Sex investment ratios in eusocial Hymenoptera support inclusive fitness theory

Inclusive fitness theory predicts that sex investment ratios in eusocial Hymenoptera are a function of the relatedness asymmetry (relative relatedness to females and males) of the individuals controlling sex allocation. In monogynous ants (with one queen per colony), assuming worker control, the theory therefore predicts female‐biased sex investment ratios, as found in natural populations. Recently, E.O. Wilson and M.A. Nowak criticized this explanation and presented an alternative hypothesis. The Wilson–Nowak sex ratio hypothesis proposes that, in monogynous ants, there is selection for a 1 : 1 numerical sex ratio to avoid males remaining unmated, which, given queens exceed males in size, results in a female‐biased sex investment ratio. The hypothesis also asserts that, contrary to inclusive fitness theory, queens not workers control sex allocation and queen–worker conflict over sex allocation is absent. Here, I argue that the Wilson–Nowak sex ratio hypothesis is flawed because it contradicts Fisher's sex ratio theory, which shows that selection on sex ratio does not maximize the number of mated offspring and that the sex ratio proposed by the hypothesis is not an equilibrium for the queen. In addition, the hypothesis is not supported by empirical evidence, as it fails to explain ‘split’ (bimodal) sex ratios or data showing queen and worker control and ongoing queen–worker conflict. By contrast, these phenomena match predictions of inclusive fitness theory. Hence, the Wilson–Nowak sex ratio hypothesis fails both as an alternative hypothesis for sex investment ratios in eusocial Hymenoptera and as a critique of inclusive fitness theory.     

COLONY SEX RATIOS,CONFLICT BETWEEN QUEENS AND WORKERS,AND APPARENT QUEEN CONTROL IN THE ANT PHEIDOLE DESERTORUM

Sex-ratio conflict between queens and workers was explored in a study of colony sex ratios, relatedness, and population investment in the ant Pheidole desertorum. Colony reproductive broods consist of only females, only males, or have a sex ratio that is extremely male biased. Colonies producing females (female specialists) and colonies producing males (male specialists) occur at near equal frequency in the population. Most colonies apparently specialize in producing one reproductive sex throughout their life. Allozyme analyses show that relatedness does not differ within male-specialist and female-specialist colonies and they do not appear to differ in available resources. In the population, workers are nearly three times more closely related to females than males; however, the investment sex ratio is near equal (1.01, female/male), which is consistent with queen control. Selection should be strong on workers to increase investment in reproductive females, so why do workers in male-specialist colonies produce only (or nearly only) males? One hypothesis is that queens in male-specialist colonies prevent the occurrence of reproductive females, perhaps by producing worker-biased female eggs. An earlier simulation study of genetic evolution of sex ratios in social Hymenoptera (Pamilo 1982b) predicts that such mechanisms can result in the evolution of bimodal colony sex ratios and queen control. Results on P. desertorum are generally consistent with that study; however, information is not currently available to test some of the model's predictions and assumptions.     

Nestling sex ratio is associated with both male and female attractiveness in rock sparrows

According to theory, in species in which male variance in reproductive success exceeds that of the females, sons are more costly to produce; females mated with high quality males or those in better condition should produce more sons. In monogamous species, however, the variance in the reproductive success of the two sexes is often similar and mate choice is often mutual, making predictions regarding sex allocation more difficult. In the rock sparrow Petronia petronia, both males and females have a sexually selected yellow patch on the breast, whose size correlates with individual body condition. We investigated whether the brood sex ratio co‐varies with the size of the yellow patch of the father and the mother in a sample of 173 broods (818 chicks) over 8 breeding seasons. While the size of the yellow patch of the mother and the father did not predict per se a deviation from the expected 1:1 sex ratio, brood sex ratios were predicted by the interaction of male and female yellow patch size. This result is surprising, as the ornament is sexually selected by both males and females as an indicator of quality in both sexes and should therefore be inherited by all offspring irrespective of their sex. It indirectly suggests that other sex‐specific traits associated with patch size (e.g. polygyny in males and fecundity in females) may explain the sex allocation bias observed in rock sparrows. Thus, female individual quality alone, as expressed through the size of the yellow patch, was not associated with the biases in sex ratios reported in this study. Our results rather suggest that sex allocation occurs in response to male attractiveness in interaction with female attractiveness. In other words, females tend to preferentially allocate towards the sex of the parent with more developed ornament within the pair.     

Transfer of a parasitic sex factor to the nuclear genome of the host: A hypothesis on the evolution of sex-determining mechanisms in the terrestrial Isopod Armadillidium vulgare Latr.

In A. vulgare sex is usually determined either by a cytoplasmic feminizing factor (F symbiotic bacteria) or by another feminizing factor (f) which behaves like a mobile element of DNA and which seems to correspond to a fragment of bacterial DNA. By inhibiting the expression of male genes carried by the Z heterochromosome, these feminizing factors induce differentiation of neo-females [ZZ(+F) or ZZ(+f)]. Such a mechanism leads to the production of progenies whose sex ratio is highly female biased. In some populations in which F and/or f factors are present, genetic females (WZ) have disappeared and all individuals (males and females) are genetic males. However in other populations, cohabitation of ZZ(+f) neo-females and females in all points similar to genetic females is observed. Such a situation may be unstable and is not likely to be explainable only by migrations of individuals from distinct populations. Owing to certain types of crosses, in particular those which involve an artificial neo-male ( = female reversed into a functional male by an implant of androgenic gland) we show here that the f factor can be transmitted as a Mendelian gene. In these progenies Z_fZ females may appear: like WZ females, they breed broods whose sex ratio is unbiased. The hypothesis that the “F bacteria—A. vulgare” symbiosis may have led, after a complex co-evolutive process (F bacteria → f mobile element → insertion of f on Z heterochromosome), to the creation (from a male genotype) of a female genotype, is put forward. The consequences of such a phenomenon on the composition and the evolution of A. vulgare populations are examined.     

An analysis of birth sex ratio bias in captive prosimian species

The extent to which sex ratio bias is a common reproductive characteristic of prosimians has not been well established. The present study analyzed reproduction in 13 breeding groups of captive prosimians for evidence of birth sex ratio bias. A substantial male bias was demonstrated in nongregarious, but not gregarious, breeding groups. Analyses of birth sex ratios of individual mothers suggested that the observed bias did not result from the tendency of a few mothers to overproduce males, but rather from a small but reliable excess of male births in general. An examination of infant mortality revealed that male Otolemur garnettii and Microcebus murinus infants were more vulnerable to preweaning mortality, whereas female Eulemur fulvus albifrons infants were more vulnerable. An analysis of birth order by sex found that mothers of one group (O. garnettii) tended to produce males initially and females later. Additionally, a distinct pattern of birth seasonality was noted among Malagasy prosimians that was absent in the African prosimians. Greater length of period of sexual receptivity for nongregarious females as compared to gregarious females is proposed as a possible mechanism of male birth sex ratio bias. © 1996 Wiley-Liss, Inc.     

SEX RATIO VARIATION IN THE LESSONIA NIGRESCENS COMPLEX (LAMINARIALES,PHAEOPHYCEAE): EFFECT OF LATITUDE,TEMPERATURE, AND MARGINALITY1

Little is known about variation of sex ratio, the proportion of males to females, in natural populations of seaweed, though it is a major determinant of the mating system. The observation of sexual chromosomes in kelps suggested that sex is partly genetically determined. However, it is probably not purely genetic since the sex ratio can be modified by environmental factors such as salinity or temperature. In this paper, sex ratio variation was studied in the kelp Lessonia nigrescens Bory complex, recently identified as two cryptic species occurring along the Chilean coast: one located north and the other south of the biogeographic boundary at latitude 29°–30° S. The life cycle of L. nigrescens is characterized by an alternation of microscopic haploid gametophytic individuals and large macroscopic fronds of diploid sporophytes. The sex ratio was recorded in progenies from 241 sporophytic individuals collected from 13 populations distributed along the Chilean coast in order (i) to examine the effect of an environmental gradient coupled with latitude, and (ii) to compare marginal populations to central populations of the two species. In addition, we tested the hypothesis that the sex ratios of the two cryptic species would be affected differently by temperature. First, our results demonstrate that sex ratio seems to be mainly genetically determined and temperature can significantly modify it. Populations of the northern species showed a lower frequency of males at 14°C than at 10°C, whereas populations of the southern species showed the opposite pattern. Second, both species displayed an increased variation in sex ratio at the range limits. This greater variation at the margins could be due either to differential mortality between sexes or to geographic parthenogenesis (asexual reproduction).     

Male‐skewed adult sex ratio,survival, mating opportunity and annual productivity in the Snowy Plover Charadrius alexandrinus

Sex differences in adult mortality may be responsible for male‐skewed adult sex ratios and male‐skewed parental care in some birds. Because a surplus of breeding males has been reported in serially polyandrous populations of Snowy Plover Charadrius alexandrinus, we examined sex ratio, early‐season nesting opportunities, adult survival and annual reproductive success of a Snowy Plover population at Monterey Bay, California. We tested the hypotheses that male adult survival was greater than female survival and that a sex difference in adult survival led to a skewed adult sex ratio, different mating opportunities and different annual productivity between the sexes. Virtually all females left chicks from their first broods to the care of the male and re‐nested with a new mate. As a result, females had time to parent three successful nesting attempts during the lengthy breeding season, whereas males had time for only two successful attempts. Among years, the median population of nesting Plovers was 96 males and 84 females (median difference = 9), resulting in one extra male per eight pairs. The number of potential breeders without mates during the early nesting period each year was higher in males than in females. Adult male survival (0.734 ± 0.028 se) was higher than female survival (0.693 ± 0.030 se) in top‐ranked models. Annually, females parented more successful clutches and fledged more chicks than their first mates of the season. Our results suggest that in C. alexandrinus a sex difference in adult survival results in a male‐skewed sex ratio, which creates more nesting opportunities and greater annual productivity for females than for males.     

寄主大小及寄生顺序对蝇蛹佣小蜂寄生策略的影响

寄主大小模型认为寄生蜂后代性比与寄主大小相关,寄生蜂倾向于在大寄主上产出更多雌性后代,在小寄主上产出更多雄性后代.探讨了以家蝇蛹为寄主时,蝇蛹佣小蜂后代产量和性比变化;单次寄生情况下,寄主大小及寄生顺序对寄生蜂后代性比等影响.结果表明,蝇蛹佣小蜂的产卵期为(8.93±3.34)d,单头雌蜂能产雌性后代(34.11±16.34)头和雄性后代(11.04±8.87)头,且雄性百分比为0.24±0.11.随成蜂日龄的增大,寄生蜂产生雄性后代的比率显著增加.蝇蛹佣小蜂在寄生家蝇蛹时,会优先选择寄生个体较大的蛹;在单次寄生的情况下,蝇蛹佣小蜂倾向于在较大的家蝇蛹内产出更多的雌性后代.     

小地老虎的交配行为和能力

在温度为(25±1)℃、相对湿度为70%±7%、光周期(L∶D)为14∶10h的条件下对小地老虎Agrotis ypsilon(Rottemberg)的交配行为和能力进行研究。结果表明:成虫在羽化后1d才进行交配。雄蛾和雌蛾都可以多次交配。交配能力受性比的影响很大,当1头雄蛾仅与1头雌蛾相处时,其交配能力低;当1头雄蛾与多于2头的雌蛾在一起时或1头雌蛾与多于2头的雄蛾在一起时,交配能力则显著增加。还讨论了该研究结果应用的可能性。     

Z LINKAGE OF FEMALE PROMISCUITY GENES IN THE MOTH UTETHEISA ORNATRIX: SUPPORT FOR THE SEXY‐SPERM HYPOTHESIS?

Female preference genes for large males in the highly promiscuous moth Utetheisa ornatrix (Lepidoptera: Arctiidae) have previously been shown to be mostly Z‐linked, in accordance with the hypothesis that ZZ–ZW sex chromosome systems should facilitate Fisherian sexual selection. We determined the heritability of both female and male promiscuity in the highly promiscuous moth U. ornatrix (Lepidoptera: Arctiidae) through parent–offspring and grandparent–offspring regression analyses. Our data show that male promiscuity is not sex‐limited and either autosomal or sex‐linked whereas female promiscuity is primarily determined by sex‐limited, Z‐linked genes. These data are consistent with the “sexy‐sperm hypothesis,” which posits that multiple‐mating and sperm competitiveness coevolve through a Fisherian‐like process in which female promiscuity is a kind of mate choice in which sperm‐competitiveness is the trait favored in males. Such a Fisherian process should also be more potent when female preferences are Z‐linked and sex‐limited than when autosomal or not limited.     

Mating frequency, genetic structure, and sex ratio in the intermorphic female producing ant species Myrmecina nipponica

1. Myrmecina nipponica has two types of colonies: a queen colony type, in which the reproductive females are queens and new colonies are made by independent founding, and an intermorphic female colony type, in which reproductive females belong to a wingless intermediate morphology between queen and worker, and where colonies multiply through colonial budding. 2. The mating frequencies of reproductive females in both types indicate monoandry. The relatedness among nestmates in both types was almost 0.75, however relatedness between mother and daughter in intermorphic female colonies was slightly higher than that of queen colonies. 3. The sex ratio (corrected investment female ratio) was 0.70 at the population level, suggesting that the sex ratio is controlled by workers in this species, however the ratio differed greatly between the two types of colonies. Queen colonies (n = 37) had a female‐biased sex ratio of 0.77 while intermorphic female colonies (n = 33) had a ratio of 0.56. 4. Each reproductive intermorphic female was accompanied by an average of 2.9 workers (including virgin intermorphic females) in the colonial budding, and when the investment to those workers was added to the female investment, the sex ratio reached 0.81. 5. The frequency distribution of sex ratio was bimodal, with many colonies producing exclusively males or females, however mean estimated relatedness within colonies was almost 0.75. These data are inconsistent with the genetic variation hypothesis, which is one of the predominant hypotheses accounting for the between‐colony variation in sex ratio.     

Emergence and mating behavior of the oriental fruit moth Cydia molesta (Lepidoptera: Tortricidae) and its potential for reproduction

The Oriental fruit moth, Cydia molesta (Busck, 1916) (Lepidoptera: Tortricidae), is a key pest of fruit and is widely distributed around the world. There are important connections between its behavior and biology and its management in agriculture, but few studies have investigated the associations between adult behaviors and oviposition. In this study, adult emergence, mating, and reproduction were investigated under laboratory and field conditions. The ratio of females to males at eclosion was approximately 1:1. When one virgin female had access to one virgin male, 66% and 34% of the couples copulated just once and twice, respectively; and the infertility rate of eggs (21.39 ± 1.25%) did not vary daily. Males, given access to one new female daily, could copulate multiple times, whereas females seldom mated more than once, indicating a male-biased operational sex ratio, but mating status of the male parent had no effect on progeny egg reproduction. Also, the number of eggs that hatched by all female partners of a male was inversely proportional to copulation duration for the female laying the eggs for total female reproductive success; and the number of eggs laid by all female partners of a male was proportional to their number of matings for total male reproductive success. However, the total number of eggs that hatched did not significantly differ for eggs laid by a female given new virgin males daily for mating (17.75 ± 4.28) versus eggs laid by virgin females (19.17 ± 7.51) presented daily with a male that re-mated daily with the series of females. Therefore, our results showed that females engaged in mate choice and males engaged in mate competition, affecting egg production, a factor that may be used to enhance mating disruption technology against Cydia molesta.     

Testing the predictions of sex allocation hypotheses in dimorphic,cooperatively breeding riflemen

Evolutionary theory predicts that parents should invest equally in the two sexes. If one sex is more costly, a production bias is predicted in favour of the other. Two well‐studied causes of differential costs are size dimorphism, in which the larger sex should be more costly, and sex‐biased helping in cooperative breeders, in which the more helpful sex should be less costly because future helping “repays” some of its parents’ investment. We studied a bird species in which both processes should favor production of males. Female riflemen Acanthisitta chloris are larger than males, and we documented greater provisioning effort in more female‐biased broods indicating they are likely costlier to raise. Riflemen are also cooperative breeders, and males provide more help than females. Contrary to expectations, we observed no male bias in brood sex ratios, which did not differ significantly from parity. We tested whether the lack of a population‐wide pattern was a result of facultative sex allocation by individual females, but this hypothesis was not supported either. Our results show an absence of adaptive patterns despite a clear directional hypothesis derived from theory. This appears to be associated with a suboptimal female‐biased investment ratio. We conclude that predictions of adaptive sex allocation may falter because of mechanistic constraint, unrecognized costs and benefits, or weak selection.     

Sex reversal and primary sex ratios in the common frog (Rana temporaria)

Sex reversal has been suggested to have profound implications for the evolution of sex chromosomes and population dynamics in ectotherms. Occasional sex reversal of genetic males has been hypothesized to prevent the evolutionary decay of nonrecombining Y chromosomes caused by the accumulation of deleterious mutations. At the same time, sex reversals can have a negative effect on population growth rate. Here, we studied phenotypic and genotypic sex in the common frog (Rana temporaria) in a subarctic environment, where strongly female‐biased sex ratios have raised the possibility of frequent sex reversals. We developed two novel sex‐linked microsatellite markers for the species and used them with a third, existing marker and a Bayesian modelling approach to study the occurrence of sex reversal and to determine primary sex ratios in egg clutches. Our results show that a significant proportion (0.09, 95% credible interval: 0.04–0.18) of adults that were genetically female expressed the male phenotype, but there was no evidence of sex reversal of genetic males that is required for counteracting the degeneration of Y chromosome. The primary sex ratios were mostly equal, but three clutches consisted only of genetic females and three others had a significant female bias. Reproduction of the sex‐reversed genetic females appears to create all‐female clutches potentially skewing the population level adult sex‐ratio consistent with field observations. However, based on a simulation model, such a bias is expected to be small and transient and thus does not fully explain the observed female‐bias in the field.     

Oviposition behavior and progeny allocation of the polyembryonic waspCopidosoma floridanum (Hymenoptera: Encyrtidae)

Oviposition behavior was used to determine the primary clutch size and sex ratio of the polyembryonic wasp Copidosoma floridanumAshmead (Hymenoptera: Encyrtidae) parasitizing Pseudoplusia includens(Walker) (Lepidoptera: Noctuidae). The laying of a female egg was associated with a pause in abdominal contractions during oviposition, while the laying of a male egg was associated with uninterrupted abdominal contractions. Although unmated females produced only male broods, they also displayed male and female egg oviposition movements. Wasps always laid a primary clutch of one or two eggs. For mated females if only one egg was laid, the emerging secondary clutch was all male or female, but if two eggs were laid a mixed brood of males and females was almost always produced. The secondary clutch of single sex broods was usually between 1000 and 1200 individuals, but the secondary clutch of mixed broods averaged 1143 females and 49 males. Thus, the primary sex ratio for mixed broods was 0.5 (frequency males), but the secondary sex ratio was 0.042. Manipulation of the sequence of male and female egg oviposition or of the primary clutch did not produce major alterations in the secondary clutch size or sex ratio.     

Reproductive strategies of Diaeretiella rapae (Hymenoptera: Aphidiinae) during fluctuating temperatures of spring season in New Zealand

Reproductive activities of naturally occurring population of Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiinae) on Myzus persicae were studied during spring season in New Zealand. The cabbage seedlings were highly infested with the aphids (272±25 individuals/plant) with about 30% on average parasitised by D. rapae. Rate of parasitism was positively correlated with the aphid density (R ²=0.64). Adult emergence from aphid mummies was 90%, with a higher frequency of females than males. Increase in female/male sex ratio was found between early and late spring (1.1 vs. 1.8). Mating in D. rapae occurred throughout the day. Nearly half of the mating pairs collected were male–male pairs, which were especially prevalent during morning and evening while more male–female mating pairs were found during midday. Male–male mounting was probably because of low number of virgin females in morning and evening populations. About 80% females were mounted by smaller size males. Male–male mounting is discussed in correlation with operational sex ratio of D. rapae population.     

Offspring sex ratio in sheep,cattle, goats and pigs: influence of season and lunar phase at conception

This study assessed the relationship between season and lunar phase at conception on offspring sex ratio of four livestock species (sheep, cattle, goats and pigs). The sex of 66,830 lambs (1995–2015); 25,546 calves (2011–2015); 5671 kids (2002–2007) and 1916 piglets was recorded. Moon phases were categorized as either new moon, crescent moon, full moon or decrescent moon. Sex ratio, expressed as proportion of males (males/males + females), was tested against the expected value of 1:1. In sheep, offspring sex ratio and lunar phase were not correlated; season had a significant (p = 0.002) effect on offspring sex ratio. The proportion of males born of spring and winter matings was significantly higher than it was among offspring born of summer (p < 0.05) or autumn (p < 0.01) conceptions. Offspring sex ratios in spring (p < 0.05), autumn (p < 0.01) and winter (p < 0.05) differed significantly from the expected. In cattle, moon phase and season did not affect the offspring sex ratio; however, the interaction effect was highly significant (p = 0.001). The overall piglet sex ratio (0.522), and the sex ratios among piglets conceived during a crescent moon and those conceived in summer differed significantly (p < 0.05) from 1:1. Research including additional factors such as hormonal treatments prior to insemination, food availability, weather and maternal and paternal factors might provide the underlying reasons for the effects of season and moon phase on offspring sex ratio in some livestock species.     

Effects of parental age at mating on the fecundity and progeny sex ratio of <Emphasis Type="Italic">Campoletis chlorideae</Emphasis>, an endolarval parasitoid of the pod borer, <Emphasis Type="Italic">Helicoverpa armigera</Emphasis>

Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), commonly called gram pod borer, is a serious pest of pulse crops in India and damages chickpea (Cicer arietinum L). On average a 30% crop loss is reported. One of the potential natural enemies reported for its biological control is Campoletis chlorideae Uchida (Hymenoptera: Ichneumonidae), an idiobiont parasitic wasp that attacks second instar larvae of the pod borer. Male-biased sex ratios hinder efforts to mass release parasitic Hymenoptera for biological control by making the production of females costly. Parental age at time of mating is known to affect the progeny sex ratio in some Braconidae. In this view, we examined the reproduction and survival of the parasitoid C. chlorideae in the laboratory [22 ± 4°C, 70 ± 10% R.H. and 10:14 h light:dark photoperiod]. All the nine (i.e. 3 × 3) combinations of possible mating were made for males and females, being each of different age groups (0–12, 48–60 and 96–108 h old). Second instar larvae of the pod borer were reared on chickpea and exposed to mated females of different mating age group combinations. Results revealed that (a) newly emerged females (0–12 h old) mated to aged males yielded more progeny contrasted to the older females inseminated by newly emerged males (0–12 h old). This implies that increased maternal age at mating caused greater reduction in the progeny yield than that of paternal age; (b) the progeny sex ratio was lowest (0.344 ± 0.057) (mean ± SD) when parents mated just after emergence (0–12 h old). It became more and more male biased as parents were deprived of mate and was highest (0.666 ± 0.701) for 96–108 h old parents. The analysis of variance of the data shows that mate deprived males caused greater contribution in the production of sons, resulting a male-biased progeny sex ratio. Our conclusion indicate that newly emerged parasitoids (0–12 h old) are most fecund and should be used in rearing practices in order to enhance the progeny yield, particularly with respect to daughters. Handling Editor: Torsten Meiners     

Experimental study of temperature effects on the sex ratio of broods in Terrestrial Crustacea Armadillidium vulgare Latr. Possible implications in natural populations

The woodlouse Armadillidium vulgare is characterized by female heterogamety (ZW) and male homogamety (ZZ). However, in several populations, sex determination is influenced by cytoplasmic sex factors (endosymbiotic bacteria = F). At 20 °C these maternally transmitted bacteria reverse genetic males into functional neo-females (ZZ + F) producing highly female broods. When these neo-females were reared at 30° C, the sex ratio of their broods became male-biased. The major process involved in this heat-induced sex ratio inversion was the disappearance of bacteria in embryos in the course of their development, which allowed the young to express a phenotype that conforms with their genotype (i.e. male ZZ). No heat-sensitive stage of development was observed, but at least 35 days at 30° C seem to be necessary to induce F-degradation. The presence of F at 30° C (before its degradation) also induced mortality during vitellogenesis. Daily thermoperiods including a thermophase at 30° C had effects on F similar to that of a constant temperature of 30° C. A. vulgare can live in climates having such thermoperiods (at least during one period of the year), temperature appears to be capable of limiting the presence of F-bacteria in natural populations, and then modifying the evolution of sex-determining mechanisms in such populations.     

Impact of mating on Anagyrus kamali Moursi (Hym., Encyrtidae) lifetime fecundity, reproductive longevity, progeny emergence and sex ratio

Abstract: The solitary endoparasitoid Anagyrus kamali Moursi (Hym., Encyrtidae) and the Hibiscus mealybug Maconellicoccus hirsutus Green (Hom., Pseudococcidae), were used as a parasite/host model to test the effect of mating on several fitness parameters, i.e. longevity, lifetime fecundity, progeny emergence and sex ratio. At 27 ± 2°C, 8 h light : 16 h dark, mating significantly affected the survival of male parasitoids. Virgin males lived longer (32.2 ± 9.51 days) than mated males (23.9 ± 7.52 days). Female longevity (40.7 ± 16.3 days for virgins and 36.2 ± 10.7 days for mated females) was not affected by mating. The lifetime fecundity of female parasitoids and their oviposition period was not significantly affected by mating. However, the number of hosts parasitized was greater for mated wasps (7.54 ± 4.85 hosts parasitized/day) compared with virgin ones (5.12 ± 2.19 hosts parasitized/day). This resulted in greater progeny production from mated A. kamali females. The progeny of virgin females consisted only of males, whereas the mated ones had a more female‐biased sex ratio. The lowest sex ratio (0.41 M/F ± 0.123) was attained when females had free access to males and were multi‐mated.