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Nanoparticles (NPs) are released directly or indirectly into nature with increased production and consumption, and their effects on insects, which occupy a large place in the ecosystem, are of interest. There is also interest in the potentially toxic effects of NPs applied to hive pests on parasitoids, honey bees, and host-parasitoid relationships. The influence of aluminum oxide (Al2O3) NPs on the biological features of the hive pest Galleria mellonella, total counts of hemocyte, and hemocyte types; as well as on the biological features of the endoparasitoid Pimpla turionellae were investigated. The data obtained revealed that Al2O3 NPs caused a decrease in the larval, pupal, and adult development time of G. mellonella. The immature developmental time of P. turionellae was reduced. It was also demonstrated that Al2O3 NPs decreased the total counts of hemocytes in G. mellonella larvae; granulocyte, spherulocyte, oenocytoid, and prohemocyte counts decreased at all NP concentrations, while plasmatocyte counts increased. The data showed that Al2O3 NPs affected the biological properties of the hive pest model organism G. mellonella and indirectly affected its endoparasitoid P. turionellae. In addition, Al2O3 NPs showed a suppressive effect on cellular immune system responses, decreasing hemocyte counts. Our study results suggest that honey bees, honeycomb pests, and parasitoids may be negatively affected by NPs, which have increased in recent years as environmental pollutants, and that NPs may have insecticidal effects. [ABSTRACT FROM AUTHOR]

Endoparasitoid species devoid of symbiotic viruses inject secretions derived from their reproductive glands into their hosts during parasitism in order to avoid various immune responses of their hosts. Pimpla turionellae L. (Hymenoptera: Ichneumonidae) is an endoparasitoid that lacks polydnaviruses, and its venom has previously been shown to paralyze the host Galleria mellonella (Lepidoptera: Pyralidae) and suppress its immune reactions to ensure the egg survival. The present study demonstrates that another female-injected factor calyx fluid extracted from the P. turionellae ovary is also responsible for the suppression of G. mellonella immunity. The total hemocyte counts of G. mellonella decrease after treatment with calyx fluid in a concentration-dependent manner. Significant reductions in cell viability are also observed at all calyx fluid doses both in vivo and in vitro. The analyses of the beads injected into the insects as encapsulation targets revealed that the number of encapsulated beads reduced significantly compared to controls post-calyx fluid injection. The injection of the highest calyx fluid dose (1 female equivalent calyx) is sufficient to completely inhibit the strong encapsulation and melanization reactions of the last instar larvae 24 h post-injection. These results demonstrate that P. turionellae calyx fluid is required to regulate host immunity for successful parasitization. [ABSTRACT FROM AUTHOR]

Parasitoids are insects that use other insects as hosts. They sabotage host cellular and humoral defences to promote the survival of their offspring by injecting viruses and venoms along with their eggs. Many pathogens and parasites disrupt host epigenetic mechanisms to overcome immune system defences, and we hypothesized that parasitoids may use the same strategy. We used the ichneumon wasp Pimpla turionellae as a model idiobiont parasitoid to test this hypothesis, with pupae of the greater wax moth Galleria mellonella as the host. We found that parasitoid infestation involves the suppression of host immunity-related effector genes and the modulation of host genes involved in developmental hormone signalling. The transcriptional reprogramming of host genes following the injection of parasitoid eggs was associated with changes in host epigenetic mechanisms. The introduction of parasitoids resulted in a transient decrease in host global DNA methylation and the modulation of acetylation ratios for specific histones. Genes encoding regulators of histone acetylation and deacetylation were mostly downregulated in the parasitized pupae, suggesting that parasitoids can suppress host transcription. We also detected a strong parasitoid-specific effect on host microRNAs regulating gene expression at the post-transcriptional level. Our data therefore support the hypothesis that parasitoids may favour the survival of their offspring by interfering with host epigenetic mechanisms to suppress the immune system and disrupt development. [ABSTRACT FROM AUTHOR]

Understanding the effects of diet on metabolic events is crucial for biological control programs of parasitoid insects. As bioindicators of long-term physiological stress: survivorship of fifth instar larvae, pupation, adult survival, and developmental time for stages of endoparasitoid Pimpla turionellae L. (Hymenoptera: Ichneumonidae) were investigated by rearing the parasitoid on the host, Galleria mellonella L. (Lepidoptera: Pyralidae) pupae were treated with neomycin. First instar larvae of G. mellonella were reared on artificial diets containing 0.005, 0.01, or 0.5 g neomycin (g/100 g of diet) until seventh instar larvae; the pupae from these larvae were used as a host for rearing P. turionellae. In the control group, the pupae from larvae reared on artificial diets without neomycin were used as a host. Survivorship of fifth instar, pupal, and adult stages of P. turionellae L. reared on G. mellonella pupae as a host fed with different concentrations of neomycin were significantly decreased in comparison to the control group. Approximately eighty percent of P. turionellae L. pupae were produced from control host pupae, while other neomycin concentrations significantly decreased the pupation of the parasitoid. Pimpla turionellae L. larvae reared on control host pupae reached fifth instar in about 9.6 ± 0.61 d, while the larvae reared from a host pupae exposed to the highest antibiotic concentration completed their development to the fifth instar in about 7.4 d. These results showed that neomycin, and possibly its metabolites, contaminated P. turionellae L. larvae from a host and affected larval stages of the parasitoid. [ABSTRACT FROM AUTHOR]

Paralytic, cytotoxic, and cytolytic effects of Pimpla turionellae L. (Hymenoptera: Ichneumonidae) venom has previously been shown toward its natural host Galleria mellonella L. (Lepidoptera: Pyralidae). The effects of P. turionellae venom and parasitization on hemolymph carbohydrate and lipid levels of the host larvae and pupae were studied in the present study for a more complete understanding of metabolic alterations that accompany parasitism. Larval and pupal carbohydrate levels were increased at 4 and 24 h posttreatment at lower venom doses. Venom-induced reductions were only observed at the highest venom dose in larval stage at two time points posttreatment. Parasitization reduced the pupal hemolymph carbohydrate at 24 h postoviposition compared to untreated control. The magnitude of differences in lipid content of larva was not dose dependent and fluctuated among treatments. However, in pupal stage venom caused an elevation in total lipid content except for 0.05 VRE. Total lipid amounts of G. mellonella pupae were reduced by>50% postparasitization. We conclude that experimental envenomation and parasitization of G. mellonella by the idiobiont endoparasitoid P. turionellae altered carbohydrate and lipid contents depending on host developmental stage. [ABSTRACT FROM AUTHOR]

The effects of indol-3-acetic acid (IAA) were investigated on biological parameters of Galleria mellonella (Linnaeus, 1758) (Lepidoptera: Pyralidae) and its endoparasitoid Pimpla turionellae (Linnaeus 1758) (Hymenoptera: Ichneumonidae) reared on hosts treated with 50 to 10,000 ppm of IAA in their diet. Percent fecundity of first generation of G. mellonella females increased by 12% at 50 ppm whereas the most effective decrease, by >33%, was observed at 5,000 ppm. Percent fertility decreased by >20% at 1,000 ppm. All treatments displayed ±5% variations when compared to controls except for a >20% increase in corrected percent sterility at 1,000 ppm. The results did not reveal any considerable effect of IAA on egg hatching, larval and pupal developmental, or adult emergence times. The most striking effect observed was a decline in second generation pupal developmental time by >47% at 1,000 and 10,000 ppm. No dose-wise alterations were observed in adult longevity, weight, size and female sex ratio of G. mellonella. Treatment with IAA caused a slight prolongation in adult emergence and decrease in longevity of P. turionellae reared on hosts; longevity of wasps declined by >27% at higher doses. Neither wasp size nor weight displayed significant changes upon IAA treatment. [ABSTRACT FROM AUTHOR]

The impacts of the plant growth regulator, gibberellic acid (GA3) were investigated on hemolymph free amino acids (FAAs) of Galleria mellonella L. (Lepidoptera: Pyralidae) larvae and its endoparasitoid Pimpla turionellae L. (Hymenoptera: Ichneumonidae) reared on host treated with different doses (50-5,000 ppm) of GA3 in diet. High-performance liquid chromatographic analysis of the hemolymph revealed that out of the 20 amino acids detected, 18 FAAs were found in the hemolymph of treated and untreated host larvae, whereas 19 were present in that of parasitoid. The total pool of FAAs in host larvae after treatment by GA3 fluctuated among doses and the ratio of essential amino acids in the pool increased to reach 9.54% at 1,000 ppm. Parasitoid larval total FAA concentration exhibited an increase at all treatments. However, the ratio of essential amino acids in the pool decreased >50% at all doses except for 50 ppm. Dose-dependent variations in individual FAAs in larval hemolymph of both species were also detected. Tyrosine, methionine, isoleucine, lysine, and tryptophan generally occurred in lowest amount both in control and treated G. mellonella larvae. The amount of serine, asparagine, glycine, isoleucine, leucine, and phenylalanine displayed differences only among GA3 doses in treatments. Great variations in the amount of all amino acids occurred at most of the treatment doses in wasp larvae hemolymph. Our study indicated that application of GA3 resulted in different effects on the quantity of FAAs associated with energy metabolisms of the pest species and its natural enemy. [ABSTRACT FROM AUTHOR]

The endoparasitic wasp Pimpla turionellae L. (Hymenoptera: Ichneumonidae) injects its pupal host with venom during oviposition. Venom from P. turionellae has previously been shown to contain a mixture of biologically active components, which display potent paralytic, cytotoxic and cytolytic effects towards lepidopteran and dipteran hosts. This study was undertaken to investigate if parasitism and/or envenomation by P. turionellae affects the encapsulation and melanization responses of its host Galleria mellonella L. (Lepidoptera: Pyralidae) in larval and pupal stages. Analysis of the effects of venom on encapsulation and melanization of the Sephadex A-25 beads revealed that the number of beads strongly encapsulated and melanized were reduced by more than 50% at 4 and 24 h post-venom injection into pupae. Injection of a lethal dose of venom (0.5 venom reservoir equivalent) in the last instar larvae was sufficient to reduce the ability of haemocytes to encapsulate the beads by more than 50% at 4 h post-injection. Similar results were also obtained when beads were recovered from parasitized pupae indicating that parasitization by P. turionellae suppressed haemocyte-mediated encapsulation in G. mellonella. We found that the cellular defence reactions occur more rapidly in larvae compared with pupae of G. mellonella, indicating the higher susceptibility of pupal haemocytes to parasitism and venom injection. [ABSTRACT FROM AUTHOR]

Effects of an organophosphorus insecticide, malathion, on survivorship and lipid peroxidation of the greater wax moth, Galleria mellonella (L.), pupae were investigated by rearing the newly hatched larvae on an artificial diet containing 0.01, 0.1, 1, 10, and 100 ppm of the insecticide. As bioindicators of long-term physiological stress responses, the adult emergence rate, longevity, and fecundity associated with lipid peroxidation level and antioxidant enzyme activity in the endoparasitoid Pimpla turionellae (L.) (Hymenoptera: Ichneumonidae) were determined by rearing the parasitoid on a factitious host, G. mellonella pupae treated with malathion. At 100 ppm, malathion significantly decreased pupation rate of G. mellonella larvae and the rate of adult emergence of the parasitoid from these pupae. This concentration resulted in a significant increase in the lipid peroxidation product malondialdehyde (MDA) in both the host and the parasitoid. Malathion at 1 and 10 ppm significantly increased pupation rate and lipid peroxidation level of G. mellonella pupae. The adult emergence rate of P. turionellae was significantly decreased from 63.7 to 20% by these concentrations, whereas MDA content was increased by two- and three-fold, respectively, compared with the control (45.3 ± 3.2 nmol/g protein). The longevity of adults was significantly extended from 52.5 ± 5.7 to 75.7 ± 6.3 d when the parasitoids emerged from host pupae exposed with 0.1 ppm malathion. At low concentrations (0.01 and 0.1 ppm), malathion significantly increased the number of eggs laid per female per day. However, the lowest concentration (0.01 ppm) had no significant effect on hatchability, whereas 0.1 ppm of the insecticide resulted in significant decrease in egg hatch compared with the control. A significant increase in total superoxide dismutase (SOD) activity for low concentrations of malathion (0.01-1 ppm) was found compared with the control. There was a significant positive correlation of SOD activities with adult longevity and fecundity. This study suggested that malathion-induced oxidative stress was causative factor in the deterioration of biological fitness and that increased SOD activities may have resulted in decreased oxidative damage, which retarded the rate of deteriorative physiological changes in P. turionellae in response to sublethal doses of malathion. [ABSTRACT FROM AUTHOR]

[Display omitted] • The LC 50 value of venom for G. mellonella pupal stage was 0.44 µg/2 µl/pupa. • Effective concentrations of P. turionellae venom tested for the model host G. mellonella. • Envenomation by endoparasitoid induced anti-oxidative response in the host pupa. • Envenomation by P. turionellae induced DNA and chromosomal damages in host pupa. Parasitoid species regulate the nutritional and physiological states of their hosts to ensure their eggs and larvae successfully develop inside the host. Due to the insecticidal and paralyzing properties of venoms from idiobiont parasitoids, parasitic wasps are important natural enemies of several insect pests. For this purpose, in this report, we investigated the oxidative, genotoxic, and mutagenic potential of venom from Pimpla turionellae L. (Hymenoptera: Ichneumonidae) on the laboratory host Galleria mellonella L. (Lepidoptera: Pyralidae). The insecticidal assay showed the LC 50 and LC 99 values of endoparasitoid venom for G. mellonella pupal stage to be 0.44 µg and 1.17 µg in 2 µl insect saline buffer, respectively. According to the mechanical stimulus–response (MSR) assay, pupal paralysis increased significantly within four hours post-injection at LC 50 and higher venom concentrations. Envenomation by LC 10, LC 30, and LC 50 concentrations of endoparasitoid venom and parasitism reduced the activities of superoxide dismutase, catalase, and glutathione-S-transferase enzymes and the level of malondialdehyde in the hemolymph of host pupae 1, 2 and 4 h post-treatment. On the other hand, comet and micronucleus assays displayed that, envenomation by the effective concentrations of P. turionellae venom-induced concentration and time-dependent DNA and chromosomal damages in host hemocytes. Therefore, these data indicated that envenomation by P. turionellae induces anti-oxidative stress, genotoxicity, and mutagenicity which alter the hosts' physiological state to create a suitable host environment for the successful development of their progeny. In conclusion, we suggest that this study could provide useful information for bioinsecticidal potential of idiobiont wasp venom for sustainable integrated pest management programs. [ABSTRACT FROM AUTHOR]