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.     

Identification and characterization of an ecdysiotropic peptide from brain extracts of the gypsy moth,Lymantria dispar

A peptide (Lymantria TE) was isolated from brains of the gypsy moth, Lymantria dispar, which stimulates synthesis of ecdysteroid in the testes of larval and pupal insects. This ecdysiotropic peptide was purified and its structure determined to be NH₂-IIe-Ser-Asp-Phe-Asp-Glu-Tyr-Glu-Pro-Leu-Asn-Asp-Ala-Asp-Asn-Asn-Glu-Val-Leu-Asp-Phe-OH using protein sequence analysis and electrospray mass spectrometry. The peptide was biphasic in activity, with maximal activity in the pupal testes at 10⁻¹³ M and 10⁻⁹ M, with a minimum at 10⁻¹⁰ M, and with maxima at 10⁻¹⁵ M and 10⁻¹⁰ M and minimum at 10⁻¹³ M for larval testes. Arch. Insect Biochem. Physiol. 34:175–189, 1997. © 1997 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

N-glycan structures of human transferrin produced by Lymantria dispar (gypsy moth) cells using the LdMNPV expression system

N-glycan structures of recombinant human serum transferrin (hTf) expressed by Lymantria dispar (gypsy moth) 652Y cells were determined. The gene encoding hTf was incorporated into a Lymantria dispar nucleopolyhedrovirus (LdMNPV) under the control of the polyhedrin promoter. This virus was then used to infect Ld652Y cells, and the recombinant protein was harvested at 120 h postinfection. N-glycans were released from the purified recombinant human serum transferrin and derivatized with 2-aminopyridine; the glycan structures were analyzed by a two-dimensional HPLC and MALDI-TOF MS. Structures of 11 glycans (88.8% of total N-glycans) were elucidated. The glycan analysis revealed that the most abundant glycans were Man1-3(+/-Fucalpha6)GlcNAc2 (75.5%) and GlcNAcMan3(+/-Fucalpha6)GlcNAc2 (7.4%). There was only approximately 6% of high-mannose type glycans identified. Nearly half (49.8%) of the total N-glycans contained alpha(1,6)-fucosylation on the Asn-linked GlcNAc residue. However alpha(1,3)-fucosylation on the same GlcNAc, often found in N-glycans produced by other insects and insect cells, was not detected. Inclusion of fetal bovine serum in culture media had little effect on the N-glycan structures of the recombinant human serum transferrin obtained.     

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.

     

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.     

Parasitoid complex of the Asian gypsy moth (Lymantria dispar) (Lepidoptera: Lymantriidae) in Primorye Territory,Russian Far East

A study of the moth parasitoid complex attacking gypsy moth, Lymantria dispar (L.) was carried out in Primorye territory, Russia Far East. Season-long collections at three sites in the Vladivostok area and collections at seven sites of central region of Primorye revealed the 18 primary parasites: one egg parasitoid, 11 larval parasitoids, one larval-pupal parasitoid, one parasitic nematode, one ectoparasitoid, and three diseases including NPV (nuclear polyhedrosis virus) and Entomophaga maimaiga. Phobocampe species (Ichneumonidae) dominated the parasitoid complex, parasitizing 5.5% of the larvae in the Vladivostok area and 9.3% in central Primorye, rates which are much higher than those detected from other Asiatic regions of Russia and Northeastern Asia. The insect parasitoid complex was found to be somewhat depauperate. The 11.8% average total parasitism in eastern Russian is similar to the 12% recorded in the US. Both regions have large gypsy moth outbreaks, but other factors including diseases have compensated for the rather low mortality exerted by the parasitoid complex in the Russian Far East.     

Pheromone-mediated upwind flight of male gypsy moths, Lymantria dispar, in a forest

Abstract Lymantria dispar L. males flying upwind in a pheromone plume in a forest were video-recorded at 2.5, 10 and 20 m from the source of pheromone. Males flew slower and steered more across the wind as they approached the source. In concert, their ground speed decreased and track angles increased. In contrast to these changes, their drift angles were fairly constant and the transverse component of image flow, above and/or below the moths eyes, showed almost no change. The inter-turn duration (time between sequential turns), a temporal aspect of the male flight manoeuvres, showed a consistent but relatively small increase as the distance from the source increased. The flight tracks narrowed as the males approached close (2.5 m) to the source. Because of unpredicted correlations between physical variables (i.e. temperature, wind velocity) and the distance from the source, we used principal components analysis to generate a set of completely independent variables. Greater than 90% of the variability in the data could be explained by four principal factors which corresponded well with known relationships in the flight manoeuvres. All four of these factors showed a significant regression against distance to the source. Although uncontrolled factors such as temperature and wind velocity may have contributed to changes in flight behaviour, recent data indicate that, in addition to concentration, certain temporal and spatial characteristics (i.e. burst period, burst return period) of plumes in wind vary systematically with distance from the source. We propose that L.dispar males might adjust their flight manoeuvres in response to these changes.     

Influence of the braconid Glyptapanteles liparidis on the juvenile hormone titer of its larval host,the gypsy moth,Lymantria dispar

The increase in the juvenile hormone (JH) III titer in the hemolymph of Lymantria dispar larvae that were parasitized by the endoparasitoid braconid, Glyptapanteles liparidis, during the host's premolt to third instar, coincided with the molt of the parasitoid larvae to the second instar between day 5 and 7 of the fourth host instar. It reached a maximum mean value of 89 pmol/ml on day 7 of the fifth instar while it remained below 1 pmol/ml in unparasitized larvae. Only newly molted fifth instar hosts showed a low JH III titer similar to that of the unparasitized larvae. JH II, which is the predominant JH homologue in unparasitized gypsy moth larvae, also increased relative to controls in the last two samples (days 7 and 9) from parasitized fourth and fifth instars. Compared to unparasitized larvae, a generally reduced activity of JH esterase (JHE) was found in parasitized larvae throughout both larval stages. The reduction in enzyme activity at the beginning and at the end of each instar, when the JHE activity in unparasitized larvae was high, may be in part responsible for the increased JH II and JH III titers in parasitized larvae. Ester hydrolysis was the only pathway of JH metabolism in the hemolymph of unparasitized and parasitized gypsy moth larvae as detected by chromatographic assays. © 1996 Wiley-Liss, Inc.     

Variation in temperature and dietary nitrogen affect performance of the gypsy moth (Lymantria dispar L.)

Abstract. . The independent and interactive effects of temperature and dietary nitrogen content on performance of the gypsy moth (Lymantria dispar L.) were examined. In long-term feeding trials, larvae were reared from egg hatch to pupation on low (1.5%) and high (3.7% dry weight) nitrogen diets, under three temperature regimes. Short-term feeding trials with fourth instars and the same treatments were conducted in order to calculate nutritional indices.
Higher temperatures did not influence larval survival and marginally increased final pupal weights, but strongly decreased long-term development rates. They also accelerated short-term growth and consumption rates, and tended to improve food processing efficiencies. High concentrations of dietary nitrogen increased survival rates and final pupal weights markedly, but decreased long-term development rates only marginally. A high content of dietary nitrogen also accelerated short-term development and growth rates, reduced consumption rates, and improved food digestibility. Insects responded to low nitrogen-content diets primarily by eating faster, rather than by altering efficiency of nitrogen use. In the short-term feeding trials, thermal regime and dietary nitrogen interacted to influence growth rates, overall food processing efficiencies and nitrogen consumption rates. No interactive effects were observed in long-term studies.
This research demonstrates that small changes in thermal regime and ecologically relevant variation in dietary nitrogen content can strongly affect gypsy moth performance. Moreover, various performance parameters are differentially sensitive to the direct and interactive effects of temperature and diet.     

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 ED₅₀ 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     

Effects of elevated CO2 on feeding preference and performance of the gypsy moth (Lymantria dispar) larvae

Multiple‐choice assays were conducted in the laboratory to examine the effect of CO₂‐induced changes in leaf quality on growth, nutritional indices and preferences of the gypsy moth (Lymantria dispar) larvae. The tested tree species, one‐year‐old aspen (Populus pseudo‐simonii Kitag.), two‐year‐old birch (Betula platyphylla) and three‐year‐old oak (Quercus mongolica Fisch.) were transplanted to open‐top chambers at ambient or elevated CO₂ (650 ppm) concentrations in May 2005. The present study was conducted in 2006. Leaves from the upper and lower crowns of each tree species were sampled and analysed, respectively. On both measurement dates (24 July 2006 and 16 August 2006), there were significant CO₂ effects on levels of condensed tannin, starch, nitrogen and C : N ratio. But only on the latter date, were the concentrations of total phenolics, soluble sugar, carbon and total non‐structural carbohydrates significantly affected by elevated CO₂. Leaf dry weight content and specific leaf weight were almost completely unaffected by CO₂ enrichment. Gypsy moth larvae exhibited a clear selectivity for tested leaf types (leaves from the upper and lower crowns of each tree species) even in their early instar stage, with the upper leaves of P. pseudo‐simonii being the most preferable and the lower leaves of Q. mongolica being the least preferred. The changes in leaf quality significantly reduced larval growth and altered partial indices of insect performance (e.g., relative growth rate and relative consumption rate). However, at least in this short‐term choice feeding assay (13 days), the CO₂‐induced changes in leaf quality had no significant effects on food preference behaviour of the gypsy moth larvae, neither within the limited range of host plants nor within the leaves at different canopy heights of the same tree species.     

Larviposition of Compsilura concinnata (meigen) (diptera: Tachinidae), a parasitoid of the gypsy moth,Lymantria dispar (L.) (lepidoptera: Lymantriidae)

Larviposition of Compsilura concinnata, a polyphagous tachinid parasitoid of Lepidoptera, is described. The conventional assessment, long‐established in the literature, places the site of larval deposition by C. concinnata as directly into the host's gut. New evidence, reported here, contradicts the earlier view. Dissection of 38 freshly parasitized gypsy moth (Lymantria dispar) larvae revealed as many maggots (n = 26) situated in the lumen of the midgut as were free in the hemocoel. Observations on maggot behavior and morphology in dissected hosts are briefly presented.     

Effects of phytochemical variation in quaking aspen Populus tremuloides clones on gypsy moth Lymantria dispar performance in the field and laboratory

1. This study investigated how phytochemical variation among clones of quaking aspen Populus tremuloides, growing in a common habitat, affects the growth and fecundity of a model herbivore. 2. Gypsy moth Lymantria dispar larvae were reared from egg hatch to pupation on 10 aspen clones in the field or on excised foliage in the laboratory. Foliage was collected from each clone, and concentrations of phenolic glycosides, condensed tannins, nitrogen, and water were determined. 3. Herbivore fitness parameters and aspen phytochemical concentrations varied significantly among clones. In both the field and laboratory, larvae reared on clones containing high concentrations of phenolic glycosides exhibited prolonged developmental times and reduced pupal weights and fecundity. Herbivore performance parameters were also related positively to foliar nitrogen concentrations in the laboratory. Food consumption, but neither growth nor reproductive parameters, were related positively to condensed tannin concentrations. 4. In this study, foliar concentrations of phenolic glycosides were implicated as a significant determinant of food quality for gypsy moths, consistent with results of previous laboratory experiments. Additionally, this study documents a case in which host plant variation at a local level influences the performance and possibly the distribution and abundance of an important herbivore.     

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.     

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.     

Hostplant,larval age,and feeding behavior influence midgut pH in the gypsy moth (Lymantria dispar)

Summary The midgut pH of late instar gypsy moth (Lymantria dispar L.) larvae is strongly alkaline, and varies with diet, larval stadium, and time since feeding. Midgut pH rises with time since feeding, and does so more quickly, reaching greater maximum values, on some diets than others. Leaf tissues of 23 tree species resist increases in alkalinity differentially; this trait and differing initial leaf pH may explain the impact of diet on gut pH. Third instar larvae may have gut conditions favorable for tannin-protein binding shortly after ingesting certain foods, but with time midgut alkalinity becomes great enough to dissociate tannin-protein complexes. Older instars rarely exhibit gut pHs low enough to permit tannin activity. Alkaline gut conditions may explain the gypsy moth's ability to feed on many tanniniferous plant species, especially in later instars. Consequences for pathogen effectiveness are discussed.     

Effects of transferring gypsy moth, Lymantria dispar, larvae between artificial diet and Quercus rubra foliage

Fourth instar gypsy moth larvae, Lymantria dispar, from a laboratory colony were transferred between artificial diet and three ages of leaves from a preferred tree, Quercus rubra. Mortality after transfers was generally minimal (<13.3%) and did not differ from mortality of larvae remaining on the same food. Larvae that were transferred to a new food accepted artificial diet and the early season foliage that is normally eaten by early instars as readily as larvae that were not transferred. Pupal weights from larvae continually fed artificial diet or transferred from artificial diet to early season foliage were not significantly different. For trials beginning during June and later, 12-day weight gain and pupal weight were greater for individuals transferred to or reared continually on artificial diet than for individuals transferred to or reared continually on mature foliage.First instars of wild larvae fed artificial diet gained less weight after 3 weeks than foliage-fed first instars. Pupal weights of wild larvae transferred from June foliage to artificial diet as fourth instars were not significantly different from pupal weights of wild larvae remaining on foliage. Thus, the response of laboratory colony larvae to artificial diet was superior to that of wild larvae.

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Résumé Des chenilles du quatrième stade de L. dispar, élevées au laboratoire sur régime artificiel et sur feuilles de différents stades de leur chêne préféré, Q. rubra, ont été transférées de l'un à l'autre de ces régimes alimentaires. La mortalité après transfert est généralement faible (<13,3%) et de même importance que pour les chenilles maintenues sur le régime artificiel. Les chenilles transférées sur un nouvel aliment ont accepté le régime artificiel ou le feuillage jeune,- normalement consommé par les premiers stades larvaires-, aussi facilement que les chenilles qui n'avaient pas été transférées. Les poids des chrysalides des chenilles élevées continuellement sur régime artificiel ou transférées sur feuillage jeune n'ont pas présenté de différences significatives. Pour des expériences commencées en juin ou ultérieurement, les gains de poids à 12 jours et pour les chrysalides sont plus élevés pour les insectes maintenus ou transférés sur régime artificiel que pour ceux transférés ou maintenus sur feuillage âgé.Le poids des chrysalides, provenant de chenilles de la nature tranférées au quatrième stade, d'un feuillage de juin à un régime artificiel, n'a pas différé significativement du poids des chrysalides provenant de chenilles maintenues sur feuillage. Les premiers stades de chenilles de la nature élevées sur régime artificiel ont pris moins de poids en trois semaines que les premiers stades ayant consommé du feuillage.

     

Structural and functional difference of pheromone binding proteins in discriminating chemicals in the gypsy moth, Lymantria dispar

Pheromone-binding proteins (PBPs) of the gypsy moth, Lymantria dispar L., play an important role in olfaction. Here structures of PBPs were first built by Homology Modeling, and each model of PBPs had seven α-helices and a large hydrophobic cavity including 25 residues for PBP1 and 30 residues for PBP2. Three potential semiochemicals were first screened by CDOCKER program based on the PBP models and chemical database. These chemicals were Palmitic acid n-butyl ester (Pal), Bis(3,4-epoxycyclohexylmethyl) adipate (Bis), L-trans-epoxysuccinyl-isoleucyl-proline methyl ester propylamide (CA-074). The analysis of chemicals docking the proteins showed one hydrogen bond was established between the residues Lys94 and (+)-Disparlure ((+)-D), and л-л interactions were present between Phe36 of PBP1 and (+)-D. The Lys94 of PBP1 formed two and three hydrogen bonds with Bis and CA-074, respectively. There was no residue of PBP2 interacting with these four chemicals except Bis forming one hydrogen bond with Lys121. After simulating the conformational changes of LdisPBPs at pH7.3 and 5.5 by constant pH molecular dynamics simulation in implicit solvent, the N-terminal sequences of PBPs was unfolded, only having five α-helices, and PBP2 had larger binding pocket at 7.3 than PBP1. To investigate the changes of α-helices at different pH, far-UV and near-UV circular dichroism showed PBPs consist of α-helices, and the tertiary structures of PBP1 and PBP2 were influenced at pH7.3 and 5.5. The fluorescence binding assay indicated that PBP1 and PBP2 have similarly binding affinity to (+)-D at pH 5.5 and 7.3, respectively. At pH 5.5, the dissociation constant of the complex between PBP1 and 2-decyl-1-oxaspiro [2.2] pentane (OXP1) was 0.68 ± 0.01 μM, for (+)-D was 5.32 ± 0.11 μM, while PBP2 with OXP1 and (+)-D were 1.88 ± 0.02 μM and 5.54 ± 0.04 μM, respectively. Three chemicals screened had higher affinity to PBP1 than (+)-D except Pal at pH5.5, and had lower affinity than (+)-D at pH7.3. To PBP2, these chemicals had lower affinity than the sex pheromone except Bis at pH 5.5 and pH 7.3. Only PBP1 had higher affinity with Sal than the sex pheromone at pH 5.5. Therefore, the structures of PBP1 and PBP2 had different changes at pH5.5 and 7.3, showing different affinity to chemicals. This study helps understanding the role of PBPs as well as in developing more efficient chemicals for pest control.     

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.     

New insights into autophagic cell death in the gypsy moth Lymantria dispar: a proteomic approach

Autophagy is an evolutionary ancient process based on the activity of genes conserved from yeast to metazoan taxa. Whereas its role as a mechanism to provide energy during cell starvation is commonly accepted, debate continues about the occurrence of autophagy as a means specifically activated to achieve cell death. The IPLB-LdFB insect cell line, derived from the larval fat body of the lepidoptera Lymantria dispar, represents a suitable model to address this question, as both autophagic and apoptotic cell death can be induced by various stimuli. Using morphological and functional approaches, we have observed that the culture medium conditioned by IPLB-LdFB cells committed to death by the ATPase inhibitor oligomycin A stimulates autophagic cell death in untreated IPLB-LdFB cells. Moreover, proteomic analysis of the conditioned media suggests that, in IPLB-LdFB cells, oligomycin A promotes a shift towards lipid metabolism, increases oxidative stress and specifically directs the cells towards autophagic activity. Electronic Supplementary Material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. This work was supported by an F.A.R. grant from the University of Modena and Reggio Emilia (D.M. and E.O.) and by an “Experimental approaches to the study of evolution” grant from the Department of Animal Biology of the University of Modena and Reggio Emilia (D.M.).