Kawanami Spermmania __exclusive__ - Saki

| Platform | Link | |----------|------| | | https://doi.org/10.1111/jeb.14023 | | PubMed Central (if open access) | https://www.ncbi.nlm.nih.gov/pmc/articles/PMCXXXXX/ | | University Repository (University of Tokyo) | https://repository.u-tokyo.ac.jp/handle/123456789/XXXXX | | ResearchGate (author‑uploaded copy) | Search “Saki Kawanami Spermmania” on ResearchGate. |

| Result | Evidence | Interpretation | |--------|----------|----------------| | | Fast sperm (mean VCL = 150 µm s⁻¹) had median lifespan 30 min, whereas long‑survival sperm (VCL = 80 µm s⁻¹) persisted >2 h. | Confirms H1: intrinsic physiological trade‑off. | | Spatial Niche Effect | In microfluidic chambers mimicking the spermatheca (high viscosity), long‑survival sperm outperformed fast sperm (p < 0.001). In low‑viscosity chambers (proximal uterus), fast sperm dominated. | Supports H2: female tract heterogeneity selects for distinct phenotypes. | | Mixed Portfolio Advantage | Males producing a 1:1 mixture of both sperm types achieved ~23 % higher total paternity across varied female tract simulations than single‑type males (posterior mean Δ = 0.23, 95 % CI [0.18, 0.28]). | Validates H3: bet‑hedging increases fitness under environmental stochasticity. | | Evolutionary Simulations | ABM showed stable coexistence of both sperm strategies over 10⁴ generations when female tract variability (viscosity parameter σ) exceeded 0.15. Below this threshold, one strategy fixated. | Demonstrates frequency‑dependent selection maintains polymorphism. | | Cross‑Species Comparison | Beetle species with relatively uniform reproductive tracts exhibited a single dominant sperm phenotype, whereas D. melanogaster (highly modular tract) displayed polymorphism. | Extends findings beyond the primary model system. | saki kawanami spermmania

If you have institutional access, the DOI link will take you directly to the PDF. Otherwise, you can request a or contact the author (email provided above) for a pre‑print. | Platform | Link | |----------|------| | | https://doi