Insemination Of Females Research Articles

Mating alters the cuticular hydrocarbons of female Anopheles gambiae sensu stricto and aedes Aegypti (Diptera: Culicidae).

The cuticular hydrocarbons of female Anopheles gambiae Giles sensu stricto and Aedes aegypti (L.) mosquitoes were analyzed before and after they mated. In An. gambiae, the proportions of the two cuticular hydrocarbon components, n-heneicosane and n-tricosane, were significantly reduced as the female aged and after it mated. There were no changes in the hydrocarbon composition of males after they mated. Hydrocarbon extracts from mated and unmated An. gambiae females as well as those from males caused a reduction in the rates of female insemination when they were applied to unmated females. Female Ae. aegypti showed significant changes in the proportions of n-heptadecane, n-pentacosane and n-hexacosane in their cuticles after mating. These data suggest that cuticular hydrocarbons may play some role in chemical communication during mosquito courtship.

Obtaining an Interspecific Hybrid of Cranes by Artificial Insemination with Frozen–thawed Semen

Studies of artificial insemination of cranes and cryoconservation of their semen have been carried out in the nursery of rare species at the Oka Biosphere Reserve for many years. The criterion of successful cryoconservation of the semen is the obtaining of fertilized eggs after artificial insemination by the thawed semen. An experiment is described on artificial insemination of females of the white-naped crane Grus vipio by the frozen–thawed semen of the Siberian white crane G. leucogeranusafter one-year storage of semen in liquid nitrogen. As a result, an interspecific hybrid of cranes was obtained, which confirmed the possibility of producing a bank of cryoconserved crane semen. The use of the white-naped crane females was due to the absence of conspecific males and unavailability of Siberian white crane females. Problems of artificial insemination and cryoconservation of semen of rare crane species are discussed.

Multiple insemination increases reproductive success of female Montandon's newt ( Triturus montandoni , Caudata, Salamandridae)

The adaptive significance of multiple matings for females is a matter of much controversy. In insects, supplying the female’s sperm reserves with portions of fresh spermatozoa may be the main function of multiple matings. This simple explanation may also be applied to other animals which produce large numbers of eggs over prolonged periods of time. We tested the fertility insurance hypothesis in Montandon’s newt (Triturus montandoni, Amphibia, Salamandridae). T. montandoni females are inseminated internally by spermatophores they have picked up, and subsequently lay eggs fertilized by spermatozoa released from the spermatheca. We compared the reproductive success of singly and multiply inseminated females of Montandon’s newt in the laboratory. Multiply inseminated females laid more eggs and had a lower percentage of non-developing eggs than females who mated only once. Our data suggest that remating increases the reproductive success of multiply inseminated females by replenishing sperm reserves in the spermatheca or by supplying females with fresh portions of spermatozoa with high fertilizing capacity.

Influence of group size and neonatal handling on growth rates, survival, and tameness of juvenile houbara bustards

AbstractThe influence of group size, sex, year, and environmental enrichment on growth of a large sample of captive‐bred houbara bustards was examined, as well as the influence of regular handling on survival. Growth rates of chicks kept in groups of eight were depressed compared with chicks in groups of five. Differences in growth rates between males and females were not significant at fledging (∼35 days), but were so by 80 days, although interindividual variation still precluded reliable sexing by body mass at this age. Growth rates varied between years, suggesting that management practices may affect growth, and potentially the reproductive performance of birds. Survival of birds receiving extra handling, mainly in the form of regular weighing, was significantly higher than that of birds receiving little handling. The effect of environmental enrichment on tameness was also assessed. Tameness is desirable in the captive flock, where stress is perceived as a major impediment to reproductive performance, preventing the successful collection of semen from males and insemination of females, delaying recruitment, and causing nonbreeding among both sexes. Extra handling and environmental enrichment was applied to a sample of chicks, and tameness of juveniles was assessed in a variety of ways (open field test, subjective assessments), but no significant difference was found between the enriched birds and a control group. The enrichment protocol might be improved by increasing the period of time during which birds were handled and associating handling with food rewards, although the time required to carry out such a protocol may be constrained when large numbers of chicks are produced. Zoo Biol 20:423–433, 2001. © 2001 Wiley‐Liss, Inc.

Growth of Penaeus monodon× Penaeus esculentus tiger prawn hybrids relative to the parental species

Interspecies hybrids were produced by artificial insemination of Penaeus monodon females with P. esculentus males. Successful spawnings (those in which some eggs hatched) were achieved from nine of the 17 P. monodon× P. esculentus matings attempted (53%). Mean egg numbers produced ranged from 158,000 to 438,000 but hatch rates were low (<4% in all cases). Cumulative survival of the hybrids and both parental species was similar, and around 30% at 4 weeks. There was no indication of hybrid vigour for growth. However, growth rate of hybrid larvae (0.048 g day −1), was the same as those of pure P. monodon (0.047 g day −1) and significantly greater than that of P. esculentus larvae (0.033 g day −1). The relative growth rate among parental species and the hybrids was determined accurately by rearing progeny of pure and hybrid matings in parallel under controlled conditions. The colour pattern of the hybrids was intermediate between that of P. monodon and P. esculentus. Sex ratio was significantly skewed in favour of males in the hybrids (proportion of males was 0.86 compared with 0.56 in the parental species), possibly suggesting females are the heterogametic sex in penaeids. The hybrids had the fast growth rate of P. monodon, and some of the attractive colour pattern of P. esculentus.

Ultrastructural investigations of the female genital system of Epiperipatus biolleyi ( Bouvier 1902) (Onychophora, Peripatidae)

Brockmann, C., Mummert, R., Ruhberg, H. and Storch, V. 1999. Ultrastructural investigations of the female genital system of Epiperipatus biolleyi (Bouvier 1902) (Onychophora, Peripatidae). — Acta Zoologica (Stockholm) 80: 339–349.The female genital system of the neotropical peripatid Epiperipatus biolleyi was examined using transmission and scanning electron microscopy. Special attention is given to the two accessory organs of the paired oviducts: the receptacula seminis and the ovarian funnels (Ovarialtrichter). The latter occur only in the Peripatidae, whereas receptacula seminis may also be present in the Peripatopsidae, the only other family in the Onychophora. The ovarian funnels of E. biolleyi are thin‐walled and closed from the haemocoel. This trait has also been reported from Epiperipatus trinidadensis, Macroperipatus torquatus, and Eoperipatus weldoni, whereas other peripatids have ovarian funnels which have been reported to open into the haemocoel. The occurrence of artificially opened ovarian funnels, caused by tissue rupture during specimen preparation, is discussed. The presence of spermatozoa both in the receptaculum seminis and in parts of the uterus of the female examined in this study supports the hypothesis that in E. biolleyi insemination of juvenile females occurs directly via the genital opening. The female contained one unstalked cleavage embryo in each uterus horn. Two features of the uterus were found to be unique to E. biolleyi: (1) a second cell layer overlying the uterine epithelium with a pronounced secretory activity (2) embryos are enclosed in a noncellular coat interspersed with numerous transport vesicles.

Regulation of mating behavior by nutrition and the corpus allatum in both male and female Phormia regina (Meigen)

Both dietary protein and the corpus allatum (CA) were required for normal mating behavior in both male and female black blow fly, Phormia regina (Meigen). Nutrition (protein diet) activated the CA in both sexes. More than 10 mg of dietary liver was required for each male to result in 80% insemination of females, while 20 mg of liver was required for each female to allow 78% of females to become inseminated. Between 10 to 15 mg of protein meal (i.e., liver) was required to activate sexual receptivity in 71% of the females, while between 15 to 20 mg of liver was needed to support full oöcyte development in 70% of the females (Yin, C.-M., Zou, B.-X., Li, M.-F., Stoffolano, J.G., Jr. 1994. Discovery of a midgut peptide hormone which activates the endocrine cascade leading to oogenesis in Phormia regina Meigen. Journal of Insect Physiology, 40, 283–292). Allatectomy suppressed mating behavior more than 2-fold in both sexes. Topical application of 10 μg of S-methoprene (a juvenile hormone analogue) at 12 h after the onset of liver feeding restored sexual activity of both allatectomized males and females. Incidence of successful insemination increased as the oöcyte development progressed. Ovariectomy suppressed sexual receptivity more than 3-fold in liver-fed females. Thus, in addition to nutrition and the CA, ovaries and their developmentaal status can also affect the sexual receptivity in female P. regina.

Female x male interactions in Drosophila sperm competition.

In several organisms, the success of a male's sperm in multiply inseminated females depends on the male's genotype. In Drosophila, the female also plays a role in determining which sperm are successful. Pairwise tests among six isogenic lines of Drosophila melanogaster were performed to determine whether there is a genotype-specific interaction in the success of sperm. The success of a particular male's sperm was found to depend on the genotype of the female with which he mates, providing evidence for an interaction with profound evolutionary consequences.

Synchrony and conception to insemination or embryo transfer in beef females treated with an intravaginal progesterone releasing device with or without an injection of estradiol

Synchrony and conception to insemination or embryo transfer in beef females treated with an intravaginal progesterone releasing device with or without an injection of estradiol

The effects of injection of amphetamine on female insemination in the black blow fly, Phormia regina (Diptera: Calliphoridae)

Abstract. An earlier study on the blowfly Phormia regina (Meigen) demonstrated that the injection of amphetamine (12 μg) depletes biogenic amine levels in the CNS. In the present study, P. regina females were injected with amphetamine (12 μg), each female was placed with three males and insemination success was determined. Amphetamine inhibited female insemination by 43.3% at 2–90 min post‐injection and by 70% at 10–60 min post‐injection. At 180–270 min post‐injection, there was no significant inhibition of female insemination. This study indicates a possible role in insects for the biogenic amines in female insemination.

Improved Rearing Methods for Heleidomermis magnapapula (Nematoda: Mermithidae), a Larval Parasite of Culicoides variipennis sonorensis (Diptera: Ceratopogonidae)

Improvements in rearing techniques have decreased maintenance needs and have increased the parasitism rate of larval Culicoides variipennis sonorensis Wirth & Jones by the mermithid nematode, Heleidomermis magnapapula Poinar & Mullens. In colony pans with 2,500-3,000 larval C. v. sonorensis, H. magnapapula adults emerged from 22.5% of hosts, with an average yield of 159 female H. magnapapula per pan. H. magnapapula females refrigerated for 1 wk showed no decline in preparasite infectivity compared with nonrefrigerated females. Female insemination did not differ with various mating combinations of 1 or 2 females with 1 or 2 males; 37-47% of these pairs failed to produce fertilized eggs. In 9-cm petri dishes, the optimal preparasite/host ratio was 900 infective preparasites (1 female's entire clutch) to 650-700 C. v. sonorensis larvae. Overall, parasite production was more time- and labor-efficient when larvae were parasitized in regular colony pans compared with petri dishes.

A pharmacological and endocrinological study of female insemination inPhormia regina (Diptera: Calliphoridae)

Injections of octopamine, dopamine, and the octopaminergic agonists, clonidine and naphazoline, into the thoracic hemocoel enhanced female insemination in sugar-fed (sexually unreceptive)Phormia regina. Topical applications of the juvenile hormone (JH) analogue, methoprene, also enhanced female insemination in sugar-fed (sexually unreceptive)P. regina. Since JH plays a role in receptivity in protein-fed females, it was originally hypothesized that one agonist, clonidine, enhanced female insemination by acting on the corpus allatum (CA) to increase JH biosynthesis. Two or three doses of the antiallatal agent, precocene II, prior to administration of clonidine, did not inhibit clonidine-enhanced female insemination. Removal of the corpus allatum also did not have a significant effect on clonidine-enhanced female insemination. Measurement of juvenile hormone (JH) biosynthesis/release in corpora allata, which were removed at 1, 3, 5, and 7 h postinjection, revealed that clonidine does not affect JH biosynthesis/release. Our study reveals a possible role for the biogenic amines in female insemination in insects. We suggest that the octopaminergic agonist, clonidine, acts downstream from the corpus allatum on the regulatory mechanisms involved in female insemination.

Polymorphism in genes that influence sperm displacement.

Paternity of offspring of multiply inseminated females is in many organisms highly skewed, with an advantage generally going to the male that most recently mated. Variation in sperm competitive ability can result in strong natural selection, and one expects that a gene that offers an advantage in sperm displacement would, all else being equal, be rapidly fixed, leaving low equilibrium levels of variability in sperm competition. However, empirical studies have demonstrated genetic variation in sperm displacement, begging the question of how this variation can be maintained. Here we develop a population genetic model to find conditions that maintain polymorphism in alleles that influence sperm displacement. We consider a one-locus model in which allelic variants have pleiotropic effects on fecundity and mating ability in addition to sperm displacement. This model can admit more than one stable polymorphism, and we find conditions for protected polymorphism. Induced overdominance is not necessary for stable polymorphism. These results have direct bearing on the observed variation in the ability of resident sperm to defend against displacement.

Role of the petasma and appendices masculinae during copulation and insemination in the penaeoid shrimp,Sicyonia dorsalis(Crustacea: Decapoda: Dendrobranchiata)

Summary The role of presumed male gonopods in the insemination of females was investigated in the penaeoid shrimp Sicyonia dorsalis. Males with partially ablated petasmata or with ablated appendices masculinae did not copulate with females, while control males with exopods removed from the third pleopods copulated frequently and successfully inseminated females. However, males with petasmata altered by blockages at the tip or at the base did copulate with females but were unable to inseminate them. The hypothesis that the petasma of Sicyonia is a sperm injection device is rejected. Evidence against this hypothesis includes the structure of the gonopods, the position of the male at right angles below the female during copulation, the brevity of copulation, the frequency of copulation during normal matings, and the ability of males to inseminate only the spermatheca on one side per successful copulation. It is hypothesized that the male uses the petasma, supported by the endopods of the second pleopods, to ...

Interspecific hybridization of the tiger prawns Penaeus monodon and Penaeus esculentus

Interspecies hybrids were produced by artificial insemination of Penaeus monodon females with P. esculentus males. Successful spawnings were achieved from two of the 13 matings attempted. Hatch rates were low (< 4%) but 85% of the vigorous larvae produced survived to PL1. The hybrid identity of the larvae was confirmed by allozyme analysis at five diagnostic loci. Tank-reared juveniles grew at an overall rate of approximately 0.09 g day −1 to a weight of 10 g in tanks until the prawns were stressed at 4.5 months. A number of viral diseases were expressed subsequently, including IHHNV, and the experiment was terminated. There was no indication of hybrid vigour in growth rates, and the high growth rate of P. monodon was not combined simply with the colour patterns of P. esculentus. A variety of body colour and pattern variants, ranging between those of P. monodon and P. esculentus, was observed in the hybrids.

Spawning of ocean pout ( Macrozoarces americanus L.): evidence in favour of internal fertilization of eggs

Sperm physiology, in vivo artificial insemination and spawning of the ocean pout ( Macrozoarces americanus L.), a marine bottom fish, were studied. Milt was collected from the reproductive tract of mature males by suction using a catheter. The uncontaminated milt, having a very low sperm concentration, contains highly motile spermatozoa and sperm motility was retained in vitro at 4 °C for at least 24 h in both seminal plasma and ovarian slime collected from the oviduct of pre-spawning females. Instead of activating sperm, dilution in sea water instantly immobilized the spermatozoa of ocean pout. Osmolarity and pH of ocean pout seminal plasma were in the ranges 365–406 mOsM and 7.2–7.5, respectively. A study of the ionic composition of ocean pout seminal plasma demonstrated the presence of various ions including Na +, K +, Ca 2+, Mg 2+, and Cl −, with a remarkably lower K + concentration compared to that from other fish species. Since injections of milt containing motile sperm into the ovaries of pre-spawning females, which spawned in the absence of males, yielded fertilized ocean pout eggs, it is concluded that the ocean pout exhibits internal fertilization. The larvae hatched after 3 months of egg incubation in ambient sea water (9–10 °C). With proper timing of in vivo artificial insemination of mature females, fertilized ocean pout eggs can be obtained from fish reared in captivity.

Adaptive Topography in Fertility-Viability Selection Models: The Haplodiploid Case

A linear combination of partial changes of mean fitnesses from one generation to the next one is shown to be approximately equal to the additive genetic variance in fitness after enough generations and away from equilibrium in random mating haplodiploid populations under arbitrary weak frequency-dependent selection on sex-differentiated viability of individuals and sex-differentiated fertility of matings controlled at a single multiallelic locus. The result can be applied to X-linked locus models in diploid populations. The result is used to deduce approximate adaptive topographies far frequency-independent selection models in the cases of nonsex-differentiated fertilities and multiplicative sex-differentiated fertilities and for kin selection models in family-structured populations under the assumptions of single insemination and multiple insemination of females. Multiple insemination creates frequency-dependent selection regimes.

Reproduction of Darkblotched Rockfish off the Oregon Coast

Seasonal reproductive development, size and age at sexual maturity, and fecundity were described for darkblotched rockfish Sebastes crameri collected off the Oregon coast. Altogether, 1,060 fish captured by commercial groundfish and shrimp trawlers between July 1986 and July 1987 were examined. Reproductive events were protracted. Insemination of females occurred from August to December, and fertilization and parturition followed from December through March. Spermatozoa were observed within both vitellogenic and previtellogenic ovaries between July and November. Reproductive events in smaller males and females were delayed relative to those in larger individuals. Females attained 50% maturity at a greater size (36.5 cm total length) and age (8.4 years) than males (29.6 cm total length; 5A years). The unimodal development of eggs and larvae indicated one parturition per year. Most age-6, age-7, and age-8 females possessed ovaries in an intermediate “maturing” condition. Histological analysis revealed that most of these females were immature; ovaries showed no evidence of previous spawning, oocytes never developed beyond an early vitellogenic stage, and during months of parturition, many of these females were resorbing their advancing oocytes. Total fecundities ranged from 19,815 to 489,064 oocytes per ovary pair and increased exponentially with increasing fish length, linearly with fish weight, and asymptotically with fish age (6 to 66 years).

Male Gametic Strategies: Sperm Size, Testes Size, and the Allocation of Ejaculate Among Successive Mates by the Sperm-Limited Fly Drosophila pachea and Its Relatives

The gametic strategy of males comprises the amount of energy invested per sperm, the total amount invested in sperm production, and the pattern of sperm allocation among successive reproductive bouts. All of these variables were measured for each of the four species constituting the nannoptera species group of the Drosophilidae. Extreme interspecific variation was identified for all variables and enigmatic male reproductive strategies, including submaximal insemination of females, partitioning of ejaculate among successive mates, and production of few large sperm, were observed. Variation among species in female remating behavior was found to occur concomitantly with male remating behavior, probably because of female fertility demands. Relationships among testes size, sperm size, sperm numbers, and mating systems in these fruit flies are examined. These relationships are not consistent with patterns identified in studies of vertebrate taxa and suggest fundamental differences between vertebrates and invertebrates with respect to these traits. Hypotheses to explain the maintenance of male ejaculate delivery patterns that are consistent with sperm competition and bet-hedging theory are examined, as are potential selection pressures responsible for sperm-size evolution.

Timing of insemination in terms of age of new reproductive females of a temperate-zone polistine wasp,Polistes snelleni (Hymenoptera: Vespidae)

The present study investigated the age at which insemination takes place in Polistes snelleni, a species in which mating begins while new reproductives are still emerging from the nest. Insemination of new reproductive females began as early as 5 days of age, and most females were inseminated by 10 days of age.