygotic isolating factor in sympatric speciation in Rhagoletis flies: Reduced response of hybrids to parental host‐fruit odors. Proceedings of the National Academy of Sciences of the United States of America, 101, 17753–17758. 10.1073/pnas.0408255101 PubMed DOI PMC

Linn, C. , Feder, J. L. , Nojima, S. , Dambroski, H. R. , Berlocher, S. H. , & Roelofs, W. (2003). Fruit odor discrimination and sympatric host race formation in Rhagoletis . Proceedings of the National Academy of Sciences of the United States of America, 100, 11490–11493. 10.1073/pnas.1635049100 PubMed DOI PMC

Liu, F. , & Liu, N. (2015). Human odorant reception in the common bed bug, Cimex lectularius . Scientific Reports, 5, 15558. PubMed PMC

McPheron, B. A. , Smith, D. C. , & Berlocher, S. H. (1988). Genetic differences between host races of Rhagoletis pomonella . Nature, 336, 64–66. 10.1038/336064a0 DOI

Scriber, J. M. (1979). The effects of sequentially switching foodplants upon biomass and nitrogen utilization by polyphagous and stenophagous Papilio larvae. Entomologia Experimentalis Et Applicata, 25, 203–215. 10.1111/j.1570-7458.1979.tb02872.x DOI

Sharon, G. , Segal, D. , Ringo, J. M. , Hefetz, A. , Zilber‐Rosenberg, I. , & Rosenberg, E. (2010). Commensal bacteria play a role in mating preference of Drosophila melanogaster . Proceedings of the National Academy of Sciences of the United States of America, 107, 20051–20056. 10.1073/pnas.1009906107 PubMed DOI PMC

Siljander, E. , Gries, R. , Khaskin, G. , & Gries, G. (2008). Identification of the airborne aggregation pheromone of the common bed bug, Cimex lectularius . Journal of Chemical Ecology, 34, 708–718. PubMed

Stouthamer, R. , Breeuwer, J. A. , & Hurst, G. D. (1999). Wolbachia pipientis: Microbial manipulator of arthropod reproduction. Annual Review of Microbiology, 53, 71–102. PubMed

Szalanski, A. L. , Austin, J. W. , McKern, J. A. , Steelman, C. D. , & Gold, R. E. (2008). Mitochondrial and ribosomal internal transcribed spacer 1 diversity of Cimex lectularius (Hemiptera: Cimicidae). Journal of Medical Entomology, 45, 229–236. 10.1093/jmedent/45.2.229 PubMed DOI

Ueshima, N. (1964). Experiments on reproductive isolation in Cimex lectularius and Cimex columbarius . Pan‐Pacific Entomologist, 40, 47–53.

Usinger, R. L. (1966). Monograph of Cimicidae (Hemiptera, Heteroptera). College Park, MD: Entomological Society of America.

Via, S. , Bouck, A. C. , & Skillman, S. (2000). Reproductive isolation between divergent races of pea aphids on two hosts. II. Selection against migrants and hybrids in the parental environments. Evolution, 54, 1626–1637. 10.1111/j.0014-3820.2000.tb00707.x PubMed DOI

Wawrocka, K. , Balvín, O. , & Bartonička, T. (2015). Reproduction barrier between two lineages of bed bug (Cimex lectularius) (Heteroptera: Cimicidae). Parasitology Research, 114, 3019–3025. 10.1007/s00436-015-4504-1 PubMed DOI

Wawrocka, K. , & Bartonička, T. (2013). Two different lineages of bedbug (Cimex lectularius) reflected in host specificity. Parasitology Research, 112, 3897–3904. 10.1007/s00436-013-3579-9 PubMed DOI

Werren, J. H. (1997). Biology of Wolbachia . Annual Review of Entomology, 42, 587–609. PubMed

Werren, J. H. , Baldo, L. , & Clark, M. E. (2008). Wolbachia: Master manipulators of invertebrate biology. Nature Reviews Microbiology, 6, 741–751. 10.1038/nrmicro1969 PubMed DOI

Despite genetic isolation in sympatry, post-copulatory reproductive barriers have not evolved between bat- and human-associated common bedbugs (Cimex lectularius L.)