Summary1. Theoretical models predict that ejaculate expenditure will positively covary with the level of sperm competition but trade-offs between either different measures of sperm quality or sperm quality traits and sperm number are expected. However, empirical results have generally failed to find trade-offs between sperm number, size, velocity and longevity or viability. 2. We analyzed the sperm traits of the grass goby, Zosterisessor ophiocephalus , and the black goby, Gobius niger , two fish characterized by alternative male reproductive tactics, long lasting egg deposition and intra-specific variability in ejaculate characteristics. Indeed, in both species sneaker males release ejaculates with greater sperm number and lower seminal fluid content than territorial ones. 3. We showed that sperm of grass goby males have a similar quality, whereas in the black goby sneakers have faster swimming speeds, greater viability and higher ATP content than those of territorial males. The effectiveness of territorial male mate guarding differs in the two goby species and might account for the observed difference in the intra-specific variability of sperm quality. 4. The pattern of variation that we found in the investment of sperm numbers and sperm quality in goby territorial and sneaker males, supports the results found in other species of fish with alternative mating tactics, suggesting that ejaculate quality traits are usually not traded off one against the other when ejaculate effort is increased in response to increased levels of sperm competition.

Protein tyrosine phosphatases (PTPs) are crucial components of cellular signal transduction pathways. We report here that red blood cells (RBCs) from mice lacking PTPε (Ptpre −/− ) exhibit abnormal morphology and increased Ca 2+ -activated-K + channel activity, which was partially blocked by the Src-Family-Kinases (SFKs) inhibitor PP1. In Ptpre −/− mouse RBCs, the activity of Fyn and Yes, two SFKs, were increased, suggesting a functional relationship between SFKs, PTPε and Ca 2+ -activated-K + -channel. The absence of PTPε markedly affected the RBC membrane tyrosine (Tyr-) phosphoproteome, indicating a perturbation of RBCs signal transduction pathways. Using signaling network computational analysis of the Tyr-phosphoproteomic data, we identified 7 topological clusters. We studied cluster 1, containing Syk-Tyr-kinase: Syk-kinase activity was higher in wild-type than in Ptpre −/− RBCs, validating the network computational analysis and indicating a novel signaling pathway, which involves Fyn and Syk in regulation of red cell morphology.

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