Effects of male mating interval on spermatophore formation,transfer, and subsequent female receptivity and fecundity in the sorghum plant bug,Stenotus rubrovittatus

Males of the sorghum plant bug, Stenotus rubrovittatus (Matsumura) (Heteroptera: Miridae), transfer a spermatophore to females during copulation. After a 1‐day interval between the first and second copulation, males transferred both sperm and a spermatophore to females during the second copulation. However, when male mating interval was <1 h, they transferred sperm but no spermatophores to females during the second copulation. Therefore, the male mating interval probably produces two types of mated females, those with and those without a spermatophore. Mated females of S. rubrovittatus do not remate for at least 3 days after mating, even when courted, and lay more eggs than virgin females at the beginning of the oviposition period. The effects of spermatophores on female sexual receptivity and fecundity were examined using mated females with or without a spermatophore. Only one of the 40 (2.5%) mated females with a spermatophore remated, whereas 10 of the 26 (38.5%) without a spermatophore remated. Furthermore, mated females with a spermatophore laid more eggs than those without a spermatophore. These results suggest that spermatophores participate in reducing female sexual receptivity and enhancing female fecundity in S. rubrovittatus.     

Spermatophore and Sperm Allocation in Males of the Monandrous Butterfly Pararge aegeria: the Female’s Perspective

In insects, spermatophore production represents a non‐trivial cost to a male. Non‐virgin males have been shown to produce small spermatophores at subsequent matings. Particularly in monandrous species, it may be an issue to receive a sufficiently large spermatophore at the first and typically only mating. Females of the monandrous Speckled wood butterfly Pararge aegeria (L.) produce fewer offspring after mating with a non‐virgin male. After mating, females spend all their active time selecting oviposition sites and typically ignore other males. Here, we show that females did not discriminate between a virgin male and a recently mated male in our laboratory experiments. We demonstrate that the number of eupyrene sperm bundles relative to spermatophore mass differed with subsequent male matings. Males transferred a significantly smaller spermatophore after the first copulation, but the spermatophore mass did not decrease further with subsequent matings. However, the number of eupyrene sperm bundles decreased linearly. Therefore, there was proportionally more eupyrene sperm in the male’s second spermatophore compared with the first and the later spermatophores. Such a pattern has been shown in polyandrous species. Hence, it suggests that differences in sperm allocation strategy between polyandrous and monandrous butterflies may be quantitative rather than qualitative. There was also a tendency for females that had mated with a recently mated male to have higher propensity to remate than did females that had mated with a virgin male. We discuss the results relative to the mating system in P. aegeria, including female remating opportunities in the field and male mate‐locating behaviour.     

The Effects of Age and Previous Mating Experience on Pre- and Post-copulatory Mate Choice in Female House Crickets (<Emphasis Type="Italic">Acheta domesticus</Emphasis> L.)

Although females’ mating preferences are influenced by male characteristics, there are a number of factors intrinsic to females and unrelated to male phenotype that can modulate female choice. We assessed the effects of age and mating experience on mechanisms of pre- and post-copulatory mate choice in female house crickets, Acheta domesticus L., by randomly assigning males to females, but independently varying the age and number of previous matings of females at the time of experimental matings. Latency to mating, a measure of a female’s pre-copulatory preference, was influenced by female age at the time of mating, with older females mating sooner than younger females. The reduced selectivity of older females appears consistent with life-history theory, which predicts that the reproductive value of females should decline with age. The length of time that females retained the spermatophore after mating, a measure of a female’s post-copulatory mating preference, was not influenced by female age at the time of mating, the number of previous matings, or any interaction between the two main effects. Contrary to previous reports, male mass had no effect on either the latency to mating or female retention of the spermatophore in A. domesticus. We conclude that female age and mating experience can moderate female selectivity, but that their impact varies according to the mechanism by which females favor particular sires.     

Delayed mating and its cost to female reproduction in the butterfly,Eurema hecabe

The timing of mating of females under semi-natural condition, male ejaculate production and their effects on female fecundity were examined inEurema hecabe. Age of the first mating of females varied, and the number of matings increased with age. Male spermatophore production depended on age and body mass. The spermatophore mass at the second mating depended only on the interval between the first and second matings. The timing of the first mating and the spermatophore mass did not affect female fecundity. The timing of mating of females relative to the role of male spermatophores in female fecundity and male mating strategy are discussed.     

Paternity Analysis in a Hexapod (Orchesella cincta; Collembola) with Indirect Sperm Transfer

In species where males and females interact during mating, the role of females in sexual selection cannot always be demonstrated unambiguously. Here we present a model system to study female choice for mates. Orchesella cinca is a soil-dwelling hexapod with indirect sperm transfer. Females and males do not interact physically for reproduction. We gave females the choice between spermatophores produced by two different males. Paternity analysis based on microsatellite variation revealed that offspring in one clutch were sired by one male only. Direct observations showed that after a female has taken up a spermatophore, the female's receptivity to further spermatophore uptake seem to end. Our results imply that the female is in full control of paternity.     

Male Gryllus bimaculatus Guard Females to Delay Them from Mating with Rival Males and to Obtain Repeated Copulations

Three hypotheses for the function of postcopulatory mate guarding were tested in the field cricket Gryllus bimaculatus De Geer. The duration of spermatophore attachment was greater in the absence than in the presence of a guarding male. The ejaculate protection hypothesis was, therefore, rejected. The duration of mate guarding was found to be equal to the interval between copulations, supporting the spermatophore renewal hypothesis. In support of the rival exclusion hypothesis, the presence of a guarding male did increase the duration of spermatophore attachment when a rival male was also present. The presence of a guarding male also delayed the female from mating with the rival male. Female mating status had a significant effect on the duration of spermatophore attachment. Females mating for the first time retained the spermatophore for a significantly longer period of time than females that had mated previously.     

多次交配对小菜蛾精包形成与生殖力的影响

【目的】小菜蛾Plutella xylostella是主要为害十字花科作物的一种世界性害虫,强大的生殖能力是其成为田间最难防治的害虫的主要原因之一。交配是营两性生殖昆虫繁衍后代必要的一个生理过程,明确小菜蛾雌雄成虫的交配行为及交配后的生理响应,对于小菜蛾种群监测和综合防治具有重要意义。【方法】解剖观察小菜蛾成虫生殖腺及精包形成;利用行为学与生物学实验,测定和分析小菜蛾成虫交配与再交配能力、精包形成与消化,以及交配次数对精包形成以及雌虫生殖力的影响。【结果】小菜蛾雄成虫在交配过程中精液以精包的形式传递给雌成虫,在交配囊中精包呈白色、不透明、气球状结构,交配结束后精包可被充分消化和吸收。成虫交配能力观测结果显示,小菜蛾雌雄成虫均具有多次交配行为。首次交配后,雄成虫表现出短暂的再交配延迟,20 min内其交配成功率为54.6%,显著低于首次交配。虽然交配次数不会影响雄成虫的交配时长,但雄成虫交配史对其自身的精包大小以及雌成虫的生殖力均具有显著的抑制作用。雌成虫表现出明显的再交配抑制性,交配过的雌成虫在12 h内的交配率显著低于未交配雌成虫的,这可能取决于首次交配后精包的消化和吸收速率。雌成虫多次交配后,其产卵量和卵孵化率与单次交配的相比没有显著差异。【结论】多次交配会使小菜蛾雄成虫再交配延迟,雌成虫再交配受到抑制;多次交配产生的雄成虫精包显著减小,雌成虫产卵量与卵孵化率并没有从多次交配中获得收益。本研究为解析小菜蛾雌雄成虫生殖调控机制奠定理论基础。     

Last–male sperm precedence in the bushcricket Poecilimon veluchianus (Orthoptera, Tettigonioidea) demonstrated by DNA fingerprinting

Males of the bushcricket Poecilimon veluchianus pass a large spermatophore to the female during mating. The spermatophore is eaten by the female after copulation. Because females mate with several males during their reproductive life, the competition between spermatozoa of different males affects a male's reproductive success. In order to determine the outcome of sperm competition, the paternity of the progeny of double–mated females was established by DNA fingerprinting with the oligonucleotide (GATA)₄. Typical P. veluchianus DNA fingerprints consisted of 15 scoreable fragments per individual. The proportion of bands shared between presumably unrelated bushcrickets was 17%. After the second copulation the second mating male clearly predominated at fertilization. The mean proportion of eggs fertilized by the second male was 90.1%. There was no significant relationship between the level of sperm precedence and the time of ovipositions after the second mating. If female P. veluchianus increase the fitness of their offspring by the incorporation of spermatophore–derived substances in developing eggs, there is little chance for the feeding male to fertilize eggs containing his nutrients, because of the very short mating intervals of females and the observed high level of last–male sperm precedence in this species. Under such conditions the last mating male would fertilize many eggs containing nutrients from a prior male. Because nuptial gifts, like the tettigoniid spermatophore, function only as paternal investment if the donating male's progeny benefit from the gift, a paternal investment function of the P. veluchianus spermatophore seems to be unlikely.     

Mating Behavior and Spermatophore Morphology of the Cave Pseudoscorpion Maxchernes iporangae (Arachnida: Pseudoscorpiones: Chernetidae)

The mating behavior of the cave pseudoscorpion Maxchernes iporangae Mahnert & Andrade, 1998 (Chernetidae), was studied under laboratory conditions. A total of 24 pairings was observed. Mating was divided into three phases: predeposition (dance), spermatophore deposition and transfer, and posttransfer phase. The mean mating duration was 67.3 min based on 10 observations. Spermatophore morphology is described and consists of a stalk, a drop of fluid, and an -shaped sperm package. Males and females can mate several times in the same reproductive period. However, consecutive mating was not observed between a female and the same or another male.     

Sperm transfer during mating, movement of sperm in the female reproductive tract, and sperm precedence in the common cutworm Spodoptera litura

Abstract. Mating behaviour, sperm transfer and sperm precedence were studied in the moth Spodoptera litura (Fabr.) (Lepidoptera: Noctuidae). There existed a rhythmic, diel pattern of mating behaviour of this moth during the scotophase, presumably set with respect to an endogenous activity rhythm. Approximately 30 min after copulation had started, the formation of the corpus of the spermatophore began in the bursa copulatrix of the female moth, but full inflation of the corpus was not completed until 45–60 min after mating had started. The mature spermatophore contained about 350 eupyrene sperm bundles and a large number of individual (loose) apyrene spermatozoa. The mating status and the age of the male insect influenced the number of sperm transferred to the female within the spermatophore, and also affected the consequent fertility. There was no evidence of sperm reflux within the male tract. Within the female, dissociation of eupyrene sperm bundles was evident within the spermatophore less than 15 min after the completion of mating. Spermatozoa began to move from the bursa (in which the spermatophore is lodged) into the spermatheca 30–45 min after the end of the copulation, and the quantity of sperm in the spermatheca reached a plateau at 90 min after mating. Apyrene sperm reached the spermatheca first, followed by eupyrene sperm. Examination of total (apyrene plus eupyrene) sperm in the female tract showed that 86% of mated females received an apparently normal amount of total sperm from the male. Examination of eupyrene sperm alone showed that 81% of matings resulted in an apparently normal transfer of eupyrene sperm. A small proportion (approximately 8%) of the matings, however, were identified as transferring a clearly subnormal quantity of eupyrene sperm to the spermatheca. The eggs produced as a result of such pairings displayed much reduced fertility (about 43%) compared to those from matings confirmed to have transferred normal quantities of sperm, which showed about 92% fertility. This shows that the availability of eupyrene sperm in the spermatheca may be an important constraint on fertility in normal populations of insects. In the laboratory, S. litura females exhibited multiple matings. Of the females, 93% mated, and the mean frequency of mating was 1.69. Mating with a fertile male led to the oviposition of an increased number of eggs. This effect continued even when the female subsequently mated with an infertile male. Displacement of sperm from previous matings is known to be an important factor in the evolution of multiple mating strategies. Our results on sperm utilization by S. litura indicated that after a second mating, the sperm utilized for subsequent fertilization were almost exclusively from the last mating with little mixing. The proportion of eggs fertilized by sperm from the second mating (P₂) was calculated as 0.95, indicating almost complete sperm precedence from the last mating.     

Receptivity of female remating and sperm number in the sperm storage organ in the bean bug,Riptortus clavatus (Heteroptera: Alydidae)

This study examines the relationship between the number of sperm in the seminal receptacle (spermatheca) and the receptivity of female remating in the bean bugRiptortus clavatus Thunberg. On the 21 st day after the first mating when receptivity to remating was > 70%, females receptive to remating had significantly fewer sperm ( < 40 on average) in the spermathecae than females reluctant to do (about 150 on average). However, averages of the number of eggs laid by receptive and reluctant females within 21 days were almost same. The proportion of fertilized eggs for receptive females at 15–21 days after copulation was significantly lower than that for reluctant females. Spermatozoa transferred from a male to a female’s spermatheca were detected 5 min after copulation and then increased continuously to about 500 with the first hour. When copulation durations were manipulated artificially, the shorter the copulation period (=females had less sperm in their spermathecae), the higher the remating rate became. Females may perceive the number of sperm in their seminal receptacles and then determine whether they copulate or not. These results support the hypothesis that females mate multiply in order to replenish inadequate sperm supplies to fertilize all eggs produced.     

Evaluating female remating rates in light of spermatophore degradation in Heliconius butterflies: pupal‐mating monandry versus adult‐mating polyandry

1. Butterflies are frequently used in comparative studies of sexual selection because of their diverse mating systems. In Heliconius, the two major clades in the genus are characterised by contrasting pupal‐mating and adult‐mating strategies. Adult‐mating females are considered to be promiscuous whereas pupal‐mating females are thought to be monandrous. 2. Counting spermatophores in female Lepidoptera is a common method for assessing patterns of female remating. However, in pupal‐mating Heliconius butterflies spermatophores can become completely degraded, potentially leading to underestimation of female remating rates. 3. We qualitatively characterised the different states of spermatophore degradation, and showed that complete degradation takes approximately 3 weeks in captive‐bred H. erato females. 4. We counted spermatophores and/or assayed spermatophore degradation in > 500 Heliconius females across 28 species sampled from natural populations. Among pupal‐maters these observations yielded a few rare observations of double mating by recently eclosed females, but generally indicated a lack of rematings. In contrast, approximately 25% of sampled adult‐mating females remated at least once. 5. Using a novel statistical analysis, we estimated remating rates from patterns of spermatophore degradation or from counts stratified by age, as indicated by wing‐wear. This analysis showed no statistically significant evidence for remating for the pupal‐mating H. erato whereas significant remating rates were detected for adult‐mating species. 6. The present results support the established view of Heliconius mating systems in which pupal‐maters are largely monandrous, whereas adult‐maters are polyandrous.     

Remating Behavior of Cnephasia jactatana Walker Females (Lepidoptera: Tortricidae)

Cnephasia jactatana Walker is an important pest of kiwifruit in New Zealand. We investigated, under laboratory conditions, the effects of multiple mating on the reproductive performance of C. jactatana females and how such effects varied with male virginity and larval nutrition. We found that in permanent pairs, remating increased female fecundity and fertility but suboptimally fed females benefited more from remating. Regardless of this benefit, mass-reared pairs had a lower remating frequency. Females remating with a virgin male or a male that had delivered a spermatophore presented similar fecundity and fertility; however, females receiving a second ejaculate from a virgin male had increased daily fecundity. Female weight clearly affected remating behavior since those that received a second ejaculate were significantly heavier. Neither mating length nor size of the first spermatophore influenced female remating. Further, mass-reared and individually reared males produced spermatophores of similar size.     

Effects of mite age, mite density, and host quality on aerial dispersal behavior in the twospotted spider mite

Mite age, population density, and host leaf quality affect various life history traits in spider mites. We investigated the effects of these factors on the aerial dispersal behavior of adult female twospotted spider mites,Tetranychus urticae Koch (Acari: Tetranychidae). The proportion of adult females exhibiting the dispersal behavior dropped significantly with age following adult emergence, particularly in the first 3 days. Sixty to eighty percent of female mites 2-days old or younger displayed the behavior under test conditions, whereas less than 20% of female mites older than 3-days-old showed the behavior. Younger adult females also exhibited shorter latency for the behavior, although this trend was not as clear. Leaf quality experienced during deutonymph development had no effect on the behavior adults subsequently displayed. On the other hand, adult females that fed on poor quality leaves after emergence were twice as likely to display the behavior (90% vs. 45%), and with shorter latency (37 vs. 77 min), than those that fed on high quality leaves. When newly emerged adult females encountered high mite density and dry leaves, the incidence of the behavior increased (69% vs. 47%) and latency decreased (69 vs. 93 min) compared to mites that encountered low density on well watered leaves. Our results suggest that both starvation and desiccation of adult females may enhance their dispersal behavior.     

Mating Behavior and Reproductive Potential in the Turnip Moth Agrotis segetum (Lepidoptera: Noctuidae)

We investigated the lifetime mating potential and the reproductive behavior of male and female turnip moths Agrotis segetum (Schiff.) under field and laboratory conditions. The sex ratio was 1 : 1 in a lab-reared population as well as in two wild populations. Males were capable of mating repetitively a relatively large number of times (mean of 6.7 ± 2.7 matings) when given access to new virgin females throughout their lifetimes. Females seldom mated more than once (mean ± 1.3 ± 0.6 matings), indicating a male-biased operational sex ratio. The mean potential lifetime mating was five times higher in males, while the coefficient of variance was lower in males. There was no differences in longevity between animals that were allowed to mate and animals not allowed to mate, indicating no direct costs or benefits of mating in physiological terms. In males, the number of matings was positively correlated with longevity, but this was not the case in females. Nor was there a correlation between the number of female matings and the number of fertilized eggs. There was a negative correlation between the number of eggs fertilized and the number of times males had previously mated, indicating that male ejaculates were limited. Male spermatophore size also decreased with number of achieved matings. Laboratory-reared females attracted males in the field throughout their lifetimes, with a peak at 3–7 days of age. Wild males, allowed to choose between pairs of caged females in the field, were attracted in equal numbers to females of different ages. Females did not show any mate-rejection behavior in the field. They mated with the first male that courted them. No incidence of mate replacement by males arriving later to already courted females were recorded.     

Male larval nutrition in Choristoneura rosaceana (Lepidoptera: Tortricidae): an important factor in reproductive success

This study examines how Choristoneura rosaceana male quality, as determined by larval diet, age and mating history, affects the reproductive success of both sexes. While the size of the spermatophore produced at first mating increased linearly with male age, the frequency of mating was significantly higher for middle-aged males (2–4 days old) than younger (0–2 days old) or older (6–8 days old) individuals, when both sexes were fed on artificial diet. However, the duration of copulation was longer in couples with older than younger males. The observed age-related changes in spermatophore size had no significant effect on female longevity, fecundity or fertility, suggesting no direct relationship between male investment and spermatophore size under these experimental conditions. Different larval food sources (artificial diet, maple and hazelnut) did not affect the proportion of 2-day-old virgin males that mated; however, the proportion that remated was significantly higher for males reared on high-quality food (maple and artificial diet) than those on hazelnut, a poorer food source. There was a 5-fold decline in spermatophore size between the first and second matings on all diets, but female reproductive output was reduced by only 25%. In contrast, while the first spermatophore produced by males on hazelnut was 1.5 times smaller than those produced on maple and artificial diet, the fecundity of their mates was 40% less than those mated with high-quality virgin males. These results provide additional support to the idea that spermatophore size is not a valuable indicator of male quality. Most tethered females placed in the field during the first flight period mated with virgin males (based on the size of the spermatophore), suggesting that female choice exists in this species. These results are discussed in relation to the incidence of polyandry in naturally occurring populations of Choristoneura and the potential use of size and/or chemical cues by females to assess male quality.     

Limits to Nuptial Gift Production by Male Fireflies, Photinus ignitus

Males of diverse insect species provide females with nuptial gifts, and limits on males' ability to produce these gifts may influence courtship behavior and mating systems. In the firefly Photinus ignitus, males transfer a complex spermatophore to females during mating. We provided firefly males unlimited access to responsive females to examine whether spermatophore production limits male mating success. Male spermatophore mass decreased significantly across sequential matings, and the percentage of successful matings declined during the second half of each male's life span. Male body mass explained a significant proportion of variation in size of the first spermatophore produced by P. ignitus males, but this relationship disappeared with second spermatophores. This study indicates that males' ability to produce spermatophores declines over their lifetime and that limits on nuptial giftproduction can constrain male mating success in Photinus fireflies.     

Impact of male condition on his spermatophore and consequences for female reproductive performance in the Glanville fritillary butterfly

In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality, and in some cases also to female body maintenance. The production of the spermatophore, however, represents a cost for the male and, in polyandrous species, ejaculates are sometimes allocated adaptively across matings. Nonetheless, although the ecological factors affecting the reproductive success of female butterflies have been the topic of numerous studies, little information exists on the factors affecting males’ contribution to reproduction, and the indirect impacts on female fecundity and fitness. We used the Glanville fritillary butterfly, Melitaea cinxia (Linnaeus, 1758) (Nymphalidae), in order to assess variation in male allocation to matings. In this species, smaller males produce smaller spermatophores, but variation in spermatophore size is not correlated with female reproductive success. We show that spermatophore size increases with male age at first mating, decreases with mating frequency and adult food‐deprivation, and is not influenced by developmental food‐limitation. The length of copulation period does not influence the spermatophore size nor influences the polyandrous mating behavior in this species. Male contribution to his spermatophore size is clearly influenced by his condition and adult‐resource at the time of mating. Despite this variation, spermatophore size does not seem to have a direct impact on female reproductive output or mating behavior.     

Mating Resets Male Cricket Aggression

An animal’s motivational state can significantly impact its behavior. We examined the effects of mating on the aggression of male Acheta domesticus crickets. Pairs of males were allowed to establish dominance and subordinance and were then physically separated. Subordinate males were then allowed to either copulate with a female or to have chemo-tactile contact with, but to not copulate with, a female. Less than 15 min after separation, all male pairs engaged in a second agonistic encounter. Subordinate males that copulated with females were significantly more aggressive toward their dominant partners than un-mated subordinate males. Many mated subordinates became dominant. Allowing a subordinate male to contact, but not copulate with, a female had a similar effect, suggesting that chemo-tactile cues from the female are sufficient to elicit this change in aggression.     

Mating behavior and male mating success in wildAnastrepha Ludens (Diptera: Tephritidae) on a field-caged host tree

Mating behavior and factors affecting mating success of males were studied using wild Anastrepha ludens on a fieldcaged host tree. The most common courtship sequence had five components: (1) male calls from the underside of a leaf, (2) female arrives to the maleoccupied leaf, (3) male orients to female and stops calling, (4) one or both approach to a face-to-face position 1–3 cm apart, and (5) male mounts female after 1–2 s. Courtship behavior was almost identical to that of laboratoryculture flies observed previously under laboratory conditions. Most malefemale encounters occurred at a height of 1–2m, well inside the outer canopy of the tree. Differential mating success by males occurred. No male mated more than once per day, owing possibly to a very short sexual activity period. Factors favoring mating success of males were survival ability and tendency to join male aggregations and to fight other males. Thorax length and age (9–11 days difference) had no effects on male copulatory success. Overall win/loss percentage was not related to mating success because the males that were most successful at mating fought mostly among themselves, driving their win/loss percentage down. However, these successful males (at mating) won most of their fights against less successful males. Results confirmed a lek mating system: males aggregated, called, and defended territories; territories did not contain femalerequired resources; and females exercised mate choice, apparently through selection of sites within leks.