First evidence of neurons in the male copulatory organ of a spider (Arachnida,Araneae)

Spider males have evolved a remarkable way of transferring sperm by using a modified part of their pedipalps, the so-called palpal organ. The palpal organ is ontogenetically derived from tarsal claws; however, no nerves, sensory organs or muscles have been detected in the palpal bulb so far, suggesting that the spider male copulatory organ is numb and sensorily blind. Here, we document the presence of neurons and a nerve inside the male palpal organ of a spider for the first time. Several neurons that are located in the embolus are attached to the surrounding cuticle where stresses and strains lead to a deformation (stretching) of the palpal cuticle on a local scale, suggesting a putative proprioreceptive function. Consequently, the male copulatory organ of this species is not just a numb structure but likely able to directly perceive sensory input during sperm transfer. In addition, we identified two glands in the palpal organ, one of which is located in the embolus (embolus gland). The embolus gland appears to be directly innervated, which could allow for rapid modulation of secretory activity. Thus, we hypothesize that the transferred seminal fluid can be modulated to influence female processes.     

Sperm dumping in a haplogyne spider

The present study shows that females of Silhouettella loricatula (Arachnida: Araneae: Oonopidae) manage to process sperm in an unusual and previously unknown way. The male ejaculate consisting of spermatozoa and globular secretion is enclosed in a secretory sac. This may avoid the mixing of sperm from different males and at least severely limit sperm competition. The process of sperm enclosure occurs within the female's sperm storage site (receptaculum) as the ejaculate is not surrounded by a sac inside the male's sperm-transferring organs (palpal bulbs). The secretion forming the sac is produced by glands adjoining the receptaculum. The possibility that globular secretions in the male palpal bulbs partly contribute to the sac cannot be ruled out completely. It is suggested that in S. loricatula , the main function of sperm enclosure in a sac is enabling females to dump the ejaculate of a male. The present study represents the first report on sperm dumping in the family Oonopidae. During five first and three second copulations in the laboratory, the dumping of a sac was observed. One dumped sac was sectioned and contained spermatozoa. Two couples were flash-fixed with liquid nitrogen early during copulation, which revealed the mechanism of the sac dumping. By muscle contractions, the receptaculum is bent backwards and the sac moved into the genital opening. The actual sac dumping occurs most probably in cooperation with the male, which moves his pedipalps rhythmically during the entire copulation. Extensions and furrows on the emboli suggest that they may additionally be used as copulatory courtship devices. The enclosure of sperm from the current male in secretion takes place during or immediately following copulation as all mated females sacrificed after copulation had a new sac containing spermatozoa in the receptaculum. Dumping sperm of a previous male during the next copulation may allow females to bias sperm precedence.     

Live for the moment—Adaptations in the male genital system of a sexually cannibalistic spider (Theridiidae, Araneae)

Monogyny in spiders culminates in extreme traits, like dramatic male self-sacrifice and emasculation of the male by the female during copulation. Here we show that monogynous males can be highly adapted for this fatal sexual behaviour. Dwarf males of the one-palped theridiid spider Tidarren argo, which are cannibalised immediately after the insertion of their single copulatory organ, stop spermiogenesis when reaching adulthood. Their testes atrophy, which might economise the energy expenditures of these males. We also found that the amount of seminal fluid produced is stored in an enlarged seminal vesicle until the single sperm induction takes place. The volume of the seminal vesicle is similar to the sperm droplet taken up into the copulatory organ (palpal organ). Sperm uptake takes much longer than in related species most likely due to the large amount of seminal fluid. As shown by histological observations males are able to fill one of the paired female sperm storage organs during copulation thereby presumably impeding subsequent charging by rival males.     

Sexual differentiation in the CNS of the moth,Manduca sexta. I. Sex and segment-specificity in production,differentiation, and survival of the imaginal midline neurons

We analyzed the development of several sets of postembryonic sex-specific motoneurons in Manduca sexta which belong to a group of homologous lineage of neurons called the imaginal midline neurons (IMNs). Adult female oviduct motoneurons and male sperm duct motoneurons are IMNs that show similar anatomical features and differentiate during metamorphosis, despite appearing in different segments: A7 for oviduct neurons, A9 for sperm duct neurons. These cells are born at the same time and, initially, similar sets are found in A7 and A9 ganglia of larvae of both sexes. The dimorphic adult pattern is generated by sex-specific production and cell death. A7 IMNs differentiate in both sexes through early pupal stages, whereupon they disappear in the male and become the oviduct motoneurons in the female. A9 IMNs are overproduced in the male, and subsequent cell death reduces male cell number and eliminates the small complement of female cells; the surviving male cells develop into the sperm duct motoneurons. Similar IMN arrays are generated in nongenital ganglia, but show non-sex-specific fates. This suggests that both the sex of these cells and their segment of residence play major roles in their subsequent differentiation. 1994 John Wiley & Sons, Inc.     

Adult Responses to Larval Population Size in the Almond Moth, Cadra cautella

Juvenile population size may affect the potential for future mating opportunities and therefore potentially sperm competition; this may favour ontogenetic adjustments in sperm production. Theory predicts that males should optimize their ejaculatory investment in accordance with the risk of sperm competition. Evidence for these theories is typically revealed in males of highly polyandrous species. Whether such responses to environmental cues exist for females, or are maintained in mildly polyandrous species in which most females do not re-mate, is unknown. Male lepidopterans produce normal, fertilizing sperm (eupyrene) and non-fertilizing (apyrene) sperm. Apyrene sperm are associated with reduced female receptivity, suggesting a role in sperm competition. We tested the effect of juvenile population size on life-history parameters and reproductive investment in the mildly polyandrous almond moth, Cadra cautella , a species in which current male ejaculate traits suggest previous selection for paternity protection consistent with a sperm-competitive environment. Larvae were reared at high (H) or low population sizes (L). We recorded larval development time, adult longevity and male gametic investment. Our results show a response by adults to signals in the juvenile environment. H males transferred more apyrene, but not eupyrene sperm. We also examined potential trade-offs between somatic characters and reproductive behaviours. Larval duration was longer for H individuals, females and heavier individuals. Further, H females and L males lived longer than L females. Our data are consistent with the theory that males should adjust their reproductive investment in accordance with sperm competition risk.     

Morphogenesis of Pseudopallene sp. (Pycnogonida, Callipallenidae) I: embryonic development

Embryonic development of Pycnogonida (sea spiders) is poorly understood in comparison to other euarthropod lineages with well-established model organisms. However, given that pycnogonids potentially represent the sister group to chelicerates or even to all other euarthropods, their development might yield important data for the reconstruction of arthropod evolution. Using scanning electron microscopy, fluorescent nucleic staining and immunohistochemistry, the general course of embryonic morphogenesis in Pseudopallene sp. (Callipallenidae), a pycnogonid with prolonged embryonic development, is described. A staging system comprising ten stages is presented, which can be used in future studies addressing specific developmental processes. The initially slit-like stomodeum anlage forms at the anterior end of an eight-shaped germ band and predates proboscis outgrowth. The latter process is characterized by the protrusion of three cell populations that are subsequently involved in pharynx formation. In later stages, the proboscis assumes distally a horseshoe-like shape. At no time, a structure corresponding to the euarthropod labrum is detectable. Based on the complete lack of palpal and ovigeral embryonic limbs and the early differentiation of walking leg segments 1 and 2, the existence of an embryonized protonymphon stage during callipallenid development is rejected. The evolution of pycnogonid hatching stages, especially within Callipallenidae and Nymphonidae, is re-evaluated in the light of recent phylogenetic analyses. Specifically, the re-emergence of the ancestral protonymphon larva (including re-development of palpal and ovigeral larval limbs) and a possible re-appearance of adult palps in the nymphonid lineage are discussed. This challenges the perception of pycnogonid head appendage evolution as being driven by reduction events alone.     

中国河北省弱蛛科一新属新种记述(蜘蛛纲,蜘蛛目)

记述了采自于中国河北省赞皇县嶂石岩风景区(九女峰景区)的弱蛛科1新属新种:宽跗皱弱蛛Rhysscoleptoneta latitarsa gen.nov.et sp. nov..皱弱蛛属Rhyssoleptoneta gen.nov.与该科其它属的主要区别在于雄性触肢跗节较宽,端部无分叉,背面具1个短小的突起;雄性触肢生殖球结构复杂等.模式标本保存于中国科学院动物研究所.     

三种蚤生殖系统的细微结构:雄性生殖腺的发育

本文研究了缓慢细蚤Leptopsylla segnis(Schnherr),不等单蚤Monopsyllus anisus (Rothschild)和猫栉首蚤指名亚种Ctenocephalides felis felis(Bouché)雄性生殖腺的结构,观察了从3龄幼虫至成虫成熟各发育时期雄性生殖腺的内部结构变化。依据睾丸芽的发育、精子细胞的生成、变形、精子束的发育和雄性生殖腺的成熟等,把雄性生殖腺的发育分为五期10个阶段。本文对睾丸的结构、精囊数目与精子束数目的关系、精子束的发育及精子束在睾丸内的运动、雄蚤羽化晚于雌蚤的原因、睾丸塞的发育与雄蚤的成熟等问题进行了分析和探讨。     

Inference of phylogenetic relationships within Fabriciidae (Sabellida,Annelida) using molecular and morphological data

Cladistic relationships among fabriciids have to date been explored in the context of adult morphology, but resolution has been declining as more species are described. In this study, we incorporated data on the reproductive system, including features related to the male sperm and sperm storage by females, to supplement existing data on adult morphology (for a total of 50 characters). Three nuclear DNA markers (18S rDNA approximately 1800 bp, the D1 region of 28S rDNA approximately 320 bp, and histone H3 approximately 330 bp) were sequenced from 21 species of fabriciids. We assessed the phylogeny of Fabriciidae based on an integrative analysis of these morphological and molecular characters. Our results show that, in addition to three previously recovered apomorphies for Fabriciidae (absence of ventral lips, modification of abdominal uncini to an elongate manubrium, and presence of branchial hearts), six more apomorphies associated with the reproductive system can be used to support this clade—spermiogenesis only in the thorax, spermiogenesis in large clusters with a central cytophore, single dorsal sperm duct, sperm nuclear projection, thickening of the sperm nuclear membrane and the sperm extra‐axonemal sheath. The results require the erection of two new genera and two new species, which are described. © The Willi Hennig Society 2010.     

蟋蟀精子形成部分时期尾部超微结构观察

通过对黄脸油葫芦精子尾部形成过程4～10期超微结构的观察,发现该虫精子细胞发育至第6期轴丝微管束9 9 2完整形成;7、8两期精子细胞内一些高尔基体、内质网膜系统结构包绕着轴丝;第9期精子细胞及成熟精子轴丝内副微管、双微管中的A微管、中央单微管内充满小圆柱状纤维;中心粒侧体纤维状,成熟精子的线粒体衍生体内不具纵嵴;细胞质膜外不具发达的糖蛋白套。通过比较发现该虫精子与蝗总科癞蝗科精子类型比较相似,同属于原始类型精子。     

Complex genital system of a haplogyne spider (Arachnida, Araneae, Tetrablemmidae) indicates internal fertilization and full female control over transferred sperm

The female genital organs of the tetrablemmid Indicoblemma lannaianum are astonishingly complex. The copulatory orifice lies anterior to the opening of the uterus externus and leads into a narrow insertion duct that ends in a genital cavity. The genital cavity continues laterally in paired tube-like copulatory ducts, which lead into paired, large, sac-like receptacula. Each receptaculum has a sclerotized pore plate with associated gland cells. Paired small fertilization ducts originate in the receptacula and take their curved course inside the copulatory ducts. The fertilization ducts end in slit-like openings in the sclerotized posterior walls of the copulatory ducts. Huge masses of secretions forming large balls are detectable in the female receptacula. An important function of these secretory balls seems to be the encapsulation of spermatozoa in discrete packages in order to avoid the mixing of sperm from different males. In this way, sperm competition may be completely prevented or at least severely limited. Females seem to have full control over transferred sperm and be able to express preference for spermatozoa of certain males. The lumen of the sperm containing secretory balls is connected with the fertilization duct. Activated spermatozoa are only found in the uterus internus of females, which is an indication of internal fertilization. The sperm cells in the uterus internus are characterized by an extensive cytoplasm and an elongated, cone-shaped nucleus. The male genital system of I. lannaianum consists of thick testes and thin convoluted vasa deferentia that open into the wide ductus ejaculatorius. The voluminous globular palpal bulb is filled with seminal fluid consisting of a globular secretion in which only a few spermatozoa are embedded. The spermatozoa are encapsulated by a sheath produced in the genital system. The secretions in females may at least partly consist of male secretions that could be involved in the building of the secretory balls or play a role in sperm activation. The male secretions could also afford nutriments to the spermatozoa.     

开普蛛科(蛛形纲,蜘蛛目)在越南的新纪录

报道了越南蜘蛛1新纪录科,开普蛛科Caponiidae。描述了越南1新纪录种:刚毛老挝蛛Laoponia saetosa Platnick & Jager,2008和1新种:拟刚毛老挝蛛L.pseudosaetosa sp.nov.。这2个种的雄性触肢器的形状基本相同,但是触肢器生殖球的大小差异十分显著,该结构在拟刚毛老挝蛛中显著小于刚毛老挝蛛(P<0.05)。标本采集于越南北部的3个国家公园:库风国家公园(Cuc Phuong National Park),吉婆岛国家公园(CatBa National Park)和三岛国家自然公园(Tam DaoNational Park)。拟刚毛老挝蛛,新种Laoponia pseudosaetosa sp.nov.(图6～8,10,13)正模♂,副模20♂♂,越南永丰省三岛国家公园,2007-04-01至2008-03-31,范鼎飒采。词源:新种因生殖器结构与刚毛老挝蛛Laoponiasaetosa Platnick & Jager,2008相似而得此名。     

Sense organs in post-embryonic stages of Hyalomma marginatum marginatum Koch, 1844 (Acari: Ixodida: Ixodidae). II. Palpal organ.

Light microscopy and scanning electron microscopy (SEM) studies show the differences in structure, number and topography of terminal setae in the palpal organ in different stages of Hyalomma marginatum marginatum Koch, 1844. The palpal organ contains eight terminal setae in larvae and nymphs, and ten setae in adults. The length of these setae increases in the course of post-embryonic development. Other setae on palpal segments also undergo quantitative and morphological changes.     

Cloning and characterization of cDNA sequences corresponding to myosin light chains 1, 2, and 3, troponin-C, troponin-T, alpha-tropomyosin, and alpha-actin

A library of cDNA clones was constructed from adult rat skeletal muscle mRNA, from which a set of contractile protein clones was selected. These clones were identified by sequencing the cDNA inserts and comparing the derived amino acid sequences with published sequences of rabbit contractile proteins. In this manner, clones corresponding to myosin light chains 1, 2, and 3, troponin-C, troponin-T, alpha-tropomyosin, and alpha-actin were identified. A high degree of amino acid sequence conservation was found upon comparison of the rat and rabbit proteins. Using the cDNA clone panel, we analyzed the expression of abundant rat muscle mRNAs. We show that abundant rat muscle mRNAs can be classified into four developmentally regulated groups, based upon their expression at different stages of myogenesis. One class of mRNAs is expressed during all stages of muscle development. Since these mRNAs are also present in nonmuscle tissues, we conclude that they code for housekeeping proteins. The second class of mRNAs is present in both embryonic and adult muscle, while a third class of mRNAs is expressed only in adult muscle. A small number of mRNAs, which are present at greater levels in undifferentiated myoblasts than in adult muscle, comprise a fourth class. These results suggest the existence of at least four modes of gene control during myogenesis.     

A new genus of hard ticks in Cretaceous Burmese amber (Acari: Ixodida: Ixodidae)

A hard tick larva in Cretaceous Burmese amber is described as Cornupalpatum burmanicum n. g., n. sp. Diagnostic characters include a subcircular body with a marginal groove, 11 festoons, elongate four-segmented palpi with the fourth segment distinct and apical, the absence of an anal groove and eyes, and the presence of claws on palpal segment 3. The last character is unique for all members of the Ixodida, both fossil and extant. Aside from the palpal claws and marginal groove, features of the tick larva closely resemble those of members of the genus Aponomma Neumann 1899, considered one of the most primitive tick lineages today, whose hosts are primarily reptiles.     

Reproduction,Chromosome Number,and Postembryonic Development of Panagrellus redivivus (Nematoda: Cephalobidae)

Panagrellus redivivus (L.) T. Goodey reproduced amphimictically; the sexual primordia of males had nine chromosomes, those of females had ten. Eggs contained five chromosomes, sperm four or five. There were four molts, all after hatching. The sexes could be separated at the second molt by development of a lobe of somatic cells in the gonad, anteriorly in males, posteriorly in females. The lobe in males reflexed posteriorly at the third molt and joined the rectum at the fourth molt. Third molt females had a thickened vaginal primordium and at the fourth molt the spermathecal and uterine primordia were evident. The uterus elongated enormously in the adult. The 15 ventral chord nuclei between esophagus and rectum in the first stage increased to approximately 63 during the first molt; specialized nuclei, not evident until the third molt, participate in vaginal lining formation in fourth molt females. Sperm were first produced at the late fourth molt. Eggs, not produced until after copulation, hatched within the uterus.