同种雄性竞争对手的存在对星豹蛛雄蛛求偶和交配行为的影响

越来越多的研究发现,雄性产生精子(精液)也需付出代价。雄性除了依据配偶质量和竞争对手的竞争强度适应性调整生殖投入外,雄性在求偶和交配行为上也相应产生适应性反应,求偶和交配行为具有可塑性。目前雄性求偶和交配行为可塑性研究主要集中于雌性多次交配的类群中,在雌性单次交配的类群中研究甚少。以雌蛛一生只交配一次而雄蛛可多次交配的星豹蛛为研究对象,比较:(1)前一雄性拖丝上信息物质对后续雄蛛求偶和交配行为的影响,(2)雌雄不同性比对雄蛛求偶和交配行为的影响。研究结果表明,星豹蛛前一雄蛛拖丝上的信息物质对后续雄蛛求偶潜伏期、求偶持续时间和交配持续时间都没有显著影响,但前一雄蛛拖丝上的信息物质对后续雄蛛求偶强度有显著抑制作用。同时,性比对星豹蛛雄蛛求偶和交配行为都没有显著影响。可见,星豹蛛雄蛛对同种雄性拖丝上的化学信息可产生求偶行为的适应性调整,而对性比不产生适应性反应。     

雌星豹蛛性信息素的行为学证据

采用星豹蛛(Pardosa astrigera)成熟雄蛛求偶时潜伏时间、静止时间、身体震动和第一墩步足伸展次数等行为参数,利用行为学方法测定了不同性别、日龄和生殖状态的星豹蛛雌蛛释放的拖丝对雄蛛求偶行为的影响。结果表明,雄蛛第一对步足伸展和身体震动等典型求偶行为是进行星豹蛛性信息素生物测定的可靠评价指标。星豹蛛雄蛛能通过拖丝上的性信息素辨别星豹蛛的性别、日龄和生殖状态。雄蛛在成熟3周未交配雌蛛拖丝处理过滤纸上潜伏时间和静止时间都相应最短,在交配未产卵雌蛛、雌亚成蛛和成熟雄蛛拖丝上时间中等,在卵孵化雌蛛拖丝处理滤纸上潜伏时间和静止时间都相应最长。成熟3周未交配雌蛛和交配未产卵雌蛛释放的拖丝都能引起雄蛛第一对步足伸展和身体震动等典型求偶行为,雄蛛对成熟3周未交配雌蛛拖丝典型求偶行为的频率都相应高于交配未产卵雌蛛。卵孵化雌蛛释放的拖丝虽也能引起雄蛛第一对步足伸展行为,但其伸展频率显著降低;而其它拖丝都不能引起雄蛛典型求偶行为。     

Changes in courtship behaviour following rejection: The influence of female phenotype in Drosophila melanogaster

Courtship can be costly and so selection should favour individual males that reduce courtship towards female types that have a low probability of resulting in copulation. One way males can do this is by associating previous courtship failure with the traits of particular rejecting females. We characterised changes in male Drosophila melanogaster courtship behaviour following a failed mating attempt with one of the four female phenotypes that varied in size, age or mating status. To do this, we assessed individual courtship behaviour for each male presented again with a female of the same phenotype that previously rejected him. Males reduced subsequent courtship most strongly for recently mated (sexually non‐receptive) females. More interestingly, males also significantly reduced courtship activity following a failed mating experience from old females but did not do so for control (large, young, virgin) or small females. As such, males significantly reduced courtship towards both female types possessing chemical cues associated with their phenotype (age and mating status), but not towards a female phenotype based on physical characteristics (body size). Our results suggest that males are able to modify their courtship behaviour following experience, but that they are better prepared to associate chemical traits that may be more reliable indicators of the likelihood of courtship failure.     

Silk‐ and volatile‐based male mate choice in the genital plug‐producing spider

Female mating history can have a strong effect on male fertilization success. Although males often prefer to mate with virgin females, they often also engage with mated females. As the intensity of sperm competition can differ among mated females, males are expected to evolve means to identify their status. In spiders, males often use female silk to gather information about female quality. Males of many spider species deposit mating plugs into female genitalia to hinder further copulations. We tested whether males of the foliage‐dwelling, plug‐producing spider Philodromus cespitum, which is an important natural enemy of pests, discriminate between females of different mating status and whether they can determine the extent of genital plugging in mated females solely on the basis of cues gained from deposited female silk. We presented males with draglines of females that varied in either mating status (virgin vs. mated), the extent of plugging (small vs. big plug), or the age of the plug (fresh vs. old plug) and examined their mate preferences. Additionally, we tested whether males were attracted to volatile cues produced by female bodies. Our experiments revealed that males preferred draglines of virgin females to those of mated females, and mated females with small plugs to those with large plugs. They were also attracted to female volatile cues. This study suggests that males are able to extract fine‐scale information on mating status from female draglines.     

Chemosensory cues allow male Tenebrio molitor beetles to assess the reproductive status of potential mates

Males of many insect species, including beetles, choose their mates according to their reproductive status. However, the ways in which male beetles evaluate female reproductive status have received little attention. We tested the existence of male mate choice in the mealworm beetle, Tenebrio molitor, by observing mating and courtship behaviour of males given simultaneous access to pairs of females differing in their reproductive status: (1) mature versus immature; (2) virgin versus previously mated; (3) familiar (mated with the experimental male) versus unfamiliar (mated with a different male). Males courted and mated preferentially with mature and virgin females. To determine whether chemical cues played a role in these discriminations, we exposed males to filter paper squares bearing chemical cues from different types of females: (1) virgin versus mated; (2) mature versus immature. Males were significantly more attracted to those squares bearing chemical cues from virgin and mature females, suggesting that males can assess female reproductive status on the basis of chemical cues alone.     

Mating Behavior and Dual‐Purpose Armaments in a Camel Cricket

Sexual selection has often been dichotomized into intersexual and intrasexual components of selection, favoring ornaments and weapons, respectively. Here, we show that a weapon used in male–male combat is sometimes also used in a functionally similar manner for grasping females during mating. The hind legs of adult males of some species of Pristoceuthophilus camel crickets have strongly bent tibia and stout femora with two large conspicuous spines. Here, we show that (1) leg armature is positively allometric, (2) males use these leg modifications when fighting other males, (3) males sometimes use the same leg modifications in the same functional manner for grabbing and holding females for mating, (4) virgin females show more interest in males than do non‐virgin females, and (5) males are more likely to use their leg modifications to grab and hold females when paired with non‐virgin females than when paired with virgin females. We interpret these results as suggesting that males employ an alternative coercive mating strategy when paired with unreceptive females; alternative explanations are also discussed.     

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.     

Courtship role reversal in bush crickets: another role for parasites?

The last decade has seen an increasing body of evidence in supportof the idea that parasites can play a role in sexual selection.Parasites have been shown to influence mate choice and matingcompetition. Here I demonstrate a further role for parasitesin that they can determine the courtship roles of males andfemales and thus the sex on which sexual selection acts. Malebush crickets, Requena verticalis, feed their mates during inseminationwith a nutritious meal, the spermatophylax, that increases femalefecundity. I show how the ability of males to donate nutrientswas reduced by increased intensities of infection of a protozoangut parasite. Further, increased intensity of infection reducedfemale fecundity. Mating trials showed that when females wereuninfected the typical courtship roles prevailed; females werethe coy, discriminating sex. However, when infected with gutparasites, females attempted to mate more often and males adoptedthe coy discriminative role in courtship. Thus it appeared thatmale donations were of greater importance for reproductivelyconstrained, infected females. The infection status of the malehad no influence on courtship role reversal supporting the ideathat proximate cues in female behavior determine the courtshiprole adopted by males. It is argued that parasites will be animportant determinant f courtship role reversal in any specieswhere male gifts influence female fecundity, and parasites constrainhost reproduction, because of the opposing way in which reproductiveconstraints will influence male and female mating frequency.     

No Coolidge Effect in Decorated Crickets

Female decorated crickets, Gryllodes sigillatus , obtain genetic benefits by mating with different males and, when given a choice, prefer novel males over previous mates. It is unknown, however, whether males exhibit a similar preference for novel females. Although female crickets control copulation, there are at least two ways in which males can exercise choice: (1) the amount of courtship directed towards prospective mates and (2) the size of the spermatophore transferred to the female at mating. To determine whether males devote more courtship effort to novel females while controlling for female behavioral cues, male courtship effort toward two dead females, one, a previous mate and the other, a novel female, was measured. To determine whether males manufacture larger spermatophores when paired with novel females, males were mated to novel or previous mates, and the different components of the spermatophore weighed. Males did not spend more time courting dead novel females than previous mates. There was no difference in the latency to remating of males confined with novel females and those paired with previous mates, and there was no difference in the mass of spermatophores transferred to novel and familiar females. Contrary to previous studies in other taxa, this study suggests that male crickets do not prefer novel mates and thus, are not subject to the Coolidge effect. Although mating with novel females may be beneficial to males, selection on males to identify and discriminate against previous mates may be relaxed because of a strong female preference for novel males.     

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。     

Male Courtship Behavior and Weapon Trait as Indicators of Indirect Benefit in the Bean Bug,Riptortus pedestris

Females prefer male traits that are associated with direct and/or indirect benefits to themselves. Male–male competition also drives evolution of male traits that represent competitive ability. Because female choice and male–male competition rarely act independently, exploring how these two mechanisms interact is necessary for integrative understanding of the evolution of sexually selected traits. Here, we focused on direct and indirect benefits to females from male attractiveness, courtship, and weapon characters in the armed bug Riptortus pedestris. The males use their hind legs to fight other males over territory and perform courtship displays for successful copulation. Females of R. pedestris receive no direct benefit from mating with attractive males. On the other hand, we found that male attractiveness, courtship rate, and weapon size were significantly heritable and that male attractiveness had positive genetic covariances with both courtship rate and weapon traits. Thus, females obtain indirect benefits from mating with attractive males by producing sons with high courtship success rates and high competitive ability. Moreover, it is evident that courtship rate and hind leg length act as evaluative cues of female choice. Therefore, female mate choice and male–male competition may facilitate each other in R. pedestris. This is consistent with current basic concepts of sexual selection.     

Male Performance and Body Size Affect Female Re-Mating Occurrence in the Orb-Web Spider Leucauge mariana (Araneae, Tetragnathidae)

Females can affect male probabilities of paternity success through behavioural, morphological and/or physiological processes occurring during or after copulation. These processes under female-control include the acceptance or rejection of mating attempts by subsequent males. Leucauge mariana is an orb weaving spider that shows male mate guarding of penultimate females, male–male competition on female webs and copulatory plugs, suggesting a polyandric mating system. The aim of the present study was to ascertain whether male behaviour during courtship and copulation in L. mariana relate with female re-mating decisions. Forty-three virgin females were exposed to up to three males until they mated. In 24 cases, the copulatory plug was absent after mating and females were exposed the next day to up to three other males. Eighteen females accepted a second mating. Relatively larger females were more receptive to second matings and were more likely to copulate if the second male was smaller. Longer duration of female tapping and abdominal bobbing during courtship, and first copulations with less short insertions and more flubs, were associated with increased female acceptance to second matings. The results indicate cryptic female choice on male courtship and copulatory performance and suggest female-control over the determination of male mating success in this spider species.     

Sexual Strategies of a North American ‘Tarantula’ (Araneae: Theraphosidae)

Despite their general notoriety and popularity as pets, little is known of the behavioural ecology of ‘tarantulas’ or theraphosid spiders. We studied a theraphosid of the Arizona deserts, Aphonopelma sp., to determine behavioural events crucial to successful courtship and mating. Males search for spatially scattered females and, at short range, may detect females by substrate-borne cues. When two males are present with a single female, no direct competition such as aggression is observed. Both males may mate with a single female in rapid succession, with no evidence of post-copulatory mate guarding. Despite the potential for sexual cannibalism, courtship and mating behaviour patterns exhibit few aggressive elements and males nearly always survive sexual encounters with females. The mating system of this Aphonopelma species may best be described as a type of scramble-competition polygyny, in which the ability of males to locate receptive females is an important determinant of mating success in males. Multiple mating by females renders predictions concerning fertilization success uncertain, due to the possibility of sperm competition and ‘cryptic’ female mate choice.     

The role of olfaction during mating in the southern temperate spiny lobster Jasus edwardsii

Chemosensory communication may be crucial during mate choice and mating in the southern temperate spiny lobster Jasus edwardsii to ensure that females mate with large males capable of supplying adequate numbers of sperm during the short mating window. To clarify the role of pheromones during this process, three laboratory experiments were carried out. In an experiment where the output of urine, which contains sex-specific pheromones, from large and small catheterized males was switched, large post-molt females did not make a clear choice of mate. This indicates that while females distinguish among females, males, and juveniles using their chemosensory sense, they distinguish among males using visual and tactile senses in combination with olfaction. Further, two antennule-ablation experiments were carried out to determine if detection of pheromones by the antennules of females or males was critical for mate selection, courting, or mating. In both cases, we observed a (nonsignificant) trend of slightly delayed mating of treatment females. We found that disruption of female olfaction causes less impact on courtship or mating than ablation of male antennules which increased the variance in the length of the period between molting and mating and resulted in a systematic reduction in clutch size. This lesser impact of female ablation may be because females can still respond to their own internal cues about egg ripeness whereas males cannot. In J. edwardsii, unlike the American clawed lobster, Homarus americanus, one fully functional partner of either sex appears sufficient to initiate mating.     

A preference for a sexual signal keeps females safe

Predation is generally thought to constrain sexual selection by female choice and limit the evolution of conspicuous sexual signals. Under high predation risk, females usually become less choosy, because they reduce their exposure to their predators by reducing the extent of their mate searching. However, predation need not weaken sexual selection if, under high predation risk, females exhibit stronger preferences for males that use conspicuous signals that help females avoid their predators. We tested this prediction in the fiddler crab Uca terpsichores by increasing females' perceived predation risk from crab-eating birds and measuring the attractiveness of a courtship signal that females use to find mates. The sexual signal is an arching mound of sand that males build at the openings of their burrows to which they attract females for mating. We found that the greater the risk, the more attractive were males with those structures. The benefits of mate preferences for sexual signals are usually thought to be linked to males' reproductive contributions to females or their young. Our study provides the first evidence that a female preference for a sexual signal can yield direct survival benefits by keeping females safe as they search for mates.     

Size-biased Mating in Both Sexes of the Black-horned Tree Cricket, <Emphasis Type="Italic">Oecanthus nigricornis</Emphasis> Walker (Orthoptera: Gryllidae: Oecanthinae)

Previous studies on tree crickets have demonstrated female choice of males based on size and courtship feeding but less is known about sexual selection under conditions of direct mating competition. I studied courtship, aggression and mating of the black-horned tree cricket Oecanthus nigricornis (Walker) to test size-related sexual selection under conditions of direct sexual competition. Results show that larger individuals of both sexes mated more frequently than their smaller counterparts, and this was due to the ability of large individuals to out compete rivals. Large males achieved the advantage by aggressively reducing courtship by small males, whereas large females responded to male courtship more quickly but with little aggression. Although there was no evidence here for mate choice, there were advantages for having larger mates; fecundity increased with female size and spermatophores (which females consume after mating) increased with male size. Size of the specialized metanotal courtship gift, however, was not related to male size.     

拟环纹豹蛛雄蛛触肢上黑白相间毛饰物的功能

狼蛛科雄蛛附肢上多样化的饰装往往与求偶行为相偶联,这些特殊的饰装通常被认为是雌性选择的结果。拟环纹豹蛛Pardosa pseudoannulata,属狼蛛科豹蛛属,雄蛛触肢胫节密被白毛,跗舟密被黑毛,具有典型的性二型现象;同时,只有成熟的雄蛛才展现触肢黑白相间的毛饰物。推测拟环纹豹蛛雄蛛触肢这种黑白相间的毛饰物可能在物种识别中具重要作用。在室内我们拟通过涂抹操作对拟环纹豹蛛雄蛛触肢黑白相间毛饰物的功能进行分析。实验分为4组,分别是对照组(A组,雄蛛不做任何处理)、雄蛛触肢白色胫节全部涂成黑色(B组)、雄蛛触肢黑色跗舟全部涂成白色(C组)和雄蛛触肢的黑色跗舟被涂成黑色(D组),然后采用雌雄配对进行求偶交配行为测定。实验结果表明,B组雄蛛的交配成功率显著低于A、C和D组的雄蛛,而后3组雄蛛的交配成功率无显著差异。相反,B组雄蛛被雌蛛相食百分率显著高于其它3组。可见拟环纹豹蛛雄蛛触肢上黑白相间毛饰物,尤其是其胫节上的白色饰物在雌蛛种间识别中起重要作用。     

Visual and Olfactory Female-Borne Cues Evoke Male Courtship in the Aphid Parasitoid Aphidius colemani Viereck (Hymenoptera: Braconidae)

We investigated the courtship and mating behavior of the pan-tropical polyphagous endoparasitoid Aphidius colemani Viereck. The courtship and mating displays, the magnitude of male-male sexual approaches and the role of female-borne cues evoking male courtship behavior were quantified. The sequence of events leading to copulation in this parasitoid did not differ from that found for other braconids. Females refused to copulate more than once. Same-sex courtships were observed among males and their possible role in an adaptive context is discussed. Olfactory female-borne cues played a key role in eliciting the courtship responses of males. Males were attracted by freshly dead females, but not by dead females soaked in hexane, nor by visual cues from females alone. Intense male wing fanning behavior was elicited by crushed abdomens of virgin females, suggesting that the female abdomen is the source of a short-distance pheromone crucial in evoking male courtship. Further studies are required to clarify the exact nature of the chemicals involved.     

Paternal investment in relation to size in the deathwatch beetle,Xestobium rufovillosum (Coleoptera: Anobiidae), and evidence for female selection for large mates

Male X. rufovillosumdonate on average 13.5% of their body weight to the female during copulation. The weight transferred is significantly greater in heavier males and declines in subsequent matings. When virgin females are offered a choice of several mates, they tend to mate with a heavy male. Females appear to be selective during courtship, refusing to mate with light males. Artificial weights attached to males increase the frequency of acceptance as mates by females, but not significantly. The evolutionary origins and significance of a large paternal investment and apparent female selection for heavy mates are discussed.     

Mate preference for multiple cues: interplay between male and nest size in the sand goby, Pomatoschistus minutus

Female mating preferences are often based on more than one cue.In empirical studies, however, different mate choice cues aretypically treated separately ignoring their possible interactions.In the current work, we studied how male body size and sizeof the male's nest jointly affect mate preferences of femalesand gobies, Pomatoschistus minutus. The females were givena binary choice between males that differed either in body sizeor size of their nest or both. We found that neither body sizenor size of the nest alone affected male attractiveness, buttogether these 2 cues had a significant effect. Specifically,large males were more popular among females when they had alarge nest than when they occupied a small nest. The resultssuggest that if interaction effects between multiple mate choicecues are not considered, there is a danger of ignoring or underestimatingthe importance of these cues in sexual selection by female choice.