生态因素对蛾类昆虫交配与生殖的影响

对于两性生殖的昆虫而言,两性交配过程是产生后代及维持种群繁衍的必要环节。然而,昆虫的生殖行为经常受到一系列的内部生理因素和外部生态因素的影响,最终导致昆虫的生殖适合度产生差异。本文以蛾类昆虫为例,通过检索国内外文献,分析比较了气候因素(温度、湿度和光照)、生物因素(寄主植物、天敌和共生菌)和农事活动等生态因素对这类昆虫交配行为和生殖适合度的影响。结果表明,这些因子不但影响该类昆虫的交配行为(包括求偶与交配高峰、交配成功率、交配次数和交配持续时间等),还影响其生殖适合度(如产卵前期、产卵期、产卵量、孵化率和寿命等)。这些研究为深入开展蛾类昆虫的生殖行为生态学研究提供理论基础,同时为揭示蛾类昆虫的种群暴发机制以及该类害虫的科学防控提供线索。     

抗药性昆虫相对适合度的研究进展

杀虫剂抗性基因的突变对昆虫生理生化的影响体现为种群适合度的变化.种群抗性等位基因频率和生物学适合度可用来表征抗性昆虫相对适合度.抗性相关靶标和代谢酶的突变会改变昆虫正常的生理功能,抗性基因过量表达会引起昆虫体内生理能量分配失衡,两者均会造成抗性代价.但是,抗性等位基因置换和修饰基因可以抵消抗性代价.抗性昆虫相对适合度的表现型取决于抗药性形成的遗传背景和抗性水平.此外,其表现型还受到各种生态因素的影响.抗性昆虫相对适合度的研究结果可为预测抗药性发展趋势、开展抗药性治理提供科学依据.     

黄地老虎飞行能力研究

黄地老虎Agrotis segetum是一种重要的农业迁飞性害虫,研究飞行生物学对明确其迁飞机理有重要意义。本项研究利用昆虫飞行磨系统对黄地老虎的飞行能力进行了测定。对实验室种群飞行能力的测定结果表明:1日龄成虫的飞行能力最弱;3日龄飞行能力最强,其24 h平均飞行时间、平均飞行距离和平均飞行速率分别达到12.16±0.74 h、48.94±3.40 km和3.76±0.12 km/h。雌蛾与雄蛾间的各项飞行参数均无显著差异,但处女成虫平均飞行距离和平均飞行速率均显著高于已交配个体。对渤海湾野外迁飞种群飞行能力的测定显示,早季节北迁个体和晚季节回迁个体的平均飞行时间和平均飞行距离无显著差异,但皆显著低于实验室种群。黄地老虎具有较强的飞行能力,日龄和交配是影响其飞行能力的关键因素。     

甘蓝夜蛾Mamestra brassicae Linnaeus飞行能力研究

【目的】测定日龄、性别、交配等因素对农业迁飞性害虫甘蓝夜蛾Mamestra brassicae Linnaeus飞行能力的影响,为其迁飞行为研究和异地测报提供理论依据。【方法】在气温为(24±1)℃、相对湿度为75%±5%的实验室环境下,利用飞行磨系统对甘蓝夜蛾实验室种群1~5日龄未交配个体、已交配的3日龄个体以及野外迁飞种群分别进行连续24 h吊飞测试,记录其累计飞行时间、累计飞行距离、平均飞行速率等参数。【结果】甘蓝夜蛾实验室种群的飞行能力随日龄增长而变化,初羽化时即具有较强的飞行能力,2~3日龄达到峰值,4~5日龄的飞行能力显著下降;雌性甘蓝夜蛾的飞行能力强于雄性甘蓝夜蛾;交配的甘蓝夜蛾平均飞行速率显著小于处女甘蓝夜蛾,但二者的平均飞行时间和飞行距离均无显著差异。此外,渤海湾迁飞种群中晚季节南迁种群的飞行能力显著强于早季节北迁种群和过渡种群。【结论】日龄和交配状态是影响甘蓝夜蛾飞行能力的关键因素。     

番茄潜叶蛾求偶与交配节律研究

明确昆虫求偶及交配等生殖行为的节律,对于性信息素引诱剂的研发与田间合理应用具有重要的指导意义。本研究对番茄潜叶蛾雌虫的求偶行为和雌雄成虫的交配行为节律进行了探究。结果表明,番茄潜叶蛾雌虫主要在亮期进行求偶,亮期开始前少数个体出现求偶现象,亮期开始求偶率迅速增加,在0.5 h内达到高峰期,高峰期平均求偶率达80%以上。不同日龄求偶率不同,2～3日龄为该虫求偶最活跃龄期。番茄潜叶蛾雌雄间交配主要发生在亮期,亮期0.5 h到达高峰期,交配率达90%,与雌虫求偶高峰期吻合。番茄潜叶蛾雌、雄虫一生均可进行多次交配,雌虫7 d内最高交配4次。相对于雌雄比1∶1,雌雄比1∶2的交配率有所降低,而雌雄比2∶1的交配率和平均交配时长均有所上升。本研究证实了番茄潜叶蛾主要在亮期进行求偶和交配,且求偶和交配行为存在明显的节律性,雌、雄蛾一生均可进行多次交配。     

浅谈昆虫世界的求偶交配行为

在昆虫世界的大观园里,大部分昆虫的受精产卵、生殖繁育都需要经过两性交配的过程才能完成。昆虫种类齐全,求偶行为更是多种多样。本文介绍了几种具有代表性的昆虫的求偶行为。对于昆虫吸引异性,延续种群,繁育后代,并维持物种间的生殖隔离具有重要意义。     

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.     

昆虫同域物种形成机制及检验

从生物学、生态和遗传的角度阐述昆虫同域物种形成过程中涉及到的可能性机制。昆虫同域种的分化与作用于同域初始种群的歧化选择密切相关,歧化选择间接导致种群生态特征和遗传特征的分化,促进同域近缘种群间的生殖隔离。同域物种形成的过程中涉及到性状替换、性选择、同型交配等机制。寄主专化型多见于昆虫同域种的分化过程中,一般以植食性昆虫为主。有关昆虫同域物种形成的检验机制有多种,归纳起来主要包括同型交配的检验、遗传漂流的量化、遗传分化程度和连锁不平衡(LD)的检测、杂交后代适合度的估算等。目前发现在许多昆虫种类中存在同域物种形成的可能性,但是有关其隔离机制并没有得到充分的解释。     

粘虫（Mythimna separata）迁飞行为研究

粘虫成虫期取食、飞翔、求偶或性反应交配和产卵一系列行为是各具相对独立性和顺序性的阶段。飞翔在取食、飞翔、求偶或性反应交配、产卵等期内都有发生,并有不同的飞翔特征,在迁飞中以飞翔期的飞翔最为重要,雌雄蛾的飞翔期在羽化后3－10日龄,因求偶、性反应前期变化而有变异,粘虫雌蛾求偶前期2－11d,平均为5.93d,雄蛾性反应前期3－11d,平均为7.14d。求偶、性反应与迁飞潜力有密切关系。随求偶、性反应前期加长,求偶、性反应前飞翔量呈“S”型曲线增长;求偶或性反应迟的个体有飞翔期,且有1－2个飞翔峰（日）。根据有无飞翔期和求偶、性反应与飞翔量曲线确定雌蛾求偶前期大于5d,雄蛾性反应前期大于4d的个体为迁飞型个体。自然种群中雌蛾迁飞型个体占52.47%,雄蛾占97.14%;不同地理种群江苏、吉林、山东和广东1－4代粘虫,雌蛾迁飞个体依次占47.64%、49.29%、47.22%和68.22%,求偶前期平均依次为5.75,5.64,5.58和6.77d。影响求偶前期的生态因素主要是温度逐渐上升和食料不断老化,两者可能是引起粘虫迁飞的主要因素,讨论了粘虫成虫期行为、繁殖与迁飞潜力及迁飞过程的关系。     

昆虫的求偶行为特征及应用

求偶是动物两性间相互吸引并完成各种生殖活动的一种本能行为,形式丰富,意义深远,对于动物繁衍和生物的进化具有重要的作用。通过求偶,昆虫吸引异性前来交配,进而产卵,为种群的延续注入动力。不同物种的求偶行为具有特异性,通过揭示不同昆虫求偶行为的特点及应用,为农业生产和昆虫分类提供理论依据。     

The effect of flight on reproduction in an outbreaking forest lepidopteran

Post‐flight reproductive investment by female insects may be limited as a result of a trade‐off in resource allocation between flight and reproduction. Outbreaking forest pests reduce their habitat quality as a result of severe defoliation when population densities are high. Female relocation to better‐quality habitats can increase offspring survival but reduce their reproductive fitness through flight. In the present study, the effect of flight on the capacity of female Choristoneura conflictana (Walker) (Lepidoptera: Tortricidae) to mate and produce eggs is examined. Females are flown on flight mills, and the subsequent reproductive capacity of each moth is assessed through measures of mating success and egg production. There is no effect of flight on commencement or the duration of mating. Although flight does not affect egg production directly, energy expenditure as a result of flight (as measured by weight loss) shows a negative correlation to potential fecundity, possibly indicating the resorption of eggs in some females. The effect of female size on fecundity is dependent on mating status, suggesting that energy allocated to reproduction is not dependent on flight treatment. Female moth longevity also has a significant effect on egg production but is dependent on flight and mating treatments. There is a relationship between energy expenditure to flight and reproduction in C. conflictana. Females that fly away from dense populations may produce fewer offspring, although this cost may be mitigated by improved offspring survivorship in less defoliated habitats.     

Larval food limitation in butterflies: effects on adult resource allocation and fitness

Allocation of larval food resources affects adult morphology and fitness in holometabolous insects. Here we explore the effects on adult morphology and female fitness of larval semi-starvation in the butterfly Speyeria mormonia. Using a split-brood design, food intake was reduced by approximately half during the last half of the last larval instar. Body mass and forewing length of resulting adults were smaller than those of control animals. Feeding treatment significantly altered the allometric relationship between mass and wing length for females but not males, such that body mass increased more steeply with wing length in stressed insects as compared to control insects. This may result in changes in female flight performance and cost. With regard to adult life history traits, male feeding treatment or mating number had no effect on female fecundity or survival, in agreement with expectations for this species. Potential fecundity decreased with decreasing body mass and relative fat content, but there was no independent effect of larval feeding treatment. Realized fecundity decreased with decreasing adult survival, and was not affected by body mass or larval feeding treatment. Adult survival was lower in insects subjected to larval semi-starvation, with no effect of body mass. In contrast, previous laboratory studies on adult nectar restriction showed that adult survival was not affected by such stress, whereas fecundity was reduced in direct 11 proportion to the reduction of adult food. We thus see a direct impact of larval dietary restriction on survival, whereas fecundity is affected by adult dietary restriction, a pattern reminiscent of a survival/reproduction trade-off, but across a developmental boundary. The data, in combination with previous work, thus provide a picture of the intra-specific response of a suite of traits to ecological stress.     

The costs of being dark: the genetic basis of melanism and its association with fitness‐related traits in the sand cricket

Melanism is an important component of insect cuticle and serves numerous functions that enhance fitness. Despite its importance, there is little information on its genetic basis or its phenotypic and genetic correlation with fitness‐related traits. Here, we examine the heritability of melanism in the wing dimorphic sand cricket and determine its phenotypic and genetic correlation with wing morphology, gonad mass and size of the dorso‐longitudinal muscles (the principle flight muscles). Previously demonstrated trade‐offs among these traits are significant factors in the evolution of life history variation. Using path analysis, we show that melanization is causally related to gonad mass, but not flight muscle mass. Averaged over the sexes, the heritability of melanism was 0.61, the genetic correlation with gonad mass was ?0.36 and with wing morph was 0.51. The path model correctly predicted the ranking of melanization score in lines selected for increased ovary mass, increased flight muscle mass, an index that increased both traits and an unselected control. Our results support the general hypothesis that melanization is costly for insects and negatively impacts investment in early reproduction.     

An integrated analysis of phenotypic selection on insect body size and development time

Most studies of phenotypic selection do not estimate selection or fitness surfaces for multiple components of fitness within a unified statistical framework. This makes it difficult or impossible to assess how selection operates on traits through variation in multiple components of fitness. We describe a new generation of aster models that can evaluate phenotypic selection by accounting for timing of life‐history transitions and their effect on population growth rate, in addition to survival and reproductive output. We use this approach to estimate selection on body size and development time for a field population of the herbivorous insect, Manduca sexta (Lepidoptera: Sphingidae). Estimated fitness surfaces revealed strong and significant directional selection favoring both larger adult size (via effects on egg counts) and more rapid rates of early larval development (via effects on larval survival). Incorporating the timing of reproduction and its influence on population growth rate into the analysis resulted in larger values for size in early larval development at which fitness is maximized, and weaker selection on size in early larval development. These results illustrate how the interplay of different components of fitness can influence selection on size and development time. This integrated modeling framework can be readily applied to studies of phenotypic selection via multiple fitness components in other systems.     

Synergistic effects of temperature and plant quality,on development time,size and lipid in Eccritotarsus eichhorniae

Body size is an important biotic factor in evolutionary ecology, since it affects all aspects of insect physiology, life history and, consequently, fitness in ectothermic insects and how species adapt with their environment. It has been linked to temperature, with lower temperatures resulting in larger size. In this study, we tested the combined impact of temperature and plant quality on the body size, and development time from egg to adult of Eccritotarsus eichhorniae (Hemiptera: Miridae), an herbivorous insect used as a biological control agent against the invasive aquatic weed, water hyacinth Eichhornia crassipes (Pontederiaceae). We quantified insect size in individuals exposed to three temperatures (20, 25 and 30°C) combined with three qualities of host plant (high, medium and low) by calculating development time and measuring four traits: tibia length, forewing length, dry body mass and lipid content, and we also determined the wing loading index. The development time, dry body mass and lipid content decreased linearly with increasing temperature and decreasing plant quality. The decrease in size was the greatest when high temperature interacted with low plant quality. Smaller individuals had proportionately less lipid content. Wing loading decreased significantly with lower quality of host plant, resulting in individuals likely to have theoretically higher flight ability. The results support the temperature-size rule (TSR) and that plant quality could influence the relationship between development time and the TSR. Results also provide novel evidence for a possible food quality-size rule for both sexes.     

Does wing reduction influence the relationship between altitude and insect body size? A case study using New Zealand's diverse stonefly fauna

Researchers have long been intrigued by evolutionary processes that explain biological diversity. Numerous studies have reported strong associations between animal body size and altitude, but insect analyses have often yielded equivocal results. Here, we analyze a collection database of New Zealand's diverse endemic stonefly fauna (106 species across 21 genera) to test for relationships between altitude and plecopteran body size. This insect assemblage includes a variety of wing‐reduced (26 spp) and fully winged (80 spp) taxa and covers a broad range of altitudes (0–2,000 m). We detected significant relationships between altitude and body size for wing‐reduced, but not fully winged, stonefly taxa. These results suggest that, while the maintenance of flight apparatus might place a constraint on body size in some fully winged species, the loss of flight may free insects from this evolutionary constraint. We suggest that rapid switches in insect dispersal ability may facilitate rapid evolutionary shifts across a number of biological attributes and may explain the inconsistent results from previous macroecological analyses of insect assemblages.     

Development time mediates the effect of larval diet on ageing and mating success of male antler flies in the wild

High-quality developmental environments often improve individual performance into adulthood, but allocating toward early life traits, such as growth, development rate and reproduction, may lead to trade-offs with late-life performance. It is, therefore, uncertain how a rich developmental environment will affect the ageing process (senescence), particularly in wild insects. To investigate the effects of early life environmental quality on insect life-history traits, including senescence, we reared larval antler flies (Protopiophila litigata) on four diets of varying nutrient concentration, then recorded survival and mating success of adult males released in the wild. Declining diet quality was associated with slower development, but had no effect on other life-history traits once development time was accounted for. Fast-developing males were larger and lived longer, but experienced more rapid senescence in survival and lower average mating rate compared to slow developers. Ultimately, larval diet, development time and body size did not predict lifetime mating success. Thus, a rich environment led to a mixture of apparent benefits and costs, mediated by development time. Our results indicate that ‘silver spoon'' effects can be complex and that development time mediates the response of adult life-history traits to early life environmental quality.     

Field estimates of fitness costs of the pace‐of‐life in an endangered damselfly

Theory predicts that within‐population differences in the pace‐of‐life can lead to cohort splitting and produce marked intraspecific variation in body size. Although many studies showed that body size is positively correlated with fitness, many argue that selection for the larger body is counterbalanced by opposing physiological and ecological selective mechanisms that favour smaller body. When a population split into cohorts with different paces of life (slow or fast cohort), one would expect to detect the fitness–size relationship among and within cohorts, that is, (a) slower‐developing cohort has larger body size and higher fitness than faster‐developing cohort, and (b) larger individuals within each cohort show higher fitness than smaller individuals. Here, we test these hypotheses in capture–mark–recapture field surveys that assess body size, lifespan, survival and lifetime mating success in two consecutive generations of a partially bivoltine aquatic insect, Coenagrion mercuriale, where the spring cohort is slower‐developing than the autumn cohort. As expected, body size was larger in the slow‐developing cohort, which is consistent with the temperature‐size rule and also with the duration of development. Body size seasonal variation was greater in slow‐developing cohort most likely because of the higher variation in age at maturity. Concordant with theory, survival probability, lifespan and lifetime mating success were higher in the slow‐developing cohort. Moreover, individual body size was positively correlated with survival and mating success in both cohorts. Our study confirms the fitness costs of fast pace‐of‐life and the benefits of larger body size to adult fitness.     

Variations in life history traits and flight capacity among populations of the light brown apple moth Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae)

Abstract The empirical study of interpopulation variation in life history and other fitness traits has been an important approach to understanding the ecology and evolution of organisms and gaining insight into possible sources of variation. We report a quantitative analysis for variations of five life history traits (larval developmental time, adult body weight, adult lifespan, age at first reproduction, total fecundity) and flight capacity among populations of Epiphyas postvittana originating from four localities in Australia and one in New Zealand. These populations were compared at two temperatures (15° and 25°C) after being maintained under uniform laboratory conditions for 1.5 generations, so that the relative role of genetic divergence and phenotypic plasticity in determining interpopulation variation could be disentangled. Genetic differentiation between populations was shown in all measured traits, with the greatest divergence occurring in developmental time, fecundity and adult body size. However, these traits were highly sensitive to changes in environmental temperatures; and furthermore, significant interactions between population and temperature occurred in all traits except for flight capacity of female moths. Thus, phenotypic plasticity may be another cause of interpopulation variation. The interpopulation variation for some measured traits was apparently related to climatic differences found where the populations originated. Individuals of the populations from the warmer climates tended to develop more slowly at immature stages, producing smaller and less fecund moths but with stronger flight capacity, in comparison to those from the cooler regions. It seems, therefore, that natural populations of E. postvittana have evolved different strategies to cope with local environmental conditions.