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PubMed1977

Protein synthesis inhibition alters Drosophila mating behavior.

Fruit fly Drosophila pseudoobscura virgin AR females mate preferentially with AR males given a choice between AR and or males. However, AR females which mated with or males when young show a significant change in sexual selection in favor of or over AR males in subsequent simultaneous choice tests. Ingestion of food moistened with 4 ml cycloheximide (400 microng/ml) produces 75% protein synthesis inhibition in the female flies. Females exposed to cycloheximide (CXM) immediately after their initial copulation with or males resemble virgin flies in their choice of mates, and mate preferentially with AR males. Females exposed to CXM before their initial copulatory experience with or males resemble or-experienced but untreated (no CXM) flies in their choice of mates, and mate preferentially with or males. The change in sexual preference shown by females with prior copulatory experience resembles learning in that it is subject to disruption by CXM in ways analogous to those reported in the literature.

Animals↗

PubMed1982

Directionality of yeast mating-type interconversion.

The mating-type a and alpha alleles of the yeast Saccharomyces cerevisiae interconvert by a transposition-substitution reaction where replicas of the silent mating loci, at HML and HMR, are transmitted to the expressed mating-type locus (MAT). HML is on the left arm and HMR on the right arm, while MAT is in the middle of chromosome III. Cells with the genotype HML alpha HMRa switch mating type efficiently at a frequency of about 86%. Since well over 50% of the cells switch, it is thought that switches do not occur randomly, but are directed to occur to the opposite mating-type allele. In contrast, we report that strains possessing the reverse HMLa HMR alpha arrangement switch (phenotype) inefficiently at a maximum of about 6%. The basis for this apparent reduced frequency of switching is that these strains preferentially yield futile homologous MAT locus switches--that is, MATa to MATa and MAT alpha to MAT alpha--and consequently, most of these events are undetected. We used genetically marked HM loci to demonstrate that alpha cells preferentially choose HMR as donor and a cells preferentially choose HML as donor, irrespective of the genetic content of the silent loci. Because of this feature, HML alpha HMRa strains generate predominantly heterologous while HMLa HMR alpha strains produce predominantly homologous MAT switches. The control for directionality of switching therefore is not at the level of transposing heterologous mating-type information, but only at the level of choosing HML versus HMR as the donor. In strains where the preferred donor locus is deleted, the inefficient donor becomes capable of donating efficiently. Thus the preference seems to be mediated by competition between the HM loci for donating information to MAT.

Alleles↗

PubMed1982

Failure of the orally active progestin, Regu-mate, to overcome confinement-induced delayed puberty in gilts.

Thirty-three crossbred gilts that were raised in total confinement were randomly allotted to two adjacent pens in a finishing unit at 144.7 +/- .5 days of age and 58.0 +/- 1.7 kg body weight. At approximately 253 days of age, 16 gilts were group fed a daily dose of 20 mg of Regu-mate per gilt for 18 days and 17 control gilts were group fed the same diet without Regu-mate for 18 days. Ovarian morphology was examined on 11 or 12 days after the last feeding of Regu-mate. Based on estrous behavior and ovarian morphology only one Regu-mate gilt displayed an estrus but did not ovulate and only three of the control gilts displayed estrus and ovulated at least once before the start of treatment. Three of the 16 Regu-mate gilts displayed estrus and ovulated 7.3 +/- .3 days after the last feeding and within the same time period the 3 control gilts, which previously displayed estrus, continued to have estrous cycles. One additional control gilt displayed estrus and ovulated 5 days after the last feeding of the control diet. Therefore, the proportion of gilts that displayed estrus and ovulated by the end of the experimental period were similar for the treated (25.0%) and control (23.5%) groups. Based on these results we conclude that treatment of gilts in a state of confinement-induced delayed puberty with 20 mg Regu-mate daily for 18 days failed to result in a synchronized onset of puberty in a significant proportion of gilts.

Journal Article↗

PubMed1988

Synchronization of estrus in beef cows with Norgestomet-Alfaprostol or Syncro-Mate B.

In the spring of 1986, 506 beef cows were used to evaluate the effectiveness of two estrus synchronization systems. Cows were synchronized with either a 6-mg Norgestomet implant placed in the ear for 14 d followed by a 6-mg Alfaprostol injection given 16 d after implant removal (Norgestomet-Alfaprostol) or with Syncro-Mate B (6-mg Norgestomet implant for 9 d with an injection containing 5 mg estradiol valerate and 3 mg Norgestomet at the time of implantation). The Alfaprostol injection in the Norgestomet-Alfaprostol group was given the same day as implant removal in the Syncro-Mate B group. These treatment groups were compared to a group of untreated controls. Cows were allotted to treatments by days postpartum, age and breed. Syncro-Mate B cows had a higher estrous response within 5 d after treatment (78.6 vs 64.0%) and a shorter interval to estrus (39.2 vs 66.7 h) than did Norgestomet-Alfaprostol cows (P < 0.05). Controls had a significantly lower estrous response compared to either of the synchronized groups (27.1%). The degree of estrus synchrony was identical in both synchronization systems (72.7%). Synchronized conception rate tended to be higher (P = 0.06) in the Norgestomet-Alfaprostol cows than in the Syncro-Mate B cows (74.5 vs 62.5%). Synchronized, 21-d, 25-d and breeding season pregnancy rates were 51.2, 70.8, 76.8 and 92.9% for Norgestomet-Alfaprostol cows; 48.5, 63.0, 73.2 and 87.8% for Syncro-Mate B cows; and 15.6, 56.3, 61.3 and 86.9% for control cows. The four pregnancy rates were not different between the two synchronization treatments (P > 0.10). Controls had lower synchronized and 25-d pregnancy rates when compared to either of the synchronized groups (P < 0.05). Days postpartum had no effect on the reproductive performance of cows synchronized with Norgestomet-Alfaprostol. Our results indicate that the Norgestomet-Alfaprostol system is as effective as Syncro-Mate B in synchronizing estrus in beef cows.

Journal Article↗

PubMed1985

The influence of mating status and age on the induction of chromosome aberrations and dominant lethals in irradiated female mice.

Young and old hybrid female mice were given 0.5 Gy or 2 Gy acute x-irradiation, followed by (i) in utero examination for dominant lethal mutations, or (ii) examination of metaphase I oocytes for chromosome aberrations 2-3 weeks after the irradiation. Some of the old females had been mated when young to males of a specific locus stock. Others were left unmated until after the irradiation when they, and the young females, were mated to the same specific locus stock and allowed to have 1 (if given 2 Gy) or 2 (if given 0.5 Gy) litters before the dominant lethal test. In both the 0.5-Gy and 2-Gy series, mean sizes of first litters in the old late-mated group were markedly lower than in the old early-mated or young groups, the differences being significant at the 2-Gy level. The intrauterine examinations showed that this difference was largely the result of a reduced ovulation rate in the old late-mated females. Preimplantation loss tended to be higher in all the old females than in the young ones, but differences between the groups in postimplantation lethality were less pronounced. In the chromosome studies, only about half as many oocytes were recovered from the ovaries of old females than from young ones. At both the 0.5-Gy and 2-Gy dose levels interchange frequencies were non-significantly higher in old than in young females (with no clear-cut effect of mating status), while the overall frequency of aberrations (interchanges + fragments) was significantly higher in oocytes of old than young females after 2 Gy X-rays (35.5% against 12.5%). No specific locus mutations were found in 5616 offspring of unirradiated females.

Age Factors↗

PubMed1993

Effect of avermectin residues in sheep dung on mating of the Australian sheep blowfly Lucilia cuprina.

Male and female Lucilia cuprina adults were separated after emergence and then fed either dung excreted from sheep after an oral treatment with ivermectin (Ivomec) or non-treated sheep dung. Fresh dung (non-treated or ivermectin-treated) was collected daily and fed to adults for 6 days after drenching. After this feeding period, males and females from each feeding treatment were paired and all aspects of mating behaviour recorded. Feeding on avermectin residues by adults had a significant effect on two components of mating: (1) males fed on ivermectin-treated dung directed less mating attempts at females compared with males fed on non-treated dung; (2) mating duration by males fed on ivermectin-treated dung was longer compared with males fed on non-treated dung. There was no significant difference in the level of sexual receptivity (percentage mating) between females fed on either ivermectin-treated dung or non-treated dung, although subsequent oviposition by females fed ivermectin-treated dung was significantly delayed. Both female and male mortality was significantly greater when feeding on ivermectin-treated dung compared with non-treated dung. The effects on mating, when coupled with the deleterious effects on ovarian development and adult mortality, demonstrate the potential for avermectin usage in a control strategy against L. cuprina.

Animals↗

PubMedDate not supplied

Decreased teratogen susceptibility in mouse fetuses obtained from delayed mating.

We examined whether the susceptibility of fetuses to a teratogen differs between fetuses from delayed mating and those from normal mating. Mitomycin-C (MMC; 2.5 mg/kg or 5.0 mg/kg) was administered to pregnant mice intraperitoneally on day 10 of gestation after either normal or delayed mating (6 h). The incidence of MMC-induced malformations in fetuses from delayed mating was significantly lower than in those from the normal mating group when the treatment time was adjusted to be at the same critical period according to the "catch-up" phenomenon of developmental progression in the delayed mating group.

Animals↗

PubMed2004

Medullary noradrenergic neurons release norepinephrine in the medial amygdala in females in response to mating stimulation sufficient for pseudopregnancy.

In the female rat, stimuli from the uterine cervix and vagina are carried to the brain areas involved in the mating-induced pseudopregnancy (PSP) response via the ventral noradrenergic bundle. Noradrenergic neurons projecting through this tract synapse in many forebrain areas including the amygdala, and neurons in the posterodorsal medial amygdala (MePD) are activated following mating. The goal of this experiment was to investigate whether norepinephrine (NE) is released into the MePD after mating using microdialysis and to determine the origin of this release. Ovariectomized estrogen- and progesterone-treated rats were implanted unilaterally with guide cannulae aimed at the MePD. Females were placed with males until they received 15 intromissions (15I), 5 intromissions (5I) or 15 mounts-without-intromission (MO). Dialysate samples collected every 20 min for 2 h before to 3 h after mating were analyzed for NE using HPLC with electrochemical detection. A significant increase in mean NE release in the MePD was seen at 80 min after mating onset in females receiving 15I, and no increase was seen in animals receiving 5I or MO. The time of peak NE release varied in 15I animals from 60 to 160 min after mating. Mean baseline levels of NE did not differ between groups. The retrograde tracer FluoroGold (FG), administered through the probe after cessation of dialysis sampling, was observed within identified noradrenergic cells primarily within the A1 and A2 cell groups. Infusion of anti-dopamine-beta-hydroxylase-saporin (DBH-SAP) into the MePD lesioned noradrenergic neurons located in the A1 and A2 cell groups. Because high levels of NE release occurred in the MePD only after the females received a number of intromissions sufficient to induce PSP, these results suggest that NE release within the MePD may be important for the establishment of PSP.

Amygdala↗

PubMed2005

Strategic mating with common preferences.

We present a two-sided search model in which individuals from two groups (males and females, employers and workers) would like to form a long-term relationship with a highly ranked individual of the other group, but are limited to individuals who they randomly encounter and to those who also accept them. This article extends the research program, begun in Alpern and Reyniers [1999. J. Theor. Biol. 198, 71-88], of providing a game theoretic analysis for the Kalick-Hamilton [1986. J. Personality Soc. Psychol. 51, 673-682] mating model in which a cohort of males and females of various 'fitness' or 'attractiveness' levels are randomly paired in successive periods and mate if they accept each other. Their model compared two acceptance rules chosen to represent homotypic (similarity) preferences and common (or 'type') preferences. Our earlier paper modeled the first kind by assuming that if a level x male mates with a level y female, both get utility -|x-y|, whereas this paper models the second kind by giving the male utility y and the female utility x. Our model can also be seen as a continuous generalization of the discrete fitness-level game of Johnstone [1997. Behav. Ecol. Sociobiol. 40, 51-59]. We establish the existence of equilibrium strategy pairs, give examples of multiple equilibria, and conditions guaranteeing uniqueness. In all equilibria individuals become less choosy over time, with high fitness individuals pairing off with each other first, leaving the rest to pair off later. This route to assortative mating was suggested by Parker [1983. Mate Choice, Cambridge University Press, Cambridge, pp. 141-164]. If the initial fitness distributions have atoms, then mixed strategy equilibria may also occur. If these distributions are unknown, there are equilibria in which only individuals in the same fitness band are mated, as in the steady-state model of MacNamara and Collins [1990. J. Appl. Prob. 28, 815-827] for the job search problem.

Animals↗

PubMed2006

Mating and immunity in invertebrates.

Mating and immunity are intimately linked to fitness. In both vertebrates and invertebrates, recent investigations into mate choice for immunity, tradeoffs between reproduction and immunity, and the relationships between post-mating processes and immune function have revealed that mating and immunity are also intimately linked to each other. Here, we focus on invertebrates and critically examine the evidence that immunity is under sexual selection, both pre- and post-mating, and explore other hypotheses linking mating and immunity. We find little evidence for a consensus regarding which theories best account for the accumulating empirical data. However, we suggest that progress can quickly be made by exploiting the intrinsic strengths of invertebrate model systems.

Animals↗

PubMed2005

Hormonal state influences aspects of female mate choice in the Túngara Frog (Physalaemus pustulosus).

Females alter their mate choices as they transition through different reproductive stages; however, the proximal mechanisms for such behavioral fluctuation are unclear. In many taxa, as females transition through different reproductive stages, there is an associated change in hormone levels; therefore, we examined whether fluctuation in hormone levels serves as a proximal mechanism for within-individual variation in mate choice in female túngara frogs (Physalaemus pustulosus). We manipulated hormone levels of females by administering 0, 10, 100, 500 or 1,000 IU of human chorionic gonadotropin (HCG), which is a ligand for luteinizing hormone (LH) receptors and will therefore cause increased gonadal hormone production. Phonotaxis assays were conducted to measure three aspects of mate choice behavior before and after HCG administration; receptivity (response to a conspecific mate signal), permissiveness (response to a signal that is less attractive than conspecific signals) and discrimination (ability to discern signal differences). The probability of response to a conspecific and an artificial hybrid signal significantly increased at the highest HCG doses. The difference in mean response time between pre- and post-HCG tests was significantly different for both the receptivity and permissiveness tests among the five doses. Increased permissiveness, however, was not due to decreased discrimination because females could discriminate between calls even at the highest HCG doses. These hormonal manipulations caused the same behavioral pattern we reported in females as they transitioned through different reproductive stages (Lynch, K.S., Rand, A.S., Ryan, M.J., Wilczynski, W., 2005. Plasticity in female mate choice associated with changing reproductive states. Anim. Behav. 69, 689-699), suggesting that changes in hormone levels can influence the female's mate choice behavior.

Animals↗

PubMed2006

Variability of GnRH secretion in two goby species with socially controlled alternative male mating tactics.

Male reproductive phenotypic plasticity related to environmental-social conditions is common among teleost fish. In several species, males adopt different mating tactics depending on their size, monopolizing mates when larger, while parasitizing dominant male spawns when smaller. Males performing alternative mating tactics are often characterized by a strong dimorphism in both primary and secondary reproductive traits. According to studies on sex-changing species and on species where only one male morph is reproductively active, male alternative phenotypes are expected to vary also in gonadotropin-releasing hormone (GnRH) neurons in forebrain preoptic area (POA). Here, we compared the intra- and inter-sexual variations in number and size of GnRH neurons, along with gonads and male accessory structure investment, in two goby species, the grass goby, Zosterisessor ophiocephalus, and the black goby, Gobius niger, characterized by male alternative mating phenotypes. In both species, older and larger males defend nests, court and perform parental care, while younger and smaller ones try to sneak territorial male spawning. We found that grass goby and black goby have different patterns of GnRH expression. Grass goby presents a clear intra-sexual dimorphism in GnRH expression, related to the occurrence of alternative mating tactics, while in the black goby, only inter-sexual differences are observed. The inter- and intra-specific variability in the GnRH neurons in these two goby species is discussed in light of the differences in migratory behavior, nest type, and mating system.

Analysis of Variance↗

PubMed2003

Rapid induction of Arc is observed in the granule cell dendrites in the accessory olfactory bulb after mating.

The activity-regulated cytoskeleton-associated protein (Arc), encoded by the immediate early gene arc, is enriched in the brain and is hypothesized to play a role in the activity-dependent neuronal plasticity in the hippocampus. In the present study, the time course of Arc expression during the post-mating period was determined immunocytochemically, and the localization of Arc in the neurons in the accessory olfactory bulb (AOB) of female mice after mating was analyzed using immunocytochemical electron microscopy. Transient increases in the number of Arc-immunoreactive cells were observed in the glomerular, mitral/tufted cell and granule cell layers of the AOB after mating. In particular, the increase in the granule cell layer was remarkable, and larger than the increases in the other layers. In addition, electron microscopic observation revealed that Arc immunoreactivity was in the dendrites of the granule cells 1.5 h after mating. These results indicate that expression of Arc protein is induced rapidly and transiently in granule cell dendrites after mating. It is postulated that Arc protein has a role in the neuronal plasticity of the AOB after mating.

Animals↗

PubMed2003

Behavioral and adrenocortical responses to mate separation and reunion in the zebra finch.

The adaptive value of social affiliation has been well established. It is unclear, however, what endogenous mechanisms may mediate affiliative behavior. The Australian zebra finch (Taeniopygia guttata) breeds colonially and adults maintain lifelong pair bonds that may be disrupted in the wild due to high mortality rates. Many of its natural, social behaviors are maintained in laboratory conditions, making this species well suited for studying the mechanisms of affiliation. This study examines the behavioral and neuroendocrine responses to pair mate separation and reunion in zebra finches. We measured plasma corticosterone (CORT) and behavioral changes following separation from a pair bonded mate, and again upon reintroducing the mate or an opposite-sex cagemate. Plasma CORT concentrations were: (1). elevated during pair mate separation, even in the presence of other same-sex individuals, and (2). reduced to baseline upon reunion with the pair mate but not upon re-pairing with a new opposite-sex partner. These findings show that zebra finches exhibit hormonal responses to separation and reunion specifically with a bonded pair mate and not with other familiar conspecifics. In addition, alterations in behavior during separation and reunion are consistent with monogamous pair bond maintenance. This study presents evidence for adrenocortical involvement in avian pair bonding, and for hypothalamic-pituitary-adrenal activation in response to an ecologically relevant social stressor.

Acoustic Stimulation↗

PubMed1997

Mating behaviour of Echinostoma caproni and E. trivolvis in concurrent infections in hamsters.

Young adults of Echinostoma caproni and E. trivolvis were recovered from hamsters. Some worms of each species were exposed to [3H]tyrosine for 1 h to label sperm, and these were transplanted singly to uninfected hamsters with various combinations of unexposed worms of either the opposite species or both species. Worms recovered 5 days later were serially sectioned, processed for autoradiography and observed for the location of radioactive sperm. Interspecies mating was detected when E. caproni was the sperm donor and E. trivolvis the recipient, but not the converse. The cross-insemination rate during interspecies mating was very low (13%) when compared to the normal rate of E. caproni intraspecies mating (52%). When single donor adults of either E. caproni or E. trivolvis had a choice of both recipient species, no interspecies mating took place, but both self- and cross-inseminated in a non-restrictive mating pattern typical of echinostome species. After transplantation, both species localized in their normal habitat within the hamster intestine. However, 25% of opposite species recoveries were found within 1 cm of each other, making interspecies mating a possibility.

Animals↗

PubMed2002

Lifetime ovipositional patterns of mated and virgin onion flies, Delia antiqua (Diptera: Anthomyiidae).

Over their 47.2+/-1.9 (mean+/-SEM) day lifespan, mated onion flies, Delia antiqua, oviposited more uniformly than did virgins. Mated females began ovipositing at 6.4+/-0.2 days old and regularly deposited 14.2+/-0.6 eggs/day for 3-4 weeks. Thereafter, oviposition slowed and stopped at about 1 week before death. Virgin flies began ovipositing 24.7+/-1.5 days into their 59.0+/-3.8 day lifespan, and deposited eggs at an increasing rate for 3-4 weeks, generating a mean overall ovipositional rate of 5.8+/-0.5 eggs/day. The later onset of virgin oviposition (ovipositional activation) and not a shorter ovipositional period largely accounted for the disparity between virgin and mated female lifespans. Mean lifetime egg production of mated females was 475+/-27 eggs versus 179+/-30 eggs for virgins. Ovipositional and post-ovipositional periods (34.4+/-1.8 and 7.2+/-1.0 days) for mated females were not significantly different from those of virgin females (30.9+/-3.6 and 6.7+/-1.2 days). Over 90% of virgin females laid eggs. The distinction between mated and virgin ovipositional patterns may be specifically attributed to differences in: (1) egg maturation, (2) age at ovipositional activation, and (3) egg-laying rate.

Journal Article↗

PubMed2003

Quantification and visualization of Dippu-AST mRNA in the brain of adult Diploptera punctata: mated females vs. virgin females vs. males.

YXFGLa-allatostatins (ASTs) are a family of neuropeptides that inhibit juvenile hormone biosynthesis in vitro by the corpora allata of cockroaches and crickets. We have investigated the levels of AST expression in the brain of adult mated and virgin females, and adult males of the cockroach Diploptera punctata, for 11 days following emergence. To quantify Dippu-AST mRNA we have used an optimized, sensitive and specific quantitative competitive reverse-transcriptase polymerase chain reaction (QC-RT-PCR) method. Using this technique, we show that Dippu-AST is expressed at higher levels in the brains of mated females than in the brains of virgin females. Specifically, levels of Dippu-AST mRNA in day 0 mated females are 2.5x higher than levels in day 0 virgin females. By day 6-7, levels in mated females are 20x higher than those in virgin females. However, the general pattern of expression is preserved in mated and virgin females; levels of Dippu-AST mRNA are relatively high in newly eclosed females, fall steadily to significantly lower levels on day 5 (mated) and day 5-7 (virgins), and then increase and remain relatively stable until at least day 10. No significant changes in Dippu-AST mRNA are apparent in male brains during the observation period. However, the general pattern of expression is virtually the inverse of that seen in females. Dippu-AST mRNA in male brains is relatively low following emergence, increases to maximum levels on day 5, following which, levels steadily fall. In situ hybridization suggests that fluctuations in Dippu-AST mRNA expression are a result of differential transcription within medial and lateral cells of the pars intercerebralis in both males and females. In addition to yielding insights into Dippu-AST function, the quantification of Dippu-AST expression under normal conditions is useful in providing a basis for comparison of Dippu-AST expression following various physiological manipulations.

Aging↗

PubMed2003

Juvenile hormone titre and egg production in Tenebrio molitor infected by Hymenolepis diminuta: effect of male and/or female infection, male age and mating.

Infection of Tenebrio molitor with Hymenolepis diminuta induces curtailment of female fertility. We examined ovulation and oviposition, and associated titres of juvenile hormone (JH), in relation to parasitism and mating. Oviposition was significantly increased in infected mated and virgin beetles by days 6 and 9 post-emergence. Ovulation was not changed by infection; by the end of the 18-day experiment, the total number of laid eggs was not significantly altered. On day 6, JH levels were significantly higher in virgin infected insects, compared to non-infected controls (236+/-37.7 and 107+/-9.62 pg/g wet weight). Oviposition increased after mating, but total eggs ovulated remained the same. JH levels were higher in mated females on days 12 and 18 post-emergence, for infected and control insects. Previous studies suggested that male reproductive potential might rise following infection, because uninfected females lay more eggs when mated to infected males. We tested whether this caused an increase in female JH. Males were mated on days 5 or 12, when significant changes in their reproductive physiology begin to be observed, and are maximal, respectively. However, male age was of greater significance in promoting JH levels in females (p=0.001), than infection status of either partner (p=0.33).

Age Factors↗