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1.
During bean seed storage, yield can be lost due to infestations of Acanthoscelides obtectus Say, the bean weevil. The use of resistant varieties has shown promising results in fighting these insects, reducing infestation levels and eliminating chemical residues from the beans. The expression of resistance to A. obtectus in bean varieties is frequently attributed to the presence of phytohemagglutinins, protease inhibitors and alpha-amylase, and especially to variants of the protein arcelin, which reduce the larval viability of these insects. To evaluate the effect of bean seed storage time on the resistance expression of bean varieties to A. obtectus , tests with seeds of three ages (freshly-harvested, 4-month-old, and 8-month-old) were conducted in the laboratory, using four commercial varieties: Carioca Pitoco, Ipa 6, Porrillo 70, ônix; four improved varieties containing arcelin protein: Arc.1, Arc.2, Arc. 3, Arc.4; and three wild varieties also containing arcelin protein: Arc.1S, Arc.3S, and Arc. 5S. The Arc.5S, Arc.1S, and Arc.2 varieties expressed high antibiosis levels against the weevil; Arc.1 and Arcs expressed the same mechanism, but at lower levels. The occurrence of oviposition non-preference was also observed in Arc.5S and Arc.1S. The Arc.3 and Arc. 4 varieties expressed low feeding non-preference levels against A. obtectus. The expression of resistance in arcelin-bearing, wild or improved varieties was affected during the storage of seeds, and was high under some parameters but low in others. The results showed that addition of chemical resistance factors such as protein arcelin via genetic breeding may be beneficial in improving the performance of bean crops.  相似文献   

2.
Life history traits of the phytophagous ladybird beetle,Epilachna niponica were compared between a non-pest population feeding on wild thistle and a pest population feeding on cultivated solanaceous crops, mainly potato. The pest population had larger females, a higher population growth rate, a more continuous oviposition schedule, and a shorter developmental period in the immature stages, compared with the non-pest population. The two populations showed no clear differences in phenology from spring to autumn, egg mass size, hatchability, and larval survival rate. Significant differences were found in number of eggs laid per female during the first and second periods, and in the developmental period of the immature stages. These life history traits were influenced primarily by food plant. A higher fecundity and shorter immature period appear to be readily altered by the host shift from thistle to potato.  相似文献   

3.
Life history and reproductive parameters of the generalist predatory mite Euseius (Amblyseius) finlandicus (Oudemans) were studied in the laboratory at 25 +/- 1 degrees C, with a 16L:8D photoperiod and 60 +/- 15% RH, to investigate its response to different food sources: an eriophyid mite Aceria sp., tulip pollen Tulipa gesnerana L., and two-spotted spider mite Tetranychus urticae Koch. Total developmental time of the immature stages was the shortest on eriophyid mites, followed by pollen, and then spider mites. Fecundity was highest on pollen (43.69 eggs; 1.63 eggs/female/day), then eriophyid mites (39.73 eggs; 1.37 eggs/female/day) and lowest on spider mites (18.16 eggs; 0.80 eggs/female/day). Intrinsic rate of increase (Rm), net reproductive rate (Ro) and finite rate of increase (lambda) followed the same pattern [pollen (0.168, 27.96 and 1.183, respectively), eriophyid mites (0.153, 20.81 and 1.167), spider mites (0.110, 9.44 and 1.119)]. Mean generation time (days) was the shortest on pollen (19.90), followed by eriophyid mites (20.02), and then spider mites (20.59). Average spider mite larvae consumed by E. finlandicus during immature stages were 9.18 for males and 11.85 for females. Adult E. finlandicus females consumed an average of 166.38 spider mite protonymphs during adult stage compared to an average of 66.55 by males. The number of prey protonymphs consumed per day by females was highest in the oviposition period, lower in the pre-oviposition period and the lowest in the post-oviposition period. The eriophyid mite as a prey recorded the shortest developmental time, while pollen as food recorded the highest oviposition rate in E. finlandicus. The potential of this predator as a biocontrol agent against T. urticae is discussed.  相似文献   

4.
Virgin females of Lobesia botrana Denis & Schiffermüller were mated at ages of 1, 3, 5, 8, 12 and 16 days and the effect of mating delay on reproductive output assessed. Delayed mating did not affect female mating success but fertilization was reduced in 16-day-old females. Increased mating delays substantially affected daily oviposition pattern and resulted in a significant reduction of both fecundity and fertility, so that mean number of viable eggs laid decreased from 150 to 22 in 1- and 16-day-old mated females, respectively. Heavier females were more constrained than lighter ones by mating delays and female reproductive efficiency (no. viable eggs/female body weight) was also significantly reduced. Female longevity significantly increased and oviposition period gradually declined with mating delay. The number of viable eggs was positively correlated with both female weight and oviposition period; female longevity and female weight were also significantly correlated. However, the significance of these correlations declined with increased mating delay. Results overall indicated that mating delay drastically reduces female L. botrana reproductive output. The implications of delayed mating of females are discussed from an ecological perspective in relation to L. botrana control using mating disruption.  相似文献   

5.
Abundant lectin-related proteins found in common beans (Phaseolus vulgaris L.) have been shown to confer resistance against the larvae of a number of bruchid species. Genes encoding for these proteins are members of the lectin multigene family, the most representative components being arcelins, phytohemagglutinins and -amylase inhibitors. Arcelins have been described in seven variants, some of which are resistance factors against the Mexican bean weevil (Zabrotes subfasciatus), a major bean predator. In this study the isolation and sequencing of arcelin genes from wild P. vulgaris genotypes, containing Arc3 and Arc7 variants, is reported, and similarities and evolutionary relationships among the seven known arcelins are described. The evolutionary analysis shows that arcelins 3 and 4 cluster together and are the most-ancient variants. A duplication event gave rise to two additional clusters, one comprising arcelins 1, 2 and 6 and separated from the cluster of arcelins 5 and 7. A multiple number of arcelin genes were found in arcelin 3 and 4 genotypes indicating that more than one type of arcelin gene may be present in the same locus. Some of these sequences are reminiscent of ancient duplication events in arcelin evolution demonstrating that arcelins have evolved through multiple duplications. A further aim of this paper was to better understand and describe the evolution of the entire lectin multigene family. Beside arcelins, a number of other types of sequences, such as putative lectins and sequences not easily classifiable, were found in genotypes containing Arc3 and Arc4. These results, together with the evolutionary analysis, indicate that lectin loci are quite complex and confirm their origin by multiple duplication events.Communicated by J.S. Heslop-HarrisonL. Lioi and F. Sparvoli contributed equally to the work  相似文献   

6.
The role of sex-controlling behaviour at oviposition in generating primary sex ratios, and the effect of larval competition on secondary sex ratios, were studied in the gregarious endoparasitoid, Trichogramma chilonis. The production of a fertilized (female) egg is indicated by the incorporation of a pause in abdominal movements during oviposition, while the absence of it indicates the production of an unfertilized (male) egg. During each ovipositional bout, the first male egg is deposited at the second oviposition, and thereafter at intervals of about eight eggs. This simple pattern enables the wasps to adjust their progeny sex ratios under local male competition to a wide range of host size. Inexperienced wasps do not distinguish between parasitized and healthy hosts. Immature mortality is not significantly different between the sexes when a host is attacked by a single wasp, while females suffer higher immature mortality than males when superparasitism occurs.  相似文献   

7.
This study evaluated the predatory capacity of Euseius alatus (DeLeon) as a biological control agent of the pest mite Oligonychus ilicis (McGregor) on coffee leaves under laboratory conditions, using arenas containing 25 O. ilicis per coffee (Coffea arabica) leaf to one specimen of each stage of the predator mite. The functional response and oviposition rate of adult females of E. alatus were evaluated on coffee leaf arenas and offered from 1 to 125 immature stages of O. ilicis per arena. The number of preys killed and the number of eggs laid by the predator were evaluated every 24 h during 8 days. The preys consumed were daily replaced. Male and female adults of E. alatus were the most efficient in killing all developmental stages of O. ilicis. Larvae and nymphs of O. ilicis were the most consumed by all stages of the predatory mite. The functional response and oviposition rates of E. alatus increased as the prey density increased, with a positive and highly significant correlation. Regression analysis suggested a type II functional response, with a maximum predation of 22 O. ilicis/arena and a maximum oviposition rate of 1.7 eggs/day at a density of 70 O. ilicis/arena.  相似文献   

8.
The protein composition of various developmental stages of Dipetalonema viteae was analysed on polyacrylamide slab gels in the presence of sodium-dodecylsulphate. When the total proteins of adult male and female parasites, microfilariae, eggs, and third-stage larvae were compared, apparent qualitative similarities between mature and immature filariae were observed. However, several stage specific components were also identified.  相似文献   

9.
High levels of resistance to Apion godinani Wagner have been reported in bean, Phaseolus vulgaris L., landraces from Mexico. We report on the role of hypersensitivity to A. godmani in five resistant and three susceptible bean genotypes. In susceptible genotypes (cultivars 'Canario 107','Jamapa', and 'Zacatecas 45'), the eggs and first instars of A. godmani were embedded in the pod mesocarp and usually were surrounded by healthy tissue. In contrast, in resistant landraces ('Amarillo 154', 'Amarillo 155', 'J-117', 'Puebla 36', and 'Pinto 168'), necrotic tissues developed concentrically around the oviposition site, encapsulating eggs and dead larvae. An inverse relationship between percentage egg and larval encapsulation at the early immature pod stages and percentage of damaged seeds at harvest was found. Results indicate that hypersensitivity in developing pods plays an important role in antibiosis to A. godmani in beans. This information will facilitate future genetic and biochemical research and provide much needed information concerning the phenotypic basis of resistance to A. godmani in bean.  相似文献   

10.
在15~35℃、RH80%~85%条件下,研究了加州新小绥螨Neoseiulus (Amblyseius) californicus (Mcgregor)以截形叶螨Tetranychus truncatus Ehara为猎物时,不同螨态的发育和实验种群生命表。结果表明,加州新小绥螨在此温度范围内能完成世代发育,世代发育历期随着温度升高而逐渐缩短。该螨能适应35℃的高温条件,雌性的发育历期最短仅为6.14d。平均产卵期和平均寿命均随着温度的上升逐渐缩短。20℃~25℃时,该螨的平均产卵量最大,达53.73粒/雌。净增殖率在20℃时最高(48.2525),且雌雄性比最大。15℃时内禀增长率和周限增长率均最低,分别为0.0638和1.0659,种群倍增时间最长(10.8669d),35℃时内禀增长率和周限增长率均最高,分别为0.1954和1.2158,种群倍增时间最短(3.5477d)。  相似文献   

11.
A phenology simulation model was developed for Scotinophara lurida (Burmeister). The components for the model were a degree-day immigration flight model of overwintered adults, temperature-dependent developmental models of each stage, survival rates of each stage, and an adult oviposition model. A degree-day model for immigration flight of overwintered adults was developed with blacklight trap catch data by a Weibull function. Laboratory experiments using seven constant temperature regimens were conducted to determine the effect of temperature on the development of immature stages. Developmental rates of each immature stage fit well to a linear model. Distribution of developmental time for each immature stage was successfully modeled against physiological age by a Weibull function. To determine the temperature effect on longevity, fecundity, and survival of female adults, laboratory and greenhouse experiments were conducted. The adult developmental rate (1/median longevity) was described by a linear model. The oviposition model was developed incorporating the three components of average total fecundity, cumulative oviposition rate function, and survival rate function. The simulation model predicted the time of peak occurrences of life stages of S. lurida well.  相似文献   

12.
Bioefficacy of two vegetable oils, namely ethyl oleate and Acorus calamus, were conducted against the pulse beetle Callosobruchus maculatus (Fabr.) under a constant temperature of 29 ± 1 °C and a relative humidity of 65 ± 5% R.H. Four concentrations (0.125, 0.25, 0.5 and 1.0%) of each oil were used against the adult and tested their latent effect on the immature stages of the beetle. The results obtained show insecticidal effect of both ethyl oleate and A. calamus oil; however, A. calamus oil proved to be more toxic to the adults at all the concentrations tested in comparison to the ethyl oleate oil. As the concentration of the oils decreased, the percentage mortality decreased. The obtained results concentrated on biological efficacy of the oils tested against the adults. Both oils affected the longevities of both male and female C. maculatus adults in comparison to the control. The oviposition periods of the adult female were affected significantly in comparison to the control. A. calamus oil prohibited oviposition completely at high concentrations of 0.5 and 1.0% and caused complete sterility to the females. Lower concentrations decreased the oviposition period greatly and reduced the number of eggs laid in comparison to the control. Ethyl oleate had an inconsiderable latent effect on the incubation period as well as the percentage of hatching of the resulting eggs. A. calamus oil decreased the percentage of egg hatchability with serious increase in the percent sterility. The two tested oils had slight extension in either larval or pupal stage of the resulting progeny of C. maculatus. Both oils show oviposition deterrency towards C. maculatus adults. The oviposition deterrent index was 100% when mung bean seeds were treated with A. calamus oil. The bruchid females laid all eggs on control seeds and no eggs were laid on treated seeds.  相似文献   

13.
In this article, the ontogeny and reproductive biology of Diadegma semiclausum (Hym.: Ichneumonidae), an important parasitoid of Plutella xylostella (Lep.: Plutellidae) are described in detail. We did dissect parasitized P. xylostella larvae in phosphate-buffered saline and determine the external morphology of its parasitoid at all developmental stages. The developmental duration of its immature stages, adult longevity, total oviposition period and fecundity of the parasitoid are determined at 24 ± 1 °C, 65  ±  5% R.H., and a photoperiod of 16:8 h L:D. The mean duration of egg and larval stages is 9.56 days and the prepupa and pupa stages last for 8.27 days. In average, female longevity is 1.31 times longer than that of males, and females lay 300 eggs in total. The peak of D. semiclausum oviposition is on the eighth day after mating. The egg loading pattern of D. semiclausum was investigated to determine the parasitoid ‘ovigeny index’ throughout the female's parasitoid lifetime. Initial egg load in immature females (<2 h age) is 1.45 per female and the mean lifetime potential fecundity (total immature and mature oocytes), at four interval ages, is 34. With an ovigeny index value of 0.038, D. semiclausum is considered moderately to strongly synovigenic. In the absence of the host, after 3 days, the number of eggs is decreased in D. semiclausum. Our results demonstrated that there is a negative relation between the ovigeny index and egg resorption in this parasitoid.  相似文献   

14.
The silverleaf whitefly is one of the most harmful pests that attack bean crops, mainly for extracting large quantities of phloem sap and transmitting the bean golden mosaic virus. Resistant germoplasm plants can be an important method for controlling this pest. The biological aspects of Bemisia tabaci B biotype on bean (Phaseolus vulgaris) genotypes were evaluated. The tests were conducted under laboratory conditions, with the following genotypes: Arc 1, Arc 3s, Arc 5s, G13028, G11056 and Porrillo 70. The bean plants in a stage IV-1 were infested during one day with silverleaf whiteflies. Afterwards the eggs and nymphs were observed until adult emergence. Longevity and fecundity of emerged insects were also evaluated. The longest development time occurred for nymphs fed on Arc 3s genotype (26.5 days), following by G11056 (25.9 days) and G13028 (25.3 days). The development period was 5.5 days longer in Arc 3s when compared with Porrillo 70. Also, the wild genotypes Arc 3s and G11056 showed higher mortality rates (94.7% and 83.1%, respectively), which may suggest antibiosis and/or feeding nonpreference resistance type. For this reason, although longevity and fecundity were not influenced when the whitefly fed on resistant genotypes (Arc 3s, G11056, G13028 and Arc 5s), those genotypes can be used for bean breeding program towards B. tabaci B biotype.  相似文献   

15.
Summary The life table of a local strain of grape phylloxera was determined to evaluate the resistance of the most commonly used rootstocks: Rul40, R99, and 3309C, and one local variety ‘Helwani’. The study was carried out by applying both in vitro dual culture and small root pieces testing systems. The results showed that there was a great variation in percentage mortality of immature stages, number of eggs laid, adult fertility, oviposition period, and developmental time between all tested rootstocks and the local variety, regardless of the applied testing systems. Based on the population prediction, Helwani would be a suitable host as it would be susceptible to the destructive insects in the field and the rootstocks would be resistant. However, Rul 40 rootstock was more susceptible than R99 and 3309C rootstocks.  相似文献   

16.
Iphiseiodes zuluagai Denmark & Muma is an important predator of Brevipalpus phoenicis (Geijskes) on citrus in Brazil. The suitability of Tyrophagus putrescentiae (Schrank) as a food source of I. zuluagai in laboratory rearing was investigated at 25.5 +/- 0.5 masculineC, 88 +/- 7% RU and photophase of 12h. Initially, levels of oviposition of the predator fed on eggs were evaluated, as well as the dead or live post-embryonic stages of T. putrescentiae, in a period of 10 days. The daily oviposition rate was 1.3 egg per female when they were fed on eggs on T. putrescentiae, 0.7 egg per female when they were fed on dead post embryonic stages and about 0.3 egg per female when they were fed on live post-embryonic stages. Later, the life table of I. zuluagai was constructed, when eggs of T. putrescentiae were offered to the predators as prey. The immature stages were observed every 8h, to determine the corresponding durations. In the adult phase, the mites were observed every 24h, to determine the reproductive parameters. The intrinsic rate of natural increase (r m) was 0.11 female/ female/day; resulting in a finite rate of increase of 1.11 (l). The net reproductive rate (R0) was 7.1 females/generation, with a mean generation time (T) 18.6 days. The results show that T. putrescentiae is a favorable food source for the development of I. zuluagai.  相似文献   

17.
Artificial oviposition sites were used to estimate egg deposition rates in the field. Females laid an average of 10.76 eggs/minute with a mean duration of 22.81 minutes, giving an average clutch size of 245 eggs. Since one mating corresponded to one clutch of eggs, lifetime mating success was used as a measure of the number of clutches produced. Mean lifetime clutch production was 5.91 clutches per female, equating to 1447 eggs per female per lifetime. Eggs were hatched in the laboratory at temperatures comparable with those in the field. Hatching was highly synchronised and the overall hatching success was 75.1%. Causes of egg mortality in the laboratory were limited to infertility and unhatchability. Since no other sources of egg mortality could be found at the study site, this value was a good reflection of hatching success in the field. Lifetime egg production and hatching success were used to estimate the number of viable offspring produced per female, giving a higher order estimate of reproductive success than has previously been published for a zygopteran.  相似文献   

18.
Atherigona soccata (Rondani) (Diptera: Muscidae) is one of the most important pests of sorghum, Sorghum bicolor (L.) Moench, in Asia, Africa, and the Mediterranean Europe. Exploitation of cytoplasmic male sterility (CMS) for hybrid production has resulted in considerable narrowing of the genetic base and may increase the vulnerability of this crop to insect pests. Therefore, we studied the expression of different mechanisms of resistance in sorghum to A. soccata in CMS (A) and maintainer (B) lines of 12 genotypes under field and greenhouse conditions. The CMS lines of A. soccata-resistant genotypes were preferred for oviposition (78.5 versus 71.5% plants with eggs) and suffered greater deadheart incidence (47.6 versus 41.6%) than the corresponding maintainer lines, whereas such differences were not apparent in CMS lines belonging to the susceptible genotypes (92.7 versus 92.3% plants with eggs and 75.6 versus 74.6% deadhearts) under multichoice field conditions. Similar differences also were observed under controlled conditions in the greenhouse. The larval period (9.0 versus 8.8 d) and pupal mortality (18.4 versus 13.4%) were greater on maintainer lines than that on the CMS lines in the resistant group. The male and female pupal weights, fecundity, and antibiosis index were greater on the CMS than on the maintainer lines. The maintainer lines showed better recovery resistance than the CMS lines, but no such differences were observed in tiller deadhearts. The differences in susceptibility to A. soccata were greater in the A. soccata resistant CMS and maintainer lines than in the CMS and maintainer lines belonging to susceptible genotypes. Conversion of A. soccata-resistant genotypes into alternate less susceptible cytoplasmic backgrounds may be undertaken for developing sorghum hybrids with stable resistance to A. soccata.  相似文献   

19.
【目的】本文旨在明确营养状况不同造成的梨小食心虫Grapholitha molesta(Busck)雌、雄蛹重量差异对其羽化的成虫产卵量、产卵期、寿命及下一代(F1)幼虫发育的影响。【方法】室内条件下,通过不同的饲养方法,获得个体重量不同的梨小食心虫雌、雄蛹,待其羽化交配后,记录其产卵量、产卵时间和成虫寿命;卵孵化前后,分别测量卵和初孵幼虫大小,计算卵孵化率,统计幼虫发育历期。【结果】雌蛹重量对梨小食心虫的成虫产卵量影响显著,其重量与产卵量呈正相关(y=15.505x-59.292);同一条件下,雌蛹与雄蛹重量也呈正相关(y=0.823x-0.538)。同时,雌蛹重量对成虫产卵期影响也较大,蛹重大的个体羽化的雌虫比蛹重小的个体羽化的雌虫产卵高峰期提前1 d;较重、中等和较轻蛹羽化出的雌虫个体每天产卵量高于10粒/雌的时间分别为9~10,7和5~6 d;产卵量高于5粒/雌的时间分别为12~13,9和6~7 d。而雄蛹重量对产卵量、雄成虫寿命影响没有明显影响。较轻的蛹羽化的雌成虫寿命比较重蛹羽化的雌成虫短2~3 d;而雄蛹重量对其羽化的雄成虫寿命影响没有明显规律。雌、雄蛹重量对其羽化成虫的卵孵化率、卵和初孵幼虫的大小影响均不显著,对F_1幼虫发育历期影响也不显著。【结论】梨小食心虫雌蛹重对羽化成虫的产卵量和产卵期等影响显著,田间防治时应注意在不同条件下完成发育的个体,尤其是雌虫,由于营养差异引起的个体大小对随后种群增长的影响。  相似文献   

20.
在实验室条件下研究了辣椒碱对烟粉虱的生物活性及生长发育和生殖力的影响.结果表明:辣椒碱对烟粉虱各虫态均有杀虫活性,且随辣椒碱浓度的增大活性增强;辣椒碱浸叶法/浸虫法处理对烟粉虱成虫、卵和若虫的毒力(LC50分别为3525.79、1603.29和1526.27mg·L-1))均高于内吸法处理(LC50分别为5360.04、2359.19和5897.43 mg.L-1),两种处理方法下辣椒碱对烟粉虱卵的毒力均明显高于对成虫的毒力;2000和4000 mg·L-1浓度辣椒碱对烟粉虱成虫具有明显的拒食作用,烟粉虱在该两种浓度辣椒碱处理过的棉花叶上取食24 h的蜜露分泌量均显著低于取食非处理棉花叶后的蜜露分泌量;辣椒碱各试验浓度对烟粉虱成虫均表现出较强的产卵忌避作用,当辣椒碱处理浓度达4000 mg·L-1时,对烟粉虱的选择性产卵忌避率和非选择性产卵忌避率分别高达94.2%和83.0%.500、1000和2000 mg·L-1辣椒碱浸渍处理对烟粉虱存活卵和若虫的发育历期、成虫羽化率均没有影响,但辣椒碱4000mg·L-1处理明显延长烟粉虱若虫发育历期、降低成虫羽化率.不同浓度辣椒碱处理均明显抑制烟粉虱生殖力,且这种抑制作用随辣椒碱浓度的增大而增强.  相似文献   

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