Koichi Goka

Koichi Goka
National Institute for Environmental Studies · Ecological Risk Research Team

Professor

About

138
Publications
28,674
Reads
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4,526
Citations
Citations since 2017
24 Research Items
2352 Citations
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20172018201920202021202220230100200300400

Publications

Publications (138)
Article
Full-text available
Although numerous ecotoxicological assessments of European honeybee (Apis mellifera L.) have been performed, Japanese wild bees are less well studied in this regard. To address this knowledge gap, we assessed the mortality and acute toxicity (LD50) of 3 common agricultural insecticides (clothianidin, fipronil, and diazinon) on as many as 6 species...
Article
Full-text available
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...
Article
Full-text available
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...
Article
Full-text available
The European honey bee, Apis mellifera, is the most common and important pollinator of crops worldwide. Honey bees are damaged by destructive parasitic mites, but they also have evolved a behavioral immune system to remove them. Exposures to neonicotinoids, however, can cause significant behavioral effects because these compounds alter the central...
Preprint
Full-text available
Recent studies have uncovered that biotic interaction strength varies over time in real ecosystems intrinsically and/or responding to anthropogenic disturbances. Little is known, however, about whether such interaction variability strengthens or weakens community resistance against disturbances. Here, we examine how the change in interaction streng...
Preprint
Full-text available
Efforts to eradicate invasive alien species commonly use simulations to calculate the cost-effectiveness of surveys. Although eradication of Solenopsis invicta in the early stages of an invasion is important, few simulations are available to calculate the cost-effectiveness of surveys when a single colony has been detected. In the case of S. invict...
Article
Full-text available
While research on frog chytrid fungus Batrachochytrium dendrobatidis (Bd), an infectious disease that threatens amphibian diversity, continues to advance worldwide, little progress has been made in Japan since around 2010. The reason for this is, which we pointed out in 2009, that the origin of frog chytrid fungus may be in the East Asian region, i...
Article
Full-text available
The red imported fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae), is a serious invasive alien ant around the world and has expanded its invasive range to the Pacific Rim since the early 2000s. It was first reported in Japan in 2017, and its entry through cargo has been reported numerous times in many ports. Colonies have been found in T...
Article
Full-text available
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...
Article
Pesticides are frequently used to eradicate invasive ant species, but pose ecological harm. Previous studies assessed non-target effects only in terms of the increase or decrease of abundance or species richness after pesticide applications. Positive effects of the release from pressure caused by invasive ant species have not been considered so far...
Article
Full-text available
Indirect effects of agrochemicals on organisms via biotic interactions are less studied than direct chemical toxicity despite their potential relevance in agricultural landscapes. In particular, the role of species traits in characterizing indirect effects of pesticides has been largely overlooked. Moreover, it is still unclear whether such indirec...
Article
Full-text available
As a signature of reproductive interference (RI), we reviewed hybrid production in eusocial bumblebees in Japan, by comparing introduced Bombus terrestris with native B. ignitus in Honshu (main island of Japan) and with native B. hypocrita sapporoensis in Hokkaido (northern island of Japan). In this review, we present additional new data showing hy...
Article
Systemic insecticides such as neonicotinoids and fipronil are widely applied in rice production. These insecticides have been suspected of reducing biodiversity in paddy ecosystems and reducing wild dragonfly populations in Japan. Conventional ecotoxicological risk assessment could not confirm this, as it has not considered interspecific variation...
Article
Full-text available
Dragonflies, Sympetrum spp., are indispensable to agriculture and are a central element of culture in Japan. However, S. frequens populations in rice paddy fields have declined in recent decades. Dragonfly larvae are predatory aquatic insects that feed on other organisms found in habitats with slow-moving or standing water. The increasing use of fi...
Data
Dose-response curve for S. infuscatum in the FI test of fipronil. (PDF)
Data
Comparison of nominal and actual imidacloprid, fipronil and fipronil sulfone levels. Data are presented as mean ± standard deviation (SD). (PDF)
Data
t-value, degrees of freedom and p-value in Fig 4. (PDF)
Data
t-value, degrees of freedom and p-value in Fig 5. (PDF)
Data
Dose-response curve for S. infuscatum in the FI test of fipronil sulfone. (PDF)
Data
t-value, degrees of freedom and p-value in Fig 3. (PDF)
Data
t-value, degrees of freedom and p-value in Fig 2. (PDF)
Data
t-value, degrees of freedom and p-value in Table 2. (PDF)
Article
Batrachochytrium dendrobatidis (Bd) is the pathogen responsible for chytridiomycosis, a disease that is associated with a worldwide amphibian population decline. In this study, we predicted the potential distribution of Bd in East and Southeast Asia based on limited occurrence data. Our goal was to design an effective survey area where efforts to d...
Article
Full-text available
Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicit...
Article
Full-text available
Emerging infectious diseases are reducing biodiversity on a global scale. Recently, the emergence of the chytrid fungus Batrachochytrium salamandrivorans resulted in rapid declines in populations of European fire salamanders. Here, we screened more than 5000 amphibians from across four continents and combined experimental assessment of pathogenicit...
Article
The international trade in amphibians is believed to have increased the spread of Batrachochytrium dendrobatidis (Bd), the fungal pathogen responsible for chytridiomycosis, which has caused a rapid decline in amphibian populations worldwide. We surveyed amphibians imported into Japan and those held in captivity for a long period or bred in Japan to...
Article
Full-text available
Bees are essential pollinators of many plants in natural ecosystems and agricultural crops alike. In recent years the decline and disappearance of bee species in the wild and the collapse of honey bee colonies have concerned ecologists and apiculturalists, who search for causes and solutions to this problem. Whilst biological factors such as viral...
Article
Full-text available
Although ecological differences between native and introduced ranges have been considered to drive rapid expansion of invasive species, recent studies suggest that rapid evolutionary responses of invasive species to local environments may also be common. Such expansion across heterogeneous environments by adaptation to local habitats requires genet...
Article
On the island of Hachijojima, central Japan, a formerly abundant population of native lizard, Plestiodon latiscutatus has become endangered by predation from an alien weasel (Mustela itatsi). Recently, an alien lizard, P. japonicus, became established on the island. The impact of the alien lizard and current distribution of the native lizard were a...
Article
Full-text available
In Japan, assessments of the ecological impacts of pesticides on aquatic organisms are generally based on laboratory single-species acute toxicity tests carried out in accordance with OECD guidelines. Because biodiversity conservation in agroecosystems is very important, pesticide exposure effects should be assessed using a tiered system. Here, we...
Article
Full-text available
The effects of two successive annual treatments of imidacloprid and fipronil on dragonfly nymph communities, which are one of the best-known bioindicators in Japanese agroecosystems, were monitored in experimental paddies. The abundance of dragonfly nymphs was lower in both insecticides-treated fields than it was in the controls, particu- larly fol...
Article
To determine whether the chytrid fungus Batrachochytrium dendrobatidis (Bd) found on the hellbender Cryptobranchus alleganiensis in the southern US is endemic or exotic, we identified the genetic type of this fungus using partial DNA sequences of the internal transcribed spacer (ITS) region. We identified 3 genetic types, which are found on Japanes...
Article
Full-text available
The acute toxicity (48-hr) of old (imidacloprid) and new (clothianidin) neonicotinoid insecticides to five cladoceran species and species sensitivity distribution (SSD) for cladocerans and other aquatic organisms to these insecticides are compared here. The sensitivities to both insecticides were in the following descending order: Ceriodaphnia>Daph...
Chapter
Full-text available
This review has brought some light on the direct, sublethal and indirect effects that systemic insecticides have on species populations and ecosystems. Some long-term impacts have been known for some time (e.g. carbofuran, phorate), but it is the rapid increase in the usage of neonicotinoids and other systemic products that poses a new challenge to...
Article
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The Argentine ant, Linepithema humile, has been spreading via human activities from its native range in South America across much of the globe for more than a century. This invasive ant was first detected in Japan in 1993. Its successful world-wide expansion is attributed to a social structure, namely supercoloniality, whereby individuals from sepa...
Article
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Recent increases in international trade have increased the cost to control and eradicate exotic species. Although many species are under quarantine control for agriculture, forestry, and public health, most species invisible to the naked eye are ignored because of the lack of both specialized assessors and risk assessments. We developed a species r...
Article
Japan’s economy depends on the importation of natural resources, and as a result, Japan is subjected to a high risk of biological invasion. Although Japan has quarantine systems to protect ecosystems, agriculture, forestry, fisheries, and human health against alien species, economic globalization has resulted in an ever-increasing risk of invasion....
Article
With the exception of several species, bumblebees are monandrous. We examined mating frequency in feral colonies of the introduced bumblebee Bombus terrestris in Japan. Using microsatellite markers, genotyping of sperm DNA stored in the spermatheca of nine queens detected multiple insemination paternities in one queen; the others were singly mated....
Article
Full-text available
The infrequency of tsunamis results in a lack of knowledge regarding the impact they have on ecosystems. Comparison of the floristic composition before and after tsunamis using permanent plots is an effective approach to estimate the ecological impacts of tsunamis in coastal environments. Here, we report the floristic changes in beach vegetation in...
Article
Full-text available
Our knowledge of how coastal species react to, and recover from, tsunamis is deficient because of the infrequency of these events, despite the importance of such information for ecological risk assessment of coastal hazards. To elucidate the differences in resilience among species and the successional processes of coastal sand-dune flora after tsun...
Article
Full-text available
*The new address of the web site for the questionnaire is http://webbeetlechoice.chez.com For some wildlife commodities, rare species are especially sought after. The tendency for rare commodities to be of higher value can fuel their exploitation and as numbers dwindle, the demand can increase. Consequently, this can precipitate these rare species...
Article
Full-text available
The purpose of this study was to establish a method for eradicating a chytrid fungus (Batrachochytrium dendrobatidis; Bd) from the Japanese giant salamander Andrias japonicus. The emerging agent (Bd) has a high rate of detection in this endangered amphibian species, which is designated as a special natural monument in Japan. Four Japanese giant sal...
Article
Full-text available
Differences in susceptibility of five cladocerans to the neonicotinoid imidacloprid and the phenyl-pyrazole fipronil, which have been dominantly used in rice fields of Japan in recent years, were examined based on short-term (48-h), semi-static acute immobilization exposure tests. Additionally, we compared the species sensitivity distribution (SSD)...
Article
Full-text available
The environmental risks of pesticides are typically determined by laboratory single-species tests based on OECD test guidelines, even if biodiversity should also be taken into consideration. To evaluate how realistic these assessments are, ecological changes caused by the systemic insecticides imidacloprid and fipronil, which have different physico...
Presentation
The higher value of rare items in collections is a phenomenon also found in wildlife based collections, such as insects. If rarer species are more valued and therefore more sought after, they could be disproportionately harvested in the wild, which could render them even rarer, thus even more valuable, and even more exploited. This could drive rare...
Conference Paper
Full-text available
The spread of invasive species is a rapidly increasing problem worldwide. In Japan, many lucanid (stag) beetle species have been imported from Southeast Asia as pets or collected as a leisure pursuit or hobby. Occasionally, these specimens are released into the wild by these owners. This has led to the accidental hybridization between some of the b...
Article
Full-text available
We performed this study in order to establish an effective, simple and safe treatment for chytridiomycosis. The subjects were 12 amphibians (11 anurans of 4 different species and 1 urodela) diagnosed with chytridiomycosis by clinical signs and a PCR test. A 0.01% aqueous solution of the antifungal agent itraconazole was used to treat the subjects,...
Article
Full-text available
The insecticides fipronil and imidacloprid are effectively used against sucking insect pests of rice. Since these agents are absorbed by rice seedlings and stored in their tissues, they are usually applied to nursery boxes before planting. The effects of imidacroprid and fipronil on the life history of Sympetrum frequens larvae and adults were moni...
Article
The 2004 Japanese 'Invasive Alien Species Act' was enacted to control invasive alien species and prevent the damage that they cause to ecosystems. The Act defines invasive alien species as those recognised as, or suspected of, causing damage to ecosystems, human safety, agriculture, forestry and fisheries. Invasive alien species are carefully regul...
Article
The 2004 Japanese Invasive Alien Species Act was enacted to control invasive alien species (IASs) and to prevent damage caused by IASs to ecosystems. The Act defines alien species recognized as or suspected of causing damage to ecosystems, human safety, agriculture, forestry and fisheries. IASs are regulated: raising, planting, keeping or transport...
Article
The European bumblebee, Bombus terrestris, was introduced into Japan from Europe in 1991 for pollination of tomato plants. Many ecologists had warned of biological invasion by this species, and in 1996 a naturalized colony was found in Hokkaido, indicating that the species had become naturalized. The Ministry of the Environment effected a new law,...
Article
Full-text available
Bombus terrestris L. (Apidae) is a native of temperate Eurasia and has been moved around the world since the 1800s. Dispersal of B. terrestris gained momentum in the 1980s when bees were reared artificially in Europe and supplied commercially for greenhouse pollination services. Very early after its commercial introduction, it was recognized that t...
Article
A Japanese native bumblebee, Bombus ignitus, has recently been commercialized for crop pollination. To assess the risk of genetic disturbance of local bumblebee communities, despite the fact that B. ignitis is native, we analyzed a 1048-bp sequence of the cytochrome oxidase subunit 1 (CO1) region of mitochondrial DNA in B. ignitus specimens that we...
Article
The bumblebee Bombus terrestris is not only an effective pollinator but also a potential invasive species outside its native range. Interspecific crossing of B. terrestris with indigenous B. hypocrita sapporoensis and B. ignitus can cause inviable hybrid production under laboratory conditions. Additionally, nearly 30% of B. hypocrita sapporoensis a...
Article
A serious disease of amphibians caused by the chytrid fungus Batrachochytrium dendrobatidis was first found in Japan in December 2006 in imported pet frogs. This was the first report of chytridiomycosis in Asia. To assess the risk of pandemic chytridiomycosis to Japanese frogs, we surveyed the distribution of the fungus among captive and wild frog...
Article
Kin selection theory predicts a high coefficient of genetic relatedness among nestmates, explaining the frequent evolution Kin selection theory predicts a high coefficient of genetic relatedness among nestmates, explaining the frequent evolution of eusociality in a social hymenopteran colony. The bumble bee is a primitively eusocial hymenoptera who...
Article
Full-text available
Alien ants are considered to be among the more damaging of invasive insects. Five ant species are ranked among the 100 world's worst invaders by the IUCN. Within the introduced regions, they displace or disrupt the local arthropod fauna, cause agricultural damage by protecting plant pests, and even affect human health. The Argentine Ant, Linepithem...
Article
Full-text available
Limnoperna fortunei (golden mussel) is an aggressive freshwater invasive species naturally distributed in China, Korea, and South eastern Asian countries. This species was introduced into East Asian and South American countries from 1965 to the 1990s. In Japan, the golden mussel was first found in Lake Biwa in 1992 and it is known to be distributed...
Article
The members of the genus Borrelia are transmitted by arthropods and known to be infectious to vertebrates. Here we found isolates and DNAs belonging to the Borrelia turcica and unknown Borrelia species from imported reptiles and their ectoparasites. The Borrelia strains were isolated from blood and multiple organs of exotic tortoises, and were expe...
Article
The European bumblebee, Bombus terrestris, is an invasive eusocial species whose distribution is expanding greatly beyond its native range because numerous colonies are imported to or locally produced in non-native countries for pollination of agricultural crops. Closely related species exist in Japan where the unrestricted import and use of B. ter...
Poster
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Dans certains types d’exploitation, les espèces les plus rares sont les plus attrayantes et ont une valeur supérieure. Ceci entraine une exploitation renforcée, causant une raréfaction accrue, qui peut à terme conduire à l’extinction de l’espèce. Un exemple concret de ce type d’exploitation est celui des collections d’espèces sauvages, où plus une...
Article
Full-text available
The genetic structure of populations is not necessarily reflected in the geographical proximity of individuals, because environmental gradients such as those of vegetation or climate can function as cryptic barriers to gene flow. We examined polymorphisms at nine microsatellite loci to determine and discuss whether a distinctive genetic structure w...
Article
Full-text available
Although the development of acaricide resistance in spider mites is a long-standing issue in agricultural fields, recent problems with acaricide resistance may be characterized by the development of complex- and/or multiresistance to acaricides in distinct classes. Such complexity of resistance is not likely to be a single mechanism. Pesticide resi...
Article
Full-text available
This is the first report of amphibian chytridiomycosis in Asia. We discovered a lethal outbreak in Japan, among 45 exotic frogs from 18 species kept for breeding by a private owner. Of these 45 frogs, 16 died and another 7 were found to be infected by chytrid fungus Batrachochytrium dendrobatidis (Bd) but survived after treatment. Bd was detected i...
Article
The invasive alien bumble bee Bombus terrestris may hinder the reproduction of native plants that have established specialized pollination systems with native bumble bees. To test this hypothesis, we examined the visitation frequency and behavior of native and alien bumble bee species and resultant seed production in Corydalis ambigua, a native pla...
Article
To develop a risk-assessment system for small organisms accidentally introduced with imported organisms, we investigated as a first case study parasitic canestriniid mites, which have been imported into Japan via pet lucanid beetles from Southeast Asia. We collected mites from pinned specimens of Japanese lucanids collected before 1999—when the Jap...