Schrempf Alexandra, Moser Astrid, Delabie Jacques, Heinze Jürgen
Zoology/Evolutionary Biology, University of Regensburg, Regensburg, Germany.
Myrmecological Laboratory, Cocoa Research Center CEPLAC, Itabuna, Brazil.
Integr Zool. 2016 Nov;11(6):427-432. doi: 10.1111/1749-4877.12191.
Size and shape of sperm cells vary tremendously throughout the animal kingdom. The adaptive significance of this variation is not fully understood. In addition to sperm-female interactions and the environmental conditions, the risk of sperm competition might affect number, morphology and other "quality" traits of sperm. In the male-diphenic ant Cardiocondyla obscurior, winged sneaker males have limited sperm number, because their testes degenerate shortly after adult emergence, as is typical for males of social Hymenoptera. In contrast, wingless fighter males continuously replenish their sperm supply due to their exceptional lifelong spermatogenesis. While winged males usually have to compete with several other winged males for virgin queens, wingless males are able to monopolize queens by killing all other rivals. Hence, this presents a unique system to investigate how alternative reproductive tactics and associated physiology affect sperm morphology and viability. We found that sperm-limited males invest into sperm number instead of sperm size. Variance in sperm length is smaller in winged males, probably reflecting that they have to compete with several other males. Finally, sperm viability is equally high in both male phenotypes.
在整个动物界，精子细胞的大小和形状差异极大。这种变异的适应性意义尚未完全被理解。除了精子与雌性的相互作用以及环境条件外，精子竞争的风险可能会影响精子的数量、形态及其他“质量”特征。在具有两性异形的暗纹心颚蚁中，有翅的“偷精者”雄蚁精子数量有限，因为它们的睾丸在成年后不久就会退化，这是社会性膜翅目昆虫雄性的典型特征。相比之下，无翅的“战斗者”雄蚁由于其独特的终生精子发生过程，能够持续补充精子供应。有翅雄蚁通常必须与其他几只雄蚁竞争处女蚁后，而无翅雄蚁则能够通过杀死所有其他对手来独占蚁后。因此，这提供了一个独特的系统，用于研究替代生殖策略及相关生理机能如何影响精子形态和活力。我们发现，精子数量有限的雄蚁会将资源投入到精子数量而非精子大小上。有翅雄蚁精子长度的方差较小，这可能反映出它们必须与其他几只雄蚁竞争。最后，两种雄性表型的精子活力同样高。
