Division of Invertebrate Zoology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA.
Zoology (Jena). 2010 Jan;113(1):19-32. doi: 10.1016/j.zool.2009.04.002. Epub 2009 Nov 24.
In promiscuous females, sperm ejection from the sperm storage site can be a strong mechanism to influence sperm priority patterns. Sperm dumping is reported from different animals including birds, insects, and humans. In spiders, it has been documented for four species including the oonopid Silhouettella loricatula. Oonopidae are a diverse spider family comprising many species with peculiar female genitalia. Especially in species where studies of mating behavior are difficult, morphological investigations of the genitalia help to understand their function and evolution. In the present study, the genitalia of the oonopids Myrmopopaea sp., Grymeus sp., and Lionneta sp. are investigated by means of histological serial sections and scanning electron microscopy (SEM). The results are compared with previous findings on S. loricatula. In Myrmopopaea sp. and Grymeus sp., the same morphological components are present that are involved in sperm dumping in S. loricatula. Inside the receptaculum, sperm are enclosed in a secretory sac which can be moved to the genital opening and dumped during copulation by muscle contractions. The female genitalia of Lionneta sp. are asymmetric. They show the same characteristics as S. loricatula but all the investigated females were unmated. The results strongly suggest that sperm dumping occurs in Myrmopopaea sp., Grymeus sp., and Lionneta sp. and happens by the same mechanism as in S. loricatula. Sperm dumping might even be common within a clade of oonopids. As in S. loricatula, the sperm transfer forms in the investigated species consist of several spermatozoa. Papillae with unknown function occur on the receptacula of all females.
在滥交的雌性中，从精子储存部位射出精子可以成为影响精子优先模式的强大机制。包括鸟类、昆虫和人类在内的不同动物都有报道称存在精子倾倒现象。在蜘蛛中，已经记录了包括oonopid Silhouettella loricatula 在内的四个物种存在这种现象。oonopidae 是一个多样化的蜘蛛科，包含许多具有特殊生殖器的物种。特别是在交配行为难以研究的物种中，生殖器的形态学研究有助于理解其功能和进化。在本研究中，通过组织学连续切片和扫描电子显微镜（SEM）研究了oonopids Myrmopopaea sp.、Grymeus sp. 和 Lionneta sp. 的生殖器。将结果与之前对 S. loricatula 的研究进行了比较。在 Myrmopopaea sp. 和 Grymeus sp. 中，存在与 S. loricatula 中精子倾倒相同的形态结构。在接收管内，精子被包裹在一个分泌囊中，通过肌肉收缩可以将其移至生殖器开口并在交配时倾倒。Lionneta sp. 的雌性生殖器不对称。它们具有与 S. loricatula 相同的特征，但所有被调查的雌性都没有交配。结果强烈表明，精子倾倒发生在 Myrmopopaea sp.、Grymeus sp. 和 Lionneta sp. 中，并且发生的机制与 S. loricatula 相同。精子倾倒甚至可能在 oonopid 的一个分支中很常见。与 S. loricatula 一样，在所研究的物种中，精子转移形式由几个精子组成。所有雌性的接收管上都有具有未知功能的乳突。
