三突伊氏蛛雌蛛不同交配史对雄蛛交配行为的影响

近年来越来越多研究表明,雄性产生精子(精液)也需付出代价。在多次交配的动物中,雄性为获得最大生殖潜力,必须依据配偶的质量策略性地调整每次交配的生殖投入。雄性策略性的生殖投入主要体现在两个方面,一是精子竞争(sperm competition),二是柯立芝效应(Coolidge effect)。目前精子竞争研究主要集中于昆虫类群,而柯立芝效应研究集中于高等脊椎动物,同时验证结果也时常与假说不一致。以多次交配的三突伊氏蛛为材料,以雄蛛交配行为为指标,在蜘蛛类群中探讨和验证雄性精子竞争强度假说和柯立芝效应。设定3个交配组合:2只雄蛛依次与1只雌蛛各交配1次(A组)、2只雄蛛依次与2只雌蛛各交配1次(B组)和1只雄蛛与1只雌蛛交配2次(C组),分析比较3个交配组合的三突伊氏蛛第1次交配和第2次交配在交配潜伏期、交配持续时间和交配回合数方面的差异,比较三突伊氏蛛雌蛛不同交配史对雄蛛交配行为的影响,以此验证雄性精子竞争强度假说和柯立芝效应。研究结果表明A和B组的三突伊氏蛛第2次交配的交配潜伏期和交配持续时间显著长于第1次交配。同时,C组的三突伊氏蛛第1次交配的交配潜伏期和交配持续时间与第2次交配都没有显著差异。同时,A、B和C组的三突伊氏蛛第1次交配的交配回合数与第2次交配都没有显著差异。研究结果支持精子竞争强度假说,而不支持柯立芝效应。     

Female mating status does not affect male mating behavior in the West Indian sweetpotato weevil, Euscepes postfasciatus

Because multiple mating by females encourages sperm competition, the assessment of female mating status before insemination is important for males in order to avoid the risk of sperm competition or to intensify sperm competition. When interacting with females before sperm transfer, males can alter their mating tactics according to the risk or intensity of sperm competition. Information on how mating systems are associated with sperm competition is essential for sterile insect technique eradication programs, which depend on successful mating of released sterile males with wild females. We tested whether males of the West Indian sweetpotato weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae), adjusted their mating behavior in response to female mating experience and/or age. As virgin/young female weevils accepted males more easily than non-virgin/old females, assessing females before insemination can be adaptive for male weevils. We found that E. postfasciatus males were unable to adjust their mating tactics in response to female mating status. Although this mating strategy would be costly for individual male weevils, the ability in males to discriminate female mating status can prevent the chance of mating with already-mated females containing the sperm of wild male(s). Therefore, the mating tactics of male E. postfasciatus are advantageous for sterile insect technique eradication programs.     

Male Mating Success and the Effect of Mating History on Ejaculate Traits in a Facultatively Parthenogenic Insect (Extatosoma tiaratum)

Males can typically increase their lifetime reproductive success by mating with multiple females. However, recent studies across a broad range of species have demonstrated physiological constraints on male multiple mating. In this study, we investigate male mating capacity in Extatosoma tiaratum, a facultative parthenogenetic phasmatid. Sperm limitation is thought to be one factor favouring the evolution and maintenance of parthenogenetic reproduction, but studies on male mating ability in facultative parthenogenetic species are extremely rare. To explore whether male mating success varies with mating history, we provided males with weekly mating opportunities with different females throughout their lives. We then observed mating success, and the variation in ejaculate size and quality within each mating. We showed that most, but not all, males can mate multiply, however the amount of ejaculate produced is variable and depends upon male body mass and mating history.     

水稻二化螟的交配行为

在室内条件下,对水稻二化螟Chilo suppressalis的交配行为及能力进行了研究.结果表明：大多数二化螟雌蛾一生只交配一次,平均0.92次;而雄蛾具有多次交配能力,最多达4次,平均2.72次.二化螟雌蛾的日龄影响其交配率、交配起始时间和持续时间,随二化螟雌蛾日龄的增加,其交配率逐渐下降,交配起始时间逐渐提前,而交配持续时间逐渐上升.相反,二化螟雄蛾日龄对其交配率、交配起始时间和持续时间没有明显影响.交配日龄对二化螟雌蛾的生殖力也存在显著影响,随着二化螟雌蛾交配日龄的增加,雌蛾产卵量下降,卵孵化率降低,产卵期缩短,它们都与雌蛾交配日龄存在显著的负相关;而雌蛾产卵前期和雌蛾寿命随雌蛾交配日龄的增加而延长,与雌蛾交配日龄存在显著的正相关.但二化螟雄蛾交配日龄对雌蛾的生殖力没有明显影响,二化螟雄蛾一生都具有较强的交配繁殖能力.同时,不同交配史的雄蛾与雌蛾交配,对雌蛾的生殖力也没有显著影响.表明二化螟的交配活动是由雌蛾主导控制的.最后,对这些结果在二化螟性信息素防治中应用的可行性进行了探讨.在应用性信息素控制二化螟的实践中,可以在两方面取得实效,一是性信息素可以阻碍雌雄之间正常交配,降低交配率;二是可以推迟二化螟雌虫的交配,使其产卵量和卵孵化率降低.     

Female Fitness Optimum at Intermediate Mating Rates under Traumatic Mating

Traumatic mating behaviors often bear signatures of sexual conflict and are then typically considered a male strategy to circumvent female choice mechanisms. In an extravagant mating ritual, the hermaphroditic sea slug Siphopteron quadrispinosum pierces the integument of their mating partners with a syringe-like penile stylet that injects prostate fluids. Traumatic injection is followed by the insertion of a spiny penis into the partner's gonopore to transfer sperm. Despite traumatic mating, field mating rates exceed those required for female fertilization insurance, possibly because costs imposed on females are balanced by direct or indirect benefits of multiple sperm receipt. To test this idea, we exposed animals to a relevant range of mating opportunity regimes and assessed the effects on mating behavior and proxies of female fitness. We find penis intromission duration to decrease with mating rates, and a female fecundity maximum at intermediate mating rates. The latter finding indicates that benefits beyond fertilization insurance can make higher mating rates also beneficial from a female perspective in this traumatically mating species.     

The evolution of repeated mating in the burying beetle, Nicrophorus vespilloides

Animals of many species accept or solicit recurring copulations with the same partner; i.e., show repeated mating. An evolutionary explanation for this excess requires that the advantages of repeated mating outweigh the costs, and that behavioral components of repeated mating are genetically influenced. There can be benefits of repeated mating for males when there is competition for fertilizations or where the opportunities for inseminating additional mates are rare or unpredictable. The benefits to females are less obvious and, depending on underlying genetic architecture, repeated mating may have evolved as a correlated response to selection on males. We investigated the evolution of repeated mating with the same partner in the burying beetle Nicrophorus vespilloides by estimating the direct and indirect fitness benefits for females and the genetics of behavior underlying repeated mating. The number of times a female mated had minimal direct and no indirect fitness benefits for females. The behavioral components of repeated mating (mating frequency and mating speed) were moderately negatively genetically correlated in males and uncorrelated in females. However, mating frequency and mating speed were strongly positively genetically correlated between males and females. Our data suggest that repeated mating by female N. vespilloides may have evolved as a correlated response to selection on male behavior rather than in response to benefits of repeated mating for females.     

Processes of pair formation leading to assortative mating in biological populations: dynamic interaction model

A model of pair formation that treats mating between two individuals as a dynamic process rather than an instant event is suggested. A number of cases corresponding to polygamous and monogamous matings of individuals are considered. The individual mating preferences are represented in the model by a set of "compatibility probabilities." It is shown that the mating pattern (the distribution of characters among mating pairs) established in a population as a result of the process of pair formation does not uniquely reflect the pattern of mating preferences. Quite different mating patterns may occur in populations with very similar mating preferences, as well as similar mating patterns may occur in populations with different individual mating preferences. The model demonstrates that not only mating preferences of individuals but also specific mechanisms of pair formation play an important role in determining the mating pattern of a population.     

Females benefit from multiple mating but not multiple mates in the burying beetle Nicrophorus vespilloides

Male reproductive success generally increases with number of mates but this need not be true for females. If females are the limiting sex, as few as one mate can be optimal. Despite the theoretical differences driving multiple mating in the sexes, multiple mating is the norm rather than the exception. Empirical investigations are therefore required to determine why females mate with multiple males. Both nonadaptive (correlated responses to selection on males, given the mean mating rates have to be the same) and adaptive (direct or indirect fitness benefits) can drive the evolution of multiple mating in females. Females of the burying beetle Nicorphorus vespilloides often mate repeatedly with the same male, but this appears to be a correlated response to selection on males rather than reflecting direct benefits to females for multiple mating. However, an unexamined alternative to this nonadaptive explanation is that females benefit by mating with multiple different males and therefore are selected for general promiscuity. Here we examine if mating polyandrously provides fitness benefits by examing the effects of number of mates (1, 2 or 3), mating system (monogamous, polyandrous) and their interaction. The only significant influence was mating more than once. This did not depend on type of mating. We suggest that unlike most other species examined, in N. vespilloides mating with the same male repeatedly or with several different males reflects an indiscriminate willingness to mate as a result of correlated selection on males for high rates of mating.     

The evolution of optimal female mating rate changes the coevolutionary dynamics of female resistance and male persistence

Mating decisions usually involve conflict of interests between sexes. Accordingly, males benefit from increased number of matings, whereas costs of mating favour a lower mating rate for females. The resulting sexual conflict underlies the coevolution of male traits that affect male mating success ('persistence') and female traits that affect female mating patterns ('resistance'). Theoretical studies on the coevolutionary dynamics of male persistence and female resistance assumed that costs of mating and, consequently, the optimal female mating rate are evolutionarily constant. Costs of mating, however, are often caused by male 'persistence' traits that determine mating success. Here, we present a model where the magnitude of costs of mating depend on, and evolve with, male persistence. We find that allowing costs of mating to depend on male persistence results in qualitatively different coevolutionary dynamics. Specifically, we find that male traits such as penis spikes that harm females are not predicted to exhibit runaway selection with female resistance, in contrast to previous theory that predicts indefinite escalation. We argue that it is essential to determine when and to what extent costs of mating are caused by male persistence in order to understand and accurately predict coevolutionary dynamics of traits involved in mating decisions.     

Effect of delayed mating and prolonged engorgement on the reproductive fitness of female Amblyomma limbatum (Acari: Ixodidae) in marginal population areas

Reptile ticks mate while females are attached to their host. Following mating, females engorge, detach and then lay their eggs. This study examines whether the time that females of the reptile tick Amblyomma limbatum spend on hosts prior to mating and the time they take to engorge on hosts after mating influence their reproductive fitness, as measured by the number of viable eggs they produce. When compared with females that experienced no temperature-induced delay in mating, females attached for an initial period to hosts with body temperatures too low to induce mating had no decline in their reproductive fitness, once provided with suitable temperatures for mating. However, on hosts with suitable body temperatures for mating, female ticks that took longer to mate, took longer to engorge and had reduced reproductive fitness. In addition, females that spent more than 20 days feeding on hosts after mating had reduced reproductive fitness, irrespective of the time they spent on hosts prior to mating compared with females with shorter feeding periods. Thus, the time that A. limbatum females spent on hosts prior to mating and/or after mating has a significant bearing on the number viable progeny produced. The ecological implications of these results are discussed in relation to females colonizing marginal population areas at the edge of their distributional range.     

An ecological classification of odonate mating systems: the relative influence of natural, inter-and intra-sexual selection on males

We separate the mating systems of odonates into two main groups: non-resource and resource-based systems. These two groups comprise five classes of mating system: encounter-limited mating, free female choice, resource-limitation, resource-control and female-control. These classes are consistent with previous classifications of odonate mating systems and with the overall classification of mating systems by Emlen & Oring (1977: Science, 797: 215–223). Whereas Emlen & Oring's classification of mating systems was concerned with differences in sexual selection between mating systems, our classification of odonate mating systems also addresses the influence of inter-and intra-sexual selection on males within a mating system. Predictions about such relationships are useful in multivariate analysis of odonate lifetime reproduction success. Among most odonate mating systems, much of the sexual selection on males results from male-male competition for access to mates. Sexual selection via female choice is relatively less important or operates indirectly through females' choices of times or places to mate. We place resource-control and resource-limitation at opposite ends of a resource-defence continuum and postulate female choice will have greater influence in mating systems that are more like a resource-limitation system and less influence in mating systems that are more like resource-control. Sexual selection is likely to be weak in species that resort to encounter-limited mating where longevity is likely to contribute strongly to variation in reproductive success. Females have limited opportunity to exercise choice among males in the female-control mating system and in this system selection is most likely to operate on male characters which contribute to their efficiency in searching for and capturing mates. Predictions about the differences in the intensity of sexual selection between different odonate mating systems should be made on the basis of the variation in the number of potential fertilizations per male or even per ejaculate, rather than the number of fertilizable females per male. Very different mating systems could result in similar patterns of variation in male reproductive success.     

亚洲玉米螟交配率和交配次数与其日龄、性比和精巢大小的关系

【目的】昆虫交配行为与其日龄和生殖系统发育密切相关。本研究旨在明确亚洲玉米螟Ostrinia furnacalis交配行为与其日龄、性比和雄蛾精巢大小的关系,为性信息素群集诱杀和交配干扰防控亚洲玉米螟提供理论依据。【方法】通过室内交配实验测定了不同配对晚数、日龄、性比亚洲玉米螟的交配率和交配次数,通过雄蛾精巢解剖分析了交配次数与精巢体积的关系。【结果】亚洲玉米螟的交配率随配对晚数增加而增加,但第1-5晚的增加速度大于第6-7晚的;1-4日龄蛾的交配率随日龄增加而增加,5日龄蛾的交配率显著降低;1-3日龄蛾配对1晚的交配率与新羽化蛾配对2～4晚的均无显著差异。亚洲玉米螟可以交配1～3次,但是交配3次的比例极低。雌性数量从1增为2时,雄蛾的交配率显著增加;从2增为3时,雄蛾的交配率显著降低、死亡率显著增加,交配1次的雄蛾进行二次交配的比例也增加,并且雄蛾更愿意与处女雌蛾进行第2次交配;交配1次雄蛾的精巢体积总是显著大于同期未交配雄蛾的,交配1次稍降低了雄蛾精巢的衰退速度,交配2次则明显增加雄蛾精巢的衰退速度。【结论】本研究明确了亚洲玉米螟交配与日龄、性比和雄蛾精巢体积之间的关系,从理论上证实了性信息素群集诱杀技术和交配干扰技术防治亚洲玉米螟的有效性。     

Lifetime mating success of males in a natural population of the papilionid butterfly,Atrophaneura alcinous (Lepidoptera: Papilionidae)

Lifetime mating success of males in a natural population of the papilionid butterfly, Atrophaneura alcinous, was investigated and causes of the variation were examined. The most successful males mated with 5 females, whereas about 73% of the males failed to mate. Body size of males was not correlated with their eclosion date, longevity and lifetime mating success. There was no trade-off between mating success and longevity, and long-lived males had a disproportionately high mating success. Although number of available females per male per day was not variable among males with different longevities, long-lived males had higher mating efficiency. Time interval between matings by non-virgin males was shorter than that from eclosion to the first mating. High lifetime mating success of long-lived males was strongly related to their mating experience, not to their age per se.     

Female mating status affects male mating tactic expression in the wolf spider Rabidosa punctulata

Males and females have conflicting interests on the frequency and outcomes of mating interactions. Males maximize their fitness by mating with as many females as possible, whereas choosy females often reduce receptivity following copulation. Alternative male mating tactics can be adaptive in their expression to a variety of mating contexts, including interactions with a relatively unreceptive mated female. Male Rabidosa punctulata wolf spiders can adopt distinctive mating tactics when interacting with a female, a complex courtship display, and/or a more coercive direct mount tactic that often involves grappling with females for copulation. In this study, we set up female mating treatments with initial trials and then paired mated and unmated females with males to observe both female remating frequencies and the male mating tactics used during the interactions. Males adopted different mating tactics depending on the mating status of the female they were paired with. Males were more likely to adopt a direct mount tactic with already-mated females and courtship with unmated females. Already-mated females were considerably less receptive to males during experimental trials, although they did remate 34% of the time, the majority of which were with males using a direct mount tactic. Whereas males adjusting to these contextual cues were able to gain more copulations, the observation of multiple mating in female R. punctulata introduces the potential for sperm competition. We discuss this sexual conflict in terms of the fitness consequences of these mating outcomes for both males and females.     

Male mating behavior in relation to spermatophore transfer in the white cabbage butterfly

The lifetime mating frequency of female butterflies is believed tobe dependent on the reproductive status of the males which they have mated. This report assesses those status usingPieris rapae L. Multiple mating females mated males with a short time interval after the last mating or males with many mating records. Such males, like small ones, produced small spermatophores during copulation, which may have resulted in high mating frequency of those females. The males with short time interval after the last mating or those with many mating records also showed a long mating duration. Alternative interpretations of the adaptive significance of this behavior for males are discussed.     

影响大猿叶虫交配持续时间的因素

为了探明影响大猿叶虫Colaphellus bowringi Baly交配持续时间的因素,在室内系统观察了一天中的交配起始时间、日龄、交配经历、体重、雄虫密度和温度对交配持续时间的影响.结果表明：一天中不同时间交配的成虫,其交配持续时间有显著差异,在上午8:00的交配持续时间最长,随着时间的推移,交配持续时间逐渐缩短,两者之间呈负相关.不同日龄成虫的交配持续时间有显著差异,且与成虫日龄呈明显的正相关.当雄虫与有交配经历的雌虫交配,其交配持续时间明显长于与未交配的雌虫交配,但雄虫的交配经历对交配持续时间没有影响.交配持续时间随着雌、雄体重的增加而延长,但没有显著差异.在雄虫高密度条件下的交配持续时间明显短于低密度下的交配持续时间.在22℃时成虫的交配持续时间最长,其次是25℃,28℃下最短, 温度间的交配持续时间有明显差异.这些结果表明在自然条件下大猿叶虫的交配持续时间受到许多因素的影响.     

Constraints on Size-assortative Mating in the Blister Beetle Tegrodera aloga (Coleoptera: Meloidae)

The mating system of Tegrodera aloga is similar to other blister beetles that have evolved sizeassortative mating in that males pass a cantharidin-rich spermatophore to their mates and females vary in size and fecundity. Despite this, previous studies found no assortative mating in this beetle. Results of this study suggest that nonassortative mating is not due to absolute constraints on mate choice. Males courted large females more frequently than small females, suggesting that males prefer big mates. Similarly, female choice is suggested by a large-male mating advantage in the absence of size-related male-male competition. In contrast to previous work, my results suggest that assortative mating may occur under certain conditions and may be due to large-phenotype mating advantages. The question remains, why does assortative mating occur only some of the time? One hypothesis is that assortative mating breaks down when sex ratios become male biased and males no longer discriminate between mates. However, although sex ratios can vary from day to day, assortative mating is not associated with periods when females outnumber males. Rather, the pattern appears to be associated with times of low overall population density. Hypotheses for density-dependent assortative mating are presented.     

Lifetime Number of Mates Interacts with Female Age to Determine Reproductive Success in Female Guppies

In many species, mating with multiple males confers benefits to females, but these benefits may be offset by the direct and indirect costs associated with elevated mating frequency. Although mating frequency (number of mating events) is often positively associated with the degree of multiple mating (actual number of males mated), most studies have experimentally separated these effects when exploring their implications for female fitness. In this paper I describe an alternative approach using the guppy Poecilia reticulata, a livebearing freshwater fish in which females benefit directly and indirectly from mating with multiple males via consensual matings but incur direct and indirect costs of mating as a consequence of male sexual harassment. In the present study, females were experimentally assigned different numbers of mates throughout their lives in order to explore how elevated mating frequency and multiple mating combine to influence lifetime reproductive success (LRS) and survival (i.e. direct components of female fitness). Under this mating design, survival and LRS were not significantly affected by mating treatment, but there was a significant interaction between brood size and reproductive cycle (a correlate of female age) because females assigned to the high mating treatment produced significantly fewer offspring later in life compared to their low-mating counterparts. This negative effect of mating treatment later in life may be important in these relatively long-lived fishes, and this effect may be further exacerbated by the known cross-generational fitness costs of sexual harassment in guppies.     

Effect of the mating plug on female chemical attractiveness and mating acceptance in a scorpion

After mating, females may experience a decline in sexual receptivity and attractiveness that may be associated with changes in the production and emission of sex pheromones. In some cases, these changes are produced by chemical substances or structures (e.g., mating plugs) produced by males as a strategy to avoid or reduce sperm competition. In scorpions, sex pheromones may be involved in finding potential mates and starting courtship. Here, we tested the hypothesis that the males of Urophonius brachycentrus, a species that produces a mating plug, use chemical communication (sex pheromones) to detect, localize, and discriminate females according to their mating status (virgin or inseminated), aided by chemical signaling. We also explored the effect of extracting of the mating plug on chemical communication and mating acceptance. We used Y‐maze olfactometers with different stimuli to analyze male choice and exploration time. To evaluate mating acceptance, we measured the attractiveness and receptivity of females of different mating status. We found that chemical communication occurs through volatile pheromones, but not contact pheromones. Males equally preferred sites with virgin or inseminated females with removed mating plug. In turn, females with these mating statuses were more attractive and receptive for males than inseminated females. This study suggests that the mating plug significantly affects female chemical attractiveness with an effect on volatile pheromones and decreasing sexual mating acceptance of females. The decline in the female's sexual receptivity is a complex process that may respond to several non‐exclusive mechanisms imposed by males and strategically modulated by females.     

High mating frequency and variation with lineage ratio in dependent-lineage harvester ants

Explaining the evolution of multiple mating is a challenge because of the associated costs. For social insects, mating frequency may have fitness consequences due to effects on social interactions or genetic diversity within colonies. Here, we investigated the evolution of mating frequency in a social insect species with a unique genetic system that requires multiple mating. In certain populations of Pogonomyrmex harvester ants, there are two interbreeding yet genetically distinct mitochondrial lineages. Queens must mate with males of the opposite lineage to produce workers and with males of the same lineage to produce reproductive females. We expected queens of the dependent-lineage system to exhibit high mating frequencies relative to other social insects. Furthermore, we expected queens from populations of highly asymmetric lineage ratios to exhibit even higher mating frequencies, to adequately sample the population and successfully mate with males of the less common lineage. To test these predictions, we estimated the mating frequency of 16 P. barbatus queens, and compared these mating frequencies between two populations, one with relatively equal lineage ratio (60:40) and a second with a highly asymmetrical lineage ratio (96:4). Overall, observed mating frequency exceeded 10, which is high in comparison to other social insects, and our estimates of effective mating frequency were among the highest of Pogonomyrmex species. Mating frequency at the site with the asymmetrical lineage ratio was also significantly higher than the site with the more even ratio. Our results suggest that obligate multiple mating as well as lineage ratio contribute to the evolution of high mating frequency in dependent-lineage populations.