Virgin Males Research Articles

Differences in placentophagia in relation to reproductive status in the california mouse (Peromyscus californicus)

Parturient females ingest placenta in most mammalian species, whereas fathers may do so in species in which both parents provide care for their offspring. To determine if the propensity to eat placenta varies with reproductive status in the biparental California mouse, we presented placenta to virgin (housed with a same-sex pairmate), expectant (pregnant with their first litter), and multiparous adult males and females. Liver was presented identically, 3-7 days later, as a control. Multiparous females were more likely to eat placenta than expectant and virgin females (p-values <0.016), whereas both multiparous and expectant males had higher incidences of placentophagia than virgins (p-values <0.016). Liver consumption did not differ among groups within either sex. These results suggest that propensity to eat placenta increases with maternal/birthing experience in females, and with paternal experience and/or cohabitation with a pregnant female in males.

Virgin and recently mated males are equally able to achieve new matings in Neoleucinodes elegantalis

AbstractLepidopteran male mating success is recognized to be directly related to physical and behavioural traits such as ability, vigour, activity and persistence in courtship. In the tomato fruit borer Neoleucinodes elegantalis Guenée, the mating system is known to be monogamic and therefore males' sexual investment is apparently low. The hypothesis that recently mated males have a remating probability equal to that of virgin males is tested. The impact of body size in remating success and the cost of remating are also analyzed. Mated males show as much propensity to remate as naïve ones. Copula duration and the time taken to copulate are similar in mated and virgin males. However, spermatophore size is not related to male size. The results suggest the ability of N. elegantalis males to remate within 24 h between mating events and their propensity to remate are not affected by copula investment. © 2013 The Royal Entomological Society

Male mating costs in a butterfly that produces small ejaculates

AbstractIn many insects, ejaculate size is positively related to male fitness, although the production of large ejaculates entails physiological costs that can result in decreased male longevity. Ejaculate production costs have been studied in butterfly species because males generally produce large ejaculates that are rich in resources. However, lepidopterans show interspecific variation with respect to relative investment in ejaculates (i.e. percentage of male body weight invested in ejaculates) that could influence the magnitude of costs. The physiological costs of ejaculate production are expected to differ between males with different amounts of resources stored. The effect of male size (an estimate of the amount of resources stored) on ejaculate production and on survivorship costs of multiple mating is studied in males of Leptophobia aripa Boisduval (Pieridae), the butterfly with the smallest relative investment in spermatophores recorded to date (0.31%). ‘Small males’ produce smaller spermatophores, although male size has no effect on ejaculate size (spermatophore + accessory substances), indicating that ‘small males’ make a relatively larger investment in the production of accessory substances. The results indicate that L. aripa males are able to modify the relative amount of resources invested in ejaculate production. Multiple mating has a negative effect on male longevity and this effect depends on male size: in comparison with virgin males, the longevity of ‘small males’ decreases after just one copula, whereas the longevity of ‘large males’ decreases after two copulations. The possible reasons why ‘small males’ invest relatively more resources in ejaculate production, despite the fact that they pay larger costs, are discussed.

The influence of female age on male mating preference and reproductive success in cabbage beetle, Colaphellus bowringi

The influence of female age on male mating preference and reproductive success has been studied using a promiscuous cabbage beetle, Colaphellus bowringi Baly (Coleoptera: Chrysomelidae). In a simultaneous choice test, middle-aged females had significantly greater mating success than young and old females. In single pair trials, when paired with middle-aged virgin males, middle-aged females mated faster, copulated longer, and had greater fecundity and fertility than young or old females, while the longevity of males was not significantly affected by female age. This study on C. bowringi suggests that middle-aged females are more receptive to mating, which can result in the highest male reproductive success.

Effect of mating on sex attraction in Bactericera cockerelli with evidence of refractoriness

AbstractWe investigated the effect of mating on female attractiveness and male responsiveness in the potato psyllid, Bactericera (= Paratrioza) cockerelli (Šulc) (Hemiptera: Triozidae), a major pest of potato. Assays were designed to examine response by mated or virgin males to volatile odors produced by virgin or mated females. Mating induced a behavioral refractory period during which males were not attracted to females. The refractory period was shown to include a mating‐induced lowering of male response to females, as well as a mating‐induced lowering of female attractiveness. The refractory period was longer in females (at least 48 h) than in males (less than 24 h). Following a post‐copulatory refractory period of 96 h, females were as attractive to males as virgin females. We also explored how rapidly spermatophores became depleted in females as a function of the amount of time following mating. The percent of females carrying spermatophores and the number of spermatophores per female decreased with the length of the female post‐mating period, possibly due to the absorption by females of the spermatophores and their content. By 96 h following mating, spermatophores were not visible in the majority of females, thus the absence of spermatophores in females of this species should not be used as evidence of mating status.

Reproductive strategies of the larval parasitoid Microplitis croceipes

AbstractMate choice may have important consequences for offspring sex ratio and fitness of haplodiploid insects. Mate preference of females of the solitary larval parasitoid Microplitis croceipes (Cresson) (Hymenoptera: Braconidae) for virgin and mated males, and vice versa, and the reproductive consequences (i.e., the sex ratio expressed as the proportion of male offspring) were examined in choice and non‐choice experiments. In addition, the effect of repeated rapid and daily copulation of an individual male on the sex ratio of offspring of the female mates was assessed. Males preferred virgins over mated females, whereas females copulated with a male irrespective of his mating status. In both the rapid and daily copulation assay, females copulating with a male that had copulated five times or more produced a higher sex ratio than females that had copulated with a virgin male. Females that copulated with virgin males once or twice produced a significantly and considerably lower sex ratio than females that first copulated with a sperm‐depleted male followed by a virgin male. This indicates that copulating with a sperm‐depleted male has costs and limits acquisition by the female of sperm from virgin males.

Mating Behavior of &lt;I&gt;Cnephasia jactatana&lt;/I&gt; (Lepidoptera: Tortricidae), an Important Pest of Kiwifruit

Understanding mating behavioral sequence helps us identify the mechanisms of mate assessment and choice, and better evaluate behavior-based pest control strategies. Here we describe the mating behavior of Cnephasia jactatana Walker whose females release a sex pheromone, and determine the effect of male mating status on reproductive success. The mating sequence starts when males approach females and display courtship behavior with antennation and fanning wings. Both males and females may end a mating attempt at any stage of the sequence. Both sexes assess their mates from the initial contact to copulation. Females appear to be choosier at the early and mid-stages than at the late stage of the sequence. Virgin males approach and court females significantly earlier than nonvirgin males. As compared with nonvirgin males, virgin males are approximately 1.6 times more likely to approach and 1.8 times more likely to court females, and four times more likely to achieve mating. This may be attributed to depletion of sperm and accessory gland materials and reduced ability to respond to female sex pheromones in nonvirgin males. The number of attempts by males to acquire mates may be one of the traits that females assess before choosing their mates.

Queer Virginity: Leïla Maraoune's La Vie sexuelle d'un islamiste à Paris

There is something deceptively binary about Leïla Marouane's novel, The Sexual Life of an Islamist in Paris: her male protagonist is a forty-year old virgin who wishes to “conquer” Western female bodies for whom procreation, marriage and commitment are (he hopes) irrelevant. At the same time, he does not seem able to break free from supposedly traditional Muslim values. And he is obsessed by an overpowering mother does not stop pressuring him into marrying a young Muslim virgin and having children as soon as possible. One of the possible interpretations of The Sexual Life of as Islamist in Paris is the protagonist slowly becomes mad because he is torn between two worlds and two cultures. The narrator has supposedly inherited a very precise cartography of bodies and gender that separates the world into penetrable and penetrating bodies. The trouble with that interpretation however is that it presupposes that Marouane accepts that Maghrebi sexual discourse is monolithic, opposable to a just as monolithic Western norm. Upon close reading, it becomes apparent that The Sexual Life of an Islamist in Paris is just as provocative as its title seems to promise but for reasons that have nothing to do with the reiteration or inversion of clichés. Rather than presenting a simple reversal of stereotypes (Mohamed is the male virgin and the Arab women he meets are sexually liberated), the novel complicates the construction of virginity and penetration and presents the narrative voice as an inextricable web of male and female threads. Presented as a double of the author herself, it turns the novel into a space where the construction of masculinity and femininity escapes the opposition between “the Maghreb” and “France,” a space where critique has find its own parameters through practices of constant disaligning and disidentification from gender and ethnic or religious norms.

Exposure to sperm competition risk improves survival of virgin males

Sperm competition between the ejaculates of multiple males for the fertilization of a given set of ova is taxonomically widespread. Males have evolved remarkable adaptations to increase their reproductive success under postcopulatory sexual selection, which in many species includes the ability to modify behaviour and ejaculate characteristics plastically to match the perceived level of sperm competition. Males of the model species Drosophila melanogaster increase mating duration and modify seminal fluid composition in response to short-term changes in sperm competition risk. If these responses increase a male's total investment in reproduction, he must either trade-off this cost against other life-history traits or suffer reduced survival. We tested whether mounting a plastic sperm competition response bears an instantaneous survival cost, and instead found that male D. melanogaster exposed to a high risk of sperm competition survive 12 per cent longer than those at low risk, equating to a 49 per cent reduction in the hourly hazard of death. This striking effect was found only among virgins: the high cost of mating in this species eliminates any such benefit among non-virgin males. Our results suggest that the improvement in survival found among virgins may be a product of males' tactical responses to sperm competition.

Male rats transmit Brucella abortus biotype 1 through sexual intercourse

The aim of this study was to evaluate transmission of Brucella abortus biotype 1 via sexual intercourse in rats. Male and female virgin Sprague-Dawley (SD) rats were experimentally infected intraperitoneally with 1×10(9)colony forming units (CFU) of B. abortus biotype 1, a Korean bovine isolate. At 14 days after infection, infected male rats (n=10) were housed with uninfected female rats (n=10) and infected female rats (n=10) were housed with uninfected male rats (n=10) for a period of one month. During this period all uninfected female rats became pregnant and 6 of 10 infected female rats became pregnant. Serum from two out of 10 female uninfected rats had positive reactions in the Rose Bengal Plate Agglutination Test (RBPAT), Tube Agglutination Test (TAT) or the Enzyme-Linked Immunosorbent Assay (ELISA); whereas none of the uninfected male rat had positive reactions in these tests. Using bacteriological culture and AMOS-PCR assay, B. abortus biotype 1 was isolated and identified from two uninfected female rats and all of the uninfected male rats were found negative for B. abortus biotype 1. It was concluded that transmission of B. abortus biotype 1 from infected male to uninfected female rats resulted from sexual intercourse.

Physiological and neuroendocrine responses to chronic variable stress in male California mice (Peromyscus californicus): Influence of social environment and paternal state

Social environment and parental state affect stress responses in mammals, but their impact may depend on the social and reproductive strategy of the species. The influences of cohabitation with a male or female conspecific, and the birth of offspring, on the physiological and endocrine responses to chronic variable stress were studied in the monogamous and biparental California mouse (Peromyscus californicus). Adult male California mice were housed either with a male cage mate (virgin males, VM), a female cage mate (pair-bonded males, PBM), or a female cage mate and their first newborn litter (new fathers, NF). VM, PBM and NF underwent a 7-day chronic variable stress paradigm (CVS, three stressors per day at semi-random times, n=7-8 per housing condition). Compared to control males (CON, n=6-7 per housing condition), CVS caused loss of body mass, increased basal plasma corticosterone concentrations, and increased basal expression of arginine vasopressin (AVP) mRNA in the paraventricular nucleus of the hypothalamus (PVN). These effects were independent of housing condition. Neither CVS nor housing condition altered novel-stressor-induced corticosterone release, spleen or testis mass, or basal expression of corticotropin-releasing hormone (CRH) mRNA in the PVN. Although CVS appeared to increase adrenal mass and reduce thymus mass specifically in NF, these effects were explained by the lower adrenal mass and higher thymus mass of NF compared to PBM and VM under control conditions. These results suggest that neither engaging in a pair bond nor becoming a father attenuates typical responses to CVS, but that fatherhood may provide a buffer against transient mild stressors (i.e., weighing and blood sampling in the control groups) in this monogamous and biparental rodent.

Is the rapid post-mating inhibition of pheromone response triggered by ecdysteroids or other factors from the sex accessory glands in the male moth Agrotis ipsilon?

In many animals, male copulation is dependent on the detection and processing of female-produced sex pheromones, which is generally followed by a sexual refractory post-ejaculatory interval (PEI). In the male moth, Agrotis ipsilon, this PEI is characterized by a transient post-mating inhibition of behavioral and central nervous responses to sex pheromone, which prevents males from re-mating until they have refilled their reproductive tracts for a potential new ejaculate. However, the timing and possible factors inducing this rapid olfactory switch-off are still unknown. Here, we determined the initial time delay and duration of the PEI. Moreover, we tested the hypothesis that the brain, the testis and/or the sex accessory glands (SAGs) could produce a factor inducing the PEI. Lastly, we investigated the possible involvement of ecdysteroids, hormones essential for development and reproduction in insects, in this olfactory plasticity. Using brain and SAG cross-injections in virgin and newly-mated males, surgical treatments, wind tunnel behavioral experiments and EIA quantifications of ecdysteroids, we show that the PEI starts very shortly after the onset of copulation, and that SAGs contain a factor, which is produced/accumulated after copulation to induce the PEI. Moreover, SAGs were found to be the main source of ecdysteroids, whose concentration decreased after mating, whereas it increased in the haemolymph. 20-Hydroxyecdysone (20E) was identified as the major ecdysteroid in SAGs of A. ipsilon males. Finally, 20E injections did not reduce the behavioral pheromone response of virgin males. Altogether our data indicate that 20E is probably not involved in the PEI.

Do tephritid-induced fruit volatiles attract males of the fruit flies parasitoid Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae)?

The braconid wasp Psyttalia concolor (Szepligeti) is an endoparasitoid of several tephritids of economic importance. Even if it has been reported that females of this species rely extensively on tephritid-induced fruit volatiles (TIFVs) during host location, no information is available on the behavioural role of TIFVs on males. Because P. concolor females mate only once, we hypothesized that the perception of TIFVs could be crucial for males, guiding them towards infested fruits on which they could find newly emerged females, thus raising the males’ chances to locate receptive females during their lifespan. On this basis, here we evaluate the attractiveness of synthetic TIFVs from two different trophic interactions, Ceratitis capitata–Malus domestica and Ceratitis capitata–Prunus persica towards P. concolor virgin males. The results showed that both fruit-mimicking blends, three synthetic apple-borne (1-butyl butyrate, 1-butyl hexanoate and 1-hexyl (E)-2-methylbutenoate) and four synthetic peach-borne (ethyl octanoate, nonanoic acid, decanoic acid and dodecanoic acid) compounds were found to attract males. Among these molecules, 1-butyl butyrate, 1-butyl hexanoate and decanoic acid also prolonged the time the males spent performing searching activities on the TIPV-treated surface. Because males probably use these volatiles mainly for sexual purposes, we believe that these chemicals could be classified as sexual kairomones.

Effect of reproductive status on hypothalamic–pituitary–adrenal (HPA) activity and reactivity in male California mice (Peromyscus californicus)

Previous studies indicate that reproductive condition can alter stress response and glucocorticoid release. Although the functional significance of hypothalamic–pituitary–adrenal (HPA) axis modulation by breeding condition is not fully understood, one possible explanation is the behavior hypothesis, which states that an animal's need to express parental behavior may be driving modulation of the HPA axis. This possibility is consistent with findings of blunted activity and reactivity of the HPA axis in lactating female mammals; however, effects of reproductive status on HPA function have not been well characterized in male mammals that express parental behavior. Therefore, we tested this hypothesis in the monogamous and biparental California mouse. Several aspects of HPA activity were compared in males from three reproductive conditions: virgin males (housed with another male), non-breeding males (housed with a tubally ligated female), and first-time fathers (housed with a female and their first litter of pups). In light of the behavior hypothesis we predicted that new fathers would differ from virgin and non-breeding males in several aspects of HPA function and corticosterone (CORT) output: decreased amplitude of the diurnal rhythm in CORT, a blunted CORT increase following predator-odor stress, increased sensitivity to glucocorticoid negative feedback, and/or a blunted CORT response to pharmacological stimulation. In addition, we predicted that first-time fathers would be more resistant to CORT-induced suppression of testosterone secretion, as testosterone is important for paternal behavior in this species. We found that virgin males, non-breeding males and first-time fathers did not display any CORT differences in diurnal rhythm, response to a predator-odor stressor, or response to pharmacological suppression or stimulation. Additionally, there were no differences in circulating testosterone concentrations. Adrenal mass was, however, significantly lower in new fathers than in virgin or non-breeding males. These results suggest that the behavior hypothesis does not explain HPA function across reproductive conditions in male California mice.

Spontaneous locomotor activity of drosophila subobscura under controlled laboratory conditions

The aim of this research was to examine the temporal patterns of spontaneous locomotor activity in Drosophila subobscura virgin females and males from isofemale lines collected from beech and oak forests and maintained in controlled laboratory conditions for five full-sib inbreeding generations. The flies were monitored in a circular open field arena for 30 min in the morning (8:00 AM, 9:00 AM, 10:00 AM, 11:00 AM). The distance travelled and the mobility of the flies decreased along with the registration time, whereby the slowest decreasing was observed at 8:00 AM. Females showed a greater range of variability in both parameters compared to males. In addition, there was a greater range of variability in the locomotor activities of flies from the oak forest compared to the beech. These findings could be attributed to their specific genetic background.

Influence of temperature, gender, age, and mating status on cigarette beetle (Lasioderma serricorne (F.)) (Coleoptera: Anobiidae) flight initiation

The influence of temperature in combination with gender, age, and mating status was examined to determine minimum temperature and percent of cigarette beetle, Lasioderma serricorne (F.) that initiate flight in a laboratory flight chamber. Tests were conducted on temperatures between 17.5 °C and 37.5 °C at intervals of 2.5 °C. We found that flight initiation of L. serricorne is highly dependent on environmental temperature, gender, age and mating status of individuals. The minimum detectable temperature at which all categories of males (virgin young, virgin old, mated young and mated old) initiated flight was 22.5 °C, while virgin young, virgin old, mated young and mated old females were observed to initiate flight at 25, 22.5, 25, and 27.5 °C, respectively. Young virgin males and older virgin females had the highest percentage of flight initiation among all categories of their gender and thus the greatest probability of being detected. No flight initiation is predicted for males at temperatures below 19.7 °C, thus, environmental temperature should be strongly considered when interpreting pheromone monitoring programs in food storage.

Old male mating advantage results from sexual conflict in a butterfly

Accumulating evidence suggests that sexual conflict is all pervasive, although cooperation is evidently needed in sexually reproducing organisms. While male mating success is typically positively associated with resource-holding potential, old male mating success prevails in some organisms despite old males being in greatly reduced condition. We tested whether this counterintuitive pattern is the outcome of (1) sexual conflict or (2) female preference for older males in the tropical butterfly Bicyclus anynana. Our results support the first hypothesis as females that mated with older compared to younger males showed reduced hatching success of eggs and higher remating propensity, and tended to show shorter refractory periods. Thus, females apparently try to compensate for reduced fitness arising from mating with older (low-quality) males by being more willing to remate, especially with young and/or virgin (high-quality) males. As mating with older males negatively affects female fitness, old males may acquire a mating advantage by being more aggressive and persistent during courtship, in line with the residual reproductive value hypothesis. Thus, males increase their own reproductive success at the expense of their female partners, such that the ‘cooperation–conflict balance’ between the sexes seems to be shifted towards conflict in B. anynana.

Cost of reproduction in the Queensland fruit fly: Y-model versus lethal protein hypothesis

The trade-off between lifespan and reproduction is commonly explained by differential allocation of limited resources. Recent research has shown that the ratio of protein to carbohydrate (P : C) of a fly's diet mediates the lifespan-reproduction trade-off, with higher P : C diets increasing egg production but decreasing lifespan. To test whether this P : C effect is because of changing allocation strategies (Y-model hypothesis) or detrimental effects of protein ingestion on lifespan (lethal protein hypothesis), we measured lifespan and egg production in Queensland fruit flies varying in reproductive status (mated, virgin and sterilized females, virgin males) that were fed one of 18 diets varying in protein and carbohydrate amounts. The Y-model predicts that for sterilized females and for males, which require little protein for reproduction, there will be no effect of P : C ratio on lifespan; the lethal protein hypothesis predicts that the effect of P : C ratio should be similar in all groups. In support of the lethal protein hypothesis, and counter to the Y-model, the P : C ratio of the ingested diets had similar effects for all groups. We conclude that the trade-off between lifespan and reproduction is mediated by the detrimental side-effects of protein ingestion on lifespan.

The effects of oviposition-site deprivation on Anopheles gambiae reproduction

BackgroundThe African malaria mosquito, Anopheles gambiae, depends on availability of suitable surface water for oviposition. Short and long dry spells occur throughout the year in many parts of its range that limit its access to oviposition sites. Although not well understood, oviposition-site deprivation has been found to rapidly reduce egg batch size and hatch rate of several mosquito species. We conducted laboratory experiments to assess these effects of oviposition-site deprivation on An. gambiae and to evaluate the role of nutrition and sperm viability as mediators of these effects.MethodsAnopheles gambiae adults (1–2 d old) from the G3 laboratory colony were assigned to the following treatment groups: oviposition-deprived (fed once and then deprived of oviposition site for 7 or 14 d), multiple-fed control (fed regularly once a week and allowed to lay eggs without delay), and age matched blood-deprived control (fed once, three days before water for oviposition was provided). Egg batch size and hatch rate were measured. In the second experiment two additional treatment groups were included: oviposition-deprived females that received either a second (supplemental) blood meal or virgin males (supplemental mating) 4 days prior to receiving water for oviposition.ResultsAn. gambiae was highly sensitive to oviposition-site deprivation. Egg batch size dropped sharply to 0–3.5 egg/female within 14 days, due to reduced oviposition rate rather than a reduced number of eggs/batch. Egg hatch rate also fell dramatically to 0-2% within 7 days. The frequency of brown eggs that fail to tan was elevated. A supplemental blood meal, but not ‘supplemental insemination,’ recovered the oviposition rate of females subjected to oviposition-site deprivation. Similarly, a supplemental blood meal, but not ‘supplemental insemination,’ partly recovered hatch rate, but this increase was marginally significant (P < 0.069).ConclusionsEven a short dry spell resulting in oviposition-site deprivation for several days may result in a dramatic decline of An. gambiae populations via reduced fecundity and fertility. However, females taking supplemental blood meals regain at least some reproductive success. If mosquitoes subjected to oviposition-site deprivation increase the frequency of blood feeding, malaria transmission may even increase during a short dry spell. The relevance of oviposition-site deprivation as a cue to alter the physiology of An. gambiae during the long dry season is not evident from these results because no reduction in hatch rate was evident in wild M-form An. gambiae collected in the dry season in the Sahel by previous studies.

Identification of sex pheromone components in Trissolcus brochymenae females

Long- and short-range sex pheromones appear to play a crucial role in the mate finding and courtship behaviour of most parasitic Hymenoptera. Yet these parasitoids have been rarely investigated and only a few pheromones have been identified. Recent studies have shown that sexual communication of Trissolcus brochymenae (Hymenoptera: Platygastridae), a quasi-gregarious egg parasitoid of the harlequin bug, Murgantia histrionica (Heteroptera: Pentatomidae), starts before contact between males and females when chemical compounds produced by virgin females trigger the courtship behaviour of males. In the present study, the pheromone components involved in the short-range recognition of T. brochymenae females by males were investigated using electrophysiological and behavioural methods. Female body extracts were analyzed through EAG and GC-EAD and the active compounds were identified through GC–MS. The behavioural responses of virgin males to the GC-EAD active compounds were subsequently evaluated in closed arena bioassays. Two active compounds in EAG and behavioural tests, tetradecyl acetate and (Z)-11-hexadecen-1-yl acetate, were identified as sex pheromone components. Both compounds triggered intense male antennation and mount when applied to solvent-washed female cadavers. Dose–response tests showed different curves for the two compounds. This is the first study on the identification of sexual pheromones in Platygastridae.