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Plants produce secondary metabolites for defense against herbivorous insects. In this study, the effects of different concentrations of quinine, nicotine, and tannic acid on food consumption and pupal parameters of the larva of a severe pest, Malacosoma neustria L. (Lepidoptera: Lasiocampidae), were investigated in 2007. Artificial diets containing 0.125%, 0.25%, and 0.5% concentrations of quinine or nicotine were prepared. In addition, diets containing 1.25%, 2.5%, and 5% tannin and a control diet without secondary metabolite were prepared. The feeding experiments revealed that the food consumption and pupal parameters of male and female larvae were different, and all parameters of female individuals were higher than those of male larvae. It has been determined that tannins cause more reductions in food consumption and pupal parameters than alkaloids in male and female individuals. We observed an increase in male larvae's pupal mass with increased concentration of nicotine to 0.5%. Nicotine did not cause a decrease in pupal parameters of larvae compared to quinine. In addition, all parameters of female individuals decreased with the addition of secondary metabolite. Although food consumption in alkaloid-containing diets was less than in the control group, there was a positive relationship between food consumption and pupal lipid and protein content. However, quinine had a more significant effect on triggering protein storage than nicotine. In diets containing tannins, more lipids were stored. A decrease was observed in the food consumption and pupal parameters of all individuals in the tannin-containing diets compared to the other diets.

Plants produce secondary metabolites for defense against herbivorous insects. In this study, the effects of different concentrations of quinine, nicotine, and tannic acid on food consumption and pupal parameters of the larva of a severe pest, Malacosoma neustria L. (Lepidoptera: Lasiocampidae), were investigated in 2007. Artificial diets containing 0.125%, 0.25%, and 0.5% concentrations of quinine or nicotine were prepared. In addition, diets containing 1.25%, 2.5%, and 5% tannin and a control diet without secondary metabolite were prepared. The feeding experiments revealed that the food consumption and pupal parameters of male and female larvae were different, and all parameters of female individuals were higher than those of male larvae. It has been determined that tannins cause more reductions in food consumption and pupal parameters than alkaloids in male and female individuals. We observed an increase in male larvae's pupal mass with increased concentration of nicotine to 0.5%. Nicotine did not cause a decrease in pupal parameters of larvae compared to quinine. In addition, all parameters of female individuals decreased with the addition of secondary metabolite. Although food consumption in alkaloid-containing diets was less than in the control group, there was a positive relationship between food consumption and pupal lipid and protein content. However, quinine had a more significant effect on triggering protein storage than nicotine. In diets containing tannins, more lipids were stored. A decrease was observed in the food consumption and pupal parameters of all individuals in the tannin-containing diets compared to the other diets. [ABSTRACT FROM AUTHOR]

Baculoviruses, especially prevalent in Lepidoptera, have attracted the most attention as biological insect control agents. Infection with baculoviruses is usually fatal and therefore can affect the host population density, especially if virus transmission increases with host density. Lepidoptera larvae show a strong dose-dependent response to pathogens such as baculoviruses, so their response to various pathogen exposures was studied in this work. Models of virus exposure to insect hosts are usually judged by whether or not they generate cyclical population dynamics of multiple host generations. However, the existing theoretical models based on systems of differential equations are of little use for practical application due to the large number of variables and free parameters. In this regard, the possibility of using a mathematical model for describing the epizootic Malacosoma neustria L. and Lymantria dispar L. under the influence of the nuclear polyhedrosis virus is considered. To assess the sensitivity of insects to the effects of baculoviruses, laboratory experiments were carried out on the mortality of caterpillars under various infectious loads. In this paper, we consider the possibility of constructing a model for the lifetime of insects after exposure to baculoviruses as an analog of a second-order phase transition in physical systems and give estimates of the model parameters for two insect species at different titers of baculoviruses and at different ages of caterpillars. The dependence of the parameters of the proposed model on the nuclear polyhedrosis virus strains is shown. The importance of the applied parameters for the organization of forest protection measures is substantiated. [ABSTRACT FROM AUTHOR]

The European tent caterpillar, Malacosoma neustria Linnaeus (Lepidoptera: Lasiocampidae), is a worldwide known pest that causes significant losses by feeding on many woody and shrub-like plants during the larval period. In this study, a Beauveria bassiana strain isolated from M. neustria larvae and characterized according to its morphological and molecular properties. Its insecticidal activity was tested on M. neustria larvae. Sequence results of partial ITS (ITS1-5.8S-ITS2) gene region identified the isolate (named as Mn1) as a B. bassiana strain. Phylogenetic analysis showed that Mn1 strain displays close similarity to B. bassiana ARSEF 1848 and ARSEF 751 isolates. According to the concentration-responce tests performed using 1 × 103 – 1 × 109 conidia per mL concentrations, LC50 value of the new strain was calculated as 1 × 105 conidia per mL within 7 days against the larvae of M. neustria in the laboratory conditions. B. bassiana Mn1 strain, characterized in this study, is recorded as the first entomopathogenic fungus isolated from M. neustria, and the results showed that new strain of B. bassiana has a serious potential to be utilized as a good biocontrol agent against M. neustria. [ABSTRACT FROM AUTHOR]

Malacosoma neustria is a pest for many plant species. Instead of chemical control, eco-friendly biological control methods should be used to combat this species. The purpose of this study was to evaluate the efficacy of isolates of two entomopathogenic fungi, Metarhizium brunneum (ORP-18) and Beauveria bassiana (GOPT-331), used as both oral and spray application on the 4th instar larvae of M. neustria under laboratory conditions. In addition, it was determined how the infection affected the amounts of malondialdehyde, NADPH oxidase and glutathione of the larvae. Both fungal isolates were placed in separate containers at 2 ml for each concentration (1x105, 1x106, 1x107 and 1x108 conidia/ml) in the oral group and contaminated all over the Elaeagnus rhamnoides leaves and then the contaminated leaves were offered to ten larvae in each container. For the spray group, 2 ml of spray was applied to every ten larvae placed in the containers for each concentration. As a result, it was found that both isolates killed the larvae. The ORP-18 isolate caused higher mortality rates than the GOPT-331 isolate. The spray application was more lethal than the oral application. With increasing conidial concentrations of both isolates, the amounts of malondialdehyde and NADPH oxidases increased, while the glutathione amounts decreased, which indicated the adverse effects of reactive oxygen species (ROS) on larval survival. On the basis of the results, it is recommended to use the ORP-18 isolate for the control of larvae of M. neustria. [ABSTRACT FROM AUTHOR]