Effect of diet on male reproductive tract of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae).

The morphology and histology of the reproductive tract of males of the predator Podisus nigrispinus (Dallas) fed on different diets were studied. P. nigrispinus was fed on diets of: larvae of Alabama argillacea (Hübner), Tenebrio molitor L., Musca domestica L., and an artificial diet. The male reproductive tract, independent of diet, showed testes with intense red coloration in a compact, circular, or slightly oval structure. The vasa deferentia were similar in color to the testes and formed long filaments, which joined with the yellow-cream colored ejaculatory duct. The morphological characteristics of the male reproductive tract were similar under all diets, except for the artificial one. The histological studies demonstrated that independent of the diet the testes of P. nigrispinus were composed of four to six follicles. The testes with six follicles generally had four developed and two atrophied follicles. The morphological and histological differences of the testes of P. nigrispinus when fed with different prey are presented and discussed.     

Effects of Metarhizium anisopliae (Metsch.) Sorok. and Beauveria bassiana (Bals.) Vuill. on the predatory stinkbug Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae)

Entomopathogenic fungi and the predatory stinkbug Podisus nigrispinus (Dallas) can target simultaneously the same or different pests in agroecosystems. Topical contact during fungal dispersion or spraying, walking on plant surfaces and ingestion of contaminated prey are some of possible ways of interactions between fungi and the predatory stinkbug. The impact of three isolates of Metarhizium anisopliae (Metsch.) Sorok. (866, 1022 and 1189) and Beauveria bassiana (Bals.) Vuill. (604, 634 and 561) against nymphs and adults of P. nigrispinus was investigated under laboratory conditions. M. anisopliae caused higher mortality compared to B. bassiana either by topical application or by dry residue on cotton leaves. Topic contact with both fungi caused higher mortality to the predator. No mortality confirmation was reported for the adults. Nymphs fed with cotton leafworm larvae Alabama argillacea (Hübner) (Lepidoptera: Noctuidae) contaminated by the fungi had their reproduction affected, but this was not observed when adult predators fed on contaminated larvae. These findings suggest that isolates of M. anisopliae can cause mortality of P. nigrispinus nymphs by topical contact, while isolates of B. bassiana were less harmful by all ways of infection as compared to M. anisopliae.     

Nymphal Development and Reproduction of Podisus nigrispinus (Heteroptera: Pentatomidae) Fed With Combinations of Tenebrio molitor (Coleoptera: Tenebrionidae) Pupae and Musca domestica (Diptera: Muscidae) Larvae

The development and reproduction of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) fed on Tenebrio molitor L. (Coleoptera: Tenebrionidae) and Musca domestica L. (Diptera: Muscidae) were studied in four treatments. P. nigrispinus was permitted to feed on: (1) T. molitor pupae (T 1 ); (2) Musca domestica larvae (T 2 ); (3) both prey supplied simultaneously (T 3 ); (4) both prey supplied on alternate days (T 4 ). Duration of the nymphal period of P. nigrispinus was similar in all diets studied with nymphal viability of approximately 75%. Heavier females were obtained in T 1 and T 4 , but no correlation between this factor and the reproductive rate of the predator was found. Therefore, the use of body weight as a parameter to evaluate rearing quality should be approached with caution. However, females of this predator showed higher egg and nymph production when they received both prey. For this reason P. nigrispinus should be reared with T. molitor and M. domestica simultaneously or on alternate days.     

Effect of temperature on life table parameters of Podisus nigrispinus (Het., Pentatomidae) fed with Alabama argillacea (Lep., Noctuidae) larvae

Abstract: The influence of temperature on life table parameters of Podisus nigrispinus (Dallas) (Het., Pentatomidae) fed with Alabama argillacea (Hübner) (Lep., Noctuidae) larvae was studied. This predator was kept at constant temperatures of 20, 23, 25, 28, 30 and 33±0.2°C, at relative humidity of 60±10% and photoperiod of L : D 14 : 10. Gross (GRR) and net ( R ₀) reproductive rates of P. nigrispinus ranged from 1.6 to 366.6 and from 0.02 to 189.5 females/female at temperatures of 33 and 28°C, respectively; generation time ( T  ) ranged from 33.3 (33°C) to 85.5 (20°C) days; doubling time ( D ) from 0.82 (33°C) to 17.8 (20°C) days; intrinsic rate of increase ( r _m ) from −0.13 (33°C) to 0.12 (28°C) per day; and the finite rate of increase ( λ ) from 0.88 (33°C) to 1.12 (28°C) females/female added to the population per day. The ideal age to release P. nigrispinus should be when this predator presents higher reproductive values (VR _x ); that is, its adults are about 7 days old, independent of prevailing temperature. Population growth of P. nigrispinus was affected by temperature with maximum numerical response between 28 and 30°C. The negative population growth shown at 33°C may not occur in natural conditions due to milder microclimate in the cotton agroecosystem and due to oscillations of temperature in the course of the day.     

Population growth rate of the depredating Podisus nigrispinus (Heteroptera: Pentatomidae) and of the Tuta absoluta (Leptoptera: gelechiidae) in wintering place

The fertility life table of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) preying either on Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) caterpillars or on alternative prey Tenebrio molitor L. (Coleoptera: Tenebrionidae) under greenhouse conditions (30 +/- 5 degrees C, 61 +/- 23% RH) were studied. The life table was also determined for the pest T. absoluta under the same conditions. The net reproductive rate (Ro) and the intrinsic rate of natural increase (rm) were higher 14.13 and 46.32 times for predators fed on T. molitor prey, however, the generation time (T) was similar between prey. The pest T. absoluta showed Ro and rm higher 2.15 and 32.10 times than those achieved for predators fed on this pest. However, females fed on a suitable prey T. molitor showed higher Ro and rm than those yielded for the pest. The survival curves were similar for P. nigrispinus females fed on both prey and classified as being type II by Weibull analysis. The results suggest that P. nigrispinus is able to maintain its population preying only on T. absoluta caterpillars; however, the life table parameters determined individually for both showed that the pest produces more generations per year and faster population natural growth than the predator.     

Effect of host age on life cycle and morphological characteristics of Glyptapanteles liparidis (Hymenoptera: Braconidae), a parasitoid of Acronicta rumicis (Lepidoptera: Noctuidae)

The life cycle of Glyptapanteles liparidis was 23.75 ± 1.26, 21.95 ± 2.44 and 20.83 ± 0.78 days when fed on the first, second and third instar larvae of Acronicta rumicis, respectively. Although insufficient numbers hindered statistical analysis, the life cycle of G. liparidis appeared to be shortest, 19 days, when fed on fourth instar larvae. The life cycle of G. liparidis tends to shorten as the larvae of A. rumicis fed upon are more advanced. The body length, forewing length and head capsule width of female G. liparidis fed on first instar larvae of A. rumicis were greater than those of males, while the antennae of males were longer than those of females. When fed on second instar larvae, there was no difference in body length and head capsule width between males and females, but the male antennae were longer than the female, and the female forewings were longer than the male. When fed on third instar larvae, there was no significant difference in head capsule width between the sexes, but female body length and forewing length were greater than the male, and the male antennae were longer than the female. On the whole, females were bigger than males in terms of body length and forewing length, while antennae of the males were longer than those of the females. There was no difference in head capsule width between males and females. Body length, antenna length, forewing length and head capsule width of male and female G. liparidis were relatively larger when fed on first instar larvae of A. rumicis than when fed on second and third instar larvae.     

Complexity in specificities and expression of Helicoverpa armigera gut proteinases explains polyphagous nature of the insect pest

Helicoverpa armigera is a devastating pest of cotton and other important crop plants all over the world. A detailed biochemical investigation of H. armigera gut proteinases is essential for planning effective proteinase inhibitor (PI)-based strategies to counter the insect infestation. In this study, we report the complexity of gut proteinase composition of H. armigera fed on four different host plants, viz. chickpea, pigeonpea, cotton and okra, and during larval development. H. armigera fed on chickpea showed more than 2.5- to 3-fold proteinase activity than those fed on the other host plants. H. armigera gut proteinase composition revealed the predominance of serine proteinase activity; however, the larvae fed on pigeonpea revealed the presence of metalloproteases and low levels of aspartic and cysteine proteases as well. Gut proteinase activity increased during larval development with the highest activity seen in the fifth instar larvae which, however, declined sharply in the sixth instar. Over 90% of the gut proteinase activity of the fifth instar larvae was of the serine proteinase type, however, the second instar larvae showed the presence of proteinases of other mechanistic classes like metalloproteases, aspartic and cysteine proteases along with serine proteinase activity as evident by inhibition studies. Analysis of fecal matter of larvae showed significant increase in proteinase activity when fed on an artificial diet with or without non-host PIs than larvae fed on a natural diet. The diversity in the proteinase activity observed in H. armigera gut and the flexibility in their expression during developmental stages and depending upon the diet provides a base for selection of proper PIs for insect resistance in transgenic crop plants.     

Development and reproduction of Podisus distinctus (Heteroptera: Pentatomidae) fed on larva of Bombyx mori (Lepidoptera: Bombycidae).

Biological control has been reducing the use of chemical products against insect pests, especially predatory Pentatomidae. Species of this group can present high variations in their life cycle as a result of their diet. Thus, the objective of this research was to study nymph development and reproduction of Podisus distinctus (St?l, 1860) (Heteroptera: Pentatomidae) fed on Bombyx mori L., 1758 (Lepidoptera: Bombycidae) larvae (T1), compared to those fed on Tenebrio molitor L., 1758 (Coleoptera: Tenebrionidae) (T2) and Musca domestica L., 1758 (Diptera: Muscidae) larvae (T3) at a temperature of 25 +/- 0.5 degrees C, relative humidity of 70 +/- 2%, and photophase of 12 h. Predators fed on B. mori showed duration of the nymph phase (18.68 +/- 1.02) similar to those fed on T. molitor (18.32 +/- 1.49). Pre-oviposition and oviposition periods and number of egg masses, besides eggs and nymphs per female, were higher with B. mori (5.83 +/- 2.02; 15.00 +/- 7.40; 8.42 +/- 1.84; 296.69 +/- 154.75; and 228.55 +/- 141.04, respectively) while longevity of males and females of P. distinctus was 25.76 +/- 16.15 and 35.00 +/- 16.15 days with T. molitor, and 20.57 +/- 13.60 and 23.46 +/- 12.35 days with B. mori, respectively.     

亚洲玉米螟幼虫对氮、糖的吸收和利用

本文以不同含氮和含糖量的系列人工饲料为材料,研究了亚洲玉米螟Ostrinia fur nacalis(Guen6e)幼虫对氮和糖的吸收和利用。结果表明：幼虫对饲料中氮的吸收能力随虫龄增加而下降,对糖的吸收能力则随之而增强;5龄幼虫对糖的吸收能力随所食饲料中氮含量的增加而增强,而对氮的吸收则与饲料糖含量关系不大,5龄幼虫对氮和糖的消耗速率均随饲料含糖量增加而加快,但幼虫的氮利用率和虫体含氮量则随之下降;幼虫的氮消耗速率随饲料含氮量的增加而增加,而氮利用率则下降,5龄幼虫的氮利用率比3龄幼虫的氮利用率低,导致虫体含氮量的迅速下降。这些结果说明饲料中氮含量影响幼虫对糖的吸收,高龄幼虫对糖的需要量增加而对氮的需要则较稳定,饲料中糖比氮更重要。     

Gamma irradiation as a quarantine treatment for apples infested by codling moth (Lep., Tortricidae)

Abstract: Effects of gamma radiation on the fifth instar codling moth, Cydia pomonella (L.), larvae were examined. Mature larvae were exposed to a series of gamma radiation doses ranging from 50 to 250 Gy and survival to pupae and adults was examined. The results showed that pupation and adult emergence decreased with increasing radiation dose. The results also showed that diapausing larvae were more sensitive to irradiation treatment than non-diapausing larvae, and females were more sensitive than males. A dose of 150 Gy reduced adult emergence to less than 2% in non-diapausing larvae, while a dose of 200 Gy completely prevented it. Furthermore, none of the emerging moths exposed to a dose of 150 Gy were females; at 100 Gy dose, the percentage of females was less than 14%. Irradiating larvae in apple fruit in a small-scale laboratory experiment produced similar results. Tests in which >100 000 larvae (in the fifth instar) were irradiated in an artificial rearing medium with a dose of 200 Gy resulted in no adult emergence. Similar results were also obtained when >32 000 larvae in the same stage were exposed in apple fruit to the same dose. The results indicate that the use of ionizing radiation as a quarantine treatment for codling moth infested fruits is feasible and requires a relatively low dose.     

食物对棉铃虫生长发育及繁殖的影响

用棉花、花生、玉米及人工饲料作为食料,模拟幼虫田间取食习性,同时为雌蛾设立补充和无补充营养两个处理,研究了食物对棉铃虫 Helicoverpa armigera (Hübner) 生长发育及繁殖的影响。4种食料组幼虫历期之间有显著差异;雌、雄蛹重花生组显著小于其余三组。雌蛾腹部干重及其脂肪百分含量与雌蛹体重的排列顺序一样,雌蛾腹部干重人工饲料组显著大于棉花组和花生组。雌蛾寿命和繁殖受幼虫食料和成虫食物的双重影响。喂10%蜂蜜时,雌蛾寿命、交配率和产卵量在四个幼虫食料组之间没有显著差异。但喂以清水时,花生组雌蛾均未交配,寿命和产卵量显著小于其余三组。从同种幼虫食料来看,除人工饲料组外,其余3组雌蛾喂清水时的产卵量和寿命均比喂10%蜂蜜溶液时的显著下降。基于这些结果,作者认为棉花、玉米比花生更适合于棉铃虫的生长发育和繁殖。在田间自然栽培状态下,不同食料植物的糖分含量对棉铃虫生长发育和繁殖影响较大,含氮量的变化影响小。     

Antifeedant and toxic activity of Adhatoda vasica leaf extract against Spodoptera littoralis (Lep., Noctuidae)

Abstract: The effect of crude methanolic extracts of Adhatoda vasica leaves on the feeding and performance of Spodoptera littoralis larvae was investigated in the laboratory. Feeding on fresh leaves resulted in 100% mortality of larvae after 26 days of unsubstantial growth. The extract exhibited strong antifeedant and toxic activity against the larvae when applied either on leaf discs or incorporated into artificial diet. Under choice conditions the antifeedant index calculated over 72 h for neonate larvae increased significantly (from 71.5 ± 3.2 to 92.1 ± 4.2) as the concentration of extract in the treated diet increased from 200 to 1000 ppm. Consumption by the sixth instar larvae of leaf discs dipped in 0.01, 0.1 and 0.2% extract solutions was significantly lower than consumption of control discs in both choice and no-choice tests. The latter two concentrations deterred feeding by 63.4 and 90.4%, respectively, under choice conditions, while only the 0.2% extract solution deterred feeding by 56.8% in the no-choice test. Toxicity of the extracts was manifested by a high mortality, reduced growth rates, and low weight gain by larvae fed on diets containing 200–2000 ppm of the extract. No larvae survived to pupation under the latter concentration. The time to pupation increased from 15.8 ± 0.4 to 37.9 ± 4.1 days as the extract concentration in diet increased from 0 to 1000 ppm. When fed to the fifth instar larvae, the crude extract significantly reduced consumption, growth, utilization of ingested and digested food, and approximate digestibility. The consumption-dependent growth efficiency of animals fed on extract-free diet was significantly higher than the growth efficiency of animals fed on extract-containing diets, suggesting both antifeedant and toxic activities of the extract.     

Effects of maternal diet on fecundity and larval development in the 'primitive' granivorous carabid Amara (Curtonotus) macronota

Granivory is one of the most specialized food habits in the Carabidae and has been reported for species from the tribes Zabrini and Harpalini. Most studies of carabid granivory have been conducted using specialized granivorous species, and few have examined primitive ones. This study examined effects of maternal diet on fecundity and larval development in Amara ( Curtonotus ) macronota (Solsky) (Coleoptera: Carabidae), a member of the most basal clade of the tribe Zabrini; a previous study indicated that larvae of this species are omnivores with a tendency toward carnivory. Three diet types, Tenebrio molitor L. larvae, mixed seeds [ Bidens frondosa L. (Asteraceae), Setaria spp., and Digitaria ciliaris (Retz.) Koeler (both Poaceae)], and T. molitor larvae + mixed seeds, were used as maternal diets, and larvae were reared on T. molitor larvae + mixed seeds (optimal diet) or T. molitor larvae (suboptimal diet). Fecundity differed significantly among treatments, with individuals fed the T. molitor larvae + mixed seeds diet having the highest fecundities and the mixed seeds diet producing the lowest values. Larval development [survival and duration of development through pre-overwintering stages (first and second instars)] was not significantly affected by either maternal or larval diets, but the addition of seeds to the maternal diet had a weak negative effect on larval survival. These results are in contrast with findings from specialized granivorous carabids, in which both adults and larvae performed best with pure-seed diets. Recent molecular phylogenies indicate that these specialized granivorous carabids belong to derived lineages, while A. macronota is the most basal clade of each tribe. These results are compatible with the hypothesis that carabid granivory has evolved gradually from ancestral carnivory, with omnivorous habits occurring as a transient state.     

Contribution of fungal biomass to the growth of the shredder, Pycnopsyche gentilis (Trichoptera: Limnephilidae)

1.  1. It has been accepted that aquatic hyphomycetes colonising submerged leaves increase the nutritional value of leaf detritus and suggested that fungal biomass plays a greater role in the growth of shredders than leaf tissue itself. However, it is not clear what proportion of the nutritional needs of shredders is met by fungal biomass.
2.  We fed Pycnopsyche gentilis larvae with tulip poplar ( Liriodendron tulipifera ) leaf discs colonised by the aquatic hyphomycete, Anguillospora filiformis , which had been radiolabelled to quantify the contribution of fungal carbon to the growth of the shredder at different larval developmental stages. Instantaneous growth rates of larvae on this diet were also estimated.
3.  When provided with fungal-colonised leaves (14–16% fungal biomass), the third and the fifth instar larvae of P. gentilis grew at the rates of 0.061 and 0.034 day⁻¹, respectively, but on a diet of sterile leaves, both larval instars lost weight. The incorporation rates of fungal carbon were 31.6 μg C mg⁻¹ AFDM day⁻¹, accounting for 100% of the daily growth rate of the third instar larvae and 8.6 μg C mg⁻¹ AFDM day⁻¹, accounting for 50% of the daily growth rate of the fifth instar larvae.
4.  These results suggest that leaf material colonised by A. filiformis is a high quality food resource for P. gentilis larvae, and that fungal biomass can contribute significantly to the growth of these larvae. Differences in feeding behaviour and digestive physiology may explain the significantly greater assimilation of fungal biomass by the earlier instar than the final instar. To satisfy their nutritional needs the fifth instar larvae would have to assimilate detrital mass that may have been modified by fungal exoenzymes.     

Dispersal of Podisus nigrispinus (Het., Pentatomidae) nymphs preying on tomato leafminer: effect of predator release time, density and satiation level

Abstract:   The dispersal potential of nymphal stinkbug, Podisus nigrispinus (Dallas, 1851) (Het., Pentatomidae) preying on larvae of the tomato leafminer Tuta absoluta (Meyrick, 1917) (Lep., Gelechiidae) was studied in an open-sided greenhouse. The parameters investigated were (1) the density of nymphs released per plant (one or five); (2) the release time (0600 and 1800 h); and (3) predator satiation level (satiated and 24-h-starved nymphs). Tomato plants were infested with larvae of the tomato leafminer (one third or fourth instar per leaf). The evaluations started 30 min after the release of predators second instar and hourly evaluations were carried out over 36 and 24 h for release times of 0600 and 1800 h, respectively. Starved nymphs released in the morning, either alone or in groups of five, dispersed faster than satiated nymphs. All of the starved individuals had left the plant by the end of the observation period, whereas 25 and 36% of the satiated nymphs released alone and in groups, respectively, stayed on the plant until the end of the observation period. Both satiated and starved nymphs showed slower rates of dispersal when released at 1800 h. Satiated nymphs delayed prey attack up to 9 h, whereas starved individuals started to attack T. absoluta caterpillars 1 h after their release at both densities. Our findings suggest more effective biological control of T. absoluta is possible with the release of second instar nymphs of P. nigrispinus when starved for 24 h prior to release and then released either in the morning or in the evening.     

Growth and silk formation of silkworm larvae influenced by phytoecdysones

The fourth and fifth instar larvae of the silkworm were reared on artificial diets containing ponasterone A, ecdysterone, and inokosterone. The growth of the larvae and their silk glands, fibroin-synthesizing activity, and silk formation have been investigated. With a diet containing ponasterone A, the fourth instar larvae grew slowly and only a few larvae could ecdyse, while the growth of the fifth instar larvae was disturbed and they died with a darkening of the skin. Ponasterone A also inhibited the growth of the silk glands during the fifth instar. In contrast, the other two phytoecdysones did not greatly influence larval growth. The fourth instar larvae grew rapidly and their ecdysis was advanced with a diet which contained 10 μg of inokosterone/1 g of dry diet. The diet which contained 5 μg of ecdysterone or 10 μg of inokosterone/1 g of dry diet accelerated maturation, while that containing 10 or 20 μg of ecdysterone, or 40 μg of inokosterone, delayed maturation of the fifth instar larvae.Only phytoecdysones caused a decrease in growth of the silk glands in the early half of the instar, and a large amount of phytoecdysones accelerated their growth during the last part of the fifth instar. The fibroin-synthesizing activity was levelled up by feeding ecdysterone and inokosterone, and inokosterone appreciably stimulated activity. Assay of in vitro fibroin synthesis showed that ponasterone A competed with ecdysterone in a stimulative action. Silk formation was much lower in larvae fed the diet containing 5 μg of ecdysterone or 10 μg of inokosterone/1 g of dry diet and was far greater in larvae fed the diet containing 40 μg of inokosterone than in the controls.     

Weight gain of the predator Podisus distinctus (Heteroptera: Pentatomidae) with combinations of the preys Tenebrio molitor (Coleoptera: Tenebrionidae) and Musca domestica (Diptera: Muscidae)

Little is known about Podisus distinctus (Stal) (Heteroptera: Pentatomidae) one of the Asopinae species with good possibilities for mass rearing and releasing against defoliator caterpillars in eucalyptus reforested areas in Brazil. We evaluated the impact of prey combinations on weight of nymphs and adults of P. distinctus. The prey were Musca domestica L. (Diptera: Muscidae) and Tenebrio molitor L. (Coleoptera: Tenebrionidae). The experiment was developed under 25 +/- 0.5 degrees C, 60 +/- 10% R.H. and photophase of 14 hr, with nymphs of P. distinctus individualized in Petri dishes and fed as: T1-larvae of M. domestica during its whole nymphal phase: T2-larvae of M. domestica during its II instar and of T. molitor during the other instars: T3-larvae of M. domestica during II and III instars and of T. molitor during the other instars: T4-larvae of M. domestica during II, III and IV instars and of T. molitor during the V instar; T5- larvae of T. molitor during all instars. P. distinctus presents lower weight when fed with larvae of M. domestica. For this reason it is recommended to feed P. distinctus with T. molitor during its whole nymphal phase or with larvae of M. domestica only during II and III instars and T. molitor during IV and V instars.     

Effects of transgenic Cry1A＋CpTI cotton and Cry1Ac toxin on the parasitoid, Campoketis chlorideae （Hymenoptera：Ichneumonidae）

Abstract The effect of transgenic double genes, Cry1A + CpTI cotton and Cry1Ac toxin on the parasitoid, Campoketis chlorideae Uchida of cotton bollworm, Helicoverpa armigera (Hübner), was investigated in the laboratory. Helicoverpa armigera larvae when in the first, second and third instar could not survive if fed on transgenic cotton leaves. Consequently, C. chlorideae larvae could not complete their development if parasitizing on such hosts. After H. armigera larvae were reared on transgenic or traditional cotton leaves for 12J48 hours, they were parasitized by C. chlorideae females. Parasitized larvae continued to feed on transgenic or traditional cotton for 12–48 h. The present results showed that the body weight of larvae of the parasitoids were significantly reduced when parasitized hosts fed on transgenic cotton leaves compared to those fed on traditional cotton. Duration of egg and larvae stage were significantly prolonged, pupal and adult weight of C. chloridae was decreased when the host larvae fed on transgenic cotton leaves longer than 48 h. The development duration of C. chlorideae pupae on the hosts fed on transgenic cotton leaves in each treatment was not significantly different from those of controls. The longevity of parasitoid females and males fed with a solution containing Cry1Ac toxin was not significantly different with that of the control.     

人工饲料、转Bt水稻及其亲本稻苗饲养下二化螟种群适合度的比较研究

以人工饲料、转Bt水稻"克螟稻"(cry1Ab纯和基因型)及其对照亲本"秀水11"稻苗为供试寄主植物开展二化螟Chilo suppressalis(Walker)1～5龄幼虫的室内饲养试验,以明确不同龄期二化螟种群的生活史参数。试验结果表明:二化螟在低龄时死亡率最高。克螟稻对二化螟各个龄期表现出高抗性,其各个龄期在克螟稻上均不能化蛹,随着龄期的增加二化螟的耐受性增强。以秀水11和人工饲料饲养二化螟对其蛹期、成虫期、单雌产卵量、羽化率的影响无显著性差异,以人工饲料饲养的二化螟蛹重显著高于以秀水11饲养的二化螟的蛹重,蛹重与人工饲料饲养时间呈正相关。与秀水11幼苗相比,人工饲料饲养下有利于二化螟雌虫的分化。     

茉莉酸甲酯处理对棉铃虫生长和解毒能力的影响

【目的】为明确茉莉酸甲酯（methyl jasmonate, MeJA）的不同处理方式对昆虫生长和解毒代谢能力的影响,以及MeJA熏蒸处理昆虫对植物防御和昆虫解毒代谢之间关系的影响。【方法】本文比较了取食MeJA和MeJA熏蒸等两种处理对棉铃虫Helicoverpa armigera 3龄末幼虫生长和解毒代谢酶活性的影响,并系统研究了经MeJA熏蒸处理的棉铃虫3龄末幼虫,再取食经MeJA喷雾处理的棉叶,其中肠解毒酶活性的变化。【结果】取食MeJA和MeJA熏蒸两种不同处理,对棉铃虫幼虫的生长及解毒能力的影响有所不同。取食含2.9 μg/g MeJA的人工饲料显著抑制了棉铃虫的生长,同时诱导棉铃虫幼虫P450活性增加了1.92倍,而MeJA熏蒸虽然没有影响棉铃虫幼虫的生长,但MeJA熏蒸处理使棉铃虫幼虫P450活性和羧酸酯酶活性分别增加了2.94倍和1.16倍。经MeJA熏蒸处理后的棉铃虫幼虫,再取食正常的或经MeJA喷雾处理的棉叶,其幼虫P450活性显著增加,其中经MeJA熏蒸处理的棉铃虫,再取食经MeJA喷雾处理的棉叶,其P450酶显示了最高活性。【结论】MeJA熏蒸处理棉铃虫,不仅使棉铃虫中与P450酶相关的解毒能力显著增加,而且增加了棉铃虫对于MeJA所诱导的棉花防御反应的解毒能力。