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.     

Effect of Body Weight on Reproductive Performance in Cnephasia jactatana (Lepidoptera: Tortricidae)

The larger-the-better theory predicts that fitness is positively linearly associated with body size or weight. We used the kiwifruit pest, Cnephasia jactatana Walker, to test whether larger insects perform better reproductively. We divided our insect population into three weight groups: light, average, and heavy, and assessed the reproductive performance of 9 breeding treatments (3 male weights × 3 female weights). Female fecundity is positively correlated with female body weight in low and average weight groups. There is no such correlation in the heavy weight group, suggesting that further weight increase has no fitness gain for females. The positive linear relationship between fertility and female weight in all weight groups may be attributed to the fact that permanently paired heavy females are more likely to remate, gaining more sperm and thus higher fertility. However, the previous study also indicates that mated females are less likely to be mated again when males have a choice. Therefore, in the natural environment the realized fertility may still follow an asymptotical pattern similar to the fecundity in relation to female weight. Males' beneficial effect on female reproductive outputs increases linearly with their body weight in all weight groups, indicating that male reproductive performance fits the larger-the-better theory. Fertility rate is not affected by the body weight of either sex. Heavy and average females lay eggs earlier and have higher daily fecundity and fertility than light females. Females of all weight groups have similar oviposition and postoviposition periods. Male weight and female–male weight interactions have no effect on oviposition parameters.     

Effect of mating delay on the reproductive performance of Cnephasia jactatana (Lepidoptera: Tortricidae)

The leafroller species, Cnephasia jactatana Walker, is an important pest of kiwifruit in New Zealand. The effect of mating delay on its reproductive performance was investigated in the laboratory to provide information for the development of pheromonal pest control measures such as mating disruption. Reproductive performance of both sexes is adversely affected by mating delay. Females are more severely affected by mating delay than males in terms of reproductive potential. Delaying mating in females for 3 and 4 d reduced the reproductive potential by 29 and 88%, respectively. It is suggested that mating disruption may have potential for the control of this species.     

Life cycle changes during 12 successive generations of laboratory colonisation of the leafroller Cnephasia jactatana (Walker) (Lepidoptera: Tortricidae) on artificial diet

Abstract

Close monitoring of the lepidopteran leafroller Cnephasia jactatana under laboratory colonisation revealed few distinct effects of successive rearing on artificial diet on the life cycle. The second laboratory generation had a prolonged development time and altered sex synchronism in pupation and eclosion patterns. Some deleterious changes were observed in later generations, including decreases in fertility, egg hatch and sperm motility, failure of mating adults to separate, and pupal and adult malformations. These changes were not adaptive, but were due to incompatibility with the general purpose diet (GPD) used; they were absent under sub-colonisation on a sheepnut-bean based diet (SBD). Success in the laboratory colonisation of C. jactatana is attributed to a random mating protocol, choice of environmental conditions representing the wild habitat, and a rapid rate of population growth.     

Physiological factors regulating polyandry in Lobesia botrana (Lepidoptera: Tortricidae)

Abstract. The effects of several physiological factors related to female multiple mating in the monandrous Lobesia botrana Denis and Schiffermuller (Lepidoptera: Tortricidae) were studied under laboratory conditions. Polyandry was assessed observing the induction of re-calling in previously once-mated females. Female age at first mating had no effect on induction of re-calling during practically the whole of the female lifetime, but in older females it was significantly lower. The percentage of re-calling was negatively correlated with the volume of the spermatophore received, ranging from ≅ 23% with the largest spermatophores to ≅ 75% with the smallest ones. Furthermore, the smaller the spermatophore volume, the earlier the re-calling was induced, significantly reducing die female refractory period after the first mating. Heavy females showed a significantly higher rate of re-calling (52.8%) than light ones (37.0%), but no differences were observed when females received only small spermatophores. This finding was explained by die allometric relationship between me female weight and the size of its reproductive system that affects relative replenishment by the spermatophore. Females with a supply of water displayed a significantly higher rate of re-calling (41.2%) than control females (22.8%), highlighting the effect of adult feeding (or drinking) status on the re-calling behaviour. The short-distance presence of virgin males with once-mated females promoted a re-calling rate (and subsequent matings) close to 37%, significantly higher than that of isolated females (20%). It is concluded mat re-calling and polyandry in L. botrana are controlled, as expected, by a number of mating-derived stimuli, but also to a great extent by other physiological stimuli unrelated to mating. The reproductive strategies in relation to polyandry and the mechanisms controlling female sexual inhibition are discussed.     

Courtship Roles of Male and Female European Earwigs, Forficula auricularia L. (Dermaptera: Forficulidae), and Sexual Use of Forceps

Detailed observations of the courtship and mating of the European earwig Forficula auricularia revealed a complex of sexual behaviors for both males and females. A sequential analysis of the transition frequencies between male preceding-following behaviors showed that courtship is intricate and nonstereotyped. The significance of the male forceps was demonstrated by their use in early courtship with displays and later use as a tactile stimulus for the female. A study of males from which the forceps had been removed showed no mating by altered males. Male forcep length was bimodally distributed and positively allometric, while female forcep length was normally distributed. Males with longer forceps did not have a mating advantage. Receptive females were behaviorally active during courtship. The possible evolutionary development of the sexual dimorphism of the earwig is discussed.     

Male Reproductive Success in a Promiscuous Armoured Catfish Corydoras Aeneus (Callichthyidae)

Among a variety of fish mating systems, promiscuity with random-mating seems to be most prevalent. However, detailed studies of promiscuity have been rare due partly to the peculiar difficulty in examination of male mating and reproductive success in the random mating. Females of the armoured catfish Corydoras aeneus (no sexual dimorphism other than size of males > females) spawn 10–20 egg-clutches with multiple males at a time, but an entire egg clutch is inseminated by sperm of a single male. We studied mating system of this fish in aquarium. Males had neither mating territories nor monopolized females, never being aggressive against rival males. Evidence of female preference for certain male traits including size was not detected. Females mated a male in proportion to his relative courtship frequency among males. Courtship frequency was not related to male size, and male mating success was not different between small and large males. Clutch size and insemination rate were different neither between small and large males nor between frequently and less frequently courting males. Thus, the male reproductive success will not be related to the male size, but directly to courtship frequency, indicating the random mating in this fish. There seemed to be fecundity advantage with size in female, and the consequent sexual difference in energy allocation will be responsible to the sexual dimorphism. We also discuss the low male-GSI in this promiscuous fish in which sperm competition hardly occurred.     

Effect of Mating Frequency on Female Fitness in Caloglyphus Berlesei (Astigmata: Acaridae)

We studied the effect of mating frequency on female longevity and fecundity in the mite Caloglyphus berlesei. We tested the hypothesis that high promiscuity is selected for in this species because females receive nutrients during copulation. Females were constantly exposed to either one or four males and fed either a standard or poor diet. The prediction that frequent mating benefits females was not confirmed. On the contrary, females kept with four males had significantly lower longevity on both diets and on the standard diet they also had decreased fecundity compared to females exposed to one male. On the poor diet the number of males had no significant effect on fecundity. Thus, increased mating frequency had a detrimental effect on female fitness.     

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.     

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.     

Mating Behavior of Cephalonomia tarsalis (Ashmead) (Hymenoptera: Bethylidae) and the Effect of Female Mating Frequency on Offspring Production

The courtship behavior of Cephalonomia tarsalis, a solitary semiectoparasitoid of Oryzaephilus surinamensis, was investigated in the laboratory. Courtship behavior includes a series of stereotypic movements. Males play the most active role, executing the majority of courtship action, and females respond with relatively limited observable behaviors. Males typically keep antennae still during encounters with females prior to mounting, which may be correlated with recognition of the female's sexual status. After mounting, males display a series of movements on females, such as antennae touching female's antennae, antennae or mouth touching female's head or thorax, and walking around on female, which may serve to stimulate females towards increased receptivity. Females signal receptivity by assuming a stereotypical posture of remaining stationary, with head down, and antennae still in front of the body. The male then inserts his aedeagus and the pair copulates. After an average of 40.4 s of copulation, females signal the end of copulation by waving the antennae and moving away from the copulation site. Males continue copulating for a short time after females start moving but dismount soon thereafter. After dismounting, the two wasps move away from each other immediately, and they typically begin grooming. Neither males nor females exhibit mating preference based on mate's mating status in both choice and no-choice tests. The male is polygynous and the mated female can mate multiple times within the first 3 days after starting oviposition. However, female mating frequency does not affect the production of female progeny.     

不同波长LED光源对韭菜迟眼蕈蚊生殖行为的影响

【目的】明确不同波长的LED光源对韭菜迟眼蕈蚊Bradysia odoriphaga Yang et Zhang求偶、交配及繁殖等生殖行为的影响。【方法】采用红(625~630 nm)、橙(600~605 nm)、黄(590~595nm)、绿(525~530 nm)、蓝(455~460 nm)和白(6 000~6 500 k)6种LED光源在韭菜迟眼蕈蚊成虫交配期进行照光处理,观察统计其求偶和交配行为以及单雌产卵量、卵孵化情况和有效后代数量。【结果】韭菜迟眼蕈蚊成虫求偶前期时长在橙光下最长,为28.48 min。求偶率在蓝光下最高,为86%;橙光下最低,为48%。交配期时长在蓝光下最长,为4.59 min;橙光下较短,为4.23 min。单雌产卵量在各波长光源下与对照均无显著差异。卵孵化率在蓝光下最低,仅为43.41%。有效后代数量在蓝光下最低,仅为27.00头;橙光下次之,为43.40头。【结论】LED光源的波长可影响韭菜迟眼蕈蚊的生殖行为,其中橙光(600~605 nm)不利于其求偶、交配和繁殖;蓝光(455~460nm)虽有利于其求偶和交配,但明显抑制其繁殖。     

Male age affects female mating preference but not fitness in the monandrous moth Dendrolimus punctatus Walker (Lepidoptera: Lasiocampidae)

It is widely accepted that male age can influence female mating preference and subsequent fitness consequences in many polyandrous species, yet this is seldom investigated in monandrous species. In the present study, we use the monandrous pine moth Dendrolimus punctatus to examine the effects of male age on female mating preference and future reproductive potential. In multiple male trials, when permitted free mating from an aggregation consisting of virgin males aged 0 (young), 2 (middle-aged) and 4 (old) days, virgin females preferentially mate with young and middle-aged males, although mating latency and mating duration are independent of male age. In single male trials, when virgin females are randomly assigned single virgin males of known age, a negative correlation is found between mating success and male age in this species. However, we find that male age also has no effect on mating latency and mating duration. Further fitness analysis reveals that females do not receive benefits in terms of oviposition period, total egg production, average daily egg production, percentage of egg hatching, longevity, expected reproduction and relative expected reproduction from mating with young and middle-aged males compared with mating with old males. The results of the present study are the first demonstrate that females mated preferentially with younger males but gain no apparent fitness benefits in a monandrous moth species.     

Influence of Female Copulation Calls on Male Sexual Behavior in Captive Macaca fascicularis

We investigated the function of copulation calls—vocalizations by females during mating—in captive groups of long-tailed macaques. We tested predictions of the contest-competition, sperm competition, synchronized orgasms, mate again, alpha-male notification and graded-signal hypotheses. We observed 371 copulations of 36 females wherein the presence or absence of a copulation call was clear. Females call equally often with different males and shortly after ejaculation. Copulation calls occurred equally with copulations with and without ejaculation. Calls did not incite disruptions of the mating. Following calls females mated again, more often than expected, with their mating partner. Both pregnant and fertile females uttered copulation calls. Two females conceived and mated mainly with the alpha male then. We conclude that copulation calls do not incite male contest competition for sexual access to females and that it is unlikely that calls synchronize male and female orgasms. Several hypotheses remain plausible, but not all predictions are borne out unequivocably. This alerts us to the possibility that the calls could have multiple beneficial effects; natural selection might strike a compromise among functions. Investigation of the mate again, sperm competition and alpha-male notification hypotheses, and of hypotheses not tested in our study concerning female breeding overlap and female-female agonism, is required.     

Experimental Studies on Male and Female Reproductive Success: Effects of Variation in Spur Length and Pollinator Activity on Platanthera mandarinorum ssp. hachijoensis (Orchidaceae)

Abstract Field experiments on an orchid, Platanthera mandarinorum ssp. hachijoensis , were carried out to investigate the effects of variations in spur (nectary) length and pollinator activity on reproductive success (RS) of individual plants. Experiments comprised two kinds of treatments: spur shortening and bagging to restrict pollinator activity. Plants with a natural spur lengths range show nearly equal RS, whereas plants with shortened spurs had decreased RS proportional to spur length reduction. Pollinaria attachment (a measure of male RS) to the pollinators seems to demand stricter morphological correspondence than pollen receipt (female RS). Decrease of male and female RSs in spur-treatments was smaller in the case of high pollinator activity than low pollinator activity. Results of the bagging experiments indicated that female RS was greater than male RS in cases of high pollen carryover. These facts suggest that (1) fecundity selection operates more intensely on both male and female functions in the case of low pollinator activity and more intensely on the male function in the case of high pollen carryover, and (2) individuals with different spur lengths in natural populations have nearly equal probabilities of RS after excluding the extreme variants through the reduction of male RS.     

榆木蠹蛾生殖行为及性信息素产生与释放节律

通过室内饲养与野外观察榆木蠹蛾Holcocerus vicarius (Walker)成虫的羽化、交尾、产卵行为,触角电位反应测定处女雌蛾性信息素产生与释放节律,旨在为榆木蠹蛾性信息素的鉴定和合成奠定基础。结果表明：榆木蠹蛾羽化行为全天可见,主要集中在15:00－19:00。成虫羽化当日即可交尾,21:30－0:30进行婚飞和交尾,交尾高峰出现在晚23:00左右,光期未见交尾。随着日龄的增加,召唤时间前移并且延长,2～3日龄处女雌蛾召唤时间早于1日龄雌蛾,交尾时间较短;雌蛾在羽化1 d后达到性成熟,2日龄雌蛾交尾百分率最高,达41.8%。雌蛾将产卵器伸出寻找缝隙处产卵,分多处产卵,雌虫最高产卵量达720粒,最低产卵量为105粒,卵期为12～22 d不等,孵化率为72%～88%。羽化当晚的雌蛾体内性信息素含量较低,第2天最高,以后逐日下降;2日龄榆木蠹蛾处女雌蛾性信息素的产生量从晚17:00起逐渐增加, 21:30－22:00时最高, 22:00后逐渐减小。雄蛾触角电位反应在22:30最强。21:30－23:00是雌蛾产生和释放性信息素的高峰期。榆木蠹蛾的羽化、交尾存在一定的时辰节律,通过处女雌蛾的野外诱集试验证实了性信息素释放与交配行为在时辰节律上的一致性。     

Mating compatibility among populations of codling moth Cydia pomonella Linnaeus (Lepidoptera: Tortricidae) from different geographic origins

The codling moth Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) is a serious pest of pome fruit worldwide and the sterile insect technique (SIT) provides an environmentally acceptable approach for its control. As the pest is present in both the southern and northern hemispheres it would be possible for a rearing facility in the northern hemisphere to supply sterile moths to an SIT programme in the southern hemisphere during the northern winter and vice versa. This could greatly improve the economics of moth production and the running costs of rearing facilities. However in order to develop this concept, it is important to assess if populations of codling moth from different geographical regions share mating compatibility. Twelve different laboratory and field populations from both hemispheres were sampled and field cage bisexual mating compatibility tests were carried out between selected combinations. The index of sexual isolation (ISI) and the female and male relative performance index (FRPI and MRPI, respectively) were calculated for each mating combination. In only two of the combinations was there a slight but significant deviation from random mating. There were also some significant differences in mating duration between the homotypic matings and the duration of a particular homotypic mating seemed to depend on the origin of the other population in the cage. It was concluded that there exist no barriers to mating between populations of codling moth from many parts of the world and that it would be feasible for sterile moths to be shipped from one rearing facility to SIT programmes in other parts of the world.     

Spermatophore feeding and mating behaviour in praying mantids (Mantodea: Liturgusidae)

In a number of insects, males transfer sperm to females via an externally attached spermatophore, which females subsequently remove and consume. Here I report the first study of spermatophore feeding in a praying mantid. While studies of praying mantid mating behaviour have largely focused on sexual cannibalism, this behaviour is not known in the genus Ciulfina . The general patterns of mating behaviour and spermatophore feeding are described for four species: Ciulfina rentzi , Ciulfina klassi , Ciulfina biseriata and Ciulfina baldersoni . Copulation duration and postcopulatory spermatophore attachment duration were found to vary both inter- and intraspecifically. Ciulfina rentzi exhibited a considerably longer mean copulation duration and a considerably shorter mean postcopulatory spermatophore attachment duration than the other Ciulfina species. Smaller males copulated for longer durations in C. rentzi and C. klassi . For C. baldersoni , both copulation duration and postcopulatory spermatophore attachment duration increased with female mass. The genus Ciulfina is highlighted as an intriguing new system in which to test hypotheses surrounding the function of spermatophore feeding and the significance of copulation duration.