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1.
Nonparasitized second-instar larvae of Trichoplusia ni were twice as susceptible (at the LD50 level) to the singly enveloped T. ni nuclear polyhedrosis virus as those parasitized by Hyposoter exiguae (Hymenoptera: Ichneumonidae). The LD50 values for nonparasitized and parasitized larvae were 1.58 × 103 and 3.16 × 103 polyhedra/ml of diet, respectively. The LD95 value for parasitized larvae was approximateely 5 times higher than that for nonparasitized larvae. The slopes (b values) were 1.2 for parasitized larvae and 1.7 for nonparasitized larvae. The LT50 values for parasitized larvae also were significantly longer than those for nonparasitized larvae. No significant difference was found between the food consumption of parasitized and nonparasitized T. ni larvae. 相似文献
2.
Clayton C. Beegle Leslie C. Lewis Robert E. Lynch Adelaido J. Martinez 《Journal of invertebrate pathology》1981,37(2):143-153
The addition of chlortetracycline hydrochloride to bioassay diets increased the LC50S of the HD-1 isolate of Bacillus thuringiensis 2.4–67.1 times when bioassayed against 4-day-old larvae of Trichoplusia ni, Heliothis virescens, and Ostrinia nubilalis. There were no significant differences in LC50s when bioassays were conducted with neonate larvae in the presence or absence of antibiotic, nor were there any highly significant differences between the LC50s for HD-1 when neonate larvae were used in the presence or absence of antibiotic or when 4-day-old larvae were used in the absence of antibiotic. Viable counts of B. thuringiensis did not increase over time in any of three bioassay diets. There were no differences in activity of pure chlortetracycline hydrochloride and veterinary grade Aureomycin. There was a direct correlation between amount of antibiotic and elevation of HD-1 LC50s when 4-day-old larvae were used. LC50 elevation in presence of antibiotic first appeared in 2-day-old larvae. 相似文献
3.
S Silapanuntakul S Pantuwatana A Bhumiratana K Charoensiri 《Journal of invertebrate pathology》1983,42(3):387-392
Bacillus sphaericus strain 1593 and B. thuringiensis serotype H-14 were evaluated for persistence of toxicity against two species of mosquito larvae, Culex quinquefasciatus and Aedes aegypti, in a selected simulating plot in Bangkok. Both strains of bacteria demonstrated larvicidal activity towards both species of mosquito larvae. In tap water, the toxicity of B. sphaericus strain 1593 was found to be greater towards C. quinquefasciatus larvae than A. aegypti larvae, whereas the toxicity of B. thuringiensis serotype H-14 was found to be greater towards A. aegypti larvae than C. quinquefasciatus larvae. The persistence of toxicity of these two bacteria was found to be different. The lethal concentration of B. thuriengiensis H-14 against A. aegypti decreased from LC90 to below LC50 in about 15 weeks when tested in tap water. The decrease was faster in polluted water. The toxicity of B. sphaericus 1593 towards C. quinquefasciatus larvae persisted for at least 9 months in tap water and 6 months in polluted water. The multiplication of bacteria was indicated only in populations of B. sphaericus 1593 tested with C. quinquefasciatus larvae. 相似文献
4.
Elizabeth West Davidson Samuel Singer John D. Briggs 《Journal of invertebrate pathology》1975,25(2):179-184
Numbers of viable bacteria in second instar Culex pipiens quinquefasciatus larvae were determined following ingestion of pathogenic strain SSII-1 and nonpathogenic Bacillus sphaericus. Numbers of nonpathogenic B. sphaericus recovered from larvae declined rapidly after cessation of feeding, as did numbers of pathogenic SSII-1 cells fed at LD20 dosage. When pathogenic cells were fed at LD70 dosage, the number of B. sphaericus in larvae increased following initial decline. When chloroformtreated SSII-1 cultures, in which all bacteria except spores were dead, were fed at LD10 and LD98 dosages, no viable B. sphaericus were recovered from larvae. In all SSII-1 treatments, other bacterial flora multiplied rapidly in larvae following onset of mortality; the role of this multiplication in the pathogenesis was not determined. It is proposed that toxic material is released when SSII-1 cells are digested and that multiplication of B. sphaericus in the larval gut is not essential in the pathogenesis. There appears to be no difference in the pathogenesis when differing numbers of B. sphaericus. i.e., LD10–20 or LD70–98 dosages, are ingested. Possible nature of the toxic material is discussed. 相似文献
5.
R.J. Milner 《Journal of invertebrate pathology》1976,28(2):185-190
Two methods of infection, i.e., feeding known numbers of spores and rearing larvae in contaminated peat, were used to bioassay the susceptibility of Rhopaea verreauxi to Bacillus popilliae var. rhopaea at 23°C. The susceptibility of the three larval instars was similar as measured by the ID50 and IC50 values. However, within an instar, newly molted larvae were less susceptible than mature larvae when infected by the contaminated peat method. It is suggested that this was due to reduced food intake. The range of ID50 values for all bioassays with R. verreauxi larvae were 1.1 × 107 to 4.0 × 107 spores per larva, and IC50 values were 3.4 × 106 to 5.0 × 107 spores per g of contaminated peat. The slope of the probit line was always low (0.6 to 1.8) except for young first-instar larvae infected by contaminated peat when the slope was 4.0. Disease per se did not affect food intake, though intake was reduced at high doses of contaminated peat. Young larvae often died without developing symptoms but, with increasing age, infected larvae were more likely to develop symptoms. Bioassays with Othnonius batesi and Rhopaea morbillosa indicated a much lower susceptibility per os than for R. verreauxi. It is concluded that the potential for using B. popilliae var. rhopaea to control R. verreauxi is high, but the bacillus is unlikely to be of value in control of O. batesi or R. morbillosa. 相似文献
6.
Seth H. Miller Sonia Zarate Edmund H. Smith Brian Gaylord Jessica D. Hosfelt Tessa M. Hill 《PloS one》2014,9(10)
Future climate change is predicted to alter the physical characteristics of oceans and estuaries, including pH, temperature, oxygen, and salinity. Investigating how species react to the influence of such multiple stressors is crucial for assessing how future environmental change will alter marine ecosystems. The timing of multiple stressors can also be important, since in some cases stressors arise simultaneously, while in others they occur in rapid succession. In this study, we investigated the effects of elevated pCO2 on oxygen consumption by larvae of the intertidal porcelain crab Petrolisthes cinctipes when exposed to subsequent salinity stress. Such an exposure mimics how larvae under future acidified conditions will likely experience sudden runoff events such as those that occur seasonally along portions of the west coast of the U.S. and in other temperate systems, or how larvae encounter hypersaline waters when crossing density gradients via directed swimming. We raised larvae in the laboratory under ambient and predicted future pCO2 levels (385 and 1000 µatm) for 10 days, and then moved them to seawater at ambient pCO2 but with decreased, ambient, or elevated salinity, to monitor their respiration. While larvae raised under elevated pCO2 or exposed to stressful salinity conditions alone did not exhibit higher respiration rates than larvae held in ambient conditions, larvae exposed to elevated pCO2 followed by stressful salinity conditions consumed more oxygen. These results show that even when multiple stressors act sequentially rather than simultaneously, they can retain their capacity to detrimentally affect organisms. 相似文献
7.
Christopher C. Payne G.Mark Tatchell Ceris F. Williams 《Journal of invertebrate pathology》1981,38(2):273-280
A comparison was made of the dosage-mortality responses of larvae of Pieris brassicae and P. rapae to infection by P. brassicae granulosis virus (GV). Bioassays with first, second, third, and fourth-instar larvae of both species revealed a marked difference in susceptibility between instars and between species. Median lethal dosages (LD50s) for P. rapae larvae ranged from five capsules for the first instar to 662 capsules for the fourth instar. With P. brassicae, this range extended from 66 capsules to 2.3 × 107 capsules. The time-mortality responses of the two species were similar when fed virus dosages equivalent to an LD90. Median lethal times (LT50s) ranged from 5 days for first-instar larvae to 7–8 days for fourth-instar larvae. A comparison between a long-established laboratory stock of P. brassicae and a stock recently acquired from the field showed no significant difference in their susceptibility to GV. The implications of the pronounced species differences in susceptibility to GV infection are discussed in relation to the potential field control of P. rapae and P. brassicae. 相似文献
8.
Tarsal claws, which are common attachment devices in arthropods, interlock with the surface irregularities of the substrata. Most insects have two tarsal claws, but the larvae of some aquatic insects, such as Ephemeroptera and Trichoptera, bear only one claw on their tarsi. The range of surface roughness that is sufficient for the function of the single claws of aquatic invertebrates has not yet been investigated. In the present study, we investigated the surface texture required for the function of the claws of larvae of the mayfly, Epeorus assimilis. We conducted attachment experiments using replications with defined surface roughness, white light profilometry, videotaping and scanning electron microscopy. The results demonstrate that the choice of an appropriate roughness order is very important. A setting resulting in a cut-off length of approximately thirty times the diameter of the claw tip proved most appropriate for describing the roughness order that is relevant for the functioning of the claws of E. assimilis larvae. Common technical roughness parameters such as Ra, Rq or Rz supplied sufficient differentiation between the tested substrata. E. assimilis larvae require a minimum surface roughness (Ra ~ 6.0 μm) for their claws to grip. At lesser surface roughness, the larvae left the substratum. This was surprising because E. assimilis larvae have been observed to attach even to smooth surfaces. Based on the use of sterile substrata in this experiment, we assume that coverage with biofilm considerably influences the attachment of the larvae. 相似文献
9.
Bo Yeon Kim Kwang Sik Lee Mi Ri Sohn Kee Young Kim Kwang Ho Choi Pil Don Kang Byung Rae Jin 《Journal of Asia》2011,14(3):285-288
Cathepsin D is involved in the metamorphosis of the silkworm, Bombyx mori. Here, we show the expression profile of B. mori cathepsin D (BmCatD) in the fat body during exposure to stressors, such as high temperature and H2O2. Exposure of larvae in the fifth instar stage to high temperature (28 °C) led to accelerated metamorphosis and shortened larval stage compared to control larvae grown at 23 °C. Concomitantly, the expression level of BmCatD mRNA was greatly increased during exposure to high temperature. We also detected significantly elevated H2O2 levels in the hemolymph of larvae treated with high temperature. To confirm that oxidative stress induces BmCatD expression, B. mori larvae were injected with H2O2. As predicted, we observed increased expression of BmCatD following H2O2 exposure. Based on these results, we conclude that BmCatD expression is induced by high temperature and H2O2 exposure and that this stress-induced BmCatD expression leads to early metamorphosis. 相似文献
10.
Laboratory tests of Bacillus thuringiensis var. kurstaki (strain HD-1) against Platynota idaeusalis reared on a semisynthetic diet showed that the LC50 values for neonates and 9-day-old larvae showed no significant difference in susceptibility; however, 14-day-old larvae were significantly more susceptible than neonates or 9-day-old larvae. There was no evidence of any interaction between 14-day-old larvae reared on the semisynthetic diets with and without formaldehyde and B. thuringiensis toxicity at any assessment reading. Likewise the toxicity of B. thuringiensis to 14-day-old larvae reared on apple leaves did not differ from the B. thuringiensis toxicity of 14-day-old larvae reared on semisynthetic diets with and without formaldehyde. 相似文献
11.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1993,104(2):239-245
1. Exposure of the estuarine shrimp, Palaemonetes pugio, to a juvenile hormone analogue (⩾8 μg methoprene 1−1) throughout larval development inhibited successful completion of metamorphosis.2. Methoprene exposure retarded growth in early larval stages and postlarvae, but enhanced growth in premetamorphic larvae.3. Respiration rates of early larvae were elevated by methoprene exposure, but not so older larvae or post larvae.4. Lower net growth efficiency (K2 values) in methoprene-exposed early larvae suggests that increased metabolic demands reduced assimilated energy available for growth.5. Modifications in O:N ratios of premetamorphic larvae and postlarvae suggest that methoprene altered substrate utilization patterns during metamorphosis. 相似文献
12.
Morten Poulsen Michael V.W. Kofoed Lone H. Larsen Andreas Schramm Peter Stief 《Systematic and applied microbiology》2014
Benthic invertebrates affect microbial processes and communities in freshwater sediment by enhancing sediment-water solute fluxes and by grazing on bacteria. Using microcosms, the effects of larvae of the widespread midge Chironomus plumosus on the efflux of denitrification products (N2O and N2 + N2O) and the diversity and abundance of nitrate- and nitrous-oxide-reducing bacteria were investigated. Additionally, the diversity of actively nitrate- and nitrous-oxide-reducing bacteria was analyzed in the larval gut. The presence of larvae increased the total effluxes of N2O and N2 + N2O up to 8.6- and 4.2-fold, respectively, which was mostly due to stimulation of sedimentary denitrification; incomplete denitrification in the guts accounted for up to 20% of the N2O efflux. Phylotype richness of the nitrate reductase gene narG was significantly higher in sediment with than without larvae. In the gut, 47 narG phylotypes were found expressed, which may contribute to higher phylotype richness in colonized sediment. In contrast, phylotype richness of the nitrous oxide reductase gene nosZ was unaffected by the presence of larvae and very few nosZ phylotypes were expressed in the gut. Gene abundance of neither narG, nor nosZ was different in sediments with and without larvae. Hence, C. plumosus increases activity and diversity, but not overall abundance of nitrate-reducing bacteria, probably by providing additional ecological niches in its burrow and gut. 相似文献
13.
《Animal : an international journal of animal bioscience》2022,16(11):100656
In the available literature, there are limited data about the energetic value of insect-derived products. In particular, insect fat cannot be used in practical broiler nutrition due to the lack of precise apparent metabolisable energy (AME) value. Therefore, the present study aimed to investigate the AME and apparent metabolisable energy corrected to zero nitrogen balance (AMEN) levels of Hermetia illucens larvae fat for broiler chickens of various ages. A total of 400 1-day-old male Ross 308 chicks were randomly allotted to four dietary groups (10 replicate pens per treatment; 10 birds per pen). The following treatments were applied: HI0 – basal diet without dietary fat inclusion, HI03 – basal diet enriched with 30 g/kg H. illucens larvae fat, HI06 – basal diet enriched with 60 g/kg H. illucens larvae fat, and HI09 – basal diet enriched with 90 g/kg H. illucens larvae fat. Broilers had ad libitum access to mash form feed and water. Excreta samples were collected on d 14, d 28, and d 35. To determine the AME and AMEN values of H. illucens larvae fat, the simple linear regression method was used. The results show that the AME and AMEN values of H. illucens larvae fat for broiler chickens are 9 049 kcal/kg (37.86 MJ/kg) and 9 019 kcal/kg (37.74 MJ/kg), respectively. Additionally, because the birds’ age significantly (P < 0.001) affected the AME and AMEN levels, the implementation of H. illucens larvae fat to broiler diets should be considered in each nutritional period using the recommended regression model AME = 2 559.758 + 62.989 × fat inclusion (%) + 7.405 × day of age and AMEN = 2 543.2663 + 62.8649 × fat inclusion (%) + 7.3777 × day of age. The present data emphasised that the H. illucens larvae fat metabolisable energy is similar to that of soybean oil. 相似文献
14.
Metamorphosis of the planula larvae into polyps does not occur spontaneously but depends on the reception of external trigger stimuli. Artificially, metamorphosis can be initiated by a pulse-type application of Cs+ or tumor-promoting phorbol esters (W. A. Müller (1985) Differentiation 29, 216–222). In the present study we examined the putative involvement of the phosphatidylinositol system in signal transduction. Planulae of Hydractinia echinata were preincubated with [3H]-inositol. Upon exposure of the larvae to Cs+ the label in inositol trisphosphate (InsP3) increased twofold as early as 15 sec after addition of Cs+. Within the first 60 sec the levels of inositol monophosphate (InsP1) and inositol bisphosphate (InsP2) were also elevated compared to the values in nonstimulated larvae. After 1 and 3 hr, respectively, of incubation with Cs+, only the label in InsP2 was increased. When applied to saponin-permeabilized larvae, InsP3 did not induce metamorphosis. But 1,2-dioctanoyl-rac-glycerol (diC8) was effective in inducing metamorphosis with a half-maximal effective concentration of 9 μM. The percentage of metamorphosed animals after the application of 5 μM diC8 (30 mM Cs+) was increased by the simultaneous application of 1 μM (0.1 μM) of the diacylglycerol kinase inhibitor R 59022. The results are interpreted as evidence for the involvement of the PI-signaling/diacylglycerol transduction system in the initiation of metamorphosis of planula larvae of H. echinata. 相似文献
15.
Nematospiroides dubius, unlike the closely related nematode Nippostrongylus brasiliensis, lacks a sterol requirement for the completion of its development to the L3 stage in an aqueous suspension of formalin-killed Escherichia coli. These larvae were justascapable of completing their development to adults in mice as those grown on charcoal-feces cultures. In addition, sterols had a toxic effect on the larvae of N. dubius which was removed by substituting a Krebs-Ringer solution for distilled water.In order to interpret the absence of a sterol requirement for the development of N. dubius larvae, an analysis of the egg lipids for both species was made. N. brasiliensis had about twice the sterol concentration of N. dubius eggs. A comparison of the development for both species showed, however, that N. brasiliensis grows more than twice as much as N. dubius to reach the L3 larval stage. Therefore, the amount of endogenous sterol is insufficient for N. brasiliensis to develop from the egg to the L3 stage.N. dubius and N. brasiliensis also differ in their porphyrin requirements. Unlike N. brasiliensis, coproporphyrin did not increase the size of N. dubius larvae so that they were comparable to those grown on charcoal-feces cultures. Coproporphyrin did result in larvae that were more robust in appearance than those grown without a supplement. 相似文献
16.
Wataru Kojima 《PloS one》2015,10(11)
Saprophagous (feeding on decaying matter) insects often use carbon dioxide (CO2) as a cue for finding food. Humus-feeding larvae of the giant rhinoceros beetle Trypoxylus dichotomus exhibit a clumped distribution in natural microhabitats, but the mechanisms driving the distribution were unknown. Herein, I examined whether larvae use CO2 as a cue for fermented humus and aggregate in the vicinity of the food. I found that (i) larvae of T. dichotomus are strongly attracted to CO2, (ii) larvae orient toward highly fermented humus when given a choice between highly and poorly fermented humus, (iii) the highly fermented humus emits more CO2 than the poorly fermented humus, and (iv) larvae grow larger when fed highly fermented humus rather than poorly fermented humus. The clumped distribution of larvae is probably formed along the concentration gradient of CO2 induced by heterogeneity of fermented organic materials in soil. My laboratory experiments also revealed that larvae are chemically attracted to each other. Moreover, CO2 concentrations in soil were increased by the larval respiration, and small amounts of CO2 (much less than emitted during respiration by a single larva) were sufficient for larval attraction. These results suggest that not only response to fermented food resources, but also respiratory CO2 from conspecifics may lead to aggregation. Enhanced densities resulted in reduced weight gain under experimental conditions. However, exploiting a high-value resource at enhanced densities still led to greater body weight compared to individually exploiting a low-value resource. This demonstrates the adaptive value of the response to CO2 sources in this species. 相似文献
17.
Bioassays to determine LC50 values of spores and crystals of four varieties of Bacillus thuringiensis grown on nutrient agar plates were carried out against neonate and 6-day-old European corn borer, Ostrinia nubilalis, larvae. The four bacterial varieties were equally toxic against the neonates, but only B. thuringiensis var. kenyae, var. galleriae, and var. kurstaki were toxic to 6-day-old larvae. B. thuringiensis var. tolworthi was inactive against 6-day-old larvae. Different ratios of pure spores and crystals of the bacteria also were tested against neonate and 6-day-old larvae. Pure spores are not pathogenic to neonates or 6-day-old larvae. Pure crystals were toxic to both ages of the larvae, but a combination of spores and crystals was necessary for maximum larval mortality. 相似文献
18.
The susceptibility of third state larvae of the sheep blowfly Lucilia cuprina in sand to 11 species and strains of Heterorhabditis and Neoaplectana and to one species of an undescribed steiner-nematid was tested at various dosages. Larvae were susceptible to all, although far less so to one strain of N. bibionis and to the undescribed steinernematid. Estimates of LD50 and LD90 are presented for each effective strain. Heterorhabditis spp. were able to reproduce in L. cuprina larvae subjected to low dosages of effective-stage juveniles whereas Neoaplectana spp. were not able to reproduce at any dosage. The possibility exists for using Heterorhabditis species as a control agent against L. cuprina larvae after these have left the sheep to pupate in the soil. 相似文献
19.
The ventral eversible gland (VEG) of Spodoptera littoralis triggers early responses to herbivory in Arabidopsis thaliana 总被引:1,自引:0,他引:1
The ventral eversible gland (VEG) in Lepidopteran larvae was first reported by De Geer in 1745. Secretions from VEG have been associated with defense against predators and the production of anti-aggregation pheromones; however, the role of the VEG in arthropod?Cplant interactions is still unclear. Here, we show that the ablation of Spodoptera littoralis larvae VEG affects early Arabidopsis thaliana responses to herbivory and insect??s oral secretions (OS). We measured the plasma transmembrane potential (Vm) variation in Arabidopsis mesophyll palisade cells upon feeding by untreated (N) and VEG-ablated (VEGA) S. littoralis larvae. OS from both N and VEGA were collected from larvae feeding on either artificial diet (ADOS) or Arabidopsis green leaves (GLOS) and tested for their ability to affect Vm on intact Arabidopsis leaves. Calcium and hydrogen peroxide (H2O2) signaling were also evaluated by confocal laser scanning microscopy by using the fluorescent probes calcium orange and Amplex red, respectively, upon herbivory by N and VEGA, and after application of either ADOS or GLOS from both N and VEGA to Arabidopsis leaves. Ablation of VEG prompted a significant reduction of the Vm depolarization and significantly reduced both cytosolic calcium concentration ([Ca2+]cyt) and H2O2 burst. OS extracted from VEGA larvae showed the same pattern, suggesting that a functional VEG is required for the synthesis of VEG secretions able to induce early responses in the fed plant tissues. These results suggest that VEG might contain elicitors able to trigger early responses (Vm depolarization, [Ca2+]cyt influx and H2O2 burst) of Arabidopsis to S. littoralis herbivory. 相似文献
20.
Eight species of noctuid larvae were tested for susceptibility to a nuclear polyhedrosis virus of the velvetbean caterpillar, Anticarsia gemmatalis. Velvetbean caterpillar larvae were highly susceptible to crude preparations of polyhedral inclusion bodies (PIBs; LD50 = 4.7 PIBs/larva), but preparations of purified polyhedra were much less effective against these larvae (LD50 = 319.7 PIBs/larva). Of seven other noctuid species tested, only Heliothis virescens was as susceptible to the virus as A. gemmatalis. High dosages were required to kill Heliothis zea, Trichoplusia ni, Pseudoplusia includens, and Spodoptera ornithogalli. Plathypena scabra and Spodoptera frugiperda were not susceptible. 相似文献