Eupyrene sperm migrates to spermatheca after apyrene sperm in the swallowtail butterfly, Papilio xuthus L. (Lepidoptera: Papilionidae)

When swallowtail butterflies, Papilio xuthus, are mated by the hand-pairing method, both types of sperm, eupyrene and apyrene sperm, are transferred from the male to the spermatheca via the spermatophore in the bursa copulatrix. This mechanism is demonstrated by two different kinds of experiments. The first set of experiments employed interrupted copulation, and the second set was examination of the sperm in the spermatophore and spermatheca after the termination of copulation. The sperm was transferred 30 min after the start of copulation. The eupyrene sperm was still in the bundle; the number of the bundles ranged from 9 to 108 (mean, 42.7; n = 27). The bundles were gradually released after the completion of copulation, and the free eupyrene spermatozoa then remained in the spermatophore at least 2 h before migrating to the spermatheca. On the other hand, about 160 000 apyrene spermatozoa were transferred to the spermatophore and remained there for more than 1 h. We observed 11 000 apyrene spermatozoa in the spermatheca 12 h after the completion of copulation, but most of this type of sperm disappeared shortly thereafter. In contrast, the eupyrene sperm arrived in the spermatheca more than 1 day after the completion of copulation and remained there at least 1 week. Therefore, these findings suggest that apyrene sperm migrate from the spermatophore to the spermatheca earlier than eupyrene sperm. Accordingly, if females mated multiply, the time difference might avoid the mixing of sperm. In addition, the predominance of sperm from the last mating session may occur not in the bursa copulatrix but in the spermatheca. Received: January 7, 2000 / Accepted: May 24, 2000     

Dynamics of eupyrene and apyrene sperm storage in ovipositing females of the swallowtail butterfly Papilio xuthus (Lepidoptera: Papilionidae)

A male swallowtail butterfly, Papilio xuthus, transfers both eupyrene and apyrene sperm during copulation, both of which migrate to the spermatheca via the spermatophore in the bursa copulatrix of the female. Because the spermatheca seems to remain constant in size during the female lifespan, the excess sperm migration may cause the spermatheca to overflow. Approximately 9000 eupyrene and 265 000 apyrene spermatozoa were transferred during a single copulation, and approximately 1000 eupyrene and 1100 apyrene spermatozoa successfully arrived in the spermatheca. The number of both types of spermatozoon decreased in the spermatheca after the onset of oviposition, and no eupyrene spermatozoa were found by 7 days after copulation, partly due to insemination. The spermathecal gland leading from the distal end of the spermatheca was gradually filled by eupyrene spermatozoa. Although the function of the gland remains unclear, the final destination of the sperm is likely to be the gland.     

Function of multiple sperm-storage organs in female damselflies (Ischnura senegalensis): difference in amount of ejaculate stored, sperm loss, and priority in fertilization

We studied changes in the number of sperm within two kinds of female sperm-storage organ in the damselfly Ischnura senegalensis (Odonata: Coenagrionidae): the bursa copulatrix and the spermatheca. We counted the number of sperm within each storage organ and tested their viability after a single copulation in female damselflies kept for seven days with and without oviposition. We also counted sperm and tested their viability in females that underwent an interrupted second copulation after the sperm-removal stage, and after subsequent oviposition. Our results showed that the bursa copulatrix and spermatheca have different sperm storage roles. Immediately after copulation, most eggs appear to have been fertilized with bursal sperm, which were positioned near the fertilization point. By seven days after copulation, a greater proportion of spermathecal sperm were used for fertilization, as the number of bursal sperm had decreased. We hypothesize that female damselflies use the spermatheca for long-term storage and the bursa copulatrix for short-term storage: bursal sperm are more likely to be used for fertilization but may have a higher risk of mortality due to sperm removal by a competing male and/or sperm expelling by the female, whereas spermathecal sperm are safer but will be used for fertilization only after their release from the spermatheca.     

Functional morphology of the copulatory organs of a reed beetle and a shining leaf beetle (Coleoptera: Chrysomelidae: Donaciinae,Criocerinae) using X-ray micro-computed tomography

For more than 100 years it has been known that the sclerotised median lobe of beetles harbours a membranous structure (the "internal sac" or "endophallus") which is everted during copula inside the female genital tract. In order to explore the functional role of this structure and those associated with it, we cryofixed copulating pairs of Donacia semicuprea and Lilioceris lilii and studied the relative position of the elements of the copulatory apparatus of males and females by micro-computer-tomography.We found that the everted endophallus fills the lumen of the bursa copulatrix completely. Our data suggest that in Lilioceris lilii the tip of the sclerotised distal part of the ejaculatory duct, the flagellum, is positioned exactly over the opening of the spermathecal duct inside the bursa copulatrix. The mouth of the bursa copulatrix in Donacia semicuprea is armed with a strong muscle ring, and the whole wall of the bursa is covered externally with a layer of muscle fibres. These morphological differences correspond with differences in mating behaviour: In reed beetles (Donaciinae), females seemingly can control mating to a higher degree than in lily beetles (Lilioceris spp.).     

A newly discovered sperm transport system in the female of Lygaeidae bugs

In the female reproductive system of the relatively large hemipteran, the western conifer seed bug Leptoglossus occidentalis (Heidemann), a cuticle‐lined tube extends medially along the surface of the vagina from the proximal end of the spermathecal complex anteriorly to the base of the common oviduct. This medial tube houses the proximal end of the spermathecal duct, thereby enabling the transport of material from the spermatheca at the distal end of the spermathecal complex, past the vagina (or bursa copulatrix) and directly to the common oviduct. The proximal portion of the spermathecal complex also contains an insemination duct that is separate from the spermathecal duct. The insemination duct allows the male intromittent organ to extend from the vagina to the spermatheca without navigating through the spermathecal duct. The reproductive systems of two previously studied Hemiptera, the milkweed bug Oncopeltus fasciatus (Dallas) and the box elder bug Leptocoris trivittatus (Say), possess a similar cuticle‐lined medial tube housing the spermathecal duct. This new information provides a clearer understanding of sperm transport in the female reproductive system of Lygaeidae bugs, and helps to clarify the path of the male organ during copulation, as well as the movement of sperm during egg laying.     

斑衣蜡蝉雌性生殖系统超微结构

【目的】明确斑衣蜡蝉Lycorma delicatula雌成虫生殖系统整体形态及超微结构特征,为蜡蝉总科昆虫分类及系统发育探讨提供更多形态学证据。【方法】采用光学显微镜与透射电子显微镜,观察斑衣蜡蝉雌成虫生殖系统整体形态和各主要器官的超微结构。【结果】斑衣蜡蝉雌成虫生殖系统主要包括1对卵巢、1个中输卵管、1个交配囊、1个交配囊管、1个前阴道、1个后阴道、1个受精囊、1个受精管和2根受精囊附腺。卵巢为端滋式,由14根卵巢小管组成,卵室由固有膜、滤泡细胞和卵细胞组成,卵巢小管中的滋养细胞清晰可见;中输卵管位于前阴道基部,由中输卵管腔、上皮细胞、肌肉鞘和基膜组成;交配囊膨大呈圆球状,囊壁由上皮细胞、肌肉层和基膜组成;交配囊管呈圆柱状,连接交配囊和后阴道,由肌肉鞘、上皮细胞层和管腔组成;前、后阴道超微结构相似,主要由肌肉鞘、基膜、上皮细胞和管腔组成,但后阴道上皮细胞细胞核周围存在分泌颗粒,且管腔内有大量微绒毛,而前阴道壁内包含有大量囊泡结构;受精管从中输卵管末端延伸至受精囊,由基膜、厚层肌肉鞘和管腔组成;受精囊为受精管近末端略膨大的囊状结构,由肌肉鞘、基膜、上皮细胞和囊腔构成;雌性受精囊附腺着生于受精囊末端,为均匀的螺旋管状,主要由肌肉层、上皮细胞层和附腺中心管腔组成。【结论】斑衣蜡蝉雌性生殖系统与已报道的蜡蝉总科其他类群的雌性生殖系统结构相似,但卵巢小管数目有差异;蝉亚目中不同总科雌成虫雌性附腺与受精囊附腺的形态特征存在明显区别;斑衣蜡蝉雌性生殖系统超微结构与叶蝉总科和沫蝉总科昆虫也存在部分差异。这些差异是否可以作为头喙亚目高级阶元的划分依据仍有待于进一步研究。     

Copulatory locus,structure and function of the flagellum of Cicindela tranquebarica Herbst (Coleoptera: Cicindelidae)

Summary

Dissected genitalia of mating pairs of C. tranquebarica frozen in liquid nitrogen revealed that the flagellum enters the speriçatheca duct as hypothesized by Freitag (Can. Entomol., 98 (1966) 942–952), and Freitag et al. (Freitag, R., Olynyk, J.E. and Barnes, B.L., Int. J. Invertebr. Reprod., 2 (1980) 131–135). The flagellum contains a deep groove along its entire length, and appressed hook-like structures which grip the walls of the spermatheca duct during copulation. Insertion of the flagellum probably clears the spermatheca duct of debris and allows seminal fluids to enter.     

长足大竹象生殖系统的形态解剖研究

解剖研究了长足大竹象雌雄虫牛殖系统的构造.该虫的雌性生殖系统包括一对卵巢、一对侧输卵管、中输卵管、交配囊、受精囊、生殖腔、产卵器;雄性生殖系统由一对睾九、一对输精管、一对附腺、射精管和交配器组成.     

Ultrastructure and function of long and short sperm in Cicadidae (Hemiptera)

The cicada, Graptopsaltria nigrofuscata, produces two distinct sizes of sperm, as determined by either nuclear volume of early spermatids or nuclear length of mature sperm. Between both sperm, there is no difference in location of the acrosome and flagellum during spermiogenesis. The acrosome is covered by an anteacrosomal bleb, which is inserted in a common mass, spermatodesm, derived from cyst cells. Both kinds of sperm linked to the spermatodesm form sperm bundles, respectively. During copulation, the sperm bundles are transported from the vesicula seminalis of the male to the bursa copulatrix of the female. Morphometric analyses of the nuclear length revealed that the two kinds of sperm reach the bursa copulatrix in the same condition as that found in the vesicula seminalis. Once transferred inside the latter, the sperm bundles disintegrated to individual sperm within a few hours, and the tail components, such as the axoneme and mitochondrial derivatives, become separated from each other over time. The tail completely splits from the sperm nucleus 24 h after copulation. Fertile sperm accumulate in the spermatheca, the final storage organ, where only long sperm survived for any length of time. Fertilized eggs examined by vital staining contain only sperm with long nuclei.     

The functional significance of the spermatophore and the fate of spermatozoa in the genital tract of Helix pomatia (Gastropoda: Stylommatophora)

In the Helicidae and in some other Stylommatophora the sperm are transferred in a spermatophore, even though there appears to be no need for protection of the sperm during the transfer. The function of the spermatophore and related problems concerning the genital organs of Helix pomatia were studied by means of morphological and experimental methods.
The spermatophore is necessary to ensure the functioning of the female system at copulation. Its structure allows some of the spermatozoa it contains to escape through its tail canal, pass from the stalk of the bursa and reach the spermatheca by way of the oviduct; but most of the sperm pass into the bursa copulatrix and are destroyed, as is also the fate of the spermatophore. Only foreign sperm are stored in the spermatheca.
Spermiogenesis was found to take place throughout the whole summer. At intervals some sperm are released from the hermaphrodite duct and are conducted via the spermoviduct and oviduct to the bursa, where they are digested. The two grooves of the spermoviduct are functionally separated only for a few minutes at actual copulation, when sperm are conducted to the copulatory organs, where the spermatophore is being formed.     

Functional association between female sperm storage organs and male sperm removal organs in calopterygid damselflies

Female damselflies in the family Calopterygidae have two sperm storage organs: a spherical bursa copulatrix and a tubular spermatheca. Male flies have a peculiar aedeagus with a recurved head with which to remove bursal sperm, and lateral spiny processes to remove spermathecal sperm. The lateral processes differ among species and populations in terms of their width relative to the spermathecal duct: the narrower processes are physically able to access spermathecal sperm, while the wider ones are not. In the present study, sperm storage patterns and aedeagal structures were compared between two calopterygid species with different spermathecal structures –Calopteryx cornelia and Mnais pruinosa– with respect to not only sperm quantity (number) but also sperm quality (viability), by using a recently developed method based on live/dead dual fluorescence. Calopteryx cornelia is a typical spermathecal sperm remover. In this species, viability was similar between bursal and spermathecal sperm. In contrast, in M. pruinosa, the spermatheca was much smaller than the bursa and often contained no sperm. Even when the spermatheca of this species did contain sperm, a high percentage of it was dead. Although the spermatheca of M. pruinosa has such atrophic tendencies, males have nevertheless developed long and spiny lateral processes similar to those of C. cornelia, suggesting the processes have functions other than spermathecal sperm removal. They possibly function as stoppers or guides for manipulating the aedeagal head to remove the sperm mass from the bursa.     

Expandable spermatheca influences sperm storage in the simultaneously hermaphroditic snail Arianta arbustorum

Summary

In many simultaneously hermaphroditic land snail species, the sperm storage organ (spermatheca) is highly structured, suggesting that the female function might be able to influence offspring paternity. Physical properties of the sperm storage organ, including its initial size and sperm storage capacity, may also affect fertilization patterns in multiply mated snails. We examined the structure, volume and tubule length of empty spermathecae in the land snail, Arianta arbustorum, and assessed differences in spermatheca size following a single copulation. The number of spermathecal tubules ranged from 2–7, but was not correlated with the volume of empty spermathecae. The volume of sperm stored in the spermatheca after a copulation was correlated with neither the number of spermathecal tubules nor copulation duration. Mean spermathecal volume more than doubled between two and thirty-six hours after sperm uptake, but the length of the spermathecal tubules did not change. Interestingly, the volume of sperm stored in the spermatheca seems not to be related to the size of the spermatophore and thus not to the number of sperm received (= allosperm). The amount of allosperm digested in the bursa copulatrix was highly variable and no significant relationship with the size of the spermatophore received was found. These findings suggest that numerical aspects of sperm transfer are less important in influencing fertilization success of sperm in A. arbustorum than properties of the female reproductive tract of the sperm receiver.     

Functional morphology of the glandula prostatica,ejaculatory valve,and ductus ejaculatorius of the silkworm Bombyx mori

The penis of the silkmoth, Bombyx mori, consists of two parts covered with cuticle, the corpus penis and crus penis, and a third part, the radix penis, without a cuticle but surrounded by a thick sphincter. The radix penis is divisible into anterior and posterior parts. The ductus (d.) ejaculatorius passing through the penis has no secretory cells. In the anterior radix penis, the wall of the d. ejaculatorius is thin and without folds; in the posterior section, it is thick, with folds in its lumen. The glandula (g.) prostatica is divisible into anterior and posterior parts according to differences in the histological and morphological characteristics of the cells and their secretions, which contain many heterogeneous substances. In the anterior g. prostatica, secretions accumulate separately in the anterior and posterior sections before ejaculation. Unlike the posterior region, the anterior region displays a large mass(es) at the periphery of the lumen along the secretory cell layer. Judging from staining properties, the pearly body and the first layer of the spermatophore wall, which, after copulation, form in the female bursa copulatrix, seem to be derived from the secretions of the anterior and posterior regions of the g. prostatica, respectively. The secretion of the posterior g. prostatica contains initiatorin, which acts as a sperm-activating factor in the inner and outer matrices of the spermatophore. An ejaculatory valve is found between the radix penis and the g. prostatica. The opening of this valve is regulated by the surrounding sphincter, thus impeding the back-flow of secretions and seminal fluid in the radix penis and resulting in their transport outwards during ejaculation. The musculature of the d. ejaculatorius and the corpus penis promotes further transport of these secretions into the female bursa copulatrix.     

Scanning electron microscopy of the spermatheca in Sitophilus granarius (L.)

With scanning electron microscopy the spermathecal organ of Sitophilus granarius (L.) has been examined. The only morphological attachment between this organ and other tissues is to the bursa copulatrix by the sperm duct and to the central nervous system by two nerve fibers. The nerves innervate the muscles connecting the two arms of the U-shaped spermatheca. Glandular cells are grouped together and are connected to the spermathecal lumen by a short collecting duct. Vascular sinuses opening from the body cavity into the body of the gland are observed as pores on the surface of the gland.     

Male copulatory sensory stimulation induces female ejection of rival sperm in a damselfly

Male damselflies possess very specialized genitalia. Females mate multiply and store sperm in two sperm storage organs, the bursa copulatrix and the spermatheca. During copulation, males physically remove the sperm stored in these organs using their genitalia. I document a novel mechanism by which males gain access to the spermatheca in Calopteryx haemorrhoidalis asturica. The mechanism is based on male stimulation of the female sensory system that controls egg fertilization and laying. During copulation, the aedeagus (a male genitalic structure indirectly involved in sperm transfer) distorts the cuticular plates in the female genital tract that bear mechanoreceptive sensilla. This stimulation results in sperm ejection from the spermatheca. Aedeagus width is positively correlated with the amount of sperm ejected. I propose that males have exploited a pre-existing female sensory bias to gain access to otherwise physically unreachable sperm. These results shed light on the issue of the origin of female preferences in current models of sexual selection and on the evolution of genitalia via sexual selection. It is postulated that females might use this process as a form of post-copulatory sexual selection on the basis of males'' genitalia.     

Two-step regulation of sex-pheromone decline in mated gypsy moth females

The regulation of post-mating decline of sex-pheromone in the gypsy moth, Lymantria dispar, was studied. An initial, transient suppression of pheromone production was found to be caused by the introduction of male genitalia into the bursa copulatrix, which results in mechanical pressure being transmitted via innervation of the bursa. However, if sperm was not transferred during mating, pheromone production resumed and females returned to calling behavior. Permanent suppression of pheromone production resulted from an adequate supply of sperm in the spermatheca and could be prevented in females from which spermatheca was removed. During the initial period of suppression of pheromone production females were sexually receptive and could remate. They became nonreceptive only when pheromone production was terminated and oviposition begun.     

Reproductive morphology,copulation, and inter-populational variation in the diamondback moth,Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Copulatory mechanisms and internal reproductive systems of male and female Plutella xylostella (L.) were investigated. Both male and female specimens exhibited characteristics typical of ditrysian Lepidoptera, with some peculiarities. Female structures appear to be relatively simple: the bursa copulatrix lacks cuticular signa within, the spermatheca lacks lagenar arms exhibited in some Lepidoptera, and colleterial glands have secretory system and reservoir combined. Male accessory gland ducts are joined distally, a condition that has not been described in other Lepidoptera. Genitalia of both sexes appear simple; females possess a posterior cuticular extension of abdominal sternites that houses the bursal duct and accomodates the needle-like aedeagus of a male during copulation. Despite the apparent simplicity, configuration of genitalia is highly specific in shape, angle, and size, which is likely to be important in maintaining reproductive isolation within the species. However, a population of P. xylostella from Australia showed some modification to both aedeagal and bursal structures. These variations suggest some important implications for considering species with worldwide distributions.     

Spermatophore expulsion in the carrion beetle Silpha perforata (Coleoptera: Silphidae)

Silphinae (Coleoptera: Silphidae) is an abundant decomposer that plays important roles in the ecosystem. However, there is little information about the life history of this taxon. We found sperm displacement behavior in carrion beetle Silpha perforata. Copulating males bit the female's antenna strongly and inserted the penis into the partner's genital organ more than once. We found a white substance on the tip of penis during copulation. We examined whether this white substance is a previous male's spermatophore, which was removed from the mating partner. When females were dissected just after mating, the same substance that often presents on the penis of mating males was found in the bursa copulatrix of females, although the bursa copulatrix of virgin females was empty. Male behavior during copulation with females of different mating history was also observed to confirm that the removal of spermatophores was observed only in copulation with females that have the spermatophores of previous males. Consequently, we estimated that S. perforata males removed spermatophores of previous males from mating partners. In addition, we dissected the males frozen during copulation, and inspected the penis morphology. This observation revealed that the apical part of the penis was usually hidden in the basal part of penis, but expanded and appeared during insertion. This apical part had many spines, which play an important role in sperm displacement and sexual conflict in some species. These results indicate that there is the sperm competition in S. perforata. This is the first report on sperm competition in Silphinae.     

Arhopalus ferus (Coleoptera: Cerambycidae): structure and function of the female reproductive system

Abstract

Arhopalus ferus (Mulsant) female pupae and adults were dissected, and both internal and external genitalia are described. The external genitalia involve segments 8 and 9. Segment 9 and its appendages are modified into a long ovipositor which telescopes with segment 8 into segment 7 when retracted. The internal genitalia include ovaries, bursa copulatrix, spermatheca, spermathecal gland, vagina, and accessory glands. The terminology applied to coleopteran genital anatomy is critically discussed.     

THE FERTILIZATION CANAL IN PLODIA INTERPUNCTELLA (HÜBNER) (PYRALIDAE: LEPIDOPTERA)

The spermathecal duct of Plodia interpunctella (Hübner) was studied with light and transmission electron microscopy. The lumen in the duct is enclosed by a thin chitinous wall that has a thicker band that spirals along the length of the duct. The thick spiral band pinches off part of the lumen and creates a smaller canal, which it encloses. Although the two canals are not separated, the duct appears to have a double lumen. The thin wall of the main canal provides a flexibility in which the lumen widens or narrows concomitantly with contractions of the spermatheca and the portion of the duct adjoining the spermatheca. Sperm is transferred from the spermatheca to the vestibulum where the egg is fertilized. The distention of the canal and contractions of the spermatheca thus account for the speed at which eggs are fertilized and deposited.