High-speed camera observations ot copulatory behaviour in Idiosepius oaradoxUS: function of the dimorphic hectocotyli
High-speed camera observations ot copulatory behaviour in Idiosepius oaradoxUS: function of the dimorphic hectocotyli
复制标题
高速摄像机观察 Idiosepius oaradoxUS 的交配行为：二态性胚轴的功能
DOI：
10.1093/mollus/eyt005
复制
发表时间：
2013
影响因子：
1.2
通讯作者：
Sato Noriyosi
中科院分区：
文献类型：
--
作者：
Ogura A;et al.;Sato Noriyosi
在头足类动物中，雄性通过一个复杂的过程将精子转移给雌性。雄性将精子包装在透明的鞘中，形成精囊，然后储存在李约瑟的囊内。精荚从内部终末器官挤出，并通过漏斗离开地幔。尽管一些鱿鱼分类群缺乏这种结构，但许多鱿鱼使用一只专门用来抓住精荚的手臂将精荚转移给雌性鱿鱼，这种手臂被称为双子叶(Drew，1911；Hanlon&Messenger，1996)。在转移到雌性的过程中，或者更多的是在转移到雌性之后，精原细胞经历生精反应以释放精囊，精囊的一端有一个水泥体，含有精子团(Hanlon&Messenger，1996；Mario，2012)。精囊通过水泥体附着在雌体上。一些十臂纲动物，如澳大利亚奥斯特罗西亚、橙色乌贼和太平洋罗西亚种，有两个镜像的异胚轴(例如，在雄性太平洋罗非亚中，左臂和右臂都以相同的方式分叉；Okutani，2005)。然而，雄性侏儒鱿鱼(Idiosepius Steenstrup，1881)具有二形性的异胚轴；左右腹臂都被修饰，但明显不同(von Byern&Klepal，2010)(图1 A，B)。左侧的胚轴顶端有两个瓣片(图1C)；右侧的胚轴背面有肉质的脊(图1D)。在异形异尖线虫中，雄性通过左侧的上胚轴将精托传递给雌性(Ortmann，1881)(Kasugai，2000)。在交配过程中，雄性也会将它们的右上胚轴插入雌性的臂冠(Kasugai，未发表的数据)，但右上胚轴的作用尚不清楚。据报道，在一些墨鱼物种中，雄性用手臂移走或刮去竞争雄性附着的精囊(Wada等人，2005、2006、2010)。在这项研究中，我们用高速摄像机记录了异尖姬蜂的交配行为。我们观察了精子转移的整个过程，以检查右上胚轴在交配过程中的作用。侏儒鱿鱼是从日本本州中部赤田半岛(北纬348430N，东经1368580E)近岸水域的海草Zostera marina的小床上采集的。2010年3月30日，用小拖网(1.2米；网目尺寸1.5毫米)收集成熟的侏儒鱿鱼。活体标本被放置在充气良好的海水中，并被运送到日本崎玉纪录片频道的实验室(358480N，1398440E)。侏儒鱿鱼被饲养在两个闭合循环系统的水族箱(24厘米，19厘米，27厘米)中。在水族馆底部的沙子上种植了海草，让鱿鱼粘在一起。两只雄性和两只雌性被引入每个水族馆。雄性的白色睾丸和雌性的成熟卵、齿状腺和较大的身体可以很容易地确认它们的性别。在12h光照/12h暗光周期内提供人工光，水温维持在208℃。用活体双足类(Ampithoe sp.)每天两次。视频记录是在将侏儒鱿鱼引入水族馆的一天后开始的。用装有105 mm/f2的高速照相机(Photron，Fastcam SA2)记录交配。8镜头(尼康、Micro-Nikkor)，每秒250帧。在拍摄过程中，另外使用了两个聚光灯来支持录制。我们记录了七次交配，并观察到其中六次交配的精囊位置和通过的精囊数量。在三次交配中，雄性从背侧抓住雌性，在其余四次交配中从腹侧抓住雌性。在掌握了…之后
In cephalopods, males transfer sperm to females by a complex process. Males package sperm in transparent sheaths to form spermatophores that are stored internally in Needham’s sac. Spermatophores are extruded from the internal terminal organ and exit the mantle through the funnel. Although some squid taxa lack the structure, many squids transfer spermatophores to females using an arm specialized to grab the spermatophores, called the hectocotylus (Drew, 1911; Hanlon & Messenger, 1996). During, or more often subsequent to, transfer to females, the spermatophore undergoes the spermatophoric reaction to release a spermatangium, which is a sac that contains a sperm mass with a cement body at one end (Hanlon & Messenger, 1996; Marian, 2012). The spermatangium is attached to the female body by the cement body. Some decabrachian species, such as Austrossia australis, Sepiola aurantiaca and Rossia pacifica, have two mirror-image hectocotyli (eg both left and right arms I are hectocotylized in the same manner in male R. pacifica; Okutani, 2005). However, males of the pygmy squid (genus Idiosepius Steenstrup, 1881) have dimorphic hectocotyli; both left and right ventral arms are modified, but are distinctly different (von Byern & Klepal, 2010)(Fig. 1 A, B). The left hectocotylus has two flaps at its tip (Fig. 1 C); the right hectocotylus has fleshy ridges on its aboral side (Fig. 1 D). Males pass spermatophores to females via the left hectocotylus in I. paradoxus (Ortmann, 1881)(Kasugai, 2000). Males also insert their right hectocotylus into the arm crown of the female during copulation (Kasugai, unpublished data), but the role of the right hectocotylus is unknown. In some cuttlefish species, males are reported to use their arms to remove or scrape out spermatangia attached by rival males (Wada et al., 2005, 2006, 2010). In the present study, we recorded the copulatory behaviour of I. paradoxus using a high-speed camera. We observed the entire process of sperm transfer to examine the role of the right hectocotylus during copulation. Pygmy squids were collected from small beds of the seagrass, Zostera marina, in the nearshore waters of the Chita Peninsula, central Honshu, Japan (348430N, 1368580E). Mature pygmy squids were collected using a small drag net (1 Â 2 m; mesh size 1.5 mm) on 30 March 2010. Live specimens were placed in well-aerated seawater and transported to the laboratory of the Documentary Channel in Saitama, Japan (358480N, 1398440E). Pygmy squids were maintained in two aquaria (24 Â 19 Â 27 cm) with a closed circulation system. Seagrasses were planted on the sand at the aquarium bottom to allow the squids to adhere. Two males and two females were introduced into each aquarium. Their sex can be readily confirmed by the presence of the white testis in males and ripe eggs, nidamental glands and the larger body in females. Artificial light was provided in a 12 h light/12 h dark photoperiod, and the water temperature was maintained at 208C. Pygmy squids were fed live amphipods (Ampithoe sp.) twice daily. Video recording was started a day after introducing pygmy squids to aquaria. Copulation was recorded using a high-speed camera (Photron, Fastcam SA2) fitted with a 105-mm/f2. 8 lens (Nikon, Micro-Nikkor) at 250 frames per second. During filming, two spotlights were additionally used to support the recording. We recorded seven copulations and were able to observe the placement of spermatangia and number of passed spermatangia in six of them.Males seized females from the dorsal side during three copulations and from the ventral side in the remaining four copulations. After grasping the …