Effects of different male remating intervals on the reproductive success of Choristoneura rosaceana males and females

The mass of the spermatophore transferred by a previously mated Choristoneura rosaceana male increases with time elapsed since the last mating but, even after 4 days, it never reaches the mass of the spermatophore of a virgin male. However, spermatophore mass is clearly not a good indicator of the male reproductive investment as the quantity of sperm in the second ejaculate of a previously mated male is the same as that of his first, if he is allowed a 2 (eupyrene sperm) to 3 day (apyrene sperm) recovery period. The interval between the first two matings had no influence on female fecundity or longevity but significantly affected fertility if the male had only 1 day to recover. The length of the post-copulatory refractory period was also shorter in females mated with previously mated males than in those mated with virgins, regardless of the male's remating interval. Furthermore, a significant variation in the eupyrene sperm content of the spermatophore transferred by virgin males had no influence on the length of the female refractory period. Globally, these results support the hypothesis that a factor, other than sperm numbers in the spermatheca, is responsible for maintaining the inhibition of pheromone production in this species.     

Impact of male mating history on the temporal sperm dynamics of Choristoneura rosaceana and C. fumiferana females

In the oblique-banded leafroller, Choristoneura rosaceana, and the spruce budworm, C. fumiferana, male reproductive performance decreases with consecutive matings. While the onset time of mating did not vary, the time spent mating was longer in mated than in virgin males. Furthermore, a decline observed in the spermatophore mass with successive matings was associated with a concomitant decline in its apyrene and eupyrene spermatozoa content. In the hours following mating, spermatozoa migrate from the spermatophore, located in the bursa copulatrix, to the spermatheca. Regardless of the male's previous mating history, the number of apyrene sperm dropped rapidly in the days following mating whereas the number of eupyrene spermatozoa declined gradually. As the temporal pattern of sperm movement was similar in all treatments, females mated with previously-mated males would suffer from sperm shortage sooner than those mated with virgins. Large C. rosaceana females stored more apyrene spermatozoa in their spermatheca than small ones, irrespective of the time after mating or male mating history, while only large females mated with once-mated males received more apyrene sperm and accessory gland secretions than small ones mated with virgin or twice-mated males. The results obtained in this study are discussed in relation with their potential impact on the reproductive success of both sexes.     

Costs of mating competition limit male lifetime breeding success in polygynous mammals

Although differences in breeding lifespan are an important source of variation in male fitness, the factors affecting the breeding tenure of males have seldom been explored. Here, we use cross-species comparisons to investigate the correlates of breeding lifespan in male mammals. Our results show that male breeding lifespan depends on the extent of polygyny, which reflects the relative intensity of competition for access to females. Males have relatively short breeding tenure in species where individuals have the potential to monopolize mating with multiple females, and longer ones where individuals defend one female at a time. Male breeding tenure is also shorter in species in which females breed frequently than in those where females breed less frequently, suggesting that the costs of guarding females may contribute to limiting tenure length. As a consequence of these relationships, estimates of skew in male breeding success within seasons overestimate skew calculated across the lifetime and, in several polygynous species, variance in lifetime breeding success is not substantially higher in males than in females.     

Effects of delayed mating and male mating history on longevity and reproductive performance of the rice stem borer, Chilo suppressalis (Walker) (Lep., Pyralidae)

Abstract:  The mating potential, effects of delayed mating and male mating history on longevity and reproductive performance of female rice stem borer (RSB), Chilo suppressalis , were investigated under laboratory conditions. Given the opportunity, RSB males copulated an average of 2.7 times, while females generally mated only once. Females were more severely affected by mating delay than males in terms of female longevity and reproductive performance. With increasing age at mating, females' longevity increased, while oviposition period, fecundity and egg fertility decreased. Mean fecundity and egg fertility of females mated 1 and 7 days after emergence were 251.3% and 99.2%, and 96.2% and 75.5% respectively. Both were reduced significantly when female mating was delayed beyond 4 days after emergence. However, irrespective of the first mating age and different mating history of the males, the results indicated that both did not result in a significant difference in the quality of their contributions to female longevity and reproductive performance. The results obtained in this study are discussed in relation to the potential effect on pheromone control of RSB.     

Lifetime reproductive success,selection on lifespan,and multiple sexual ornaments in male European barn swallows

Natural and sexual selection arise when individual fitness varies according to focal traits. Extra‐pair paternities (EPPs) can affect the intensity of selection by influencing variance in fitness among individuals. Studies of selection require that individual fitness is estimated using proxies of lifetime reproductive success (LRS). However, estimating LRS is difficult in large, open populations where EPPs cause reallocation of biological paternity. Here, we used extensive field sampling to estimate LRS in a population of barn swallows (Hirundo rustica) to estimate selection on lifespan and ornamental traits of males. We found selection on lifespan mediated both by within‐ and extra‐pair fertilization success and selection on tail length mediated by within‐ but not extra‐pair fertilization success. In addition, we found selection on tail white spots via extra‐pair fertilization success after controlling for selection on other traits. These results were not confounded by factors that hamper studies of LRS, including nonexhaustive sampling of offspring and biased sampling of males. Hence, natural and sexual selection mediated by LRS operates on lifespan, tail length, and size of the tail white spots in barn swallows.     

Proximate mechanisms of the differences in reproductive success of males bearing different alleles of Pgdh – a gene involved in a sexual conflict in bulb mite

Enzyme polymorphism in phosphogluconate dehydrogenase (Pgdh) is a striking example of single gene polymorphism involved in sexual conflict in bulb mite Rhizoglyphus robini. Males homozygous for the S Pgdh allele were shown to achieve higher reproductive success than FF homozygous males, while negatively influencing fecundity of their female partners. Here, we investigate proximate mechanisms responsible for the increased reproductive success of SS males and find that the S allele is associated with shorter time until copulation, higher copulation frequency and increased sperm production. We also show that Pgdh alleles are probably codominant, with SS males gaining the highest reproductive success, FF males – the lowest – and FS‐heterozygous males taking an intermediate position in all fitness parameters differentiating males of different genotypes. Additionally, we confirm the negative effect that S‐bearing males impose on the fecundity of females they mate with, showing a clear pattern of interlocus sexual conflict. We discuss that this effect is probably associated with increased copulation frequency. Whereas, contrary to what we have predicted, the S allele does not cause increased general male mobility, we speculate that the S allele‐bearing males are more efficient in forcing copulation and/or detecting females.     

Male mating success, reproductive success and multiple paternity in a natural population of sand lizards: behavioural and molecular genetics data

Sand lizard Lacerta agilis females characteristically mate with several males which, in staged mating experiments, results in multiple paternity of the offspring. In order to investigate multiple paternity in a natural population and interpret male reproductive behaviours in terms of sired young, we sampled the blood of females, potential fathers and hatchlings, and determined paternity using multilocus DNA fingerprinting as well as the variation at a single locus detected by the probe (TC) _n . The paternity analyses were preceded by a laboratory experiment in which we established that the parental alleles identified by the single locus probe were inherited in a Mendelian way. Our molecular data demonstrated that 12 out of 13 males (92%) that sired offspring were correctly identified from the 56 sexually mature males in the population. Also smaller males were accepted as sexual partners by the females, but sired fewer young in competition with larger males and were less able to maintain prolonged post-copulatory mate guarding. This may result in that some sexually successful males are only observed inside a female's home range, but never in pair-association with the female.     

Correlates of reproductive success within alternative mating tactics of the common shrew

Male common shrews (Sorex araneus) adopt two discrete matingtactics. The most successful males, in terms of number of offspringfathered, are those that establish large overlapping home rangesin areas of high female density early in the breeding season.An alternative, less successful mating tactic is to travel longdistances in search of mating opportunities. This study is aninvestigation of correlates of reproductive success for malesadopting these different mating tactics. Reproductive successunder natural conditions was assessed using DNA fingerprinting,and survival of offspring was monitored in the field. The numberof offspring fathered by males with overlapping home rangeswas positively correlated with the number of female ranges overlappedduring the breeding season and with testes mass. The numberof offspring fathered by males that made long-distance movementswas positively correlated with their epididymal sperm counts.It is argued that competitively superior (overlapping) malesachieve high reproductive success by competing to maximize thenumber of females inseminated, whereas those adopting an alternativemating tactic instead compete largely via sperm competition,aiming to maximize insemination success with any particularfemale. There was no significant difference in the fluctuatingasymmetry (FA) of males adopting different mating tactics (FAwas measured as the difference in length of the paired lateralscent glands). Fluctuating asymmetry was not related to thenumber of offspring fathered by males adopting either matingtactic, but was significantly correlated with the proportionof male offspring fathered that survived to sexual maturity.Although apparently not correlated with mating success in thisspecies, FA may reflect some aspect of genetic quality thataffects offspring survival. [Behav Ecol 7: 334–340 (1996)]     

The sublethal effects of tebufenozide on the precopulatory and copulatory activities of Choristoneura fumiferana and C. rosaceana

The sublethal effects of tebufenozide, an ecdysone agonist, on the reproductive biology of Choristoneura fumiferana (Clem) and of Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), treated during the larval stage, were evaluated using two treatment methods: the force‐feeding method and the diet method. The percentage of mortality and the developmental time of survivors increased linearly with the concentration of tebufenozide used. This ecdysone analogue proved to be more toxic to C. fumiferana than to C. rosaceana. In C. rosaceana, the weight of males and females decreased proportionally with the dose ingested, but females were affected to a greater extent. This difference might be due to a greater consumption of the treated diet, or to a differential vulnerability to tebufenozide. Tebufenozide did not modify the pre‐copulatory activities associated with chemical communication in the females. However, the consumption of tebufenozide delayed ovarian maturation, causing a reduction in the fecundity of females. Treated males had smaller spermatophores and fewer eupyrene sperms in their bursa copulatrix and spermatheca, along with lower mating success. In C. fumiferana, tebufenozide delayed the females’ onset time of calling the first night after emergence, but did not affect the mean time spent calling or the production of the main component of the sex pheromone. The males showed significantly greater difficulty in executing oriented flight in a wind tunnel, although their mating success was not affected. We concluded that tebufenozide interferes with various aspects of the reproductive biology of males and females of C. fumiferana and C. rosaceana, including some pre‐copulatory behaviors associated with sex pheromone communication.     

Influence of male mating history on female reproductive success among monandrous Naryciinae (Lepidoptera: Psychidae)

1. Multiple male copulations can have detrimental effects on female fitness due to sperm limitation. 2. Monandrous Naryciinae females are immobile while the males are short‐lived and do not feed. Multiple male mating is therefore expected to lead to sperm limitation in females. Sperm limitation and male limitation are hypothesised as causes of the repeated evolution of parthenogenetic reproduction in the Psychidae. 3. In this study, the effects of multiple male mating on female reproduction are investigated in several species of Naryciinae by allowing males multiple copulations. The results for two species, Siederia listerella and Dahlica lichenella, are compared. The sex ratios of 53 natural populations are examined for indications of male limitation. 4. Previous copulations by the male increased the female's risk of remaining unfertilised. However, contrary to expectations, those unfertilised females were capable of successful re‐mating. 5. In S. listerella, the number of previous copulations of males negatively influenced female fitness. Females produced 30% fewer offspring if they mated with a previously mated male. In D. lichenella, the older the male and the lower its number of total lifetime copulations, the higher the female's reproductive success. 6. Only a fraction of the investigated populations had a female‐skewed sex ratio, but differences in development time between males and females could lead to reproductive asynchrony. 7. In conclusion, male mating history did not lead to strong sperm limitation in Naryciinae as had been suggested by their life history.     

The contribution of multiple mating and spermatophore consumption to the lifetime reproductive success of female field crickets (Gryllus bimaculatus)

ABSTRACT.

• 1 The adaptive significance of multiple mating by female Gryllus bimaculatus (De Geer) was investigated.
• 2 Multiple mating prevented the depletion of sperm stores and, therefore, maintained high hatching success. This may not, however, explain the high frequency of remating in this species.
• 3 Male-derived egg stimulants known to be passed with sperm at mating increased the number of eggs produced only when females mated throughout their lifespans.
• 4 Spermatophore consumption appeared to provide nutrients which, while they did not increase the quantity of eggs, increased egg quality as indicated by weight. Females who consumed spermatophores had a greater hatching success.
• 5 While females may derive non-genetic benefits from mating, these are apparently long-term benefits; females must mate throughout their lives in order to accrue them.
• 6 Since the benefits of mating may not be derived from individual males, the spermatophores and their contents in this species are best considered as mating effort.

     

High male reproductive success of hermaphrodites in the androdioecious Phillyrea angustifolia

Androdioecy, the coexistence of males and hermaphrodites within a population, is a rare breeding system, often considered as unlikely to evolve because of restrictive conditions for its maintenance. Phillyrea angustifolia, a wind-pollinated shrub, is one of the handful species reported to be androdioecious. Our previous studies have shown that natural populations of this species in southern France exhibit higher male frequencies (approximately 50%) than predicted on theoretical grounds. Thus, the male functionality of hermaphrodites is still debated. To assess the functional breeding system of this species in the wild, a paternity analysis was performed with two highly polymorphic microsatellite loci on 729 seeds collected on 10 maternal shrubs in a natural population of 24 mature individuals of P. angustifolia. A large proportion of seeds were found to have been sired by pollen from outside the population. Analysis of seeds sired by individuals within the study population revealed a high male fertility of hermaphrodites resulting in a low male advantage in fertility for male plants. Intermate distances were found to have a strong impact on male reproductive success, whereas sexual morph had no effect, with males and hermaphrodites performing equivalently. This study is the first to unequivocally document the occurrence of a male function of hermaphrodites in a natural population of an androdioecious species.     

Multiple mating and lifetime reproductive output in female dobsonflies that receive nuptial gifts

In mating of the dobsonfly, Protohermes grandis (Thunberg), the male attaches the spermatophore externally to the female genitalia. The spermatophore includes a large gelatinous mass which the female detaches and feeds on after mating. While the female consumes this nuptial food gift, sperm is evacuated from the remaining portion of the spermatophore (sperm package) into her reproductive tract. Under laboratory conditions, mated females maintained receptivity throughout their lifetime, and they remated even on the day following copulation. A single insemination may supply enough sperm, as females mated only once deposited fertile eggs throughout life and, when dissected after death, all females had sperm in the spermatheca. There was a positive correlation between longevity and the number of matings. Lifetime fecundity also increased as mating multiplied. However, the size of eggs and hatchlings was not influenced by the number of matings. It seems that large spermatophore consumption by female P. grandis provides nutrients that increase fitness not in offspring quality, but in their quantity.     

Pattern of sperm storage and migration in the reproductive tract of the swallowtail butterfly Papilio xuthus: cryptic female choice after second mating

Females of the swallowtail butterfly Papilio xuthus L. (Lepidoptera: Papilionidae) mate multiply during their life span and use the spermatophores transferred to increase their longevity as well as fecundity. Sperm from different males may be stored in the sperm storage organs (bursa copulatrix and spermatheca). To clarify the pattern of sperm storage and migration in the reproductive tract, mated females are dissected after various intervals subsequent to the first mating, and the type and activity of sperm in the spermatheca are observed. When virgin females are mated with virgin males, the females store sperm in the spermatheca for more than 10 days. Sperm displacement is found in females that are remated 7 days after the first mating. Immediately after remating, these females flush out the sperm of the first male from the spermatheca before sperm migration of the second male has started. However, females receiving a small spermatophore at the second mating show little sperm displacement, and the sperm derived from the small spermatophore might not be able to enter the spermatheca. Females appear to use spermatophore size to monitor male quality.     

Effect of male and female age on the mating success of the obliquebanded leafrollerChoristoneura rosaceana (Lepidoptera: Tortricidae) under different ecological conditions

The present study was undertaken to test the hypothesis that male and female age, as well as temperature, can affect the mating success ofChoristoneura rosaceana, given the role that these two factors play in the pheromone biology of this species. In the laboratory, the mating success of females generally declined linearly with age, whereas in males, it increased during the first 3 days and then decreased. The decline in female mating success was more pronounced under warm than cool thermocycles, while the changes observed in males were greater under fluctuating than constant temperature regimes. The onset time of mating was unaffected by male age, however, older females always mated earlier than younger ones, with the advance being more pronounced at cool than warm temperatures. Similar results were also obtained under field conditions. When a single 3-day-old male was provided with 0-, 3-, and 5-day-old females simultaneously, older females obtained mates significantly more often than younger individuals at all temperatures, indicating that calling earlier may afford a reproductive advantage to older females. At both constant temperatures, the time spent mating was longer in older than in younger females, but not under fluctuating thermocycles. Very young and very old males generally spent more time in copula than middle-aged individuals both at constant temperatures and under the warm thermocycle. Under the cool thermocycle, the duration of mating was considerably prolonged at all ages, which could increase the risk of predation.     

Effects of fine‐scale genetic structure on male mating success in gynodioecious Beta vulgaris ssp. maritima

Plant mating systems are known to influence population genetic structure because pollen and seed dispersal are often spatially restricted. However, the reciprocal outcomes of population structure on the dynamics of polymorphic mating systems have received little attention. In gynodioecious sea beet (Beta vulgaris ssp. maritima), three sexual types co‐occur: females carrying a cytoplasmic male sterility (CMS) gene, hermaphrodites carrying a non‐CMS cytoplasm and restored hermaphrodites that carry CMS genes and nuclear restorer alleles. This study investigated the effects of fine‐scale genetic structure on male reproductive success of the two hermaphroditic forms. Our study population was strongly structured and characterized by contrasting local sex‐ratios. Pollen flow was constrained over short distances and depended on local plant density. Interestingly, restored hermaphrodites sired significantly more seedlings than non‐CMS hermaphrodites, despite the previous observation that the former produce pollen of lower quality than the latter. This result was explained by the higher frequency of females in the local vicinity of restored (CMS) hermaphrodites as compared to non‐CMS hermaphrodites. Population structure thus strongly influences individual fitness and may locally counteract the expected effects of selection, suggesting that understanding fine scale population processes is central to predicting the evolution of gender polymorphism in angiosperms.     

Multiple mating and its effect on the reproductive success of female Epiphyas postvittana (Lepidoptera: Tortricidae)

Abstract.

• 1 Multiple mating and its effect on reproductive performance of female Epiphyas postvittana (Walker) moths were studied under controlled conditions.
• 2 The age at which the moths mated for the first time ranged from the first to the tenth day after emergence, but 71% of first matings were during the first 3 days.
• 3 The majority (63%) of females had one or two spermatophores in the bursa copulatrix. Some (24%) were found with three to five spermatophores, whereas no successful mating occurred among 13% of individuals. The number of matings was partly dependent on the number of mates available to the female. Between the range of sex ratios of one male to one female and four males to one female maximal mating success occurred at the ratio of three males to one female.
• 4 Virgin females were capable of egg-laying, but mating stimulated and accelerated oviposition. Mated individuals laid twice as many eggs as unmated ones.
• 5 The level of copulatory activity did not influence the longevity of females irrespective of the number of males available to them.
• 6 Sex ratios with greater than one male to a female improved the reproductive success by marginally increasing fecundity and fertility.
• 7 It is concluded that multiple mating would enhance population growth, and is of particular benefit to populations with a preponderance of females, as is known to occur naturally in this species.

     

Influences of mating groups on the reproductive success of the Southern Sichuan Red Panda (Ailurus fulgens styani)

The reproduction of female red pandas under three different husbandry conditions (monogamy, polygamy, and polyandry) was studied at the Chengdu Research Base for Giant Panda Breeding, and Chengdu Zoological Park, China. We monitored the fecal steroid profiles of seven females by radioimmunoassay in order to understand how the different mating groupings affect the animals' reproductive success. Of the seven females studied, all gave birth except the one that was kept in the polyandrous group. Although fecal estradiol metabolites exhibited several peaks during estrus, only one coincided with mating behavior. Fecal progesterone metabolites did not display a sustained rise in the absence of mating behavior, even though estradiol displayed a peak of secretion. This suggests that the red panda may be an induced ovulator. During gestation, fecal progesterone metabolites were maintained at a comparatively high level, and were much higher than those of nonpregnant females. The female in the polyandrous group showed an abnormal estradiol metabolite profile, with a level that was four to five times higher than those of the females in the polygynous groupings. It was observed that this female always escaped and hid in the trees to avoid courtships with males, and did not give birth. This phenomenon suggests that polyandrous groupings may be unsuitable for successful reproduction in captivity. Zoo Biol 24:169–176, 2005. © 2005 Wiley‐Liss, Inc.     

Early growth,dominance acquisition and lifetime reproductive success in male and female cooperative meerkats

In polygynous species, variance in reproductive success is higher in males than females. There is consequently stronger selection for competitive traits in males and early growth can have a greater influence on later fitness in males than in females. As yet, little is known about sex differences in the effect of early growth on subsequent breeding success in species where variance in reproductive success is higher in females than males, and competitive traits are under stronger selection in females. Greater variance in reproductive success has been documented in several singular cooperative breeders. Here, we investigated consequences of early growth for later reproductive success in wild meerkats. We found that, despite the absence of dimorphism, females who exhibited faster growth until nutritional independence were more likely to become dominant, whereas early growth did not affect dominance acquisition in males. Among those individuals who attained dominance, there was no further influence of early growth on dominance tenure or lifetime reproductive success in males or females. These findings suggest that early growth effects on competitive abilities and fitness may reflect the intensity of intrasexual competition even in sexually monomorphic species.