昆虫性选择行为研究进展

本文综述了昆虫的各种性选择行为,包括与个体大小有关的性选择行为、与鸣声有关的性选择行为、与“婚礼食物”有关的性选择行为以及精子竞争等。     

成虫体型大小驱动六斑月瓢虫性间相互选择(英文)

【目的】配偶选择是性选择的中心过程,当繁殖成本发生波动和配偶质量存在差异时,传统的性别作用也随之不同。为了验证在某些条件下雄性也可以像雌性一样进行选择,我们研究了雄性和雌性六斑月瓢虫Menochilus sexmaculatus(Fabricius)的交配成功率与作为适合度指标的成虫体型大小之间的关系。【方法】从初始种群中随机选择体型小和体型大的两性成虫,进行雄性和雌性配偶选择试验。并对成功交配的各个配对组的后代也进行配偶选择试验,测试其交配成功率。【结果】配偶选择试验结果表明,在雄性和雌性交配试验中交配的成功取决于体型大小。雄性根据其品质即体型大小这一繁殖力指标对雌性进行区分。同样,在雌性交配试验中体型大的雄虫比体型小的雄虫交配成功率高。无论亲本体型如何,体型大的雌虫都比体型小的雌虫产卵量高;不过,体型大小不影响卵的存活力。体型大的亲本的后代比体型小的亲本的后代发育更快,寿命更长,但是将其与来自初始种群的后代进行配偶选择时,它们在性合意(sexual desirability)或竞争力方面没有表现任何优势。【结论】六斑月瓢虫中存在以体型大小为目的性状的相互配偶选择。     

采用人工生命方法模拟七星瓢虫捕食行为进化

自从 2 0世纪 70年代Ｂｕｒｋｓ[1] 提出人工生命的概念后 ,人工生命作为一个全新的研究领域 ,以其特有的优势在近些年来得到迅猛地发展。人工生命的基本思想是去构造某种人工系统以达到对生物的生长、发育、遗传、变异、生殖、进化、学习等生命过程重要特征的模拟 ,从而认清这些生命现象的本质。人工生命有广泛的应用 ,它所使用的方法也是多样的。粗略地说 ,可分为湿件 (Ｗｅｔｗａｒｅ ,意为采用化学方法模拟 )、硬件 (Ｈａｒｄｗａｒｅ ,意为用机器人模拟 )和软件 (Ｓｏｆｔｗａｒｅ ,意为用程序模拟 )。本文集中在采用软件方法进行行为…     

多次交配对异色瓢虫雌虫寿命及适合度的影响

异色瓢虫Harmonia axyridis(Coleoptera:Coccinellidae)为多次交配型昆虫,通过设计不同的交配次数,观察并记录不同交配组的雌虫产卵量、卯孵化率及成虫寿命等参数,探究多次交配对异色瓢虫雌虫适合度的影响.结果 表明多次交配对雌性异色瓢虫成虫的寿命有显著影响(P<0.05),交配次数越多雌性瓢虫的寿命越短;单次交配组在交配后第一周的产卵量明显低于多次交配组,为55.00±17.90枚,而4次、7次、14次交配组产卵量分别为102.29±11.97枚、93.60±13.09枚和93.36±14.95枚;多次交配可以提高异色瓢虫卵的孵化率,多次交配组卵的孵化率明显高于单次交配组,其中7次交配组最高(88.71%±0.29%),多次交配对异色瓢虫雌虫有直接利益,多次交配可以提高雌性异色瓢虫的适合度.     

飞蝗抱对行为的进化意义及两型间相异的交配策略

飞蝗Locusta migratoriaL.不仅交配时间长,而且进行频繁的、长时间的交配前抱对。一般认为,交配前抱对行为是雄虫为了等待时机获取适时的交配。最近的研究表明,飞蝗的交配时间与P2值(最后交配雄虫子代的比例)、交配前抱对时间与交配时间存在显著的正相关关系,即飞蝗长时间的交配前抱对行为能延长其后续的交配时间,从而提高P2值。飞蝗具变型现象,散居型和群居型在形态特征、生理机能、行为及体色等方面存在明显差异。最近的研究结果显示,散居型较群居型具更高的P2值,较短的交配前抱对和较长的交配时间。冲绳和筑波种群散居型成虫的交配前抱对时间与交配时间存在显著的正相关关系,而群居型无此相关性。这些结果证实飞蝗散居型和群居型之间存在着繁殖策略的差异。     

大蜡螟的性选择行为

【目的】针对大蜡螟Galleria mellonella L.的性选择行为进行系统观察分析,为大蜡螟性信息素全组分的结构鉴定及利用信息素行为调控技术防控该虫提供依据。【方法】分别对不同体重、不同日龄和不同交配经历的大蜡螟成虫进行标记,在红光灯下观察并记录大蜡螟雌雄虫的性选择行为。【结果】在（26±0.5）℃、相对湿度60%、全黑暗条件下,无论雌虫还是雄虫,均倾向于选择与之体重相接近的异性个体进行交配。雌雄成虫均偏向于选择3日龄的异性个体进行交配;雌虫对不同日龄雄虫的选择率大小顺序为3日龄> 5日龄> 1日龄,而雄虫对不同日龄雌虫的选择率大小顺序为3日龄>1日龄> 5日龄。交配经历影响大蜡螟的性选择行为,雌虫优先选择已交配的雄虫进行交配,选择率为74.6%;雄虫也优先选择已交配的雌虫进行交配,选择率为79.4%。【结论】雌雄虫体重、日龄和交配经历能不同程度的影响大蜡螟的性选择行为,这为进一步研究雌雄交配信号奠定基础。     

异色瓢虫对蚜虫性外激素的行为反应研究

蚜虫性外激素假荆芥内酯(Z,E-Nepetalactone,NEP)能够吸引多种捕食性和寄生性天敌昆虫,它专一性强,生物活性突出,对非靶标生物安全。异色瓢虫Harmonia axyridis(Pallas)作为一种重要的捕食性天敌,被广泛应用于农业生产中。为明确异色瓢虫对蚜虫性外激素的行为反应,本研究在室内用\"Y\"型嗅觉仪测定了异色瓢虫成虫对不同剂量NEP的嗅觉行为反应;并在田间,每7 d释放100μL浓度为1 mg/m L的NEP,测定了NEP对异色瓢虫种群数量变动的影响。室内嗅觉测定试验结果表明异色瓢虫雌虫对10μL剂量NEP有显著的选择性,而雄虫对1μL剂量NEP有显著的选择性;田间试验发现,释放NEP的处理区异色瓢虫数量显著高于对照区。本研究为蚜虫性外激素在害虫绿色防控中的应用提供了依据。     

昆虫在多次交配与精子竞争格局中的雌雄对策

绝大多数昆虫雌性一生中不但与不同雄性交配许多次,而且在其特殊器官中还可长期贮藏雄性精子,因此来自不同雄性的的精子在与雌性卵子受精时发生激烈的精子竞争。本文综述了昆虫在多次交配与精子竞争格局中的雌雄对策。雄性对策表现在对自身与配偶身体质量状况的正确评估、精子竞争风险预测、精子异型及延长交配时程和配后保护等,雌性对策则表现在对雄性质量状况的正确评估、对精液的主动操纵及精子偏向性等,从而很好地适因多次交配和精子竞争而带来的强烈自然选择和性选择压力。     

异色瓢虫越冬聚集行为对其能量代谢的影响

异色瓢虫以成虫滞育越冬,越冬期间聚集行为尤为显著。为探讨异色瓢虫越冬聚集行为的适应意义,本研究利用便携式红外线CO2分析仪测定了6 种聚集度（分别用1头、2头、5头、10 头、20头和50头表示）下异色瓢虫越冬成虫的呼吸量,并通过呼吸量计算得到各聚集度下的呼吸速率（Respiration rate, Rr）和能量代谢速率（Metabolism rate, Rm）。结果表明: 不同聚集度间异色瓢虫越冬成虫的呼吸速率和能量代谢速率均存在显著性差异,相关性分析表明Rr和Rm值与聚集度之间呈显著负相关。即随着聚集度的增加,越冬成虫的呼吸速率和能量代谢速率呈逐渐降低的趋势。此外,利用“Y”形嗅觉仪测定了异色瓢虫实验种群和越冬种群成虫对不同味源的选择趋性,表明异色瓢虫均对各自的群体表现出趋性,而其越冬聚集行为的发生需要一种特殊的气味物质。本研究表明聚集行为可以有效降低异色瓢虫的新陈代谢速率,减少能量消耗,有利于其种群成功越冬,这对其越冬来说具有非常重要的意义。     

昆虫多次交配的策略和利益

简要回顾昆虫交配系统的研究历史,并简述Bateman的性选择原理,讨论雌雄昆虫在交配过程中的角色和性选择压力的相对关系。一般而言,由于雌雄两性在交配过程中的角色和对后代投入的不同,往往是雄虫试图与尽可能多的雌虫交配,即雄虫使自己被尽可能多的雌虫接受,雌虫选择最好的雄虫进行交配,即雌虫选择交配对象。雄虫因而发展出各种类型的交配策略,以获取与更多雌虫的交配机会;而雌虫也通过交配选择权,选择对自己更有利的雄虫进行交配,雌虫在交配过程中除了可以获得基因利益,还可以获取物质利益。文章分别就昆虫的交配策略和利益展开叙述和讨论。     

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.     

Sex allocation and investment into pre- and post-copulatory traits in simultaneous hermaphrodites: the role of polyandry and local sperm competition

Sex allocation theory predicts the optimal allocation to male and female reproduction in sexual organisms. In animals, most work on sex allocation has focused on species with separate sexes and our understanding of simultaneous hermaphrodites is patchier. Recent theory predicts that sex allocation in simultaneous hermaphrodites should strongly be affected by post-copulatory sexual selection, while the role of pre-copulatory sexual selection is much less clear. Here, we review sex allocation and sexual selection theory for simultaneous hermaphrodites, and identify several strong and potentially unwarranted assumptions. We then present a model that treats allocation to sexually selected traits as components of sex allocation and explore patterns of allocation when some of these assumptions are relaxed. For example, when investment into a male sexually selected trait leads to skews in sperm competition, causing local sperm competition, this is expected to lead to a reduced allocation to sperm production. We conclude that understanding the evolution of sex allocation in simultaneous hermaphrodites requires detailed knowledge of the different sexual selection processes and their relative importance. However, little is currently known quantitatively about sexual selection in simultaneous hermaphrodites, about what the underlying traits are, and about what drives and constrains their evolution. Future work should therefore aim at quantifying sexual selection and identifying the underlying traits along the pre- to post-copulatory axis.     

Multiple paternity in reptiles: patterns and processes

The evolution of female promiscuity poses an intriguing problem as benefits of mating with multiple males often have to arise via indirect, genetic, effects. Studies on birds have documented that multiple paternity is common in natural populations but strong evidence for selection via female benefits is lacking. In an attempt to evaluate the evidence more broadly, we review studies of multiple paternity in natural populations of all major groups of nonavian reptiles. Multiple paternity has been documented in all species investigated so far and commonly exists in over 50% of clutches, with particularly high levels in snakes and lizards. Marine turtles and lizards with prolonged pair-bonding have relatively low levels of multiple paternity but levels are nevertheless higher than in many vertebrates with parental care. There is no evidence that high levels of polyandry are driven by direct benefits to females and the evidence that multiple paternity arises from indirect genetic benefits is weak. Instead, we argue that the most parsimonious explanation for patterns of multiple paternity is that it represents the combined effect of mate-encounter frequency and conflict over mating rates between males and females driven by large male benefits and relatively small female costs, with only weak selection via indirect benefits. A crucial step for researchers is to move from correlative approaches to experimental tests of assumptions and predictions of theory under natural settings, using a combination of molecular techniques and behavioural observations.     

Mating rate and fitness in female bean weevils

Females of most animal taxa mate with several males during theirlifespan. Yet our understanding of the ultimate causes of polyandryis incomplete. For example, it is not clear if and in what sensefemale mating rates are optimal. Most female insects are thoughtto maximize their fitness by mating at an intermediate rate,but it has been suggested that two alternative fitness peaksmay be observed if multiple costs and benefits interact in determiningthe relationship between mating rate and fitness. We studiedthe relationship between female fitness and mating rate in thebean weevil, Callosobruchus maculatus (Coleoptera: Bruchidae),a species in which several distinct direct effects of matingto females have been reported. Our results show that femalefitness, measured as lifetime offspring production, is lowestat an intermediate mating rate. We suggest that this patternis the result of multiple direct benefits to mating (e.g., spermreplenishment and hydration/nutrition effects) in combinationwith significant direct costs to mating (e.g., injury from malegenitalia). Females mating at low rates may efficiently minimizethe costs of mating, whereas females mating at high rates insteadmay maximize the benefits of mating. If common, the existenceof bimodal relationships between female mating rate and fitnessmay help explain the large intra- and interspecific variationin the degree of polyandry often seen in insects.     

Genital damage in the orb-web spider Argiope bruennichi (Araneae: Araneidae) increases paternity success

The morphology of male genitalia often suggests functions besidessperm transfer that may have evolved under natural or sexualselection. In several species of sexually cannibalistic spiders,males damage their paired genitalia during mating, limitingthem to one copulation per pedipalp. Using a triple-mating experiment,we tested if genital damage in the orb-web spider Argiope bruennichiincreases male fitness either through facilitating his escapefrom an aggressive female or by obstructing the female's inseminationducts against future copulation attempts from other males. Wefound no survival advantage for males damaging their pedipalps;however, copulations into a previously used insemination ductwere significantly shorter when the previous male had left partsof his genitalia inside the insemination duct. Because copulationduration determines paternity in this species, our result suggeststhat male genital damage in A. bruennichi is sexually selected.By breaking off parts of their intromittent organs inside avirgin female, males can reduce sperm competition and therebyincrease their paternity success.