Die Rolle phänotypischer Plastizität der Spermienfunktion in der Artbildung
Ökologie und Biodiversität der Tiere und Ökosysteme, Organismische Interaktionen
Zusammenfassung der Projektergebnisse
We tested reproductive isolation directly or indirectly at many postmating hierarchical levels. We found plenty of variation in many different sperm function traits. However, our extensive approach revealed that reproductive isolation between HL and BL is not extensive as we found initially, and not based on sperm characters. Unfortunately, this prevented a large paper following all the individual steps of the role of sperm plasticity in speciation. Instead we had to resort to a number of smaller papers. However, the quality of the proteomics and lipidomics data is such that impactful papers can still be expected. Genetic distance per se did not explain any characters or isolation, rejecting our first proposed model. In indirect test of reproductive isolation, using full-factorial crosses, diet was identified as the overwhelmingly important factor for most sperm traits measured. These data provide support for the Current ecology model and so explaining the lack of reproductive isolation. Some characters were in line with the idea of an adaptation to ecological conditions. Consequently, it remains unclear how the strong genetic differentiation is maintained in sympatry if no post-copulatory barriers involving sperm traits exist between lineages. The existing isolating factors must be particularly strong given that sperm traits are likely to foster homogenisation rather than isolation of populations. Our work provides substantial evidence for environmental factors impacting sperm characters, including sperm metabolism. While this supports previous critical views, its consequences remain to be fully accepted. For example, if diet is so much more important than genotype to shape sperm performance, the rapid evolution of sperm traits is less likely to be driven by sexual selection. Similarly, if diet affects sperm traits in other species as well, ecological isolation and speciation of host races would require strong scrutiny to correct for phenotypic plasticity. Our work also contributes to establishing a nuanced view of sperm performance in reproductive and evolutionary biology, in particular the subtle shifts between glycolysis and oxidative phosphorylation require a more complex view than motility or ATP production. We also provide the first evidence that seminal fluid indeed affects sperm metabolism. Ex vivo, the glycolytic ratio was dependent on diet and lineage in a way that foreign diet caused a more glycolytic state in both male lineages, whereas OxPhos was unaffected. The observation that the activity pattern of metabolic enzymes is lineage-dependent, and that the ex vivo changes in the sperm metabolism over time differed between the lineages, indicates that the response to metabolic stress has a genetic component as well. We confirm previous work showing a strong change in sperm metabolism as soon as sperm enters the females (i.e. also a change of the sperm environment). Surprisingly, sperm in storage had reduced glycolysis and mitochondria became more active, a process that may be driven by high mitochondrial activity at low sperm density but not sperm competition. Pending final analysis, it appeared as if any metabolic differences in sperm between male lineages would become levelled out during female storage. We are aiming characterise female diet and lineage effects on sperm metabolism from the existing FLIM dataset. We show that sperm characters are substantially moulded by environmental effects, mainly male diet. Unpredicted, we found little reproductive isolation in actual population crosses and almost no isolation in fully factorial designs where BL and HL were forced through the other line’s diet in replicate populations and sperm traits were measured. We did not confirm the very strongly reduced cross fertility (i.e. almost complete postmating isolation). Our proteomics and lipidomics work is novel but still pending full analysis.
Projektbezogene Publikationen (Auswahl)
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Identification and age-dependence of pteridines in bed bugs (Cimex lectularius) and bat bugs (C. pipistrelli) using liquid chromatography-tandem mass spectrometry. Scientific Reports, 10(1).
Křemenová, Jana; Balvín, Ondřej; Otti, Oliver; Pavonič, Michal; Reinhardt, Klaus; Šimek, Zdeněk & Bartonička, Tomáš
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Male diet affects female fitness and sperm competition in human- and bat-associated lineages of the common bedbug, Cimex lectularius. Scientific Reports, 11(1).
Křemenová, Jana; Bartonička, Tomáš; Balvín, Ondřej; Massino, Christian; Reinhardt, Klaus; Sasínková, Markéta; Weig, Alfons R. & Otti, Oliver
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Seminal fluid and sperm diluent affect sperm metabolism in an insect: Evidence from NAD(P)H and flavin adenine dinucleotide autofluorescence lifetime imaging. Microscopy Research and Technique, 85(1), 398-411.
Massino, Christian; Wetzker, Cornelia; Balvin, Ondřej; Bartonicka, Tomáš; Kremenova, Jana; Sasinkova, Markéta; Otti, Oliver & Reinhardt, Klaus
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Ecological lipidology. eLife, 11.
Trautenberg, Laura Christin; Brankatschk, Marko; Shevchenko, Andrej; Wigby, Stuart & Reinhardt, Klaus
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Age-related mating rates among ecologically distinct lineages of bedbugs, Cimex lectularius. Springer Science and Business Media LLC.
Bartonička, Tomáš; Křemenová, Jana; Balvin, Ondrej; Šimek, Zdeněk & Otti, Oliver
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Changes in body size and fertility due to artificial and natural feeding of laboratory common bed bugs (Heteroptera: Cimicidae). Journal of Medical Entomology, 61(1), 34-45.
Sasínková, Markéta; Křemenová, Jana; Chajma, Petr; Bartonička, Tomáš; Massino, Christian; Otti, Oliver & Balvín, Ondřej
