Soluble cuticular phenoloxidase in the gypsy moth Lymantria dispar

The soluble enzyme phenoloxidase (tyrosinase) from the larval cuticle of Lymantria dispar has been partially purified using Ultrogel ACA 34, and the activity has been determined using phenolic substrates. The enzyme exhibited more activity toward O-diphenolic substrates and monophenolic substrates. The enzyme is inhibited by diethyl dithiocarbamate, phenylthiourea, and thiourea. The enzyme has been localized in the 7% slab and disc PAGE as an intense band. The enzyme is suggested to be involved in wound healing. © 1992 Wiley-Liss, Inc.     

Development of male-incubated ovaries in the gypsy moth,Lymantria dispar

Ovaries from Lymantria dispar females were transplanted into an environment lacking vitellogenin, the male milieu, in order to determine how the presence of vitellogenin in the hemolymph affects the process of protein uptake by gypsy moth oocytes. When undeveloped ovaries from newly ecdysed last instar females were transplanted into males of the same stage, follicles detached from the germarium and increased in size, but the growth of oocytes proceeded more slowly than those from female controls. Although chorion fromation was delayed in male-grown ovaries, scanning electron microscopy of chorionated eggs recovered from adult males showed that a chorion with normal surface architecture was formed by the adult stage. SDS-PAGE analysis of the male-grown ovaries and hemolymph from males receiving ovaries showed that vitellogenin production was not stimulated by the organ transplant and only male hemolymph proteins were internalized by the male-incubated ovaries. Thus, in the absence of vitellogenin, endocytosis of male hemolymph proteins occurred, but the rate of oocyte growth was slowed.     

Aedes aegypti TMOF modulates ecdysteroid production by prothoracic glands of the gypsy moth, Lymantria dispar

Trypsin modulating oostatic factor (TMOF) is a decapeptide that inhibits the biosynthesis of trypsin-like enzymes in the midgut of several insect species and, as such, serves as a dipteran oostatic hormone. In vitro incubation of lepidopteran prothoracic glands with Aedes aegypti TMOF revealed that this decapeptide, in the presence of brain extract, modulates ecdysteroid production. The modulatory effect was highly dependent on both the concentration of TMOF and brain extract. Typically, TMOF was stimulatory in the presence of lower concentrations of Lymantria dispar brain extract (0.01 and 0. 025 brain equivalent), and either neutral or inhibitory at higher concentrations (0.25, 0.5, and 1.0 brain equivalent) of extract. In the presence of European corn borer (Ostrinia nubilalis) brain extract, TMOF also exhibited modulatory effects, effects that again were dependent on the concentrations of both brain extract and TMOF present in the incubation medium. At 1.5 brain equivalents, TMOF was inhibitory at all but the highest concentration tested (5x10(-6) M), at 1.0 brain equivalent, TMOF was stimulatory at 10(-6) M and at 0. 5 brain equivalents, TMOF did not significantly affect PTG synthesis of ecdysteroids. Results suggest the presence of a modulatory peptide(s), which fine tunes the synthesis and release of ecdysteroids by PTGs in accordance with the insect's developmental/physiological requirements.     

Vertical transmission and overwintering of microsporidia in the gypsy moth, Lymantria dispar

Vertical transmission and the overwintering success of three different microsporidia infecting Lymantria dispar (Lepidoptera: Lymantriidae) larvae were investigated. Endoreticulatus schubergi, a midgut pathogen, was transmitted to offspring via female and male via the egg chorion (transovum transmission). Between 8% and 29% of the emerging larvae became infected. No spores of E. schubergi were found in surface-washed eggs. Nosema lymantriae, a microsporidium that causes systemic infections, was transovarially transmitted. Between 35% and 72% of the progeny were infected. Vairimorpha disparis, a fat body pathogen, was not vertically transmitted. The infectivity of spores that overwintered in cadavers of infected L. dispar varied by species, placement in the environment, and weather conditions. Spores of E. schubergi were still infective after an eight month exposure period of cadavers on the ground. Spores of N. lymantriae and V. disparis remained highly infective only when cadavers overwintered under a more or less continuous snow cover for four months.     

Ultrastructural studies of male-incubated ovaries of the gypsy moth,Lymantria dispar

Ovaries from Lymantria dispar females were transplanted into an environment lacking the vitellogenin ligand; i.e., the male milieu. Transmission electron micrographs comparing the terminal oocytes of male-grown ovaries and normal ovaries showed that yolk sphere diameters were reduced in the male-grown oocytes. However, there were larger numbers of these small yolk spheres per unit area of cytoplasm, indicating that the coalescence of endosomes into yolk spheres is reduced in the absence of vitellogenin. Although there are larger numbers of yolk spheres in male-grown oocytes, the smaller diameter of yolk spheres resulted in less area being taken up by yolk spheres per unit area of cytoplasm in male-grown oocytes, yielding lowered yolk production. This lowered yolk production is a result at least in part of the lowered number of coated vesicles per unit area of submembrane space and in part of the reduced interfollicular spaces seen in male-grown ovaries.     

Structure-activity studies with pheromone-binding proteins of the gypsy moth,Lymantria dispar

Pheromone olfaction in the gypsy moth, Lymantria dispar, involves accurate distinction of compounds with similar structure and polarity. The identified sex pheromone is (7R,8S)-2-methyl-7,8-epoxyoctadecane, 1a, and a known antagonist is (7Z)-2-methyloctadec-7-ene, 4a. The first step in pheromone olfaction is binding of odorants by small, soluble pheromone-binding proteins (PBPs), found in the pheromone-sensing hairs. We have studied the molecular determinants recognized by the two PBPs found in the gypsy moth, using three pheromone/PBP binding assays. Results indicate that (i) PBPs bind analogs of the pheromone with some discrimination; (ii) PBPs experience enhancement of binding when presented with 1a or its enantiomer and 4a simultaneously; and (iii) the binding enhancement is also seen at high ligand:PBP ratios. We found no evidence of allostery, so the synergistic binding effects and the concentration effect may only be explained by multimerization of PBPs with each other, which leads to more than one population of binding sites. We suggest that the enhanced ligand binding at high ligand:PBP ratios may serve to sequester excess ligand and thereby attenuate very strong signals.     

Underestimated mitochondrial diversity in gypsy moth Lymantria dispar from Asia

相似文献   

Pheromonotropic activity in the gypsy moth Lymantria dispar: evidence for a neuropeptide

The brain-suboesophageal ganglion complex of the gypsy moth, Lymantria dispar, contains pheromonotropic activity detectable using a Helicoverpa zea in vivo bioassay for pheromone-biosynthesis-activating neuropeptide. Pheromonotropic activity was detected as early as the third larval instar and was present throughout development and through day 6 post-eclosion. Activity in the adult is presumably associated with pheromone production, while it is speculated that larval activity may be related to melanization. Adult pheromonotropic activity is associated with a peptide of approximately 3.500 kDa. It is heat labile and only partially stable when incubated at 35°C or exposed to freeze-thawing. Isolation of L. dispar pheromonotropic factor should facilitate the elucidation of the mechanism of pheromone production in this insect pest.Abbreviations ED ₅₀ dose at which one-half maximal response is observal - eq equivalent - MRCH melanization and reddish colorization hormone - MW molecular weight - PBAN pheromone biosynthesis activating neuropeptide - SOG suboesophageal ganglion - TFA trifluoroacetic acid - Z11-16: Ald (Z)-11-hexadecenal     

亚洲型舞毒蛾在北美的适生性

采用DYMEX V2.0软件和ArcGIS分析工具相结合的方法,提出亚洲型舞毒蛾Lymantria dispar(L.)的DYMEX参数指标体系和适生性评判标准,分析亚洲型舞毒蛾在北美的适生范围与适生程度。研究表明,加拿大的南部、美国的大部分地区以及墨西哥中南部极少部分区域为该虫的适生区。研究结果将为国家植物保护部门提供有关亚洲型舞毒蛾的植物检疫决策支持。     

Male death resulting from hybridization between subspecies of the gypsy moth,Lymantria dispar

We explored the origin of all-female broods resulting from male death in a Hokkaido population of Lymantria dispar through genetic crosses based on the earlier experiments done by Goldschmidt and by testing for the presence of endosymbionts that are known to cause male killing in some insect species. The mitochondrial DNA haplotypes of the all-female broods in Hokkaido were different from those of normal Hokkaido females and were the same as those widely distributed in Asia, including Tokyo (TK). Goldschmidt obtained all-female broods through backcrossing, that is, F1 females obtained by a cross between TK females (L. dispar japonica) and Hokkaido males (L. dispar praeterea) mated with Hokkaido males. He also obtained all-male broods by mating Hokkaido females with TK males. Goldschmidt inferred that female- and male-determining factors were weakest in the Hokkaido subspecies and stronger in the Honshu (TK) subspecies. According to his theory, the females of all-female broods mated with Honshu males should produce normal sex-ratio broods, whereas weaker Hokkaido sexes would be expected to disappear in F1 or F2 generations after crossing with the Honshu subspecies. We confirmed both of Goldschmidt''s results: in the case of all-female broods mated with Honshu males, normal sex-ratio broods were produced, but we obtained only all-female broods in the Goldschmidt backcross and obtained an all-male brood in the F1 generation of a Hokkaido female crossed with a TK male. We found no endosymbionts in all-female broods by 4,′6-diamidino-2-phenylindole (DAPI) staining. Therefore, the all-female broods observed in L. dispar are caused by some incompatibilities between Honshu and Hokkaido subspecies.     

Neurological influences on pheromone release and calling behaviour in the gypsy moth, Lymantria dispar

ABSTRACT. Surgical removal of the brain or disconnection of the last abdominal ganglion from the ventral nerve cord prevented sex pheromone release in female Lymantria dispar (L.) (Lymantriidae), as assayed by the male wing-fanning response. The calling behaviour continued to occur in individuals whose terminal abdominal ganglion had been thus isolated, however, indicating that the neural mechanisms controlling calling function independently in the last abdominal ganglion.     

Long-term laboratory evaluation ofRogas lymantriae: A braconid endoparasite of the gypsy moth,Lymantria dispar

Rogas lymantriae Watanabe was reared onLymantria dispar (L.) for 125 generations in the laboratory following importation from Japan. No deleterious effects of colonization were observed and one measured parameter, successful parasite emergence, significantly improved over time. Decreased density of the host or conspecific female parasites resulted in higher levels of parasitism and numbers of females in the next generation. During 3 different years, colony production was significantly increased with little difficulty to provide parasites for inoculative releases in the field.      

Characterisation of three Alphabaculovirus isolates from the gypsy moth,Lymantria dispar dispar (Lepidoptera: Erebidae), in Turkey

In this study, Lymantria dispar dispar larvae, collected from three different localities in Turkey, were examined for the presence of inclusion bodies under phase contrast and electron microscopes. Inclusion bodies from infected larvae were subjected to polymerase chain reaction using the conserved primers for polyhedrin (polh), late expression factor 8 (lef-8) and late expression factor 9 (lef-9) genes. Sequence analysis confirmed that larvae collected from the three different localities contained multiple nucleopolyhedrosis viruses (MNPVs). These isolates were designated LdMNPV-T1, LdMNPV-T2 and LdMNPV-T3. Phylogenetic analyses of these isolates were performed using target genes polh, lef-8 and lef-9. Restriction endonuclease analysis of the three geographic isolates with EcoRI and PstI enzymes demonstrated some differences existed among the isolates. According to the EcoRI profile, the mean estimated size for the complete genome of each isolate (LdMNPV-T1, LdMNPV-T2 and LdMNPV-T3) was calculated to be approximately 170, 153 and 170?kb, respectively. Insecticidal activities of each isolate were tested on L. d. dispar larvae using four different viral concentrations between 10³ and 10⁶?OBs/ml. Results showed that the mortalities for LdMNPV-T1, -T2 and -T3 ranged between 13–53%, 47–100% and 46–93%, respectively. The LC₅₀ and LC₉₅ values of LdMNPV-T2 were not significantly different from the respective corresponding values of the other two isolates. However, isolate LdMNPV-T2 killed larvae with a LC₅₀ value that was lower than the other two isolates. Our results suggested there are promising LdMNPV isolates in Turkey that can be used for microbial control of L. d. dispar larvae.     

Neurometamorphosis of the ear in the gypsy moth,Lymantria dispar,and its homologue in the earless forest tent caterpillar moth,Malacosoma disstria

The adult gypsy moth, Lymantria dispar (Lymantriidae: Noctuoidea) has a pair of metathoracic tympanic ears that each contain a two-celled auditory chordotonal organ (CO). The earless forest tent caterpillar moth, Malacosoma disstria (Lasiocampidae: Bombycoidea), has a homologous pair of three-celled, nonauditory hindwing COs in their place. The purpose of our study was to determine whether the adult CO in both species arises from a preexisting larval organ or if it develops as a novel structure during metamorphosis. We describe the larval metathoracic nervous system of L. dispar and M. distria, and identify a three-celled chordotonal organ in the anatomically homologous site as the adult CO. If the larval CO is severed from the homologue of the adult auditory nerve (IIIN1b1) in L. dispar prior to metamorphosis, the adult develops an ear lacking an auditory organ. Axonal backfills of the larval IIIN1b1 nerve in both species reveal three chordotonal sensory neurons and one nonchordotonal multipolar cell. The axons of these cells project into tracts of the central nervous system putatively homologous with those of the auditory pathways in adult L. dispar. Following metamorphosis, M. disstria moths retain all four cells (three CO and one multipolar) while L. dispar adults possess two cells that service the auditory CO and one nonauditory, multipolar cell. We conclude that the larval IIIN1b1 CO is the precursor of both the auditory organ in L. dispar and the putative proprioceptor CO in M. disstria and represents the premetamorphic condition of these insects. The implications of our results in understanding the evolution of the ear in the Lepidoptera and insects in general are discussed. © 1996 John Wiley & Sons, Inc.     

Estimating the susceptibility of tree species to attack by the gypsy moth, Lymantria dispar

ABSTRACT.

• 1 Numbers of gypsy moth larvae feeding on each of 922 randomly sampled trees in a Quercus—Acer—Fraxinus forest in southwestern Quebec, Canada were counted in 1979 and in 1980 to quantify the larval feeding preferences as observed in the field for eighteen deciduous and one coniferous tree species at the northern range limit of the gypsy moth.
• 2 Both the diameter at breast height (dbh) and the estimated foliage biomass of the sampled trees were used to calculate the relative proportions of foliage represented by each of the nineteen tree species in the forest canopy. With these data on availability and utilization of the tree species by the gypsy moth larvae an Ivlev-type electivity index was used to quantify the larval feeding preferences. These preferences observed in the field define the susceptibility of a tree species to attack by the gypsy moth.
• 3 The feeding preferences calculated using estimated foliage biomass were comparable to the simpler calculation based on dbh (Spearman's rho = 0.79; P= 0.0001). The dbh-based feeding preferences remained almost unchanged in 1979 and 1980 (Spearman's rho = 0.83; P= 0.0001).
• 4 The composite 1979—80, dbh-based feeding preferences show Quercus rubra, Populus grandidentata, Ostrya virginiana, Amelanchier spp. and Acer saccharum were preferentially attacked by gypsy moth. Prunus serotina, Betula lutea, Acer rubrum, A. pensylvanicum, Fraxinus americana, Ulmus rubra, P. pensylvanicum and B. papyrifera were avoided. All nineteen tree species were, however, utilized to at least some degree by gypsy moth larvae.
• 5 These results quantitatively affirm and clarify earlier reports of gypsy moth feeding preferences in North America and Eurasia. The advantages and limitations of using an electivity index to estimate the susceptibility of different tree species to attack by folivores like the gypsy moth are discussed.

     

Identification of 20-hydroxyecdysone and ecdysone from the pupa of the gypsy moth,Lymantria dispar

Normal and reverse-phase high-performance liquid chromatography in conjunction with radioimmunoassay and mass spectrometry were used to identify the free and conjugated ecdysteroids (after enzymatic hydrolysis) from day-4 pupae of the gypsy moth, Lymantria dispar L. Seven ecdysteroids were searched for, but only 20-hydroxyecdysone (964 ng/g fresh weight) and ecdysone (367 ng/g fresh weight) were detected. Analysis of conjugated ecdysteriods after liberation by hydrolysis also indicated the presence of 20-hydroxyecdysone (21.6 ng/g fresh weight) and ecdysone (2.4 ng/g fresh weight). Neither 26-hydroxyecdysone nor the 3α-epimers of 20-hydroxyecdysone or ecdysone were detected.     

Population quality,dispersal and numerical change in the gypsy moth,Lymantria dispar (L.)

Summary First instars from small and large gypsy moth eggs differ significantly in their head capsule width, weight, hatching time and the length of thoracic setae. Pupal weight and the developmental period of immature stages of the gypsy moth originating from small or large eggs do not differ significantly. The mean number of eggs per mass produced by females originating from small eggs is greater than that of females from large eggs although not statistically significant. Highly significant differences in mean egg size of egg masses of each type of female were also observed. The relationship between egg size and dispersal strategies are discussed.Paper No. 2229 Massachusetts Agricultural Experiment Station. University of Massachusetts at Amherst. This research supported (in part) from Experiment Station Project No. 355     

Influence of ambient and thoracic temperatures upon sexual behaviour of the gypsy moth, Lymantria dispar

ABSTRACT. In an ambient temperature ( T _a) range of 18–28°C, thoracic temperatures ( T _th) of individual male Lymantria dispar (L.), caught at flight in the field, ranged from 21 to 36.5°C, with a correlation coefficient of 0.63 between T _th and ambient temperature ( T _a). Ambient temperature (and insolation) altered the insect's body temperature and the probabilities, latencies, and durations of preflight responses to pheromone. In a wind tunnel at 16 and 20°C, quiescent males exposed to pheromone raised their T _th by sustained wing fanning from 17 and 21°C, respectively, to c. 24°C before takeoff. At 24 and 28°C ambient, T _th rose by takeoff to 28 and 31°C, respectively. The latencies of male wing fanning in response to pheromone decreased from 1.44 min at 16°C ambient, to 0.58 min at 20°C, to 0.26 min at 24°C, and to 0.16min at 28°C. The components of behaviour (antennal twitch, body jerk, step and wing tremor) that occurred between quiescence and wing fanning were more frequent at ambients of 16 and 20°C than at 24 and 28°C.