Mating with sperm-depleted males does not increase female mating frequency in the parasitoid Lariophagus distinguendus

Sexual conflicts due to divergent male and female interests in reproduction are common in parasitic Hymenoptera. The majority of parasitoid females are monandrous, whereas males are able to mate repeatedly. Thus, accepting only a single mate might be costly when females mate with a sperm‐depleted male, which may not transfer a sufficient amount of sperm. In the present study, we investigated the reproductive performance in the parasitoid Lariophagus distinguendus Först. (Hymenoptera: Pteromalidae) and studied whether mating with experimentally sperm‐depleted males increases the tendency of females to remate. Males were able to mate with up to 17 females offered in rapid succession within a 10‐h test period. The resulting female offspring, as an indirect measure of sperm transfer, remained constant during the first six matings and then decreased successively with increasing number of copulations by the males. Experimentally sperm‐depleted males continued to mate even if they transferred only small amounts or no sperm at all. Unlike males, the majority of females mated only once during a 192‐h test period. A second copulation was observed only in a few cases (maximum 16%). The frequency of remating was not influenced by the mating status of the first male the females had copulated with, suggesting that these events are not controlled by sperm deficiency of the females. Furthermore, we investigated male courtship behaviour towards mated females. Male courtship intensity towards mated females decreased with increasing time. However, females that had mated with an experimentally sperm‐depleted male did not elicit stronger or longer‐lasting behavioural responses in courting males than those that had mated with a virgin male. As the observed behaviours in L. distinguendus are known to be elicited by a courtship pheromone, these results suggest that females no longer invest in pheromone biosynthesis after mating (as indicated by ceasing behavioural responses of courting males), irrespective of whether they have received a sufficient amount of sperm or not. We discuss the results with respect to a possible mating strategy of sperm‐depleted males.     

Effect of male and female multiple mating on the fecundity, fertility, and longevity of diamondback moth, Plutella xylostella (L.)

Abstract:  The effect of diamondback moth (DBM), Plutella xylostella (Lep., Plutellidae) male and female multiple mating on fecundity, fertility, and longevity was studied. Males could mate for five times with virgin females during scotophase. The successful copulation rates, fecundity of female, and longevity of both females and males decreased when male mating times increased, whereas copulation duration increased. Correlation coefficient between copulation duration and male mating times was significant ( r  = 0.7358, P = 0.0001, spearman rank-order correlation). There were linear relationships between mating history of males and longevities of males and females, and regression relationships between them were significant. Mated females had similar daily reproductive pattern, which laid the most eggs on the first day after mating in spite of their mates' mating history. Virgin females laid some infertile eggs before they died. Most of the females mated once during their lifespan but 19.9% of females mated twice when one female kept with one male during scotophase. There were no significant differences in the fecundity, fertility and longevity between the single- and twice-mated females. Correlation coefficient between copulation duration and female mating times was not significant ( r  = 0.0860, P = 0.8575). Results suggested that DBM females may be monandrous. Multiple mating did not increase male or female mating fitness.     

A paternity advantage for speedy males? Sperm precedence patterns and female re-mating frequencies in a sexually cannibalistic praying mantid

Scramble competition polygyny is expected when females and/or resources are widely dispersed and not easily monopolized by males, or when there is an abundance of mates during an extremely restricted reproductive period. Additional factors such as first male sperm precedence or low female re-mating rate might further explain the propensity of males to engage in scramble competition. The sexually cannibalistic praying mantid Pseudomantis albofimbriata exhibits a polygynous mating system, where females exist in low-density populations and male competition manifests as the race to find females rather than as direct physical fighting. Here, we aim to determine whether there is a paternity advantage for the first-male to mate and/or a low frequency of female re-mating. First, we determined sperm precedence patterns in P. albofimbriata using the sterile male technique. Second, we tested the likelihood of female re-mating in P. albofimbriata by comparing the close-range approach behaviour and frequency of successful mating attempts for males when paired with virgin as opposed to recently mated females, and by comparing the frequency of long-distance male attraction between virgin and mated females. We found no paternity advantage for the first male to mate, rather a second male advantage. Although mated females were not rejected by males when approached from close-range, they were chemically unattractive to males searching from a distance. Since initial mate attraction in many praying mantids, including P. albofimbriata, is mediated via long-distance chemical communication, we believe the latter result is more ecologically relevant and therefore more important. These results suggest that the relatively low frequency of female re-mating observed in P. albofimbriata may be an additional factor driving scramble competition in this system.     

Female reproductive strategies in orangutans,evidence for female choice and counterstrategies to infanticide in a species with frequent sexual coercion

Intersexual conflicts over mating can engender antagonistic coevolution of strategies, such as coercion by males and selective resistance by females. Orangutans are exceptional among mammals for their high levels of forced copulation. This has typically been viewed as an alternative mating tactic used by the competitively disadvantaged unflanged male morph, with little understanding of how female strategies may have shaped and responded to this behaviour. Here, we show that male morph is not by itself a good predictor of mating dynamics in wild Bornean orangutans but that female conception risk mediated the occurrence and quality of male–female interactions. Near ovulation, females mated cooperatively only with prime flanged males who they encountered at higher rates. When conception risk was low, willingness to associate and mate with non-prime males increased. Our results support the hypothesis that, together with concealed ovulation, facultative association is a mechanism of female choice in a species in which females can rarely avoid coercive mating attempts. Female resistance, which reduced copulation time, may provide an additional mechanism for mate selection. However, coercive factors were also important as prime males were frequently aggressive to females and females used mating strategies consistent with infanticide avoidance.     

Reproductive costs of mating with a sibling male: sperm depletion and multiple mating in Cephalonomia hyalinipennis

Polygynous parasitoid males may be limited by the amount of sperm they can transmit to females, which in turn may become sperm limited. In this study, I tested the effect of male mating history on copula duration, female fecundity, and offspring sex ratio, and the likelihood that females will have multiple mates, in the gregarious parasitoid Cephalonomia hyalinipennis Ashmead (Hymenoptera: Bethylidae: Epyrinae), a likely candidate for sperm depletion due to its local mate competition system. Males were eager to mate with the seven females presented in rapid succession. Copula duration did not differ with male mating history, but latency before a first mating was significantly longer than before consecutive matings. Male mating history had no bearing on female fecundity (number of offspring), but significantly influenced offspring sex ratio. The last female to mate with a given male produced significantly more male offspring than the first one, and eventually became sperm depleted. In contrast, the offspring sex ratio of first‐mated females was female biased, denoting a high degree of sex allocation control. Once‐mated females, whether sperm‐depleted or not, accepted a second mating after a period of oviposition. Sperm‐depleted females resumed production of fertilized eggs after a second mating. Young, recently mated females also accepted a second mating, but extended in‐copula courtship was observed. Carrying out multiple matings in this species thus seems to reduce the cost of being constrained to produce only haploid males after accepting copulation with a sperm‐depleted male. I discuss the reproductive fitness costs that females experience when mating solely with their sibling males and the reproductive fitness gain of males that persist in mating, even when almost sperm‐depleted. Behavioural observations support the hypothesis that females monitor their sperm stock. It is concluded that C. hyalinipennis is a species with a partial local mating system.     

Is egg carrying attractive? Mate choice in the golden egg bug (Coreidae,Heteroptera)

In several species of fish, females select males that are already guarding eggs in their nests. It is a matter of debate as to whether a female selects a good nest site for her offspring (natural selection) or a male for his attractiveness (sexual selection). The golden egg bug, Phyllomorpha laciniata Vill, resembles fish in the sense that mating males carry more eggs than single males, but in the bugs, female mate choice is decoupled from egg site choice. The sexual selection hypothesis predicts that if females select males using male egg load as a cue for male quality, they should not mate with a male when eggs are removed, regardless of his mating attempts. When individual females were enclosed with an egg-loaded male and an unloaded male, they mated equally often with both males, although the loaded males courted more. In addition, when only successful males were used, females mated equally often with the loaded male and the unloaded male irrespective of sex ratio. Male choice rather than female choice affected mating frequency when sex ratio was equal. Therefore, females do not select the male by the eggs he carries, but successful males may receive many eggs due to egg dumping by alien females while they mate or as a consequence of mate guarding.     

Multiple Mating Increases Fecundity, Fertility and Relative Clutch Mass in the Female Leopard Gecko (Eublepharis macularius)

Females across many taxa may mate with several males or mate more than once with the same male within one reproductive event. Although many researchers have discussed the effects of multiple mating on reproductive success of females, few studies have attempted to disentangle whether the reproductive success of females differs with respect to whether females mate with multiple males or mate more than once with one male. In this study, we hypothesized that female leopard geckos (Eublepharis macularius) increase aspects of their reproductive success, such as fecundity, fertility and relative clutch mass, by mating more than once within one reproductive event, either by mating repeatedly with the same male or multiply mating with different males. We controlled for the potentially confounding variables of mating frequency and mate number by allowing females to mate once with one male, twice with the same male, or twice with two different males. We found that females that mated with more than one male laid more clutches, exhibited increased egg fertility and invested more in clutches relative to females that mated only once with one male, whereas females that mated twice to the same male were intermediate for these variables. Thus, reproductive success is higher among female leopard geckos that mated with more than one male compared to female leopard geckos that mated only once.     

Females of the Cellar Spider Discriminate Against Previous Mates

Mate choice for novel partners should evolve when remating with males of varying genetic quality provides females with fitness‐enhancing benefits. We investigated sequential mate choice for same or novel mating partners in females of the cellar spider Pholcus phalangioides (Pholcidae) to understand what drives female remating in this system. Pholcus phalangioides females are moderately polyandrous and show reluctance to remating, but double‐mated females benefit from a higher oviposition probability compared to single‐mated females. We exposed mated females to either their former (same male) or a novel mating partner and assessed mating success together with courtship and copulatory behaviours in both sexes. We found clear evidence for mate discrimination: females experienced three‐fold higher remating probabilities with novel males, being more often aggressive towards former males and accepting novel males faster in the second than in the first mating trial. The preference for novel males suggests that remating is driven by benefits derived from multiple partners. The low remating rates and the strong last male sperm precedence in this system suggest that mating with novel partners that represent alternative genotypes may be a means for selecting against a former mate of lower quality.     

Female mate choice and mating costs in the polyandrous butterflyPieris napi (Lepidoptera: Pieridae)

Males of the green-veined white butterfly (Pieris napi L.) transfer large ejaculates that represent on average 15% of their body mass when mating for a first time. Shortly after mating a male is able to transfer only a small ejaculate when mating a second time. Male ejaculate production plays a crucial role in the mating system ofP. napi because females use male-derived nutrients for egg production and somatic maintenance. Here we study how timing of female rematings and copulation duration are influenced by the mating history of their mates and, also, study if females exert mate choice to minimize their mating costs. Mating with a recently mated male increased female mating costs by increasing time in copula and mating frequency. Virgin females that mated with virgin males remated after an average of 6 days, whereas virgin females that mated with recently mated males remated after an average of 2 days. Moreover, copulations involving recently mated males lasted on average almost 7 h, whereas copulations involving virgin males lasted on average 2 h. Recently mated males were eager to remate, in spite of the fact that the size of the ejaculate they transfer is small and that they remain in copula for a long time. Hence it seems that males are more successful in the sexual conflict over mating decisions and that females do not minimize mating costs by choosing to mate preferentially with virgin males.     

Context‐ and State‐Dependent Male Mate Choice in a Sexually Cannibalistic Spider

High male mating investment may favor selection on male mate choice particularly if females vary in quality. Terminal investment strategies constitute a maximal mating effort and have evolved independently in the absence of paternal investment in several spider taxa including the genus Argiope. To test for male mate preferences in the above context, we used the sexually cannibalistic spider A. bruennichi. We varied male state (mating status and post‐maturation age) as well as the competitive context and quantified male mate choice decisions between females of different states and developmental stages in binary choice tests. We found an overall adaptive preference for the virgin against the mated female regardless of male mating state. Furthermore, we demonstrated that older males paid more attention to female fecundity‐related traits than to mating status. In a second set of experiments, we offered males a choice between a virgin and a subadult female and varied the competitive context which had no effect on male decisions. Curiously, a preference for the virgin adult female was only apparent after exclusion of females that matured <3 d prior to the test. Repeated tests of males supported the hypothesis that males do not distinguish between a freshly matured virgin female and a subadult female. Our results show that male spiders execute mate choice based on information collected from female silk strands and that they integrate their own state into mating decisions.     

FEMALES RECEIVE A LIFE-SPAN BENEFIT FROM MALE EJACULATES IN A FIELD CRICKET

Abstract.— Mating has been found to be costly for females of some species because of toxic products that males transfer to females in their seminal fluid. Such mating costs seem paradoxical, particularly for species in which females mate more frequently than is necessary to fertilize their eggs. Indeed, some studies suggest that females may benefit from mating more frequently. The effect of male ejaculates on female life span and lifetime fecundity was experimentally tested in the variable field cricket, Gryllus lineaticeps. In field crickets, females will mate repeatedly with a given male and mate with multiple males. Females that were experimentally mated either repeatedly or multiply lived more than 32% longer than singly mated females. In addition, multiply mated females produced 98% more eggs than singly mated females. Because females received only sperm and seminal fluid from males in the experimental matings, these life‐span and fecundity benefits may result from beneficial seminal fluid products that males transfer to females during mating. Mating benefits rather than mating costs may be common in many animals, particularly in species where female mate choice has a larger effect on male reproductive success than does the outcome of sperm competition.     

MATING BEHAVIOR OF THE CAT FLEA, CTENOCEPHALIDES FELZS BOUCHE(SIPHONAPTERA:PULICIDAE) AND MALE RESPONSE TO FEMALE EXTRACT ON AN ARTIFICIAL FEEDING SYSTEM

Abstract  The mating behavior of cat flea, Ctenocepholides felis (Bouche) was studied on an artificial feeding device. Male and female can mate repeatedly with same partner or Merent ones. In the situation of male: female ratio of 1 :5, each mating lasted an average of 6.6 min, with a mean interval between matings at 2.5 min., compared to 11. 1 min and 12.1 min respectively in a cell with 5 males and 1 female. As many as 48 mating events were observed for one male during an 8 h period. One female mated 27 times in 7 h with 5 males in the same cell. Newly emerged males and females can not mate before blood meal and about 24 h blood feeding is rewuired for successful mating. Newly emerged males can not mate with fed females (fed for 48 h), but fed males can mate with newly emerged females who are feeding the blood. Significantly more male contacts and male-male mating attempts were observed after the paper treated with female extract was introduced into the cell. The paper contacts and mating attempts were 16.75–32.25 times and 15.75–31.38 times, respectively, on average during a period of 20 min when different doses (FE) of extract were provided.     

斜纹夜蛾的性选择行为

【目的】为了解斜纹夜蛾Spodoptera litura Fabricius体重、日龄、交配经历及形态特征对其性选择行为的影响。【方法】本实验通过标记成虫后,采用观察记录的方法对其进行探究。【结果】斜纹夜蛾雌虫的体重对雄虫的性选择影响比较明显,体重较大雄虫优先选择体重较小的雌虫(71.43%),而体重较小雄虫喜欢选择体重较大的雌虫(72.00%)。体重较大和体重较小的雄虫都能获得体重较大雌虫的交配选择,但是体重较大者被选择的机会更大(70.00%),体重较小的雄虫不能获得体重较小雌虫的选择。雄虫仅选择1日龄的雌虫,而雌虫偏向选择3日龄和5日龄雄虫。交配经历影响斜纹夜蛾的性选择,未交配的雄虫优先选择未交配的雌虫(86.67%),但未交配的雌虫则优先选择已交配的雄虫(66.67%)。雄虫的形态特征(体长、翅展、腹长、复眼间距和触角长)对雌虫性选择有较明显的影响,但雌虫的形态特征除翅展的大小外,其体长、腹长、复眼间距和触角长等形态特征在雄虫选择进行交配中的作用不大。【结论】体重、日龄、交配经历及形态特征都能不同程度影响斜纹夜蛾的性选择行为。     

Mating Behavior of Trissolcus basalis (Wollaston) (Hymenoptera: Scelionidae): Potential for Outbreeding in a Predominantly Inbreeding Species

The mating behavior of the quasi-gregarious egg parasitoid Trissolcus basalis (Wollaston) was investigated under field conditions. Trissolcus basalis has female-biased sex ratios and is a protandrous species, with males emerging 1–2 days before females. Males competed aggressively for control of the egg mass, with one male assuming dominance and control of the egg mass, although changes in dominance occurred at least once on each egg mass observed. Typical mating behavior involved the dominant male mating his sisters immediately upon their emergence from the egg mass. These behaviors are characteristic of an inbreeding species that manifests local mate competition. However, several aspects of the mating behavior of T. basalis are inconsistent with that of an inbreeding species. Over 18% of emerging females were not mated by the dominant male upon emergence, 13% of females were not observed to be mated at all and may have left their natal site as virgins, 25% of females were mated multiple times and sometimes by multiple males, females remained near the natal site for up to several hours after emergence before emigrating, and males dispersed away from the natal site during female emergence. Trissolcus basalis may be a predominantly inbreeding species but its emergence and mating behavior suggest that low-frequency outbreeding is also likely to occur.     

Revisiting telegony: offspring inherit an acquired characteristic of their mother's previous mate

Newly discovered non‐genetic mechanisms break the link between genes and inheritance, thereby also raising the possibility that previous mating partners could influence traits in offspring sired by subsequent males that mate with the same female (‘telegony’). In the fly Telostylinus angusticollis, males transmit their environmentally acquired condition via paternal effects on offspring body size. We manipulated male condition, and mated females to two males in high or low condition in a fully crossed design. Although the second male sired a large majority of offspring, offspring body size was influenced by the condition of the first male. This effect was not observed when females were exposed to the first male without mating, implicating semen‐mediated effects rather than female differential allocation based on pre‐mating assessment of male quality. Our results reveal a novel type of transgenerational effect with potential implications for the evolution of reproductive strategies.     

Demonstration of Multiple Mating in Heterodera glycines with Biochemical Markers

Controlled crosses of Heterodera glycines were carried out by placing one o r more virgin females of known esterase phenotype on an agar plate and adding, at various time intervals, one or more males of different esterase phenotypes. Progeny (second-stage juveniles) of such crosses were propagated on soybeans, and 30 days later young females were subjected to electrophoretic analysis to determine their esterase phenotype. Esterase phenotypes that represented the heterozygous state of the maternal and paternal genomes confirmed the hybrid nature of the progeny and identified their male parent. When each of 74 females was given the opportunity to mate successively with two males of different esterase phenotypes, 43 mated with a single male and 31 mated with both males. One female mated with three males, i.e., with a male of its own population (sib mating) and the two males provided for the cross. Inseminated females could mate for a second time soon after, or as late as 24 hours after, their first mating. When single males were given the opportunity to mate with many females, about equal numbers of them inseminated zero, one, two, or three females. In greenhouse tests, 12 females were given the opportunity to mate with many males of three different esterase phenotypes. Two females mated with one and possibly more males of the same phenotype, and 10 females mated with males of two different esterase phenotypes. In conclusion, multiple mating appears to be a common behavior of males and females of H. glycines.     

Female mate preference in an invasive phytopathogen vector: how learning may influence mate choice and fecundity in Diaphorina citri

In some arthropods, females learn in the context of reproduction to refine their mate choices and avoid males displaying traits associated with impotency. Previous studies have shown that males of the Asian citrus psyllid, Diaphorina citriKuwayama (Hemiptera: Psyllidae), associate female odor with copulatory rewards. However, it is unclear whether females similarly learn about male traits. We compared mate choice in females previously mated to either blue or orange males and found that females may associate male color with reproductive success, and avoided blue males after previous experience. Orange males mated more frequently than blue males and appeared to be more sexually aggressive in their mating attempts. In addition, females mated to orange males laid approximately twice as many eggs as those mated to blue males. We dissected male psyllids and measured the size of their reproductive organs to determine whether abdominal color was associated with reproductive development. Our morphometric analysis indicated that blue males may not be physiologically immature compared with orange males. Rather, blue males displayed larger testes and seminal vesicles than orange males, suggesting that differences in reproductive output may be behavioral in nature. Based on our data, we suggest that females learn about the appearance and mating behaviors of blue and orange males from early mating experiences, and subsequently avoid blue males in future matings. Although the roles of blue males within a population are unclear, it is possible that blue morphs may specialize in other functions such as dispersal.     

猫蚤的交配习性及雄蚤对雌蚤提取物的反应

在人工饲喂系统上研究了猫蚤的交配习性及雄蚤对雌蚤化学提取物的反应,结果表明,当5雌1雄在饲养盒内时,该雄虫可与其他雌虫进行多次交配,连续8小时内交配达48次,交配时间平均持续6．6分钟,两次交配的间隔时间平均为2．5分钟,当1雌5雄时,交配时间平均持续11．1分钟,交配间隔时间为12．1分钟,连续7小时内,该雌虫与雄虫交配27次,新羽化的雌雄虫吸血前不能交配,当把用雌虫提取物处理过的黑色滤纸片放进只有雄虫的饲养盒时,雄虫接触纸片的次数及雄－雄交配企图明显增加。     

Mate guarding behaviour in the supralittoral isopod,Ligia dentipes (Oniscidea) from the Andaman and Nicobar Islands

Precopulatory mate guarding is a characteristic feature in the mating behaviour of many Malacostraca, and a necessary prerequisite for those species in which female receptivity for males is restricted to a short period of time after the pubertal/reproductive moult. This study deals with the pre-mate guarding behaviour of the semi-terrestrial isopod Ligia dentipes living in the crevices of coral boulders and rocks in the supralittoral region of the Andaman Islands. As in other isopods, moulting in L. dentipes is biphasic, in which the posterior body part invariably moults first. The guarding male aids the female partner in the removal of the moulted exoskeleton. Mating occurs immediately after the posterior body exuviates. The male leaves the female after copulation and goes in search of another receptive female, demonstrating a polygamous mating system in these isopods. The mated females also re-mate with several other males without mate guarding. Females that had mated several times produced more young, compared to females mated only once in the laboratory. Female receptivity ceases following moulting of the anterior half. Intrasexual encounters among males lead to the large males acquiring receptive females. This study reveals interesting deviations from the general pattern of mate guarding already reported in other isopods and decapods. The evolutionary and ecological significances of mate guarding, intrasexual and intersexual conflicts, found in these semi-terrestrial isopods, are discussed.     

Effects of female and male size on female mating and remating decisions in a bean beetle

The body sizes of individuals of the choosing and chosen sexes in a mate choice may affect sequential mating of females. We examined the effects of the body sizes of females and their mates on attributes of female first mating, and the effects of body sizes of females and their previous and potential future mates on female remating in the adzuki bean beetle, Callosobruchus chinensis. Large- and small-sized adults were derived from larvae reared under conditions of low and high density in a bean, respectively. The speed of first mating of large females was not affected by the size of courting males, whereas small females initiated mating more rapidly when courted by small males. The remating probability of large females was not affected by first male size, whereas small females that mated first with smaller males were more likely to remate. These data suggest that pre- and post-copulatory female choices for male size depend on the female’s size, and the small females might be more willing to copulate with smaller males but prefer larger males to sire their offspring after copulation. A possible explanation for this preference is that small females may suffer greater harm from copulating with larger males.