Conserved infections and reproductive phenotypes of Wolbachia symbionts in Asian tortrix moths.

Wolbachia is a ubiquitous endosymbiotic bacterium that manipulates insect reproduction. A notable feature of Wolbachia is male killing (MK), whereby sons of infected females are killed during development; however, the evolutionary processes by which Wolbachia acquired the MK ability remain unclear. The tea tortrix moth Homona magnanima (Tortricidae) harbours three non-MK Wolbachia strains (wHm-a, wHm-b and wHm-c) and an MK strain wHm-t.

Diverse Molecular Mechanisms Underlying Microbe-Inducing Male Killing in the Moth Homona magnanima.

Male killing (MK) is a type of reproductive manipulation induced by microbes, where sons of infected mothers are killed during development. MK is a strategy that enhances the fitness of the microbes, and the underlying mechanisms and the process of their evolution have attracted substantial attention. Homona magnanima, a moth, harbors two embryonic MK bacteria, namely, () and (), and a larval MK virus, Osugoroshi virus (OGV; Partitiviridae).

Horizontally transmitted parasitoid killing factor shapes insect defense to parasitoids.

Interkingdom competition occurs between hymenopteran parasitoids and insect viruses sharing the same insect hosts. It has been assumed that parasitoid larvae die with the death of the infected host or as result of competition for host resources. Here we describe a gene family, (), that encodes proteins toxic to parasitoids of the Microgastrinae group and determines parasitism success.

Coexistence of Two Male-Killers and Their Impact on the Development of Oriental Tea Tortrix Homona magnanima.

Male-killing, the death of male offspring induced by maternally transmitted microbes, is classified as early, or late, male-killing. The primary advantage afforded by early male-killing, which typically occurs during embryogenesis, is the reallocation of resources to females, that would have otherwise been consumed by males. Meanwhile, the key advantage of late male-killing, which typically occurs during late larval development, is the maximized potential for horizontal transmission.

Closely Related Male-Killing and Nonmale-Killing Wolbachia Strains in the Oriental Tea Tortrix Homona magnanima.

Wolbachia are inherited intracellular bacteria that cause male-specific death in some arthropods, called male-killing. To date, three Wolbachia strains have been identified in the oriental tea tortrix Homona magnanima (Tortricidae, Lepidoptera); however, none of these caused male-killing in the Japanese population. Here, we describe a male-killing Wolbachia strain in Taiwanese H.

Multiple Infection and Reproductive Manipulations of Wolbachia in Homona magnanima (Lepidoptera: Tortricidae).

Endosymbiotic bacterium Wolbachia interacts with host in either a mutualistic or parasitic manner. Wolbachia is frequently identified in various arthropod species, and to date, Wolbachia infections have been detected in different insects. Here, we found a triple Wolbachia infection in Homona magnanima, a serious tea pest, and investigated the effects of three infecting Wolbachia strains (wHm-a, -b, and -c) on the host.

Morphological properties of the occlusion body of Adoxophyes orana granulovirus.

A granulovirus (GV) that produces occlusion bodies (OBs) having an unusual morphology was found in an Adoxophyes sp. (Lepidoptera: Tortricidae) larva in a tea field in Miyazaki Prefecture, Japan. This isolate is considered to be a mutant of Adoxophyes orana granulovirus, designated AdorGV-M, because the nucleotide sequence of its genome is 99.

An ascovirus isolated from Spodoptera litura (Noctuidae: Lepidoptera) transmitted by the generalist endoparasitoid Meteorus pulchricornis (Braconidae: Hymenoptera).

The family Ascoviridae is a recently described virus family whose members are transmitted by parasitoids and cause chronic and lethal infections in lepidopteran insects. Little is known about the biology and ecology of ascoviruses, and few isolates have been found outside the United States. We report here the isolation of a new ascovirus variant from Spodoptera litura in Japan.

Identification of an Early Male-Killing Agent in the Oriental Tea Tortrix, Homona magnanima.

Arthropods are frequently infected with inherited symbionts, which sometimes confer fitness benefits on female hosts or manipulate host reproduction. Early male killing, in which infected males die during embryogenesis, is induced by some bacteria, such as Wolbachia and Spiroplasma. A female-biased sex ratio has been found in Homona magnanima, collected from a tea plantation in Japan.

Acquired resistance to a nucleopolyhedrovirus in the smaller tea tortrix Adoxophyes honmai (Lepidoptera: Tortricidae) after selection by serial viral administration.

A laboratory colony of Adoxophyes honmai was selected for resistance over 156 generations by feeding neonate larvae of every generation with the LC or LC of its nucleopolyhedrovirus, Adoxophyes honmai nucleopolyhedrovirus (AdhoNPV). A significant difference in LC values between the selected (R-strain) and unselected (S1- and S2-strain) strains was first observed after three generations of selection, and the resistance level then increased continuously. The highest degree of acquired resistance, based on the ratio of the LC values of R- and S1-strains, was more than 400,000-fold.

Midgut-based resistance to oral infection by a nucleopolyhedrovirus in the laboratory-selected strain of the smaller tea tortrix, Adoxophyes honmai (Lepidoptera: Tortricidae).

A strain of Adoxophyes honmai resistant to Adoxophyes honmai nucleopolyhedrovirus (AdhoNPV) was established from a field-collected colony by repeated selection. Fifth-instar larvae of this resistant strain (R-strain) had over 66 666-fold greater resistance in terms of 50 % lethal concentration values to oral infection of AdhoNPV than non-selected strain larvae (susceptible for AdhoNPV; S2-strain). In this study, the mechanism of resistance to AdhoNPV was determined in R-strain larvae.

Genetic and phenotypic comparisons of viral genotypes from two nucleopolyhedroviruses interacting with a common host species, Spodoptera litura (Lepidoptera: Noctuidae).

Nucleopolyhedroviruses (NPVs) are known to be highly variable, both genetically and phenotypically, at several scales such as different geographic locations or a single host. A previous study using several geographic isolates indicated that two types of NPV, Spodoptera littoralis NPV (SpliNPV) and S. litura NPV (SpltNPV) types, were isolated from the common cutworm, Spodoptera litura (Fabricius), a polyphagous insect that causes serious damage to many forage crops and vegetables.

Entomopoxvirus infection induces changes in both juvenile hormone and ecdysteroid levels in larval Mythimna separata.

Insect viruses are among the most important pathogens of lepidopteran insects. Virus-infected larvae often show developmental defects including a prolonged larval period and a failure to pupate, but the mechanisms by which insect viruses regulate host development need further investigation. In this study, the regulation of host endocrinology by a lepidopteran entomopoxvirus (EPV), Mythimna separata EPV (MySEV), was examined.

Field efficacy and transmission of fast- and slow-killing nucleopolyhedroviruses that are infectious to Adoxophyes honmai (Lepidoptera: Tortricidae).

The smaller tea tortrix, Adoxophyes honmai (Lepidoptera: Tortricidae), is an economically important pest of tea in Japan. Previous work showed that a fast-killing nucleopolyhedrovirus (NPV) isolated from A. orana (AdorNPV) and a slow-killing NPV isolated from A.

Juvenile hormone (JH) esterase activity but not JH epoxide hydrolase activity is downregulated in larval Adoxophyes honmai following nucleopolyhedroviruses infection.

Juvenile hormones (JHs) and ecdysteroids are critical insect developmental hormones. JH esterase (JHE) and JH epoxide hydrolase (JHEH) are JH-selective enzymes that metabolize JH and thus regulate the titer of JH. Baculoviruses are known to alter host endocrine regulation.

Isolation of an Adoxophyes orana granulovirus (AdorGV) occlusion body morphology mutant: biological activity, genome sequence and relationship to other isolates of AdorGV.

A granulovirus (GV) producing occlusion bodies (OBs) with an unusual appearance was isolated from Adoxophyes spp. larvae in the field. Ultrastructural observations revealed that its OBs were significantly larger and cuboidal in shape, rather than the standard ovo-cylindrical shape typical of GVs.

Oviposition efficacy of Drosophila suzukii (Diptera: Drosophilidae) on different cultivars of blueberry.

Drosophila suzukii (Matsumura) is an important pest of thin-skinned fruits including blueberry, raspberry, strawberry, and cherry. Blueberry was introduced into Japan in the 1950s, and severe economic losses attributable to D. suzukii were first reported in 2002.

Fitness-related traits of entomopoxviruses isolated from Adoxophyes honmai (Lepidoptera: Tortricidae) at three localities in Japan.

Three entomopoxviruses (EPVs) isolated from diseased Adoxophyes honmai larvae at different localities (Tsukuba, Itsukaichi, and Miyazaki) in Japan were compared for biochemical identity and key parameters of virus fitness, fatal infection, speed of kill, and virus yield. When the structural peptides of occlusion bodies (OBs) and occlusion-derived viral particles were compared using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, no difference in banding patterns was observed. However, DNA restriction endonuclease analysis showed that the three isolates were genotypically different, but many commonly sized DNA fragments were observed.

Novel RNA sequences associated with late male killing in Homona magnanima.

Maternally inherited female-biased sex ratios have been documented in many invertebrate species. One cause of such biased sex ratios is male killing, i.e.

Current status and prospects on microbial control in Japan.

Historically in Japan, studies on the diseases of the silkworm, Bombyx mori, as a factor affecting the well-being of the silk industry, have dominated insect pathology. However, work by Hidaka in 1933 demonstrated the possibility of controlling the pine moth, Dendrolimus spectabilis, with the fungus Beauveria bassiana and since then, various attempts have been made to develop a method to control insect pests using insect pathogens. The cypovirus product, Matsukemin, was the first microbial control product to be registered in 1974, and inactive and live Bacillus thuringiensis products were also registered and put on the market as pesticides in 1981 and 1982, respectively.

An entomopoxvirus and a granulovirus use different mechanisms to prevent pupation of Adoxophyes honmai.

Adoxophyes honmai larvae inoculated with 10x the 95% lethal concentration of an entomopoxvirus (AdhoEPV) did not pupate, underwent a prolonged larval stage, and died during their final instar, unlike non-infected larvae which pupated after five larval instars. In previous work we showed that a granulovirus (AdhoGV) also retarded host development and prevented pupation of A. honmai larvae.

Genome sequence and organization of a nucleopolyhedrovirus isolated from the smaller tea tortrix, Adoxophyes honmai.

Adoxophyes honmai nucleopolyhedrovirus (AdhoNPV) has a distinctive pathology in A. honmai larvae, killing the host more slowly than other NPVs. To further understand the pathology of AdhoNPV, its genome was completely sequenced and compared with those of other baculoviruses.

Characterization of Adoxophyes honmai single-nucleocapsid nucleopolyhedrovirus: morphology, structure, and effects on larvae.

A nucleopolyhedrovirus (NPV) was isolated from a diseased larva of the smaller tea tortrix, Adoxophyes honmai, collected from a tea field in Tsukuba, Ibaraki, Japan. Electron microscopic observations confirmed that A. honmai NPV (AdhoNPV) was a single-nucleocapsid type virus.