Hironori Sakamoto

• Researcher at National Institute of Education Sciences

The red imported fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae) causes serious damage worldwide as an invasive alien species. The species has expanded its range to the Pacific Rim since 2000s and Japan has faced its multiple introductions since 2017. While colony-level control methods are urgently needed, testing living colonies of the...

Solenopsis invicta Buren (Hymenoptera: Formicidae; red imported fire ant) is an invasive species in several parts of the world. A major contributor to the spread of S. invicta is infested shipping containers. The vapor of allyl isothiocyanate (AITC), a naturally occurring organosulfur compound, is highly toxic to S. invicta ; however, AITC is highl...

Invasive alien species (IAS) can have serious negative impacts on native species in invaded areas. Researchers attempting to measure the impacts of IAS on native species at a landscape level often face challenges though, because the effects of environmental gradients and spatial autocorrelation on population structures are difficult to separate. To...

Red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae), which are among the most harmful alien ants, were first detected in Japan in a shipping container from China in May 2017, and continue to enter Japan via this trade pathway. Fumigation is one of the most effective ways to eliminate S. invicta from goods transported in conta...

Eggs of the migratory locust, Locusta migratoria (Orthoptera: Acrididae), hatch synchronously when in a pod, but only sporadically when kept separately. Here, we aimed to detect the vibrational stimuli emitted by eggs that initiate synchronous hatching. First, we recorded the vibrations emitted by an egg pod and single eggs. One bout of vibrations...

When males fight for access to females, such conflict rarely escalates into lethal fight because the risks and costs involved, that is, severe injury or death, are too high. The social spider mite, Stigmaeopsis miscanthi, does exhibit lethal male fights, and this male–male aggressiveness varies among populations. To understand the evolution of leth...

In speciation research, much attention is paid to the evolution of reproductive barriers, preventing diverging groups from hybridizing back into one gene pool. The prevalent view is that reproductive barriers evolve gradually as a byproduct of genetic changes accumulated by natural selection and genetic drift in groups that are segregated spatially...

Spider mites (Acari: Tetranychidae) include serious agricultural pests and some species have spread globally as invasive species.. For this reason, rapid and simple identification of spider mite species is necessary for agricultural field and plant quarantine inspection. DNA sequence-based molecular techniques can rapidly identify spider mites. How...

Scientific Reports 6 : Article number: srep36364 10.1038/srep36364 ; published online: 03 November 2016 ; updated: 30 March 2017 This Article contains typographical errors in Table 1. For Location E, the ?L1? value ?2 (0%)? should read ?2 (100%)?.

The genus Stigmaeopsis (family Tetranychidae) has 11 species including the serious bamboo pest, S. nanjingensis. All Stigmaeopsis species are difficult to identify by their morphology, and the diagnostic character (the length of dorsal setae) can be used only to identify fresh specimens. To identify these species at the molecular level, we sequence...

Large blue butterflies, Phengaris (Maculinea), are an important focus of endangered-species conservation in Eurasia. Later-instar Phengaris caterpillars live in Myrmica ant nests and exploit the ant colony’s resources, and they are specialized to specific host-ant species. For example, local extinction of P. arion in the U. K. is thought to have be...

Diplogasteroides nix n. sp. is described based on its typological characteristics, molecular profile and mating experiments. Diplogasteroides nix n. sp. is characterised by its tube-like stoma with three small dorsal teeth and two subventral ridges, spicule clearly ventrally bent at one-third from the anterior end, gubernaculum with a somewhat squa...

A bird-parasitic fly, Carnus orientalis [Maa, 1968][1], is recorded for the first time from Japan, and it is taxonomically reexamined on the basis of specimens collected in Okinawa Prefecture. Adult flies were found from nestlings of Ryukyu scops owl ( Otus elegans Cassin, 1852), which is a new host for C. orientalis. Bionomic remarks regarding C....

Two yeast strains, which have the ability to degrade biodegradable plastic films, were isolated from the larval midgut of a stag beetle, Aegus laevicollis. Both of them are most closely related to Cryptococcus magnus and could degrade biodegradable plastic (BP) films made of poly(butylene succinate) (PBS) and poly(butylene succinate-co-adipate) (PB...

Ecological and morphological differences were examined between two DNA clades within a myrmicine red ant, Myrmica kotokui. Twenty-four ant colonies were collected in the Japan Alps at elevations between about 1,000 and 2,200 m, and their DNA clades were determined from their mitochondrial cytochrome oxidase I gene sequences. Then, their several eco...

Background: Territorial boundaries between conspecific social insect colonies are maintained through nestmate recognition systems. However, in supercolony-forming ants, which have developed an extraordinary social organization style known as unicoloniality, a single supercolony extends across large geographic distance. The underlying mechanism is...

Raster plots for the experiments presented in Figure 4A and 4B. Impulses of the “Hoshioki” CHC sensilla on the antennae attached to the haeds (A) and “Shinkawa” CHC sensilla on the antennae attached to the haeds (B) and those of the “Hoshioki” CHC sensilla on the antennae detached from the haeds (C), which are sorted into different unit clusters, a...

Correlates of biting behaviors, Mahalanobis distances of CHC profiles, and genetic relatedness in resident or invader ants. (A) Correlation between % of invader ants and of glass beads inducing biting behavior of resident “Hoshioki” ants. (B) Correlation between aggressive behavior and average of Mahalanobis distances of CHC profiles between reside...

Blind experiments on aggressive behavior. (A) Percentage of workers from “Hoshioki” (H), “Shinkawa” (S), “Hakkenzan” (Ha) F. yessensis and C. japonicus (C) (out of total workers tested, respectively) that induced biting behavior of “Hoshioki” (upper plate) and “Shinkawa” workers (lower plate). (B) Percentage of workers from the same nests of F. yes...

Discriminant analyses of the CHC profiles (A) and relationships between Mahalanobis distance and geographic distance (B). (A) Discriminant analyses using the 2 independent nests and either “Shinkawa”, “Tarukawa” or “Ishikari” from the “Ishikari supercolony”, employing the same parameters as in Figure 2C. (B) Correlation between geographic distance...

Comparison of the Mahalanobis distances, based on the discriminant analyses of the CHC profiles. (A) Among the 4 nests within the “Ishikari supercolony”; (B) Among the 3 independent nests: “Hoshioki” within the “Ishikari supercolony”, and “Oshoro” and “Hakkenzan” outside the “Ishikari supercolony”. Each column indicates the average Mahalanobis dist...

Coleman rarefaction curve for “Hoshioki” workers. For the analysis of genetic structure, 48 ant individuals were used. The total number of alleles at seven microsatellite loci was counted by randomly choosing each number of individuals (n) from the 48 ants, and the mean number of alleles with standard deviation (bar) was calculated from 1,000 repli...

Average number of sensilla basiconica (CHC sensilla) in a worker’s antenna. (PPT)

Introduction of alien species is a worldwide problem that accompanies human activity. Invasive alien ants (Hymenoptera: Formicidae) are among those predatory invertebrates that cause the greatest damage to native ecosystems and biodiversity, and their management is difficult. Therefore, novel environmental load–reducing (i.e., highly invasive alien...

Except for sex pheromones, use of pheromones in pest management has been largely unexplored. A high concentration of trail pheromone disrupts ant trail following and foraging, and thus synthetic trail pheromone can be a novel control agent for pest ants. In this study, a year-long treatment of small areas (100 m(2) plots of urban house gardens) wit...

Cuticular hydrocarbons of workers and males from two supercolonies (“Japanese main” and “Kobe C”) of the Argentine ant. Fifty-four compounds were detected with GC/MS. Mean ± SD (%) of each compound is shown for workers and males. Compounds which highly contributed to the first and second principal components in the principal component analysis (Fig...

Some invasive ants form large networks of mutually non-aggressive nests, i.e., supercolonies. The Argentine ant Linepithema humile forms much larger supercolonies in introduced ranges than in its native range. In both cases, it has been shown that little gene flow occurs between supercolonies of this species, though the mechanism of gene flow restr...

Bacteria of the genus Spiroplasma are widely found in plants and arthropods. Some of the maternally transmitted Spiroplasma endosymbionts in arthropods are known to kill young male hosts (male killing). Here, we describe a new case of Spiroplasma-induced male killing in a moth, Ostrinia zaguliaevi. The all-female trait caused by Spiroplasma was mat...

A homologue of the sex-determining gene doublesex, Osdsx, was identified in the adzuki bean borer Ostrinia scapulalis. Three isoforms of the Osdsx transcript (Osdsx(M), Osdsx(FL) and Osdsx(FS)) differing in length were found. Osdsx(M) was specifically found in males, and contained an 852-bp ORF encoding a protein of 284 amino acids. Osdsx(FL) and O...

We newly conceived the idea of trail-following disruption of a highly inva-sive ant species, the Argentine ant Linepithema humile, using a synthetic trail pheromone component (Z)-9-hexadecenal. Along with this concept, attempts have been made to develop novel methodologies to control this cosmopolitan pest. In this report, polyethylene tube dispens...

A maternally inherited intracellular bacterium, Wolbachia, causes reproductive alterations in its arthropod hosts. In the adzuki bean borer, Ostrinia scapulalis (Walker) (Lepidoptera: Crambidae), naturally-occurring Wolbachia selectively kills male progeny. This Wolbachia strain appears to have a feminizing effect, since antibiotic treatment of inf...

Maternally inherited endosymbiotic bacteria of the genus Wolbachia induce various kinds of reproductive alterations in their arthropod hosts. In a Wolbachia-infected strain of the adzuki bean borer moth, Ostrinia scapulalis (Lepidoptera: Crambidae), males selectively die during larval development, while females selectively die when Wolbachia are el...

Wolbachia , a group of endosymbiotic bacteria in arthropods, alter the reproduction of their hosts in various ways. A Wolbachia strain (wSca) naturally infecting the adzuki bean borer moth Ostrinia scapulalis induces male killing, while another strain (wKue) infecting the Mediterranean flour moth Ephestia kuehniella induces cytoplasmic incompatibil...