天敌对棉铃虫控制效应的实验

棉田害虫天敌种类很多,它们在田间起着控制害虫发生和危害的效应。棉铃虫是棉花生产中的大敌,我们做了如下实验观察。 (一) 不同种天敌对棉铃虫的卵和幼虫日食量情况。在二代棉铃虫发生期(7月份),从田间捕捉不同种类的天敌带回室内饲养,一律饥饿4h后,并都以100(卵和幼虫)分别作食料,重复3次,观察记载日食量(24h)。平均日食量如表     

多样化的棉田生态系统控害保益功能特征研究

应用数量分析与能量测定相结合的方法 ,定量地分析和比较了华北棉区多样化的套间作棉田生态系统与单作棉田生态系统中主要害虫、天敌的种群动态及其天敌对害虫的控制作用 .结果表明 ,多样化的套间作系统中苗蚜与 2代棉铃虫发生轻 ,而伏蚜与 3代棉铃虫发生重 ;套间作系统有利于天敌群落能量的生产 ,尤其是利于捕食性蜘蛛类群的能量生产 ;从棉田生态系统棉株 害虫 天敌相互作用关系来看 ,尽管间套作系统内天敌群落生产力增加 ,保护益虫 (天敌 )作用好 ,同时也增加了害虫群落生产力 ,其控害功能较差 .     

棉铃虫类害虫抗药性研究进展

<正> 棉铃虫类害虫是世界性棉花害虫,主要种类有棉铃虫Heliothis armigera(Hubner)、美洲棉铃虫H.zea(Boddie)和烟芽夜蛾H.virescens(Fabricus)。在棉田中长期大量使用杀虫剂引起棉铃虫类害虫的抗药性不断发展,严重威胁棉花生产,给棉虫治理带来严重的挑战,引起世界各国昆虫工作者的极大关注。 一、棉铃虫类害虫抗药性的发展 自战后化学合成杀虫剂投入使用以来,世     

棉铃虫齿唇姬蜂的寄生对棉铃虫体内主要代谢物质的影响

寄生蜂是调节寄主害虫种群数量的一个重要因子.棉铃虫齿唇姬蜂Campoletis chorideae Uchida是棉铃虫Helicoverpa armigera Hübner和烟青虫Helicoverpa assulta Guenée的主要寄生性天敌,对两种害虫的田间自然控制起着非常重要的作用.本文选取棉铃虫齿唇姬蜂-棉铃虫系统为研究对象,从齿唇姬蜂的寄生对棉铃虫体内主要代谢物质的影响等方面进行了研究.试验结果显示,棉铃虫齿唇姬蜂的寄生使棉铃虫幼虫组织中糖原含量发生了明显的变化,与未被寄生的同龄棉铃虫幼虫相比,被寄生幼虫组织中的糖原含量下降了近一倍,被寄生的棉铃虫幼虫血淋巴和虫体组织中蛋白质、脂肪的含量均显著下降.     

定温条件下棉铃虫种群动态的数学模拟与分析

棉铃虫(Heliothis armigera Hubner)是我国棉花主要害虫之一,70年代以来,曾在我国南北各棉区几次严重为害,这样,对棉铃虫预测与控制的研究成为全国棉虫研究的重点课题之一。温度对棉铃虫的生长发育与生殖力的试验与分析,国内外已有报道(许明霞等,1958;齐兆生,1961;吴坤君等1978、1980),但多着重于温度对生长发育与生殖力的影响,以及实验条件下生命表的分析,应用数学模型对该种害虫在不同温度下的各发育阶段的累积     

棉铃虫磷酸甘油醛异构酶基因Hatpi 的克隆及分析

棉铃虫Helicoverpa armigera是一种严重危害棉花等经济作物的鳞翅目害虫, 开展分子水平研究对防控害虫将具有重要参考意义。本研究利用RACE（rapid amplification of cDNA ends）技术克隆了棉铃虫磷酸甘油醛异构酶(triosephosphate isomerase)基因Hatpi （GenBank登录号为AY736358）。该基因cDNA全长为1 149 bp, 编码248个氨基酸, 预测等电点为5.82, 分子量为16.4 kD。HaTPI含有磷酸甘油醛异构酶类蛋白的典型(βα)8结构、保守的活性位点（Lys12, His94和Glu165）和小肽序列（AYEPVWAIGTG和GGASLKPEF）等。RT-PCR检测分析发现Hatpi在棉铃虫卵巢、幼虫、蛹、成虫均有表达, 提示该基因可能在棉铃虫的不同发育阶段均起作用。     

棉铃虫猖獗因子研究——土壤含水量与化蛹、羽化的关系

<正> 棉铃虫Heliothis armigera(Hubner)从六十年代后期开始,成了长江下游棉区主要害虫,近十年来虫量时大时小,危害时轻时重。如江苏1977年发生量很少,但1978年却特大发生。搞清棉铃虫的猖獗因子,不仅对控制危害,确保棉花丰产有重要意义,在昆虫生态学上也有一定的价值。 棉铃虫在土内筑土室化蛹,与粘虫、地老虎、豆荚螟等害虫有若干相似之处。蛹期土壤水分状况的变化,可以影响化蛹、羽化,从而使     

含生物型增效剂棉铃虫病毒悬浮剂的应用效果研究

本文报道含生物型增效剂棉铃虫核多角体病毒(Helicoverpa armigera nucleopolyhedrovirus,HaNPV)悬浮剂对害虫的防治效果及其对天敌数量的影响.作者筛选灭幼脲类似物作为棉铃虫核多角体病毒的生物型增效剂,HaNPV+4.2ppm氟啶脲(chlorfluazuron)感染3龄初棉铃虫幼虫,感染幼虫的半致死时间(LT50)为2.24d,比单用HaNPV感染幼虫的LT50缩短2.66d.含生物型增效剂的棉铃虫核多角体病毒悬浮剂在田间应用,施药后5d,对2代和4代棉铃虫的防治效果分别为81.4%~85.2%和70.7%~82.6%,施药后7d,对2代和4代的防治效果分别为85.2%~86.3%和69.6%~82.9%.棉铃虫病毒悬浮剂中的生物型增效剂对天敌数量仅有轻微影响.含生物型增效剂棉铃虫核多角体病毒悬浮剂不仅能有效控制害虫,而且对天敌有很好的保护作用.     

江苏沿海农区转Bt基因抗虫棉的研究进展

对当地推广种植的Bt棉进行了9个方面的专题研究,包括：(1)棉花种植结构调整与Bt棉的推广过程,(2)Bt棉应用中存在的问题,(3)Bt棉田靶标和非靶标害虫的发生规律,(4)棉铃虫对Bt棉的为害损失和防治指标,(5)适用于本农区种植的Bt棉品种的筛选与评价,(6)Bt棉不同种植比例对棉铃虫的发生程度的影响,(7)Bt棉田天敌种群的消长动态与原因,(8)Bt棉田主要害虫的监测要点,(9)Bt棉田棉铃虫的协调防治措施。     

Monsanto开发新的植物抗虫性途径

Monsanto Co.(St.Louis,MO)发现了一种新的可使植物具备抗虫性的途径,即经遗传工程使植物表达胆甾醇(CO)基因。 CO技术为Monsanto提供了一种利用苏云金芽孢杆菌(Bt)毒素蛋白防治害虫的替代性方法。称CO可保护植物免受棉象虫和棉铃虫等害虫为害的Monsanto正积极地寻求美国和欧洲对此技术的专利保护。 Monsanto在Mycogen Corp.(San Diego,CA)囊括在植物中使用杀虫Bt基因的美国专利后仅一     

The Defence of First and Second Broods by Great Tit (Parus major) Parents: A Test of Predictive Sociobiology1

We examined the extent to which parental investment, as measured by brood defence, is determined by selection via life history in a short-lived bird, the great tit (Parus major). Great tit parents tending 1st and 2nd broods of the season were used to test five predictions of a cost/benefit model of brood defence based on the species average demography. The benefit was envisaged as the brood's contribution to a parent's fitness, and the cost as the potential loss if the defender dies in the act of defence; this loss was mirrored by Residual Reproductive Value plus a fraction of the brood dying as a consequence of the defender's death. Univariate and multivariate procedures were applied to six measures of defence response in 221 experimentally naive great tit pairs with nestlings. Stimuli consisted of a live raptor and a multi-species taped mobbing chorus (both of which triggered strong alarm), the latter alone, and a novel, visual stimulus inhibiting nest visits for some time. As predicted by the model, response strength and associated risk increased with (1) advancing time in the breeding season, (2) the age of young, and (3) the number of young in 2nd broods. The last finding, being non-trivial, is the strongest and the only unequivocal support for the notion that life-history has moulded parental investment also in a short-lived species; findings (1) and (2) could be alternatively accounted for by simply assuming that parents tailor their defence to environmental conditions permitting a new breeding episode. The model failed to predict the change of defence behaviour between 1st and 2nd broods. Instead, proximate factors coupled to the precise breeding area proved to be of prime importance in determining defence level, thereby falsifying the idea of a rigidly preprogrammed change of response level based on population parameter means. Instead, parents might gauge their defence to quality of young, as also allowed for in the model, or they may sometimes be constrained to display the full defence. As a by-product, the experiments permit us to narrow down the range of selective agents producing the male parent's stronger defence. The sex difference, being prevalent in 1st broods and abating in 2nd broods, indicates that the male, by its defence behaviour, not only invests in its offspring but also in its home range and/or its mate. The latter interpretation is supported most directly by the male's defence behaviour in 1st broods.     

EVOLUTION OF OBLIGATE SIBLICIDE IN BOOBIES. 2: FOOD LIMITATION AND PARENT–OFFSPRING CONFLICT

Proximate limitation on parental food delivery has long been invoked to explain the evolution of single-chick broods of pelagic seabirds such as masked boobies (Sula dactylatra). A second possible proximate limit on brood size is siblicide driven by genetic parent–offspring conflict (POC) over brood size, if siblicidal offspring can reduce brood size to one even if the parents' optimal brood size is greater than one. I tested these two hypotheses by experimentally suppressing obligate siblicide in masked booby broods and comparing breeding parameters of these broods with unmanipulated single-chick control broods. Per capita mortality rate of experimental nestlings was higher than that of controls, but this deficit was more than made up by larger brood size. Parents of experimental broods brought more food to offspring, had higher fledging success, and apparently incurred no additional major short-term cost of reproduction, relative to parents of control broods, thus refuting the food limitation hypothesis. Estimates of inclusive fitness of chicks in experimental broods were higher than were those of control nestlings, a result inconsistent with the POC hypothesis that the siblicidal offspring's optimal brood size is one while the parents' optimum is greater than one. This discrepency between natural brood size and apparent brood size optima might be resolved in several ways: experimental artifacts may give misleading estimates of optimal brood size; experimental and control offspring may have different reproductive values at the time of fledging; nestling masked boobies may face a special frequency-dependent case of POC in which the high risk of sharing a nest with a siblicidal sibling makes invasion of other behavioral genotypes difficult even when offspring and parent inclusive fitnesses are higher from a nonsiblicidal brood of two than from a brood of one.     

Larger clutch size increases fledging success and offspring quality in a precocial species

1. We tested the hypothesis that the ability of parents to raise viable offspring limits clutch size in the greater snow goose ( Anser caerulescens atlanticus L.), a precocial bird.
2. We manipulated clutch size by exchanging complete clutches between pairs of nests to increase or decrease the clutch size by zero (control), one, two or three eggs in 314 nests over 2 years.
3. Pre-fledging survival of goslings increased in enlarged broods and decreased in reduced broods compared to control. Consequently, enlarged broods fledged more offspring and the reverse was true for reduced broods.
4. Size and mass of goslings near fledging was also higher in enlarged broods than in control, which suggests that offspring quality was also enhanced by the manipulation. This is contrary to the common trade-off between offspring numbers and quality.
5. Large families were dominant over smaller ones in feeding sites, which could explain the increased survival and growth of enlarged broods.
6. Our results suggest that the ability to raise young does not limit clutch size in this species and that parents could be more successful (i.e. increase both the number and quality of their offspring) by laying more eggs. However, the time required to lay additional eggs reduces the viability of all offspring and may explain why females do not lay more eggs.     

GEOGRAPHICAL PATTERNS AND POPULATION STRUCTURE IN PERIODICAL CICADAS BASED ON SPATIAL ANALYSIS OF ALLOZYME FREQUENCIES

There are twelve major broods, or year classes, of 17-year periodical cicadas and three major broods of 13-year cicadas. Previous allozyme studies of three 13-year broods and two 17-year broods suggested that broods are distinct evolutionary units, exhibiting homogeneity within broods and heterogeneity among broods. Results from numerical phylogenetic analysis of allozyme data from these broods supported Lloyd and Dybas's (1966a, 1966b) evolutionary hypothesis and were consistent with biogeographical patterns. In the present paper, we use spatial statistics to extend the analysis of biogeographical patterns for periodical cicadas by examining geographic variation in allozyme frequencies within and among ten broods for the three most variable loci. The results from our analysis show that each gene frequency surface exhibits marked spatial autocorrelation. Three major geographic areas of similarity are indicated by the data: the eastern seaboard, the Mississippi Valley, and the eastern edge of the Great Plains. When localities are adjusted for regional membership, the autocorrelation disappears. In biological terms, broods are homogeneous breeding units. Geographically distinct localities within the same brood show little differentiation. Differentiation among populations within broods and among broods within regions exists but is less pronounced than the differentiation among geographic regions. For the particular enzymes examined, allozyme frequency differences appear to reflect the phylogenetic history of the broods rather than their environmental surroundings.     

Estimating Detection Probabilities of Waterfowl Broods From Ground-Based Surveys

ABSTRACT Brood:pair ratios could provide an economical method for assessing spatial or temporal variation in waterfowl productivity, but such estimators are severely biased by incomplete detection of broods. We conducted 3 sequential counts of 1,357 waterfowl broods in northeastern North Dakota, USA, and used closed-population mark-recapture models to estimate total brood abundance while controlling for variation in detection probabilities (p). Blue-winged teal (Anas discors) broods had the lowest average detection probability (p = 0.305), whereas diving-duck broods had the highest average detectability (p = 0.571). Detection was generally highest in morning or evening, but temporal patterns varied among species and there was no survey window that maximized detection probabilities for all species. Detection probabilities averaged 0.108 (SD = 0.056) higher for an experienced observer versus an inexperienced observer. Detection probabilities were 0.044 higher for roadside versus walk-up surveys and increased with increasing brood size, total brood abundance, survey date, wind speed, temperature, cloud cover, and amount of time spent surveying each wetland. Detection probabilities declined with increasing wetland size and amount of tall peripheral vegetation. Our mark-recapture results indicated that a traditional unreplicated brood survey would have missed 67.5% of estimated broods, summed over all species. Use of closed-population mark-recapture techniques provided an effective method for reducing this bias and identifying and quantifying factors that reduce detection probabilities of waterfowl broods. We recommend that future brood surveys incorporate 2 or 3 temporally segregated replicate counts to allow for formal estimation of detection probabilities.     

Intraseasonal effects of clutch manipulation on parental provisioning and residual reproductive value of eastern phoebes (Sayornis phoebe)

Summary First clutches of double-brooded eastern phoebes Sayornis phoebe were manipulated (up two eggs, down 2 eggs or no change) to test for intraseasonal reproductive tradeoffs and to test whether size of first brood influenced food delivery rates to nestlings and nestling quality in second broods.Considering all nests from both broods, rate of feeding nestlings increased linearly with brood size but nestling mass per nest decreased with increasing brood size. High nestling weights in small broods may have resulted from parents delivering better quality food, but we did not test this.Among treatment groups in first broods, nestlings from decreased broods weighed more than those in control or increased broods. Treatment did not influence the likelihood that second nests would be attempted after successful first nests nor did it alter the interval between nests. Nestlings of parents that renested weighed more than those of parents that did not, regardless of treatment, suggesting that post-fledging care may preclude renesting. Mass of individual females did not change between broods, regardless of brood size. Clutch sizes of second attempts were not affected by manipulations of first broods but increasing first broods reduced the number of nestlings parents were able to raise to day 11 in their second broods. However, manipulation of first broods did not affect mean nestling mass per nest of nestlings that survived to day 11.In phoebes, parents of small first broods are able to raise nestlings in better condition. We predict that in harsh years, parents of small first broods would be more likely to renest. Parents of enlarged first broods sacrificed quality of offspring in second broods, which seems a reasonable strategy if nestlings from second broods have lower reproductive value.     

Reproductive investment and parasite susceptibility in the Great Tit

1. Reproduction and parasite defence are assumed to be costly activities for hosts, and therefore trade-offs might exist between reproduction and parasite defence.
2. Brood sizes were manipulated in a population of Great Tits ( Parus major L.) to assess trade-offs between reproduction and parasite defence. Blood samples were taken from males and females during the late nestling phase, and parasite prevalence was compared among parents raising enlarged, reduced and control broods.
3. A higher prevalence of protozoan blood parasites dominated by Haemoproteus majoris was found among parents with enlarged broods, as compared with parents with control and reduced broods, respectively. Brood size manipulation did not affect parasite prevalence between the sexes or between age classes differently.
4. Mean parasite intensity (number of parasites per microscope field) among adult birds only infected with H. majoris was higher for parents with experimentally enlarged broods than controls and reduced broods, respectively.
5. These results support the hypothesis of a trade-off between parasite defence and reproduction.     

Maternal Condition Affects the Offspring Testosterone Concentration in Early Nestling Period: An Experimental Test on Tawny Owls

This study addressed the question of whether maternal condition during egg laying or the rearing environment has a greater effect on offspring testosterone levels. We tested this in field experiments on a population of tawny owls Strix aluco in Duna‐Ipoly National Park, Hungary. In the experiments with females of poor condition, when broods were supplied with extra food none of the nestlings died, whereas in control broods, which were not supplied with extra food, some nestlings did die. Large differences in testosterone levels were correlated positively with hatching order both in experimental and control broods. However, it was only in control broods that the later‐hatched nestlings with low testosterone concentrations, died. In the experiments with females of good condition, the males were removed and females and their broods were supplied with restricted amounts of food. In these broods starving nestlings, whose growth had stopped, were considered as having died and were removed from the nest and hand‐reared. In control broods all nestlings fledged, and both in experimental and control broods testosterone concentrations were more even between siblings. Both types of trials confirmed a maternal influence on offspring testosterone concentration: large between‐sibling differences in concentrations in the broods of females of poor condition, where some nestlings died, could not be reduced with increased food supply, and the more even concentrations in the broods of females in good condition, where all nestlings survived, could also not be increased by restricting the food supply.     

Hormonal Correlates of Dominance and Starvation-induced Aggression in Chicks of the Blue-footed Booby

In the blue-footed booby (Sula nebouxii), the first-hatched chick aggressively dominates its sibling and sometimes kills it when food is in short supply. To investigate the endocrine correlates of dominance-subordinance and hunger-induced agonism, we deprived 15–20-d-old single-chick and two-chick broods of food during 48 h by taping chicks' necks to prevent ingestion of parentally provided food (a protocol used previously and known to elicit escalated sibling fighting). We monitored weight and levels of circulating testosterone, oestradiol and corticosterone in deprived and normally fed broods comprising singletons, seniors (= dominants) and juniors (= subordinates), and observed behaviour to verify that aggression increased in deprived two-chick broods. During the 2 d of fasting, experimental chicks lost on average 6% of their baseline weight. After normal feeding was reinstated, seniors and singletons recovered normal (control) weight, but juniors remained significantly lighter than controls. No testosterone was detected in any nestling, but baseline corticosterone level was 109% higher in juniors than in seniors or singletons, implying that elevated corticosterone in juniors is a consequence of social subordination and may facilitate submissive behaviour. Although there was evidence that aggression of seniors increased under food deprivation, the increase was not accompanied by the rise in levels of testosterone expected under the ‘Challenge hypothesis’ (Wingfield et al. 1990). This result implies that this hypothesis probably does not apply to booby nestlings in the context of starvation-induced aggression. During the 2 d deprivation period, corticosterone levels of experimental chicks increased significantly, then declined to baseline levels a day after tapes were removed. The increase was probably due to the combined effects of starvation and frustration. We suggest that corticosterone could alter responsiveness of nestling blue-footed boobies to external stimuli, resulting in more aggression by dominants and greater readiness of subordinates to submit.     

Brood size and the economy of brood defence: examining Lack's hypothesis in a biparental cichlid fish

Synopsis We tested the explanatory value of two hypotheses reviewed by Lack (1954) in the maintenance of brood size in free-ranging convict cichlidsCichlasoma nigrofasciatum: (1) physiological constraints on egg production, and (2) behavioural constraints imposed by brood defence. Number of free-swimming young in 13 experimental (E) broods was augmented to the upper limit of the size distribution of natural broods (150 young); 18 control (C) broods were handled in the same way but brood size was not changed (mean ± SE = 69.5 ± 11.0). E and C brood sizes were measured at 5 day intervals. At day 20 (just before independence from parental care), 50.3 ± 9.4 (n = 9) young remained in E broods and 30.8 ± 7.8 (n = 8) young remained in C broods (p> 0.05). Offspring number did not differ significantly (p> 0.05) between C and E broods after day 10. Mean growth rate of offspring was significantly lower in E broods than in C broods, perhaps in response to increased density of young in the former. Both the convergence of offspring number in E and C broods and suppression of growth in E broods support a behavioural constraint; that during the first 10 days in which the young are free swimming, two parents are unable to defend large broods as successfully as small broods. A trade-off exists in parental investment between current and future reproduction. Extra-parental investment in current reproduction (eggs) does not result in an increased number of young at independence, therefore a behavioural constraint during brood defence should stabilize the evolution of clutch size.