Re-examining the relationship between sexual maturation and age of response to methyl eugenol in males of the oriental fruit fly

Males of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), are strongly attracted to, and feed voraciously on, methyl eugenol (ME) and use metabolites of this chemical to synthesize their sex pheromone. Previously, Wong et al. (1989 ) proposed that B .  dorsalis males were attracted to ME even before attaining sexual maturity. However, their interpretation is possibly confounded by the fact that, in monitoring age-related mating readiness, males were presented with equal-aged females. As a result, if females mature more slowly than males, the age of male sexual maturation may have been overestimated, which may have accounted for the discrepancy observed between male age of ME responsiveness and mating activity. Here, we re-examined the relationship between male age and mating readiness by comparing male mating activity when presented with same-aged females vs. sexually mature females. In addition, we measured the age-dependent response of B .  dorsalis males to ME by recording (i) capture in ME-baited traps, and (ii) feeding duration on ME-containing paper discs. Our data support the conclusion of Wong et al. (1989 ) that B .  dorsalis males show attraction to, and feed on, ME before attaining sexual maturity, but suggest that a marked difference in ME response and mating activity exists over a shorter age interval than indicated by Wong et al. (1989 ). Early attraction to, but not ingestion of, ME was related to accelerated sexual maturation. Unexpectedly, ingestion of ME by sexually immature males did not boost their mating success in trials conducted 10 days after feeding on the lure.     

Methyl eugenol effects on Bactrocera dorsalis male total body protein,reproductive organs and ejaculate

Methyl eugenol (ME) and inclusion of protein into the adult diet increase the mating competitiveness of the Oriental fruit fly, Bactrocera dorsalis (Hendel). Exposing males to ME or protein is a promising post‐teneral treatment for males being released in the sterile insect technique (SIT). However, the effect of this post‐teneral treatment on male reproductive organs or the male ejaculate is unknown. During mating, males transfer sperm and accessory gland products (AGPs) to females and these compounds are reported to modulate female sexual inhibition. We studied the impact of male exposure to ME and a yeast hydrolysate (YH) diet on the protein reserves of males, male reproductive organ size, and the male ejaculate through sperm and AGPs. We show that males exposed to ME regardless of access to YH accumulated a greater amount of whole body protein. Males fed on YH also had increased total body protein and had bigger reproductive organs than YH‐deprived males, but no apparent effect of ME exposure was observed on reproductive organ size. Females stored less sperm when mated with males fed on YH and ME compared to males not fed on ME. YH and ME had no effect on male AGPs. Females injected with AGPs of males fed on YH and exposed to ME were just as likely to mate as females injected with AGPs of non‐treated males. However, females injected with AGPs of males exposed to ME mated faster than females injected with AGPs of non‐exposed males. We conclude that while exposure to ME increases male copulatory success and protein reserves in the male body, there seem to be some potential trade‐offs such as lower sperm stored by females. We discuss our results in terms of pre‐release protocols that may be used for B. dorsalis in SIT application.     

Flower-feeding affects mating performance in male oriental fruit flies Bactrocera dorsalis

1. Males of the oriental fruit fly Bactrocera dorsalis are attracted to and feed on flowers of the golden shower blossom Cassia fistula. Flowers of this plant contain methyl eugenol, the metabolites of which apparently function in the synthesis of male sex pheromone. 2. The goal of the study reported here was to determine whether feeding on C. fistula flowers enhanced male mating success. Mating frequencies of unfed (control) and fed (treated) males were compared in trials conducted 0 (same day), 2, 7, or 21 days after treated males were exposed to the flowers. Trials were performed using flowers from three trees of C. fistula to investigate whether the effects of floral feeding were similar among different plants. 3. For all three trees, treated males accounted for a disproportionately large number of matings in trials performed 0, 2, and 7 days after floral feeding by the treated males. For two of the trees, treated males also had a mating advantage 21 days after flower‐feeding. 4. Additional tests were conducted to compare female attraction to perch sites of control and treated males. When at a lek, males exhibit rigorous wing‐fanning behaviour, presumably to increase dispersal of the sex pheromone. Floral feeding had no significant effect on the level of wing‐fanning. Significantly more female sightings were recorded for perches of treated than control males, however, suggesting that the treated males produced a pheromone more attractive to females than did control males.     

Prerelease exposure to methyl eugenol increases the mating competitiveness of sterile males of the oriental fruit fly (Diptera: Tephritidae) in a Hawaiian orchard

Males of the oriental fruit fly, Bactrocera dorsalis (Hendel), are strongly attracted to methyl eugenol (ME), and recent work demonstrated that ingestion of this chemical enhances male mating success, apparently owing its role as a precursor in the synthesis of the male sex pheromone. The current study expanded upon earlier laboratory and field-cage experiments by assessing whether prerelease exposure to ME increased the mating competitiveness of mass-reared, sterile males in Hawaiian orchards. Releases of sterile males from a pupal color-based sexing strain were made weekly in two fruit orchards over 8 mo, with the sterile males at one site given ME for 24 h before release (treated) and the sterile males at the other site given no ME before release (control). Fruits were collected periodically during the study period, and eggs were dissected and incubated to score hatch rate. At both sites, releases of sterile males increased the proportion of unhatched eggs well above prerelease levels, but the incidence of egg sterility was consistently, and statistically, greater in the orchard receiving ME-exposed males. Computed over the entire release period, the average value of Fried's competitive index (that characterizes the mating success of sterile males relative to their wild counterparts) for ME-treated males was 3.5 times greater than that for control males, although this difference was not statistically significant. However, when computed over the period during which egg sterility values were elevated and stable, presumably when females inseminated before the releases were rare or absent, the competitive indices were significantly higher for ME-treated sterile males. The implications of these results for implementing the Sterile Insect Technique against this species are discussed.     

Feeding behaviour of Bactrocera cacuminata (Hering) (Diptera: Tephritidae) on methyl eugenol: a laboratory assay

Abstract Many dacine (Diptera: Tephritidae) species are attracted to one of two chemical substances, 4-allyl-1,2-dimethoxybenzene (methyl eugenol (ME)) or 4-( p -hydroxyphenyl)-2-butanone (cue lure). Despite the fact that these chemicals or analogs occur naturally, their significance in the biology/ecology of the Dacinae has seldom been examined. In this study, we examine the patterns in feeding behaviour of Bactrocera cacuminata (Hering), a monophagous non-pest fruit fly, on ME. Based on a laboratory assay, we found that males of this species fed on ME multiple times within a single day and on multiple days. The pattern of repeat feeding was not related to time since previous feeding or duration of prior feeding. Our results contrast those obtained on a similar study on a related polyphagous species ( Bactrocera dorsalis (Hendel)). We discuss the implications of our findings with a view to explaining the functional significance of dacine response to these plant-derived chemicals.     

Sexual selection in a tropical fruit fly: role of a plant derived chemical in mate choice

The specific mechanisms by which selective pressures affect individuals are often difficult to resolve. In tephritid fruit flies, males respond strongly and positively to certain plant derived chemicals. Sexual selection by female choice has been hypothesized as the mechanism driving this behaviour in certain species, as females preferentially mate with males that have fed on these chemicals. This hypothesis is, to date, based on studies of only very few species and its generality is largely untested. We tested the hypothesis on different spatial scales (small cage and seminatural field‐cage) using the monophagous fruit fly, Bactrocera cacuminata. This species is known to respond to methyl eugenol (ME), a chemical found in many plant species and one upon which previous studies have focused. Contrary to expectation, no obvious female choice was apparent in selecting ME‐fed males over unfed males as measured by the number of matings achieved over time, copulation duration, or time of copulation initiation. However, the number of matings achieved by ME‐fed males was significantly greater than unfed males 16 and 32 days after exposure to ME in small cages (but not in a field‐cage). This delayed advantage suggests that ME may not influence the pheromone system of B. cacuminata but may have other consequences, acting on some other fitness consequence (e.g., enhancement of physiology or survival) of male exposure to these chemicals. We discuss the ecological and evolutionary implications of our findings to explore alternate hypotheses to explain the patterns of response of dacine fruit flies to specific plant‐derived chemicals.     

Sexual maturity and intraspecific mating success of two sibling species of the Bactrocera dorsalis complex

Bactrocera carambolae Drew & Hancock and B. papayae Drew & Hancock (Diptera: Tephritidae), two closely related sibling species in the B. dorsalis (Hendel) complex were shown to have different rates of sexual maturity. The response of B. carambolae males to methyl eugenol was observed to begin 10 days after emergence and increased with age. The attractancy peaked at 28 days after emergence and above. The males were also found to require a higher dosage of methyl eugenol (1 mg) for optimal response. These results are in contrast with those of B. papayae reported previously. The response to methyl eugenol was also observed to correspond with the age when first mating was performed.After eclosion, both sexes of B. carambolae mated approximately 2 weeks later and showed significantly lower matings/individual when compared with B. papayae in a 60-day observation period. Both sexes of B. papayae and males of B. carambolae were able to remate on the next day. However, B. carambolae females required a minimum refractory period of 8 days in order to be sexually receptive again.During the 60-day period, the mating propensity in B. papayae (100% success) was higher than B. carambolae (71–87% success) (P < 0.05). This observation was substantiated by a higher intraspecific mating success of B. papayae as compared to B. carambolae in a field cage (P < 0.001).     

Opportunities for female choice in the bed bug Cimex lectularius

Bed bugs are cited as exemplars of sexual conflict because mating can only occur via traumatic insemination. However, past antagonistic coevolution between the sexes does not necessarily preclude current female choice. Here, we investigate opportunities for precopulatory female choice in bed bugs. We examined whether females seek out mating opportunities when they gain the most benefit: when females are virgin and/or have recently fed. But, we found that female mating and feeding status had little effect on female attraction to males and male odor. To determine whether females approach male harborages (home crevices) to seek matings in nature, we investigated where matings occurred among unfamiliar pairs of bed bugs. We found that, despite female attraction to male odor, matings were most likely to take place in the female's harborage rather than the male's harborage. We also examined the effect of feeding on male and female ability to mate. Whereas previous research reported that engorgement impaired female ability to refuse matings, we found that male feeding status had a larger effect on the success of mating encounters than female feeding status. Fed males had poor mating success, suggesting that males may be faced with a trade‐off between mating and feeding.     

Optimizing methyl‐eugenol aromatherapy to maximize posttreatment effects to enhance mating competitiveness of male Bactrocera carambolae (Diptera: Tephritidae)

Methyl‐eugenol (ME) (1,2‐dimethoxy‐4‐(2‐propenyl)benzene), a natural phytochemical, did enhance male Bactrocera carambolae Drew & Hancock (Diptera: Tephritidae) mating competitiveness 3 d after ingestion. Enhanced male mating competitiveness can significantly increase the effectiveness of the sterile insect technique (SIT). ME application to mass reared sterile flies by feeding is infeasible. ME application by aromatherapy however, would be a very practical way of ME application in fly emergence and release facilities. This approach was shown to enhance mating competitiveness of B. carambolae 3 d posttreatment (DPT). Despite this added benefit, every additional day of delaying release will reduce sterile fly quality and will add cost to SIT application. The present study was planned to assess the effects of ME‐aromatherapy on male B. carambolae mating competitiveness 1DPT and 2DPT. ME aromatherapy 1DPT or 2DPT did enhance mating competitiveness of B. carambolae males whereas ME feeding 1DPT and 2DPT did not. Male mating competitiveness was enhanced by the ME aromatherapy irrespective if they received 1DPT, 2DPT or 3DPT. ME aromatherapy, being a viable approach for its application, did enhance mating competitiveness of male B. carambolae 1 d posttreatment as ME feeding did 3 d after ingestion.     

Transport of methyl eugenol-derived sex pheromonal components in the male fruit fly, Bactrocera dorsalis

Males of Bactrocera dorsalis (Diptera: Tephritidae) are attracted strongly to and feed compulsively on methyl eugenol (1,2-dimethoxy- 4 -(2-propenyl)benzene), a highly potent male attractant. Pharmacophagy of methyl eugenol results in the production of phenylpropanoids 2-allyl-4,5-dimethoxyphenol and (E)-coniferyl alcohol that are sequestered and stored in the rectal gland prior to release as sex pheromonal components during mating at dusk. While these pheromonal components have also been detected in the hemolymph and crop of methyl eugenol-fed males, there is currently little information on the transport of these compounds from the crop to rectal gland in male B. dorsalis. Therefore, using physiological techniques such as parabiosis, rectal gland transplantation and hemolymph transfusion coupled with gas chromatography-mass spectrometry (GC-MS) analyses, we were able to ascertain and confirm the role of the hemolymph in the transport of these sex pheromonal components from the crop to the rectal gland. Further, the temporal profile of these methyl eugenol-derived bioactive compounds in the hemolymph also shows an increase with time post-methyl eugenol-feeding, i.e., 2-allyl-4,5-dimethoxyphenol attaining maximum amounts 15 min after ME consumption and decreasing thereafter, while for (E)-coniferyl alcohol-the increase and decrease are more gradual. These results further demonstrate the ability of insect hemolymph to transport many diverse forms of bioactive molecules including attractant-derived sex pheromonal components.     

Effect of probiotic adult diets on fitness components of sterile male Mediterranean fruit flies (Diptera: Tephritidae) under laboratory and field cage conditions

The aim of the current study was to investigate the effect of probiotic adult diets, i.e., adult diets containing viable symbiotic intestinal bacteria, on the pheromone-calling activity, mating success, life expectancy, and survival of mass-reared male Mediterranean fruit flies, Ceratitis capitata (Wiedemann), as an avenue for improving the field performance of sterile males in release programs to eradicate, suppress, or prevent spread of wild populations. The effect of inoculation of two standard adult diets (sugar-yeast granulate [SY] and sugar agar [s]) and two experimental formulations (yeast-reduced granulate [Sy] and yeast-enhanced sugar agar [sy]) with Enterobacter agglomerans and Klebsiella pneumoniae (typically occurring in the gut of wild flies) on the different fitness components was assessed in the laboratory and on field-caged host trees. We found that, in the laboratory, males reared on the probiotic yeast-enhanced agar, sy, had a significant mating advantage over competitors fed the standard s agar (probiotic and control) or noninoculated sy agar; no effect of probiotic enrichment (or lowering the yeast content) was found with the granular diets. Mating test results obtained in the field were inconsistent with laboratory data in that no differences in the numbers of matings were observed between males reared on any of the probiotic and control agar diets (or the SY granulate), whereas males feeding on the probiotic modified granulate, Sy, scored significantly more matings than their control competitors. The pheromone-calling activity of males maintained on the granular diets was not affected by probiotic enrichment on any of the seven observation days. Agar-fed males, however, "called" more frequently on days 6 and 7 (but not on days 1-5) when their diet contained the probiotic load. Laboratory survival of granulate-fed males was found to be significantly prolonged with probiotic inoculation and lowering the yeast content of the standard SY granulate (but not with probiotic inoculation of sy). Similarly, males reared on the probiotic and control modified agars (sy) survived significantly longer than those feeding on the standard s agars (inoculated and control). Again, the results obtained in the field were inconsistent, because no differences between treated and control males were found for any of the diets. The findings are discussed in the light of other published studies on adult nutrition and behavioral ecology in C. capitata.     

Methoprene application and diet protein supplementation to male melon fly,Bactrocera cucurbitae,modifies female remating behavior

Methoprene (an analogue of juvenile hormone) application and feeding on a protein diet is known to enhance male melon fly, Bactrocera cucurbitae Coquillett (Diptera: Tephritidae), mating success. In this study, we investigated the effect of these treatments on male B. cucurbitae's ability to inhibit female remating. While 14‐d‐old females were fed on protein diet, 6‐d‐old males were exposed to one of the following treatments: (i) topical application of methoprene and fed on a protein diet; (ii) no methoprene but fed on a protein diet; (iii) methoprene and sugar‐fed only; and (iv) sugar‐fed, 14‐d‐old males acted as controls. Treatments had no effect on a male's ability to depress the female remating receptivity in comparison to the control. Females mated with protein‐deprived males showed higher remating receptivity than females first mated with protein‐fed males. Methoprene and protein diet interaction had a positive effect on male mating success during the first and second mating of females. Significantly more females first mated with sugar‐fed males remated with protein‐fed males and females first mated with methoprene treated and protein‐fed males were more likely to remate with similarly treated males. Females mating latency (time to start mating) was significantly shorter with protein‐fed males, and mating duration was significantly longer with protein‐fed males compared with protein‐deprived males. These results are discussed in the context of methoprene and/or dietary protein as prerelease treatment of sterile males in area‐wide control of melon fly integrating the sterile insect technique (SIT).     

The effect of male size on receptivity in femaleLucilia cuprina (Diptera: Calliphoridae)

The first five matings by both large and small L. cuprinamales switched off receptivity in over 90% of females for 7 days after their initial mating. Small males were virtually unable to switch off females after five matings, whereas the fifth to tenth matings by large males rendered nearly two-thirds of females unreceptive. Mating duration of large and small males was about 11 min even after numerous matings. Given the rarity of field virgins and the temporal and spatial variability of female-required resources, larger males may enjoy greater mating success due to their ability to switch off many females in succession. Virgin males preferred to mate with nonvirgin females larger than themselves; males paired with females smaller than themselves adopted mate-rejection behavior typical of unreceptive females.     

The mating-induced refractoriness of Lucilia cuprina females: manipulating the male contribution

Abstract Three manipulations of the male contribution to copulation were used to investigate what determines the switch-off of female receptivity that follows mating in Lucilia cuprina. Multiple matings by males led to a reduction in their effectiveness at switching-off females: the first twelve matings caused more than 50% of females to be switched-off 1 day after mating, while the first four matings caused more than 50% of females to be switched-off for 7 days after mating. Males mated up to twenty-three times and on average ten times during 10 h of continuous access to virgin females. The number of sperm transferred declined logarithmically through a series of matings as did the quantity of material transferred from the male accessory gland (measured as radiolabeled material) through the first six matings. Overnight isolation of multiply-mated males led to considerable recovery of their ability to switch-off females, and to limited renewal of their ability to transfer sperm. Castrated males transferred similar quantities of accessory gland material to females as did sham-operated males during their first five matings and in their first three matings switched-off 95% of females for 1 day but only 48% for 7 days. When normal mating pairs were separated at increasing intervals after coupling, an increasing proportion of females were switched-off at 1 or 7 days afterward. 7 days after 2 min matings no females were switched-off though 40% of the number of sperm transferred in a full mating had been transferred by this time. The proposed explanation for these data is that both the initial switch-off and its duration are determined by the quantity of a receptivity-inhibiting substance that normally enters the female haemo-lymph after being injected by the male into the wall of the bursa copulatrix. It is proposed that when castrated males mate, an absence of sperm results in most accessory gland secretion entering the empty spermathecae (rather than the wall of the bursa as usually occurs) and hence being unable to reach the haemolymph and exert its influence. The effective dose of the receptivity-inhibiting substance is measured on a logarithmic scale.     

Evolutionary trade-offs of insect resistance to Bacillus thuringiensis crops: fitness cost affecting paternity

Evolution of resistance to insecticides provides a useful model for examining fitness trade-offs associated with adaptation to stress. Here, we examined male reproductive costs in pink bollworm (Pectinophora gossypiella) resistant to an insecticidal protein of Bacillus thuringiensis (Bt) produced by transgenic cotton, using contrasts between two pairs of related susceptible and resistant strains. Without competition for access to females, no costs affecting reproductive success of resistant males were observed. Resistant and susceptible males had similar mating frequency and fertility. Additionally, fecundity of females mated to resistant and susceptible males was comparable. In competition for matings with virgin females, resistant and susceptible males had comparable success in one strain, whereas susceptible males tended to mate more often than resistant males in the other. However, irrespective of strain origin, resistant males that mated first sired significantly less offspring than susceptible males that mated first. The reduced first-male paternity in resistant males may involve reduced sperm precedence caused by mutations in a cadherin gene linked with resistance to Bt cotton.     

Resource limitation and responses to rivals in males of the fruit fly Drosophila melanogaster

Diet has a profound direct and indirect effect on reproductive success in both sexes. Variation in diet quality and quantity can significantly alter the capacity of females to lay eggs and of males to deliver courtship. Here, we tested the effect of dietary resource limitation on the ability of male Drosophila melanogaster to respond adaptively to rivals by extending their mating duration. Previous work carried out under ad libitum diet conditions showed that males exposed to rivals prior to mating significantly extend mating duration, transfer more ejaculate proteins and achieve higher reproductive success. Such adaptive responses are predicted to occur because male ejaculate production may be limited. Hence, ejaculate resources require allocation across different reproductive bouts, to balance current vs. future reproductive success. However, when males suffer dietary limitation, and potentially have fewer reproductive resources to apportion, we expect adaptive allocation of responses to rivals to be minimized. We tested this prediction and found that males held on agar‐only diets for 5–7 days lost the ability to extend mating following exposure to rivals. Interestingly, extended mating was retained in males held on low yeast/sugar: no sugar/yeast diet treatments, but was mostly lost when males were maintained on ‘imbalanced’ diets in which there was high yeast: no sugar and vice versa. Overall, the results show that males exhibit adaptive responses to rivals according to the degree of dietary resource limitation and to the ratio of individual diet components.     

Attraction and mortality of oriental fruit flies to SPLAT‐MAT‐methyl eugenol with spinosad†

Studies were conducted in 2007 and 2008 in Hawaii, USA to quantify attraction and feeding responses resulting in mortality of the male oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), to a novel male annihilation treatment (MAT) formulation consisting of specialized pheromone and lure application technology (SPLAT) in combination with methyl eugenol (ME) and spinosad (=SPLAT‐MAT‐ME with spinosad) in comparison with Min‐U‐Gel‐ME with naled (Dibrom). Our approach involved a novel behavioral methodology for evaluation of slow‐acting reduced‐risk insecticides. Methyl eugenol treatments were weathered for 1, 2, 4, and 8 weeks in California, USA, and shipped to Hawaii for bioassays. In field tests involving bucket traps to attract and capture wild males, and in toxicity studies conducted in 1 m³ cages using released males of controlled ages, SPLAT‐MAT‐ME with spinosad performed similar to or outperformed the standard formulation of Min‐U‐Gel‐ME with naled for material aged for up to 8 weeks in the 2008 tests. In laboratory feeding tests in which individual males were exposed for 5 min to the different ME treatments, mortality induced by SPLAT‐MAT‐ME with spinosad recorded at 24 h did not differ from that caused by Min‐U‐Gel ME with naled at 1, 2, and 4 weeks. Spinosad has low contact toxicity, and when mixed with SPLAT offers a reduced‐risk alternative for control of B. dorsalis, without many of the negative effects to humans and non‐targets of broad‐spectrum contact poisons such as naled. Our results indicate that SPLAT‐MAT‐ME with spinosad offers potential for control of males in an area‐wide integrated pest management (IPM) system without the need for conventional organophosphates.     

Assortative mating in fallow deer reduces the strength of sexual selection

Background

Assortative mating can help explain how genetic variation for male quality is maintained even in highly polygynous species. Here, we present a longitudinal study examining how female and male ages, as well as male social dominance, affect assortative mating in fallow deer (Dama dama) over 10 years. Assortative mating could help explain the substantial proportion of females that do not mate with prime-aged, high ranking males, despite very high mating skew. We investigated the temporal pattern of female and male matings, and the relationship between female age and the age and dominance of their mates.

Results

The peak of yearling female matings was four days later than the peak for older females. Younger females, and especially yearlings, mated with younger and lower-ranking males than older females. Similarly, young males and lower-ranking males mated with younger females than older males and higher-ranking males. Furthermore, the timing of matings by young males coincided with the peak of yearling female matings, whereas the timing of older male matings (irrespective of rank) coincided with the peak of older female matings.

Conclusions

Assortative mating, through a combination of indirect and/or direct female mate choice, can help explain the persistence of genetic variation for male traits associated with reproductive success.     

Optimal numbers of matings: the conditional balance between benefits and costs of mating for females of a nuptial gift‐giving spider

In species where females gain a nutritious nuptial gift during mating, the balance between benefits and costs of mating may depend on access to food. This means that there is not one optimal number of matings for the female but a range of optimal mating numbers. With increasing food availability, the optimal number of matings for a female should vary from the number necessary only for fertilization of her eggs to the number needed also for producing these eggs. In three experimental series, the average number of matings for females of the nuptial gift‐giving spider Pisaura mirabilis before egg sac construction varied from 2 to 16 with food‐limited females generally accepting more matings than well‐fed females. Minimal level of optimal mating number for females at satiation feeding conditions was predicted to be 2–3; in an experimental test, the median number was 2 (range 0–4). Multiple mating gave benefits in terms of increased fecundity and increased egg hatching success up to the third mating, and it had costs in terms of reduced fecundity, reduced egg hatching success after the third mating, and lower offspring size. The level of polyandry seems to vary with the female optimum, regulated by a satiation‐dependent resistance to mating, potentially leaving satiated females in lifelong virginity.     

Starvation and the Mating Success of Wild Male Mediterranean Fruit Flies (Diptera: Tephritidae)

Recent evidence suggests that the nutritional state of male Mediterranean fruit flies, Ceratitis capitata (Wied.) (medfly), is an important influence on various components of their reproductive biology, including mating success. The objective of the present study was to examine experimentally the effect of temporary starvation on the mating success of wild male C. capitata. Males were maintained on protein–sugar or sugar-only diets, and for each diet we compared the mating success of continuously fed males versus males starved for 18 or 24 h immediately before testing. In trials conducted on field-caged, host trees, males starved for 24 h obtained only about half as many matings as fed males for both diets. However, when the starvation period was 18 h, starved males reared on the protein–sugar diet mated significantly less frequently than fed males, whereas starved males reared on sugar mated as often as fed males. Measurements of male pheromone calling and female attraction revealed that reduced mating success likely reflected the decreased signaling activity of starved males.