Morphological characterization and distribution of antennal sensilla of Diaphania angustalis Snellen (Lepidoptera: Crambidae).

Diaphania angustalis Snellen (Lepidoptera: Crambidae) is the main defoliator of Alstonia schalaris. In this article, observation of external morphological and ultrastructure structure of adult antennae of D. angustalis was carried out using the scanning and transmission electron microscope. The results showed that both male and female antennae were filiform and could be divided into scape, pedicel, and flagellum. There are eight types and two subtypes of antennal sensilla, namely, sensilla trichodea, sensilla chaetica (I & II), sensilla coeloconica, sensilla auricillica, sensilla styloconica, sensilla squamiformia, capitate peg, and Böhm bristles. Most sensilla are concentrated in venter and the sides of antennae. Analyses on morphological and quantitative differences of antennal sensilla between male and female adults. The size of SCo is significantly different between male and female. In terms of quantity, only SSt and CP have no significant differences between male and female. By comparing the existing antennal sensilla of Crambidae, it is found that STr, SCh, SCo, and SAu are common sensilla. These results can contribute to further research on the function of sensilla of D. angustalis relating to its behavior. A detailed description is provided of the antennal sensilla in Diaphania angustalis. Diaphania angustalis has the rare sensilla of capitate peg in Crambidae. No sexual dimorphism of sensillum types is found in the species. The number and distribution of sensilla trichodea, sensilla chaetica, sensilla coeloconica, and sensilla auricillica sensillum are different.

Ultrastructure of antennal sensilla of three fruit borers (Lepidoptera: Crambidae or Tortricidae).

Three fruit borers Conogethes punctiferalis (Guenée) (Crambidae), Grapholita molesta Busck (Tortricidae), and Spilonota albicana Motschulsky (Tortricidae) are serious pests of fruit trees. In this study, their antennal morphology, types of sensilla, and distributions were observed by using SEM (Scanning Electron Microscope). Nine types of sensilla were found on the antennae of C. punctiferalis, while eight types of sensilla were presented on each of G. molesta and S. albicana. The sensilla trichodea with two subtypes were the most abundant sensilla among three fruit borers. Two subtypes of sensillum coeloconica (type I with spines and type II without spines) were observed on the antennae of C. punctiferalis and G. molesta. However, sensilla coeloconica (type I) were only found in S. albicana. Although the sensilla campaniformia were only found on the antennae of C. punctiferalis, our observations confirm sensilla campaniformia presence in the moths. In addition, the functions of these sensilla were discussed based on previously reported lepidopteran insects. As a result, our study may provide useful information for advanced electrophysiological and behavioral experiments to better understand the mechanisms related to pests control.

Sensilla on six olfactory organs of male Eogystia hippophaecolus (Lepidoptera: Cossidae).

Eogystia hippophaecolus (Hua et al.) is an important boring pest that primarily damages sea buckthorn, causing large ecological and economic damages in China. In this study, we used scanning electron microscopy to investigate the sensilla on six olfactory tissues of male E. hippophaecolus: antennae, labial palps, external genitals, propodeum, mesopodium, and metapedes. On the antennae, two types of sensillum trichodea, two types of sensillum basiconica, a type of sensillum coeloconica, and Böhm's bristles were found. The labial palps had sensilla trichodea and chaetica. On the external genitals, three types of sensilla trichodea were the only sensilla. Böhm bristles were found on the base of the tibia and at the terminus of the tarsus. Most sensilla were distributed on the tarsus of the three pairs of legs, and notably, a majority of which were sensilla trichodea and sensilla chaetica, were on the pretarsus and telotarsus of the three pairs of legs. In this study, the distribution, number, type, and morphology of the sensilla on six olfactory organs of E. hippophaecolus were determined, which established the foundation for a future immunohistochemical search of olfactory proteins. RESEARCH HIGHLIGHTS: Eogystia hippophaecolus is a serious pest of seabuckthorn. The distribution, number, type, and morphology of olfactory sensilla of E. hippophaecolus are determined. The function and distribution of sensilla are compared with those of other insects.

Morphology, ultrastructure, and chemical compounds of the osmeterium of Heraclides thoas (Lepidoptera: Papilionidae).

The osmeterium, found in papilionoid larvae, is an eversible organ with an exocrine gland that produces substances in response to the mechanical disturbances caused by natural enemies. The anatomy, histology and ultrastructure of the osmeterium, and the chemical composition of its secretion in Heraclides thoas (Lepidoptera: Papilionidae) were studied. Heraclides thoas larvae have a Y-shaped osmeterium in the thorax. The surface of the osmeterium has a rough cuticle lining cells with papillae and irregular folds, whereas the cells that limited the gland pores are irregular, folded, and devoid of papillae. Two types of cells are found: (i) cuticular epidermal cells on the surface of the tubular arms of the osmeterium and (ii) secretory cells of the ellipsoid gland within the region of the glandular pore. Cuticular epidermal cells show a thick cuticle, with several layers divided into epicuticle and lamellar endocuticle. Secretory cells are polygonal, with extensive folds in the basal plasma membrane that formed extracellular channels. The cytoplasm has mitochondria, ribosomes, and numerous vacuoles, whereas the nucleus is irregular in shape with decondensed chromatin. The chemical composition of the osmeterial secretion comprised (Z)-α-bisabolene (25.4%), α-bisabol (20.6%), ß-bisabolene (13.1%), (E)-α-bisabolene 8%), ß-pinene (9.91%), longipinene epoxide (8.92%), (Z)-ß-farnesene (6.96%), ß-caryophyllene (2.05%), farnesol (1.86%), linalyl propionate (1.86%), and 1-octyn-4-ol (1.07%). The morphological features suggest that the cuticular epidermal cells play a major role in the maintenance and protection of the osmeterium, whereas secretory cells are responsible for production of osmeterial secretions.

Squamocin induce histological and ultrastructural changes in the midgut cells of Anticarsia gemmatalis (Lepidoptera: Noctuidae).

Annonaceous acetogenins (Annona squamosa Linnaeus) comprises of a series of natural products which are extracted from Annonaceae species, squamocin proved to be highly efficient among those agents. Squamocin is mostly referred as a lethal agent for midgut cells of different insects, with toxic effects when tested against larva of some insects. In present study, LC50 and LC90 of squamocin for A. gemmatalis Hübner (Lepidoptera: Noctuidae) were calculated using probit analysis. Morphological changes in midgut cells were analyzed under light, fluorescence and transmission electron microscopes when larvae were treated with LC50 and LC90 of squamocin for 24, 48 and 72 h. Results revealed that the maximum damage to midgut cells was found under LC90 where it showed digestive cells with enlarged basal labyrinth, highly vacuolated cytoplasm, damaged apical surface, cell protrusions to the gut lumen, autophagy and cell death. The midgut goblet cells showed a strong disorganization of their microvilli. Likewise, in insects treated with squamocin, mitochondria were not marked with Mitotracker fluorescent probe, suggesting some molecular damage in these organelles, which was reinforced by decrease in the respiration rate in these insects. These results demonstrate that squamocin has potential to induce enough morphological changes in midgut through epithelial cell damage in A. gemmatalis.

A Triassic-Jurassic window into the evolution of Lepidoptera.

On the basis of an assemblage of fossilized wing scales recovered from latest Triassic and earliest Jurassic sediments from northern Germany, we provide the earliest evidence for Lepidoptera (moths and butterflies). The diverse scales confirm a (Late) Triassic radiation of lepidopteran lineages, including the divergence of the Glossata, the clade that comprises the vast multitude of extant moths and butterflies that have a sucking proboscis. The microfossils extend the minimum calibrated age of glossatan moths by ca. 70 million years, refuting ancestral association of the group with flowering plants. Development of the proboscis may be regarded as an adaptive innovation to sucking free liquids for maintaining the insect's water balance under arid conditions. Pollination drops secreted by a variety of Mesozoic gymnosperms may have been non-mutualistically exploited as a high-energy liquid source. The early evolution of the Lepidoptera was probably not severely interrupted by the end-Triassic biotic crisis.

Microstructural and ultrastructural changes in the muscle cells of the oriental armyworm Mythimna separata Walker (Lepidoptera: Noctuidae) on treatment with wilforine.

This study investigated the mode of action of wilforine, an alkaloid with insecticidal properties, extracted from Tripterygium wilfordii Hook f., on the microstructure and ultrastructure of the muscle cells of larvae and adults of the oriental armyworm Mythimna separata Walker. The bioassay results showed that wilforine had oral toxicity against both M. separata larvae (LC50=63µg/mL) and adults (LC50=36µg/mL). The typical toxicity sign was paralysis leading to death. Both light and electron microscope observations revealed that damage to the muscle cells increased with poisoning time in larvae and adults treated with the LC80 dose of wilforine. Histopathological examinations in the muscle cells of M. separata adults showed that there were large cytoplasmic spaces, disrupted Z-lines and swollen mitochondria in the muscle cells. Further, the sarcoplasmic reticulum was excessively dilated and fragmented; the nuclear membrane was ruptured; nuclear material was overflowing; and the myolemma was damaged. The similar pathological changes in the muscle cells of oriental armyworm larvae were observed, as above. In addition, a medullary sheath structure appeared and crystalline inclusion was also observed in the muscle cells of M. separata larvae. In conclusion, wilforine could induce pathological changes in the muscle cells of oriental armyworm larvae and adults, leading to their death; thus, the active site of action of wilforine maybe located in the muscle tissue of insects.

Ultrastructural and functional characterization of circulating hemocytes from Galleria mellonella larva: Cell types and their role in the innate immunity.

Galleria mellonella larvae have been widely used as a model to study the virulence of various human pathogens. Hemocytes play important roles in the innate immune response of G. mellonella. In this study, the hemocytes of G. mellonella larvae were analyzed by transmission electron microscope, light microscope, and cytochemistry. The cytological and morphological analyses revealed four types of hemocytes; Plasmatocytes, granular cells, spherule cells and oenocytoids. Differential hemocyte counts showed that under our conditions plasmatocytes and granular cells were the most abundant circulating cell types in the hemolymph. We also investigated the role of different types of hemocytes in the cellular and humoral immune defenses. The in-vivo experiment showed that plasmatocytes, granular cells and oenocytoids phagocytized FITC-labelled Escherichia coli bacteria in larvae of G. mellonella, whereas the granular cells exhibited the strongest phagocytic ability against these microbial cells. After incubation with L-DOPA, plasmatocytes, granular cells and oenocytoids are stained brown, indicating the presence of phenoloxidase activity. These results shed new light on our understanding of the immune function of G. mellonella hemocytes.

Fluorescence localization and comparative ultrastructural study of periplocoside NW from Periploca sepium Bunge in the midgut of the oriental amyworm, Mythimna separata Walker (Lepidoptera: Noctuidae).

Periplocoside NW (PSNW) is a novel insecticidal compound isolated from the root bark of Periploca sepium Bunge and has potent stomach toxicity against some insect pests. Previous studies showed that the Mythimna separata larva is sensitive to PSNW, but the Agrotis ispilon larva is insensitive. In this study, preliminary target localization on the midgut of M. separata larvae was conducted via a fluorescence labeling technique. A comparative ultrastructural study on the effects of PSNW on the midguts of M. separata and A. ispilon larvae was performed. Symptom observation results showed that typical stomach toxicity was induced by PSNW in M. separata larvae. Fluorescence localization results showed that PSNW binds to the midgut cells of M. separata larvae. Ultrastructure observations showed destruction of the microvilli, organelle, and cytomembrane in the midgut cells of M. separata larvae, whereas no obvious changes were observed in midgut cells of A. ispilon larvae. These results were consistent with the insecticidal activity of PSNW. Therefore, PSNW might act on the midgut tissues of the insects, and one or more binding sites of PSNW may exist in M. separata larvae midgut cell cytomembranes.

Structural characteristics and phylogenetic analysis of the mitochondrial genome of the rice leafroller, Cnaphalocrocis medinalis (Lepidoptera: Crambidae).

The rice leafroller, Cnaphalocrocis medinalis, is one of the most important pests on rice and possesses striking flight ability. We have determined the nucleotide sequence of the 15,377 bp of a C. medinalis mitochondrial genome (mtDNA). The mtDNA encodes 37 genes and shows a unique lepidopteran CR-M-I-Q arrangement. Three possible substructures were detected in C. medinalis and some other lepidopteran insects' control region. The findings might be relevant to the regulation of mtDNA replication and transcription. Phylogenetic relationships were reconstructed among 19 families in Lepidoptera so far. Cnaphalocrocis medinalis forms a reciprocal monophyletic group with Ostrinia in clade Crambidae instead of Pyralidae. The topology between Papilionoidea and other superfamilies showed an apparent contradiction with traditional Lepidopteran classification. As a well-known migratory insect, the molecular information contained in C. medinalis mtDNA may provide a further insight into the evolution of mitochondria genes and insect species, and may help to better understanding the energy metabolism of invertebrates.

[Macroscopic and microscopic characteristics of Chinese caterpillar fungus].

Chinese Caterpillar Fungus (CCF) is one of the rare Chinese traditional drugs. As the resource is reducing sharply, the price is rising higher and higher, and there have been much more adulterants in the markets, but until now we don't have a scientific and accurate research on the identification study for this drug. On the basis of resource investigation, during the study of the samples collected by ourselves and the specimens stored in the museum, using the macroscopic and microscopic methods, referring to the literatures of entomology, emphasizing on the characteristics of polypide part, we have studied this species in detail of the macroscopic characters such as the insertion position of the stroma part, the annulations and segments of the caterpillar, the abdominal leg, the pinaculum, and the microscopic characters of the body wall; firstly added the microscopic character of the crotchets on the planta of abdominal leg. The result turned out that the characters which we have studied are regular and stable, and it have laid the foundation for the powder products and patent medicines which have used the crude drug of CCF.

Ultrastructural and functional analysis of secretory goblet cells in the midgut of the lepidopteran Anticarsia gemmatalis.

Defoliation caused by Anticarsia gemmatalis larvae affects the commercial production of the soybean. Although regulation of the digestion of soybean components has become part of the suggested strategy to overcome problems caused by Anticarsia larvae, few studies have focused on the morphological and cellular aspects of Anticarsia intestinal tissue. We have therefore further analyzed the morphology and ultrastructure of the midgut of 5th instar larvae of A. gemmatalis. Dissected midgut was subjected to chemical or cryo-fixation and then to several descriptive and analytical techniques associated with both light and electron microscopy in order to correlate anatomical and physiological aspects of this organ. Histological analysis revealed typical anatomy composed of a cell layer limited by a peritrophic membrane. The identified lepidoptera-specific goblet cells were shown to contain several mitochondria inside microvilli of the goblet cell cavity and a vacuolar H(+)-ATPase possibly coupled to a K(+)-pumping system. Columnar cells were present and exhibited microvilli dispersed along the apical region that also presented secretory characteristics. We additionally found evidence for the secretion of polyphosphate (PolyP) into the midgut, a result corroborating previous reports suggesting an excretion route from the goblet cell cavity toward the luminal space. Thus, our results suggest that the Anticarsia midgut not only possesses several typical lepidopteran features but also presents some unique aspects such as the presence of a tubular network and PolyP-containing apocrine secretions, plus an apparent route for the release of cellular debris by the goblet cells.

Phylogenetic relationship of seven Dendrolimus (Lepidoptera: Lasiocampidae) species based on the ultrastructure of male moths' antennae and antennal sensilla.

The morphology and ultrastructure of the antennae and antennal sensilla of seven male Dendrolimus species and a male Trabala vishnou gigantina (Yang) (Lepidoptera: Lasiocampidae) were examined by light microscope and scanning electron microscope. Six morphological types of antennal sensilla were identified: Sensilla trichodea, Sensilla chaetica, Sensilla styloconica, Sensilla coeloconica, Böhm bristles, and foot-like sensilla. Six of the Dendrolimus moths and Trabala vishnou gigantina Yang share the same antennal sensilla type, as do various geographic populations of the same species. The exception, Dendrolimus spectabilis Butler, has foot-like sensilla. However, the antennal sensilla subtypes were significantly different among species and/or populations. There were no remarkable differences in the width of the scape, pedicel, subflagellum, and the side-branches between the eight male species studied. However, we observed significant differences in the number of flagellomere and the length of scape, pedicel, subflagellums, and side-branches. The length and basal diameter of various types of antennal sensilla did not vary significantly among Dendrolimus moths. Beyond that, there were no differences among populations of the same kind of species. Hierarchical cluster analysis found two clusters: the first contained D. punctata punctata (Walker), D. punctata wenshanensis (Tsai et Liu), D. tabulaeformis (Tsai et Liu), and D. spectabilis and D. superans (Butler), and the second contained D. grisea (Moore) and D. kikuchii kikuchii (Matsumura). Trabala vishnou gigantina was placed separately from the two clusters. We conclude that D. punctata wenshanensis,D. tabulaeformis, and D. spectabilis are geographic subspecies of D. punctata punctata.

The well-tuned blues: the role of structural colours as optical signals in the species recognition of a local butterfly fauna (Lepidoptera: Lycaenidae: Polyommatinae).

The photonic nanoarchitectures responsible for the blue colour of the males of nine polyommatine butterfly species living in the same site were investigated structurally by electron microscopy and spectrally by reflectance spectroscopy. Optical characterization was carried out on 110 exemplars. The structural data extracted by dedicated software and the spectral data extracted by standard software were inputted into an artificial neural network software to test the specificity of the structural and optical characteristics. It was found that both the structural and the spectral data allow species identification with an accuracy better than 90 per cent. The reflectance data were further analysed using a colour representation diagram built in a manner analogous to that of the human Commission Internationale de l'Eclairage diagram, but the additional blue visual pigment of lycaenid butterflies was taken into account. It was found that this butterfly-specific colour representation diagram yielded a much clearer distinction of the position of the investigated species compared with previous calculations using the human colour space. The specific colours of the investigated species were correlated with the 285 flight-period data points extracted from museum collections. The species with somewhat similar colours fly in distinct periods of the year such that the blue colours are well tuned for safe mate/competitor recognition. This allows for the creation of an effective pre-zygotic isolation mechanism for closely related synchronic and syntopic species.

Helium ion microscopy of Lepidoptera scales.

In this report, helium ion microscopy (HIM) is used to study the micro and nanostructures responsible for structural color in the wings of two species of Lepidotera from the Papilionidae family: Papilio ulysses (Blue Mountain Butterfly) and Parides sesostris (Emerald-patched Cattleheart). Electronic charging of uncoated scales from the wings of these butterflies, due to the incident ion beam, is successfully neutralized, leading to images displaying a large depth-of-field and a high level of surface detail, which would normally be obscured by traditional coating methods used for scanning electron microscopy (SEM). The images are compared with those from variable pressure SEM, demonstrating the superiority of HIM at high magnifications. In addition, the large depth-of-field capabilities of HIM are exploited through the creation of stereo pairs that allows the exploration of the third dimension. Furthermore, the extraction of quantitative height information which matches well with cross-sectional transmission electron microscopy measurements from the literature is demonstrated.

Studies of sex pheromone production under neuroendocrine control by analytical and morphological means in the oriental armyworm, Pseudaletia separata, Walker (Lepidoptera: Noctuidae).

Most female moths produce species-specific sex pheromone blends in the modified epidermal pheromone gland (PG) cells generally located between the 8 and 9th abdominal segments. The biosynthesis is often regulated by pheromone biosynthesis activating neuropeptide (PBAN) either in or prior to de novo fatty acid synthesis or at the formation of oxygenated functional group. In Pseudaletia separata, information about life span, calling, PG morphology, daily fluctuation of pheromone production and its hormonal regulation is limited. We measured pheromone titer daily (16:8; L:D) at 2h intervals in scotophase. Blend ratio stabilized during the 2nd day (till 4-5th) at 6th hour of scotophase, with the ratio of 27.5:12.8:44.4:15.3 for Z-11-16OH:16OH:Z-11-16Ac:16Ac, respectively. Females showed calling behavior from this time. We found with light and fluorescence microscopy that PG consisted of intersegmental membrane (A part), and dorso-lateral region of 9th abdominal segment (B part), encountering for ∼ 35% of total production revealed by gas chromatography. Ratios did not reveal difference. We did not find precursor (triacylglycerols) accumulation in form of lipid droplets, implying that PBAN stimulates de novo biosynthesis of 16:acyl precursors. In vivoHez-PBAN injections (1-3 × 5 pmol, 2h intervals) into 3 days old 16-18 h decapitated females stimulated pheromone production, both in A and B parts. Blend analyses including ratios suggest stimulation of the initial phase of synthesis, but desaturation of fatty acyl intermediates do not follow proportionally. More saturated fatty acid is converted from the available pool to the final OH and Ac, compared to females kept intact in scotophase. In vitro studies (PGs incubated 4-6h in the presence of 0.25 or 0.5 µM Hez-PBAN, especially with surplus 2mM malonyl-CoA) revealed higher saturated component ratio than the unsaturated, compared to natural blend or in vivo injections.

Pathological and ultrastructural changes in cultured cells induced by venom from the ectoparasitic wasp Nasonia vitripennis (Walker) (Hymenoptera: Pteromalidae).

The ectoparasitic wasp Nasonia vitripennis produces a proteinaceous venom that induces death in fly hosts by non-paralytic mechanisms. Previous in vitro assays have suggested that the primary cause of cell and tissue death is oncosis, a non-programmed cell death (PCD) pathway characterized by cellular swelling and lysis. However, ultrastructural analyses of BTI-TN-5B1 cells exposed to LC(99) doses of wasp venom revealed cellular changes more consistent with apoptosis and/or non-apoptotic PCD than oncosis or necrosis: By 3h after incubation with venom, susceptible cells displayed indentations in the nuclear membranes, large nucleoli, and extensive vacuolization throughout the cytoplasm. In the vast majority of venom treated cells, annexin V bound to the plasma membrane surface within 15 min after treatment, a characteristic consistent with translocation of phosphatidylserine to the cell surface during the early stages of apoptosis. Likewise, mitochondrial transmembrane potential was depressed in cells within 15 min in venom-treated cells, an event that occurred in the absence of mitochondrial swelling or rupturing of cristae. Active caspase 3 was detected by fluorescent labeling in nearly all venom treated cells 3h after exposure to venom, and in turn, the potent caspase 3 inhibitor Z-VAD-FMK attenuated the morphological changes elicited by wasp venom and afforded protection to BTI-TN-5B1-4 cells.

Histopathology and ultrastructure of midgut of Alabama argillacea (Hübner) (Lepidoptera: Noctuidae) fed Bt-cotton.

The interaction of Cry toxins from Bacillus thuringiensis in the midgut of some insect larvae determines their efficacies as insecticides, due to the expression and availability of sites of action of the toxin in the midgut. Researches point out cases of resistance to Cry toxin due to alterations in the binding sites in columnar cell membrane. We analyzed the effects of Cry1Ac toxin expressed by Bt-cotton plants on Alabama argillacea midgut morphophysiology clarifying in levels of morphological and ultrastructural. Larvae in the 4th instar of A. argillacea after 20 min from ingesting Bt-cotton leaves expressing 0.183 ng of Cry1Ac exhibited ultrastructural and morphological modifications in the columnar cells with significant changes in the mitochondrial polymorphism, cytoplasmic vacuolization, microvillus and basal labyrinth. Expressive morphological alterations were also observed in the goblet cells indicating that the columnar cells are not the only target of the Cry1Ac toxin. The regenerative cells did not modify their structures and exhibited decrease in regeneration capacity. In conclusion, the ingestion of 0.183 ± 0.077 ng of Cry1Ac was enough to promote alterations in the columnar and goblet cells, besides reducing significantly the number of regenerative cells, which may have contributed to larval death. Nevertheless, further studies are necessary to determine the true cause of death.

[Biological aspects and external morphology of immature stages of Memphis moruus stheno (Prittwittz) (Lepidoptera: Nymphalidae)]. / Aspectos biológicos e morfologia externa dos imaturos de Memphismoruus stheno (Prittwitz) (Lepidoptera: Nymphalidae).

Immature stages of Memphis moruus stheno (Prittwittz) were subject of a behavior, biological and morphological study. The morphological study was carried out through observation by stereoscopic microscopy with camera lucida and micrometric lens attached for illustrations and measurements, respectively; and scanning electron microscopy for ultrastructural analysis. Behavioral data were obtained through direct observation in the field and laboratory. Eggs were laid on the underside of leaves of two Lauraceae species. The first to third instars build frass chains, the fourth and the fifth instars build a conical shelter using a single leaf of the host plant. Before pupation, larvae bend its body ventrally and the pupae are incapable of movement. Descriptions, illustrations and photographs of egg, all five instars and pupa are given. The cephalic morphology and chaetotaxy of first instar were described and illustrated. Results are compared with other Charaxinae immature stages.

Evaluation of seven viral isolates as potential biocontrol agents against Pseudoplusia includens (Lepidoptera: Noctuidae) caterpillars.

The caterpillar Pseudoplusia includens (Walker, 1857) (Lepidoptera, Noctuidae), known as soybean looper, is a pest that has recently assumed greater importance in soybean in Brazil. Isolates of nucleopolyhedroviruses (NPVs) of this pest have been identified from cotton in Guatemala and soybean farms in Brazil, providing an interesting perspective of potential use of viral insecticide against the insect in lieu to chemical insecticides. With the objective to contribute to the characterization studies of this virus, morphological and molecular analyses and biological activity were carried out with seven P. includens viral isolates (I-A to I-G). Electron microscopy of viral samples, purified from macerated infected larvae, showed particles with typical morphology of the Baculoviridae family, genus Alphabaculovirus (Nucleopolyhedrovirus - NPV) presenting virions with only a single nucleocapsid per envelope (SNPV) occluded in a protein matrix, forming occlusion bodies (OB). This virus was then classified as P. includens single nucleopolyhedrovirus (PsinSNPV). OB particles analyzed in SDS-polyacrylamide gel showed an intense band corresponding in size to NPV polyhedrin protein. DNA restriction profiles of the PsinSNPV isolates showed differences in the fragment size and number suggesting the existence of genotypic variants, except between I-E and I-F profiles that were similar. Among the isolates tested for infectivity against P. includens, I-A, I-E and I-F were the most virulent. Survival times (ST(50)) varied according to viral concentration, with significant differences among isolates for the three higher concentrations.