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Sperm Storage (sperm + storage)
Selected AbstractsREVIEW ARTICLE: Mechanism of Prolonged Sperm Storage and Sperm Survivability in Hen Oviduct: A ReviewAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2008Shubash C Das A unique property of the avian oviduct is to store sperm for a prolonged period. The sperm storage tubules (SST) are located in the utero-vaginal junction of the oviduct, where sperm can be stored and survived for a few weeks after insemination or natural mating. The immune system in the oviduct is essential to prevent tissue infection by various microorganisms, and it may also affect the fate and survivability of sperm in the oviduct. Anti-sperm immunoresponses including infiltration of leukocytes may be induced in the vagina of the oviduct. Sperm that will participate in fertilization may be selected by these immunoresponses. However, sperm stored in the SST may be protected from the immunoresponse by SST structures and transforming growth factor ,, whose expression is increased during sperm storage in the SST. In this review, the mechanism of sperm survivability with reference to the regulation of anti-sperm immunoresponses in hen oviduct is emphasized. [source] The ultrastructure of the spermatozoa of Boa constrictor occidentalis, with considerations on its mating system and sperm competition theoriesACTA ZOOLOGICA, Issue 1 2006M. Tourmente Abstract Sperm ultrastructure has been described for several families of Squamata in which it has been considered a valuable character source for phylogenetic studies. However, sperm competition and mating systems have been demonstrated to influence variations in the sperm morphology and dynamics. The mating system of Boa constrictor occidentalis is likely to have a high degree of sperm competition. We investigated, for the first time, the ultrastructure of the spermatozoa of B. c. occidentalis and, thus, of the family Boidae. Active mating groups were captured from the field, and the spermatozoa of the males was collected by ejaculation and processed to obtain transmission electron micrographs and fluorescence micrographs. The spermatozoa are filiform and their morphology fits the general model described for snakes, and several synapomorphies belonging to the squamates can be identified in these cells. Nevertheless, the head is 25% longer and the midpiece presents a lower frequency of mitochondrial transformations than that of other snakes. We propose that this last trait, along with the extraordinary elongation of the midpiece and the system of multilaminar membranes covering this section (both synapomorphies of the snake spermatozoa), are adaptive responses to processes of sperm competition and sperm storage. [source] The effect of sperm storage and timing of mating on offspring sex ratios in the yellow dung fly Scatophaga stercorariaECOLOGICAL ENTOMOLOGY, Issue 3 2000Nicola J. Seal Summary 1. Offspring sex ratios in the yellow dung fly Scatophaga stercoraria were examined in the laboratory. 2. Previous work indicated that females using previously stored sperm to fertilise their eggs produced male-biased sex ratios. This result may have been due to female influences or the effects of sperm storage per se. 3. This pattern was not reproduced in the study presented here. Females that were allowed to mate just prior to oviposition produced similarly male-biased sex ratios to those females that used previously stored sperm to fertilise their clutch. 4. Captive-reared females may have perceived a lack of males in the population and thus produced a male-biased offspring sex ratio. Alternatively, gamete ageing or extra-chromosomal sex ratio distorters may have produced the male bias. [source] Sperm transfer, sperm storage, and sperm digestion in the hermaphroditic land snail Succinea putris (Gastropoda, Pulmonata)INVERTEBRATE BIOLOGY, Issue 2 2009Lobke Dillen Abstract. Many hermaphroditic species are promiscuous, have a sperm digesting organ and an allosperm storage organ (i.e., spermatheca) with multiple compartments (i.e., spermathecal tubules) providing opportunities for sperm competition. The relative paternity of a sperm donor drives the evolution of mating behaviors that allow manipulation of the sperm receiver's reproductive behavior or physiology. We studied the relationship between sperm transfer, sperm storage, sperm digestion, and copulation duration in the hermaphroditic land snail Succinea putris, in which an active individual mates on top of a passive individual. Specifically, we examined (i) whether the entire copulation duration was required to complete reciprocal sperm transfer, (ii) sperm transfer patterns and their relationship with activity role, and (iii) the timing of sperm storage and sperm digestion. We found that reciprocal sperm transfer was completed within the first 5 h of copulation, which is ,2,3 h before the end of copulation. Sperm transfer was mainly sequential, meaning that one individual donated all his ejaculate before its partner started to reciprocate. The initiation of sperm transfer did not depend on the activity role. The presence of allosperm in the spermatheca before sperm transfer suggests that individuals remate before they are allosperm depleted. No sperm was digested during copulation but sperm digestion took place 0,72 h after copulation. Our results suggest that contact mate guarding is a likely manipulation strategy in S. putris, because partners cannot immediately remate. In addition, staying in copula after sperm transfer is completed seems to prevent the immediate digestion of sperm and therefore may promote sperm displacement and allosperm storage. [source] Mating biology of the leaf-cutting ants Atta colombica and A. cephalotesJOURNAL OF MORPHOLOGY, Issue 10 2006Boris Baer Abstract Copulation behavior has often been shaped by sexually selected sperm competition or cryptic female choice. However, manipulation of previously deposited ejaculates is unknown in the social Hymenoptera and the degree to which sperm competes after insemination or is actively selected by females has remained ambiguous. We studied the mating process in the leaf-cutting ants Atta colombica and A. cephalotes, which belong to one of the few derived social insect lineages where obligate multiple mating has evolved. As copulations often occur at night and in remote places, direct observations were impossible, so we had to reconstruct the sequential copulation events by morphological analysis of the male and female genitalia and by tracking the process of sperm transfer and sperm storage. We show that Atta male genitalia have two external rows of spiny teeth, which fit into a specialized pouch organ in the female sexual tract. Reconstruction of the sperm storage process indicated that sperm is transferred to the spermatheca during or immediately after ejaculation and without being mixed with sperm and seminal fluids from other males. A convergent mechanism of direct sperm transfer to the spermatheca of queens is known from two species of dwarf honeybees. Direct sperm transfer may restrict female control over the sperm storage process and the number of males that contribute to the stored sperm. J. Morphol. © 2006 Wiley-Liss, Inc. [source] Early male reproductive advantage, multiple paternity and sperm storage in an amphibian aggregate breederMOLECULAR ECOLOGY, Issue 6 2003J. A. Tennessen Abstract We tested whether the order in which males encounter females affects reproductive fitness in spotted salamanders (Ambystoma maculatum). Using mating chambers in the field, we allowed one male access to a female before a second male. We then used four microsatellite markers in paternity analyses of the resulting larvae. First males sired a significantly larger number of offspring than second males, suggesting that male reproductive success is greatly enhanced by early arrival at breeding ponds. Multiple paternity was common among clutches, and frequently larvae were assigned to unidentified males that had not been in the chambers. Sperm from these males had either been stored by females for a year or obtained more recently at other breeding sites. [source] Microsatellites in the genus Xiphophorus, developed in Xiphophorus montezumaeMOLECULAR ECOLOGY RESOURCES, Issue 1 2002J. Seckinger Abstract Species of the genus Xiphophorus (swordtails and platies) are of great interest for the study of evolution of sexually selected traits like the sword, which is an elongation of ventral fin rays of the male caudal fin, that has evolved in several species within this genus. The detection of 10 microsatellites within the genus Xiphophorus will enable studies about the correlation of this trait with sexual reproductive success of males possessing swords of different lengths. These microsatellites will also be useful in determining population structure and enable paternity analysis in these species, where sperm storage is widespread. [source] Roles of antioxidants on prolonged storage of avian spermatozoa in vivo and in vitroMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 3 2003Christelle Bréque Abstract This review focuses on natural and assisted prevention against lipid peroxidation in avian spermatozoa. The presence of high levels of n-6 polyunsaturated fatty acids (PUFAs) in the plasma membrane creates favorable conditions for the formation of peroxidative products, a major cause of membrane damage which may ultimately impair male fertility. However, a complex antioxidant system involving vitamin C, vitamin E and GSH is naturally present in avian semen. Coupled with a battery of enzymatic defenses (e.g., SOD, GSH-Px either Se- or non-Se-dependent), this system acts to prevent or restrict the formation and propagation of peroxides. The presence of specialized sites dedicated to prolonged sperm storage in avian females raises the question of durable protection of sperm membranes against peroxidation. Preliminary observations have revealed the presence of a specific antioxidant system at these sites in which vitamin C could exert a major role. From a practical standpoint, the extensive use of artificial insemination in poultry, along with the emergence in some species of workable techniques to cryopreserve spermatozoa, demand better control of peroxidation occurring in the plasma membrane of spermatozoa before or during storage. Dietary supplementation with vitamin E is effective in limiting lipid peroxidation of sperm plasma membranes, both in chickens and turkeys. In addition, organic Se with or without vitamin E stimulates Se-GSH-Px activity in seminal plasma. Preliminary observations in female chickens have also revealed the effectiveness of dietary supplementation with vitamin E, organic selenium or both to sustain fertility in aging flocks. Mol. Reprod. Dev. 66: 314,323, 2003. © 2003 Wiley-Liss, Inc. [source] Copula duration and sperm storage in Mediterranean fruit flies from a wild populationPHYSIOLOGICAL ENTOMOLOGY, Issue 1 2000P.H.illip W. Taylor Summary In the Mediterranean fruit fly (Ceratitis capitata Weidemann, ,medfly'), a lekking tephritid, evidence from laboratory studies of flies from laboratory strains suggests that copulation is shorter, and sperm storage more abundant, if males are large or protein-fed, and that copulation is longer when females are large. In addition, sperm tend to be stored asymmetrically between the female's two spermathecae and this asymmetry declines with abundance of stored sperm. The primary objective of this study was to investigate whether these trends persist in other experimental contexts that bear closer resemblance to nature. Accordingly, we carried out experiments in a field-cage using males derived as adults from a wild population and virgin females reared from naturally infested fruit. The results of this study were consistent with laboratory studies in that copula duration increased with female size, that sperm were stored asymmetrically between the females' spermathecae, and that this asymmetry declined with number of sperm stored. However, we also found some previously unreported effects of female size; large females stored more sperm and stored sperm more asymmetrically between their two spermathecae than did small females. Unlike the laboratory studies, copula duration and sperm storage patterns were unaffected by male size and diet. This may be due to overwhelming variation from other sources in the wild-collected males used, as well as environmental variability in the semi-natural setting. [source] REVIEW ARTICLE: Mechanism of Prolonged Sperm Storage and Sperm Survivability in Hen Oviduct: A ReviewAMERICAN JOURNAL OF REPRODUCTIVE IMMUNOLOGY, Issue 6 2008Shubash C Das A unique property of the avian oviduct is to store sperm for a prolonged period. The sperm storage tubules (SST) are located in the utero-vaginal junction of the oviduct, where sperm can be stored and survived for a few weeks after insemination or natural mating. The immune system in the oviduct is essential to prevent tissue infection by various microorganisms, and it may also affect the fate and survivability of sperm in the oviduct. Anti-sperm immunoresponses including infiltration of leukocytes may be induced in the vagina of the oviduct. Sperm that will participate in fertilization may be selected by these immunoresponses. However, sperm stored in the SST may be protected from the immunoresponse by SST structures and transforming growth factor ,, whose expression is increased during sperm storage in the SST. In this review, the mechanism of sperm survivability with reference to the regulation of anti-sperm immunoresponses in hen oviduct is emphasized. [source] Sperm transfer through forced matings and its evolutionary implications in natural guppy (Poecilia reticulata ) populationsBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2003JONATHAN P. EVANS In species in which individuals alternate between mating strategies, males may respond to elevated predation risk by switching from conspicuous courtship displays to less risky or more profitable sneaky mating attempts. As a consequence, in such species female choice is likely to be undermined more frequently in relatively dangerous localities. We tested this prediction using the guppy, a species of fish in which individual males alternate between courtship (solicited) and forced (unsolicited) copulations according to prevailing levels of predation. We collected females at late stages of gestation from four high- and four low-predation populations in Trinidad and examined them for the presence of sperm in their gonoducts. Due to the patterns of sperm storage in guppies, sperm found in the gonoducts of such late-cycle females can only arise from unsolicited copulations. We anticipated that because female guppies are subject to greater sexual harassment in the form of forced mating attempts in high-risk localities, a higher proportion of females in these populations would contain sperm in their gonoducts arising from recent unsolicited copulations. Contrary to this prediction, only one of the four paired comparisons (from the Quaré River) revealed a significant difference in the proportion of females recently inseminated through forced copulations. The paired comparisons for the remaining three rivers revealed no significant differences in the proportion of females with recoverable sperm in their gonoducts. However, overall, we found that 44.5% (±4.3 SE) of females had sperm in their gonoduct arising from sneaky mating, a figure three times higher than previously reported for this species. We discuss these findings in relation to recent predictions concerning the strength of sexual selection in natural populations. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 78, 605,612. [source] | ||||||||||||||||||||||