铃虫交配过程中精子的转移

统计了棉铃虫交配前后贮精囊、复射精管和精包内真核精子(束)的数量,以此来验证棉铃虫交配过程中是否存在精子回流现象。结果表明,棉铃虫在交配时将复射精管内的精子全部转移至雌蛾体内,不存在精子回流现象。     

优雅蝈螽与暗褐蝈螽精子束的显微观察

本文应用微分干涉相衬法对优雅蝈螽Ｇampsocleis gratiosa Brunner von Wattenwyl和暗褐蝈螽G. sedakovii （Fischer von Waldheim） 雄性精巢管基部、输精管、贮精囊和精包,及雌性受精囊中精子束的形态变化进行了观察,对探讨螽斯近缘种的生殖隔离机制和生殖生物学具有重要意义.结果表明：这两种蝈螽的精子束通过精包转移到雌性受精囊后,精子束的形态发生了显著变化.精巢管基部的精子为游离的单个精子;输精管、贮精囊和精包中精子成束排列形成较分散的精子束,精子束头部包裹有粘液帽;雌性受精囊中的精子束的精子呈羽状排列,精子的头部汇集在中央轴上.两种蝈螽精子束形态差异不显著.     

交配状态对雄性短翅鸣螽(Gampsocleis gratiosa)交配投资的影响

雄性短翅鸣螽在交配过程中具有较大的交配投资, 包括营养投资(精包)和遗传投资(精子)两部分. 考查在交配过程中雌雄交配状态的4种组合处理对雄性释放出的精包与其组分以及精子数量的影响发现: 精包和精护鲜重与雄性体重成正相关关系, 而与雌性体重不相关, 这说明雄性营养投资强度取决于雄性质量而非雌性质量, 该结果支持父方投资假说. 精包及其精护、精荚鲜重在4种交配状态组合条件下没有差异, 而精子数目在雄性第二次交配过程中比第一次显著降低; 雄性在与已交配雌虫配对时, 没有显著提高繁殖投资, 该结果不支持精子竞争假说.     

新疆北部棉铃虫寄主来源与转基因棉区庇护所评估

转Bt基因抗虫棉长期大规模种植后,棉铃虫对其存在抗性风险,庇护所是延缓抗性上升的策略之一。但在新疆北部转基因棉区,庇护所提供敏感棉铃虫的生态功能尚未见评估。2013年5—9月期间在新疆北部石河子地区147团、121团利用棉田边缘的智能测报灯收集棉铃虫成虫,应用碳稳定同位素技术从群体水平(混合翅膀)分析虫源性质,从个体水平(雌蛾翅膀和对应精包)确定交配类型;同时通过解剖雌性棉铃虫体内的精包数量评估交配频率。结果表明:来源于C4植物的棉铃虫主要出现在5月下旬和8—9月期间,比例占到50%左右;6—7月接近100%的棉铃虫来自于C3植物上;经测定不同寄主来源棉铃虫的有效交配比例为10%左右;两个地方的棉铃虫交配频率一般在0.9—2.1次,但121团的第一代和第二代均高于147团。玉米是新疆北部地区重要的庇护所,但C3和C4来源棉铃虫同存的时间比较短,有效交配比例相对比较低,影响了庇护所的抗性稀释能力。在转基因棉区的抗性管理中不仅要考虑庇护所提供敏感棉铃虫数量大小,同时需要考虑有效交配比率,这将有利深刻理解庇护所生态功能。     

麦蛾交配过程中精包的形成

自Callahan(1958)首先用系列形态观察研究棉铃虫精包形成后,这一方法即为众多学者采用,成为研究昆虫情包形成的经典方法。作者在实际工作中,深感此法不仅工作量大,而且所见系列形态并非同一精包的连续变化过程,于是从1976年起选用麦蛾[(Sitotroga cerealella(Olivier)]作实验材料,探索直接观察精包形成过程的研究方法,至今已成功地建立了一套活体直接观察方法,从每一对材料都可看到交配授精的全过程,证实精包的形成由雄蛾独自完成,而且精包颈和精包体形成的时间、部位、成分和过程都完全不同。本文报告两种活体实验方法及其观察结果。     

昆虫雄性附腺功能蛋白研究进展

昆虫雄性附腺蛋白是精液蛋白的主要来源,对雌雄虫生殖过程具有重要生理功能,按功能可分为精包结构蛋白和功能蛋白两类。精包结构蛋白参与精包的形成;功能蛋白在交配过程中随精子一起转移到雌虫体内,导致雌虫行为和生理的深刻变化,如降低雌虫再交配率、提高产卵量、促进精子转移、储存和竞争等。随着对昆虫雄性附腺功能蛋白研究的深入,特别对果蝇附腺功能蛋白的详细研究,从分子水平上阐述蛋白质序列与功能的关系,明确其作用机制,可为进一步阐明昆虫生殖和进化机制等提供新依据。     

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。     

优雅蝈螽雌虫性选择

优雅蝈螽雌虫在交配过程中接受雄虫分泌的精包,并且在交配后一段时间内把精包吃掉。精包对雌虫的生殖是必需的,体重大的雄性分泌的精包较大。把2只鸣叫的且体重不同的雄虫放在一起,雌虫会选择体重大的个体交配。     

三种粘虫的交配囊和精包

鳞翅目昆虫的交配授精,一般是以精包的方式进行的,即交配时雄虫将生殖系统各器官分泌物世注在雌虫交配囊内,形成一个含有精液的精包。塞在雌虫交配囊内的精包一般不被溶解,明显可辨。交配几次有几个精包。因此,可根据雌虫交配囊内的精包及数目判断交配及交配次数。 交配囊和精包的变异十分显著,不同种类有所不同,因此,可作为种类鉴别的依据。 我省常见粘虫种类有粘虫Leucania separata Wal-ker、白脉粘虫 Leucania venalba Moore和劳氏粘虫Leucania loreyi(Duponchel)三种。在调查研究中,三种粘虫常可发现,但往往不易区别其种类而发生错误,同时在预测粘虫发生规律及发生数量过程中,常常需要解剖观察雌虫交配及抱卵情况。为此,将这三种粘虫交配囊和精包的形态特征作扼要介绍,供参考。     

粘虫(Leucania separata Walker)交配的研究方法

一般鳞翅目昆虫雌雄成虫交配时,雄虫将一个含有精液的精包(spermatophore)射入雌虫交配囊内。[Petersen (1907),Norris(1932),Khalifa(1950),Srivastava(1957).Callahan and Chapin(1960)及何继龙(1963)等]。 因此,历来就有许多作者利用交配囊内精包的数目来判断鳞翅目昆虫交配次数及交配时期:Williams(1931,1941)对鳞翅目中许多种类精包的形态作了鉴定,并且认为雌体交配囊内有几个精包,可以说明重复交配几次。(1932),Schulrz(1921)根据解剖观察雌虫交配囊内的精包数,判断切根夜蛾雌     

Eupyrene sperm migrates to spermatheca after apyrene sperm in the swallowtail butterfly, Papilio xuthus L. (Lepidoptera: Papilionidae)

When swallowtail butterflies, Papilio xuthus, are mated by the hand-pairing method, both types of sperm, eupyrene and apyrene sperm, are transferred from the male to the spermatheca via the spermatophore in the bursa copulatrix. This mechanism is demonstrated by two different kinds of experiments. The first set of experiments employed interrupted copulation, and the second set was examination of the sperm in the spermatophore and spermatheca after the termination of copulation. The sperm was transferred 30 min after the start of copulation. The eupyrene sperm was still in the bundle; the number of the bundles ranged from 9 to 108 (mean, 42.7; n = 27). The bundles were gradually released after the completion of copulation, and the free eupyrene spermatozoa then remained in the spermatophore at least 2 h before migrating to the spermatheca. On the other hand, about 160 000 apyrene spermatozoa were transferred to the spermatophore and remained there for more than 1 h. We observed 11 000 apyrene spermatozoa in the spermatheca 12 h after the completion of copulation, but most of this type of sperm disappeared shortly thereafter. In contrast, the eupyrene sperm arrived in the spermatheca more than 1 day after the completion of copulation and remained there at least 1 week. Therefore, these findings suggest that apyrene sperm migrate from the spermatophore to the spermatheca earlier than eupyrene sperm. Accordingly, if females mated multiply, the time difference might avoid the mixing of sperm. In addition, the predominance of sperm from the last mating session may occur not in the bursa copulatrix but in the spermatheca. Received: January 7, 2000 / Accepted: May 24, 2000     

Dynamics of eupyrene and apyrene sperm storage in ovipositing females of the swallowtail butterfly Papilio xuthus (Lepidoptera: Papilionidae)

A male swallowtail butterfly, Papilio xuthus, transfers both eupyrene and apyrene sperm during copulation, both of which migrate to the spermatheca via the spermatophore in the bursa copulatrix of the female. Because the spermatheca seems to remain constant in size during the female lifespan, the excess sperm migration may cause the spermatheca to overflow. Approximately 9000 eupyrene and 265 000 apyrene spermatozoa were transferred during a single copulation, and approximately 1000 eupyrene and 1100 apyrene spermatozoa successfully arrived in the spermatheca. The number of both types of spermatozoon decreased in the spermatheca after the onset of oviposition, and no eupyrene spermatozoa were found by 7 days after copulation, partly due to insemination. The spermathecal gland leading from the distal end of the spermatheca was gradually filled by eupyrene spermatozoa. Although the function of the gland remains unclear, the final destination of the sperm is likely to be the gland.     

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.     

Effects of 20-hydroxyecdysone on sperm release from the testes of the Mediterranean flour moth,Anagasta kuehniella (Zeller)

Abdominal injection of 1 μg aqueous 20-hydroxyecdysone into Anagasta kuehniella, anytime prior to the initiation of sperm release from the testes, prevents the impending release of eupyrene sperm bundles. Apyrene sperm release is not prevented and there is complete recovery of eupyrene release by the following cycle 24 hr later. If 20-hydroxyecdysone is administered on consecutive days, no eupyrene bundles are released and although apryene sperm release continues, it diminishes with time. The effect of 20-hydroxyecdysone in preventing eupyrene release is dose dependent. Administration of decreasing 20-hydroxyecdysone dosages results in increasing numbers of eupyrene bundles released. When a single injection of 20-hydroxyecdysone is administered to isolated abdomens, recovery time of eupyrene sperm release is slower than in whole moths and total recovery is not seen even by 5 days after administration. Apyrene sperm release is also affected to a greater extent than in whole moths, and in some cases, no apyrene release was detected at all. Treatment with 20-hydroxyecdysone prevents cupyrene bundles from passing through the testicular basilar membrane into the vasa efferentia, thus causing a build up of bundles near the basilar membrane but no disintegration of these eupyrene sperm bundles.     

Motility and dynamics of eupyrene and apyrene sperm in the spermatheca of the monandrous swallowtail butterfly Byasa alcinous

Lepidopteran males produce two sperm types: nucleated eupyrene sperm and non‐nucleated apyrene sperm. Although apyrene sperm are infertile, both sperm types migrate from the spermatophore to the spermathecal after copulation. As a dominant adaptive explanation for migration of apyrene sperm in polyandrous species, the cheap filler hypothesis suggests that the presence of a large number of motile apyrene sperm in the spermatheca reduces female receptivity to re‐mating. However, apyrene sperm are also produced in males of the monandrous swallowtail butterfly Byasa alcinous Klug. To identify the role of apyrene sperm in these males, the present study examines the number of spermatozoa produced and transferred and the dynamics and motility of spermatozoa in the spermatheca for each type of sperm. Apyrene sperm represents approximatey 89% of the sperm produced and transferred, which is comparable to polyandrous species. Two‐day‐old males transfer approximately 17 000 eupyrene and 230 000 apyrene spermatozoa to a spermatophore; approximately 5000 eupyrene and 47 000 apyrene spermatozoa arrive at the spermatheca. Eight days after copulation, most eupyrene spermatozoa remain in the spermatheca and a quarter of them are still active. However, the number of apyrene spermatozoa decreases and those remaining lose their motility after the arriving at the spermatheca. Consequently, 8 days after copulation, no motile apyrene sperm are found. The high proportion of apyrene sperm in the spermatophore, as well as in sperm migration, suggests that the production and migration of apyrene sperm is not simply an evolutionary vestigial trait. The possible functions of apyrene sperm in monandrous species are discussed.     

Effect of constant light on male sterility in the cotton leafworm Spodoptera littoralis

Females of the cotton leafworm (Spodoptera littoralis) reared in long day conditions (LD 16:8 h) and mated to males kept throughout the whole period of development in continuous light (LL) oviposit very small numbers of mostly sterile eggs. It was found that in control males reared from the first larval instar in long day conditions there was a large accumulation of euperene sperm bundles in their testes on day 1 after imaginal moult. On day 10 of adult life the number of the sperm bundles was very small. In males kept from the first instar in continuous light there was also high number of sperm bundles on day 1 after imaginal moult but it did not decrease significantly on day 10 as was observed in controls. Transfer of different developmental stages of S. littoralis from long day conditions to continuous light resulted in a big difference in the density of eupyrene sperm bundles in their testes. In control insects reared through the whole of their development in long day conditions there was a significant decrease in the density of eupyrene sperm bundles on day 10 of adult life. By contrast, in males in continuous light, regardless of their developmental stage when transferred, there was either no change in density of sperm bundles in day 10 adults or there was a significant increase in comparison with day 1 adults. The highest density of eupyrene sperm bundles was observed in day 10 adults when they were transferred to continuous light shortly before moulting to the last instar (as day 4 larvae in the last stadium or day 1 pupae). Generally, the density of eupyrene sperm bundles on day 10 of adult development was about 2–2.5 times higher in males in continuous light then those under long day conditions. The results presented here indicate that the last larval instar and the pupa are the stages most sensitive to constant light treatment, which greatly reduces the amount of eupyrene sperm bundles released from the testes.     

Sperm maturation screening and the effect of ecdysone on sperm development of silkworm Bombyx mori

There are two sperm morphs of silkworm, the nucleated spermatozoa (eupyrene) and anucleated spermatozoa (apyrene). Eupyrene sperm cannot complete fertilization successfully without the apyrene sperm. Here a modified rapid and efficient method for sperm identification was developed, after 10 s of fixation in paraformaldehyde and 30 s of 4′6-diamidino-2-phenylindole (DAPI) or propidium Iodide (PI) staining, the sperm bundles can be detected easily using a fluorescence microscope. Sperm maturation process of silkworm from the fifth instar larvae to the adult was described with the above method, the precise time of earliest elongate apyrene bundles was detected on day 2 of pre-pupation, with a ratio of 5% in total sperm bundles, after which the percentage of apyrene sperm bundles increased rapidly and attained a relatively stable ratio of 75% at the end of pupation and nearly 80% after eclosion. Delayed mating leads to apyrene sperm accumulation and damaged fertilization. Previous study showed that ecdysone can increase the frequency of apyrene sperm bundles in vitro. Here 20-hydroxyecdysone (20E) was injected into hemolymph of the 2-d-old fifth instar larvae, the worms entered into mounting period after three days injection, but no apyrene sperm bundles were induced unless day 2 of pre-pupation. Interestingly, maturation of eupyrene sperm bundles were accelerated, and the ratio of eupyrene sperm bundles increased and exhibited a dose-dependent effect after 20E injection, which indicated that the development of eupyrene sperm can be accelerated by ecdysone before pupation of silkworm in vivo. These results will provide new clues for lepidopteran pest control.     

Peristaltic squeezing of sperm bundles at the late stage of spermatogenesis in the silkworm, Bombyx mori

Silkworm (Lepidoptera) males produce dimorphic sperm, nucleate eupyrene sperm, and anucleate apyrene sperm. The eupyrene sperm is the ordinary sperm fertilizing eggs, while the function of the apyrene sperm, which are about four times as numerous as the eupyrene sperm, is still uncertain. We found the peristaltic phenomenon at the very late stage of spermatogenesis. Peristalsis occurs in both eupyrene and apyrene sperm bundles. Through peristaltic action, cytoplasm of the eupyrene sperm and both cytoplasm and nuclei of the apyrene sperm are discarded from the posterior end of the sperm bundles. Peristaltic squeezing seems to be a process to eliminate the irregular nuclei of apyrene sperm while preserving the nuclei of eupyrene sperm.     

Effects of Environmental Conditions and Aging on Eupyrene Sperm Movement in Male Adults of Polygonia c-aureum (Lepidoptera: Nymphalidae)

The effects of temperature, photoperiod and aging on eupyrene sperm movement from the testis to the duplex in Polygonia c-aureum male adults were examined in relation to seasonal form and imaginal diapause. In males of both summer and autumn forms obtained under long-day and short-day conditions, respectively, the number of eupyrene sperm bundles in the duplex increased linearly with age during the early stage of adult life at 21 degrees C, and no marked difference was observed between the two seasonal forms. Photoperiod during the adult stage did not influence the rate of sperm movement in autumn forms with diapause. The lower the temperature, the smaller the number of sperm bundles moved from the testis to the duplex. Sperm movement did not appear to occur during a period of chilling at 5 degrees C. Males of the autumn form which were pre-incubated for 30 days and chilled for 60 days failed to resume rapid sperm movement at the final incubation temperature of 21 degrees C. Those which were pre-incubated only for 15 days at 21 degrees C had much fewer sperm bundles in the duplex after chilling than those pre-incubated for 45 days. These results suggest the possibilities that eupyrene sperm movement is suppressed strongly during and after overwintering in the field, and that the eupyrene sperm to be used for reproduction in spring are transferred from the testis to the duplex before overwintering.     

Sperm reflux and its role in multiple mating in males of a butterfly Polygonia c-aureum Linnaeus (Lepidoptera: Nymphalidae)

The relationship between sperm quantity in the duplex and that in the vasa deferentia was examined in the Asian comma butterfly, Polygonia c-aureum. In virgin males, the number of eupyrene sperm bundles in the duplex increased linearly with age, whereas that in the vasa deferentia was consistently small. However, numerous sperm were found in the vasa deferentia of males immediately after mating. The number of eupyrene sperm bundles in the vasa deferentia after mating significantly increased with age and with increasing the time interval between matings. From these and other results, it was suggested that some sperm in the duplex were moved back to the vasa deferentia during mating, and that such sperm reflux provides a means to save sperm for multiple mating.