Identification and expression of odorant binding proteins in the egg-parasitoid Trissolcus basalis (Wollaston) (Hymenoptera, Scelionidae, Telenominae)

Trissolcus basalis (Wollaston) (Hymenoptera, Scelionidae) is an egg-parasitoid of the southern green stink bug, Nezara viridula (Linneaus) (Hemiptera, Pentatomidae). Many behaviors associated with female T. basalis host-finding and acceptance are mediated by chemosensory pathways, for which olfactory, gustatory and ionotropic receptors have been previously identified. Odorant binding proteins (OBPs) are small, globular proteins, one of the functions of which is the transport of odorant ligands through the aqueous lymph of chemosensory sensilla to these receptors. We identified 18 classical OBP sequences in the T. basalis genome and transcriptomes sharing an average 26.8% pairwise identity. Gene tree analyses suggest very limited lineage-specific expansion and identify potential orthologs among other scelionids and Hymenoptera. Transcriptome mapping and qPCR comparison of expression levels in antennae and bodies of both sexes determine that at least five TbOBPs are preferentially expressed in the female antennae. These are, therefore, prime candidates for further study to determine their role in detecting host-produced semiochemicals.

Trichoderma harzianum Strain T22 Modulates Direct Defense of Tomato Plants in Response to Nezara viridula Feeding Activity

Plant growth-promoting fungi belonging to genus Trichoderma are known to help plants when dealing with biotic stressors by enhancing plant defenses. While beneficial effects of Trichoderma spp. against plant pathogens have long been documented, fewer studies have investigated their effect on insect pests. Here, we studied the impact of Trichoderma root colonization on the plant defense responses against stink bug feeding attack. For this purpose, a model system consisting of tomato plant, Solanum lycopersicum cv Dwarf San Marzano, Trichoderma harzianum strain T22 and the southern green stink bug, Nezara viridula, was used. We firstly determined stink bug performance in terms of relative growth rate and survival on tomato plants inoculated by T. harzianum T22. Then, we evaluated relative expression of plant defense-related genes on inoculated plants induced by stink bug feeding. We found evidence that T. harzianum T22 affects tomato defense responses against N. viridula nymphs leading to reduction of growth rate. Our results also showed that T. harzianum T22 enhances plant direct defenses by an early increase of transcript levels of jasmonic acid marker genes. Yet this effect was time-dependent and only detected 8 h after herbivore induction. Taken together, our findings provide better understanding on the mechanisms underlying tomato induced resistance against herbivorous stink bugs.

First detection of Megaselia scalaris (Loew) (Diptera: Phoridae) as a facultative endoparasitoid of Nezara viridula (L.) (Hemiptera: Pentatomidae)

Background The phorid fly Megaselia scalaris (Loew) (Diptera: Phoridae) is an omnivorous species, capable of exploring a large variety of environments and ecological niches. It is known as an important detritivore species with maggots feeding on a variety of food of both animal and plant origin. Results The present study reports M. scalaris as an endoparasitoid attacking colonies of the southern green stink bug Nezara viridula (L.) for the first time. This case of parasitism was observed inside rearing cages of N. viridula at the Plant Protection Research Institute, Dokki, Egypt in August 2020. We firstly identified adult individuals of M. scalaris which were found moving erratically within the cages using relevant identification keys. To verify that N. viridula individuals are parasitized by the same parasitoid and they are not infected with other parasitoids, some of the parasitized bugs were transferred to a separate cage at the same laboratory conditions and the developmental stages of the dipteran parasitoid were observed until the adult emergence. Conclusion The present investigation revealed that M. scalaris could be included to the recorded parasitoid species of N. viridula, and further studies should be carried out to assess the efficacy of this fly as a biocontrol agent.

New data on invasive insects in the republic of Сrimea

In recent years, the emergence of new invaders has been discovered in Crimea – the mealy lantern fly Metcalfa pruinosa (Say, 1830) (Hemiptera: Auchenorrhyncha: Flatidae), the indian wax scale Ceroplastes ceriferus (Fabricius, 1798) (Hemiptera: Coccoidea: Coccoidea), the southern green stink bug Nezara viridula (Linnaeus, 1758) (Hemiptera: Heteroptera: Pentatomidae), the stink bug Oxycarenus lavaterae (Fabricius, 1787) (Hemiptera: Heteroptera: Lygaeidae) and palm moth Paysandisia archon (Burmeister, 1880) (Lepidoptera: Castniidae). Timely information on the penetration of new alien species that damage agricultural and ornamental crops into the entomofauna of Crimea, their distribution, biological characteristics that are relevant for specialists in the field of plant protection and landscape architecture. The number of mealy lantern fly has increased over the years of observations, and the list of host plants has also expanded, which has confirmed its polyphagia. In Crimea, a pest has appeared that can cause significant damage to fruit, berry, nut-bearing and ornamental crops. During the years of research, we discovered another alien species – the indian wax scale. As a result of damage to ornamental crops, individual branches dried out and some plants died. We assume that this phytophage was brought to the Crimea with planting material, because it occurs focally on objects of landscape architecture. Since 2018, palm trees have been damaged by the palm moth – one of the invasive pests of these plants on the southern coast of Crimea. Caterpillars damage the vascular system and the plant's growth point. As a result of the damage caused, the plants die. Since the same year, a new alien species, the southern green stink bug, has shown harmfulness on vegetable, berry and flower crops, as well as on weeds, and in 2020, for the first time in the Crimea, in the Nizhnegorsk region, another stink bug, O. lavaterae, was found on a linden. There is little information about this insect. It can form massive clusters on linden and hibiscus bark.

Qualitative detection of different enzymes from the gut and salivary glands of Nezara viridula Linn. using the chemical inference

Globally the crop insect pests damage the 30% of agriculture production due to insect spoil, and the situation is very awful in particularly developing countries such as India. There are large number of insect pest families are well known which induce the critical destroy to agriculture crops. Crop insect pest’s harm is one of the significant features that ruin the agriculture crop productivity, although the large-scale utilization of chemical pesticides. The successfulness of the pesticides depends upon the interaction of chemicals with the physiology of the insect of the pests. In India, the Nezara viridula Linn, is one of the critical insects because of its destructive feeding on major crop which is the utmost source of economic deprivation in agriculture. The enzymes present in the gut and salivary glands of the N. Viridula play key role in the feeding behaviour. Presently very little is investigated about the gut and salivary glands of the N. Viridula at minute level. We first time investigated the different enzymes existing in the gut and salivary gland using the chemical inference. This research work is carried out to analysis the enzymes for digestive and feeding behaviour of N. Viridula which will assist the biologists to manage the challenges are created by their resistance to the traditional chemical insecticides used for prevention of N. Viridula (a type of southern green stink bug) inhabitants and high reproductive amplitude. The extensive statistics of invertase enzymes, maltase, alpha galactosidase, amylase, esterase, proteinase and polypeptidase enzymes for the N. Viridula in salivary glands and gut inspired by this research imparts supplementary resource for further understanding of the biology of this Pentatomidae (Heteroptera) species.

Retention of Pantoea agglomerans Sc1R across stadia of the southern green stink bug, Nezara viridula (L.) (Hemiptera: Pentatomidae)

Southern green stink bug [Nezara viridula (L.)] adults and other pentatomid pests can transmit pathogens (e.g., the bacterium Pantoea agglomerans) that cause disease in cotton (Gossypium hirsutum L.) and other high-value cash crops worldwide. First instars of N. viridula were recently shown to ingest P. agglomerans strain Sc1R with rifampicin-resistance, and to retain the pathogen to the 2nd instar. The objective of this study was to determine the acquisition of P. agglomerans Sc1R by early instars of N. viridula and determine persistence of P. agglomerans Sc1R across subsequent stadia. In three trials, early instars (1st and 2nd) were exposed to P. agglomerans Sc1R and subsequently maintained to adulthood; cohorts were sampled at 3rd and 5th instars, as well as adults. In every trial, P. agglomerans Sc1R was detected in all stadia, including adults, but significantly higher frequencies of infection than expected were observed at the initial stage of infection (either 1st or 2nd instar). Higher densities of P. agglomerans Sc1R were detected in 1st and 2nd instars, and lower densities were observed in subsequent stadia. Densities of innate microbiota were generally lower when the initial stage of exposure was at 1st instar than when the initial stage of exposure was at the 2nd instar. Overall, half of the adults possessed P. agglomerans Sc1R. These findings demonstrated that N. viridula nymphs can acquire P. agglomerans Sc1R and retain the pathogen to adulthood. Potential avenues of research to further elucidate the implications of nymphs harboring pathogens to adulthood are discussed.