The Louisiana black bear Ursus americanus luteolus, a subspecies of the subtropical south-central USA, was protected by the U.S. Endangered Species Act in 1992 but removed from coverage in 2016 based on the alleged presence of two viable native populations that had begun to interbreed. However, historical and genetic data show that one population is descended from bears captured in the U.S. state of Minnesota, far to the north, and released on the property of a hunting club in Louisiana. A recent judicial decision ignored those data, deferring to deceptive government claims and effectively dooming the native subspecies to genomic extinction through hybridization with the introduced population.

We report the introduction of Juxtacribrilina mutabilis, a nonindigenous marine encrusting bryozoan, to eastern Canada. Previously reported as a nonindigenous species (NIS) in Europe and Maine, USA, this species is of potential ecological concern due to its propensity to foul eelgrass (Zostera marina), an ecologically important habitat-forming coastal species. By compiling prior unpublished records, re-evaluating existing specimens, and collecting new records of J. mutabilis, we discovered that the species has a widespread distribution in eastern Canada. Specimen reclassification efforts in our study indicate that J. mutabilis has been present in eastern Canada since at least 2013, but the species largely escaped notice until 2024, likely due to its similarity to other encrusting bryozoan species and other factors inhibiting its detection. In light of the distributional and genetic data collected in this study, we reconstruct the possible invasion history of J. mutabilis in eastern Canada, including potential introduction mechanisms, timing, and source regions. We also discuss the ecology of J. mutabilis in eastern Canada, evaluating the factors influencing the morphology of the bryozoan, assessing its potential to detrimentally impact its eelgrass substrate, and estimating its environmental niche. Further research into the distribution, ecology, and potential impacts of J. mutabilis in eastern Canada is recommended. This case study highlights the importance of diversity in the habitats surveyed and methods used when monitoring for marine NIS, the need for horizon scanning to raise awareness of potential NIS, and the advantages of multi-party collaboration and citizen science for early detection of such species.

The troublesome weed Johnsongrass [Sorghum halepense (L.) Pers.] is predicted to expand its range under climate change. In the process, it is likely to become more competitive in corn (Zea mays L.) production areas of the northeastern United States and southern Canada. A replicated greenhouse experiment was conducted to measure interspecific and intraspecific competition between a S. halepense biotype from central New York State (northern range edge) and corn under drought and well-watered conditions. Drought stress significantly reduced the biomass and height of corn and S. halepense in both rounds of the experiment (P < 0.001). Drought stress increased the root-to-shoot ratio of S. halepense (P < 0.001) and reduced the root-to-shoot ratio of corn (P < 0.001). In one run of the experiment, corn produced 19.3% more aboveground biomass (P < 0.001) and 6.6% more height (P < 0.001) when competing with a S. halepense plant (interspecific competition) than when competing with a second corn plant (intraspecific competition). Drought conditions increased the advantage of corn plants grown under interspecific relative to intraspecific competition (P = 0.012). In that round of the experiment, biomass of S. halepense was 12.9% higher under intraspecific competition than interspecific competition in the well-watered treatment and 15.5% higher under intraspecific competition than interspecific competition in the drought treatment (main effect of competition, P = 0.002). Differences between competition treatments were smaller in the other round of the experiment (P > 0.05). Our findings suggest that the New York S. halepense biotype used in this study may not be as competitive as biotypes found in this weed’s core range in more southern regions of the United States. However, anticipated effects of climate change may increase the abundance and competitiveness of this species in the northeastern United States.

Selective feeding by overabundant herbivores can considerably alter plant community composition and structure, often benefiting non-native species. White-tailed deer (Odocoileus virginianus) are a dominant herbivore in North America, known for their preference for native plants over unpalatable invasive species. Common buckthorn (Rhamnus cathartica L.), a widely invasive shrub, is largely avoided by deer, potentially facilitating its competitive advantage against native plants. This study investigates the interactive effects of R. cathartica invasion and deer browsing on native woody plants within a postindustrial urban forest undergoing restoration. Specifically, we employed both a long-term observational tree survey and an experimental shrub study to assess R. cathartica impacts on native trees and shrubs, and to investigate whether R. cathartica presence intensifies deer browsing. For the tree study, we surveyed 10 native tree species planted in areas with varying levels of R. cathartica invasion to assess tree health as a function of R. cathartica and canopy tree cover. For the shrub study, we examined deer and insect herbivory on five deer-resistant native shrubs with and without deer exclusion and R. cathartica removal. We found that increased R. cathartica cover correlated with reduced health in native tree species, a relationship not found between the trees and native canopy tree cover. We also found that all five planted native shrub species experienced considerable browsing, with deer and insect damage intensifying in the presence of R. cathartica. This study highlights the complex interplay between non-native plant invasions and native herbivore activity, demonstrating that R. cathartica indirectly facilitates increased deer herbivory on native species. These findings emphasize the need for integrated forest restoration strategies that address both invasive plant removal and herbivore management to support native species recovery.

Kochia [Bassia scoparia (L.) A.J. Scott] is an invasive species in the High Plains of the United States that poses formidable management challenges in agricultural systems, primarily due to its evolution of resistance to glyphosate. Resistance is due to a transposon-associated increase in 5-enolpyruvyl-3-shikimate phosphate synthase (EPSPS) gene copy number relative to the sensitive biotype. Factors behind the rapid spread of glyphosate-resistant biotypes are likely associated with certain aspects of B. scoparia biology, such as a protogynous flower morphology producing large amounts of pollen, that encourages outcrossing and favors high genetic diversity. Furthermore, its ability to tumble over long distances ensures a rapid spread of the resistance trait. Herein, we explore glyphosate resistance in B. scoparia in Colorado. There was no difference in EPSPS gene (Type I, Type II) and FAR1 copy numbers between parent and progeny B. scoparia populations across multiple years (2018, 2020, and 2022), suggesting stable inheritance of glyphosate resistance. Further, the inheritance of glyphosate resistance was investigated using three specific microsatellites or simple sequence repeat (SSR) markers viz. 2656, 2896, and 1792. SSR marker analysis revealed an outcrossing rate of 78% and a selfing rate of 22% in B. scoparia progeny. By investigating the complex interplay between B. scoparia’s biology and genetics, this study investigates the inheritance of glyphosate resistance in B. scoparia, estimates the outcrossing rate under field conditions, and underscores the importance of developing effective management strategies to mitigate its impact on agricultural ecosystems.

Plant invader genotype determines much about how the plant establishes, spreads, and impacts receiving habitat and the types of management required to achieve its control. We investigated phenology, vegetative spread, growth and biomass allocation, and response to herbicides of four flowering rush (Butomus umbellatus L.) amplified fragment length polymorphism (AFLP) genotypes (triploid: GT1; diploid: GT3, GT4, GT5) in a multiyear mesocosm experiment. Monthly observations were made over 31 mo to determine whether there were differences in timing of peak plant growth and flowering. We also applied herbicides during years 2 and 3 using imazamox or triclopyr at rates previously determined to be efficacious against B. umbellatus. By the end of year 1, all genotypes spread vegetatively within their containers. From a single sprouted axillary bud (i.e., bulbil), GT4 plants spread to cover nearly 2,000 cm2 in 6 mo. Flowering occurred May through October for all genotypes, but was reduced in years 2 and 3, including almost no flowering in triploid plants after year 1. Maximum leaf abundance occurred in August or September for all genotypes. After one season of growth, biomass was greatest for diploid genotypes, allocated primarily to leaves. However, by year 3, triploid plant biomass was greater than diploid GT4 and GT5, but not GT3. Bulbil production occurred only in diploid genotypes. At the study conclusion, GT4 and GT5 produced nearly 15,000 and 20,000 bulbils each, whereas GT3 plants produced fewer than 5,000 bulbils. Herbicides were effective in reducing biomass, but triploid plants were far more susceptible than diploid plants. Propagule production was generally reduced by herbicides, but rhizome bud production increased 240% in triploid plants treated with imazamox. These results demonstrate (1) the significant capacity for reproduction and spread of B. umbellatus and (2) the importance of investigating differences between lineages of B. umbellatus to inform management and risk assessments.

For insects whose larvae are incapable of moving between food resources, the selection of oviposition sites by females is critical to the survival and development of their offspring. In such insects, it is known that females utilise and benefit from conspecific cues for oviposition choice. Studying how information from the behaviour of conspecifics affects egg-laying decision-making is crucial for understanding the biology of insects, which can lead to novel strategies for pest management. We focused on the reproductive behaviour of the Asian long-horned beetle Anoplophora glabripennis, which has become an invasive pest species throughout the world. Here, we show that A. glabripennis avoids sites already containing conspecific cues during egg-laying decision-making. The field survey measuring the distance between neighbouring oviposition scars (in this species, females make scars through the bark of host branches for laying eggs) suggested that the selection of oviposition sites by females is not random. In laboratory oviposition-choice bioassays, females made less oviposition scars on branches containing scars made by other females than those without scars. In addition, female oviposition was also deterred by the presence of their own oviposition scars. Our results indicate that avoiding sites containing conspecific (and their own) traces realises fitness benefit such as reducing resource competition among larvae. This study provides insights into the reproductive behaviour of this invasive longhorn beetle, which is useful for developing environmentally friendly control methods such as oviposition deterrents.

In Japan, three trematode species of the genus Azygia have been recorded: A. gotoi, A. perryii, and A. rhinogobii. Here, we report the first detection of A. hwangtsiyui in Japan, identified from the introduced snakehead Channa argus. This trematode was previously known only from the snakeheads in mainland China. Between 2015 and 2024, we sampled snakeheads and snails in Japan, collecting adult trematodes and rediae. Adult trematodes were identified morphologically as A. hwangtsiyui, a determination corroborated by molecular analyses of the COI and 28S rDNA regions. Rediae extracted from the snail Sinotaia quadrata histrica were also identified molecularly as A. hwangtsiyui, indicating the snail acts as an intermediate host. Juvenile trematodes from the short-spined Japanese trident goby Tridentiger brevispinis were also morphologically identified as A. hwangtsiyui, indicating that this goby acts as a paratenic host. Given the snakehead’s introduction to Japan between 1923 and 1924, the absence of records of later introductions, and the presence of both intermediate and paratenic hosts in Japan at that time, A. hwangtsiyui was likely introduced concurrently with the snakehead. As the detection of three COI haplotypes suggests multiple introductions, subsequent introductions via the aquarium trade or other pathways involving the transport of freshwater fish and mollusks from Asia to Japan are also plausible.

Lionfish, as an invasive species, significantly disrupts marine ecosystems. Promoting lionfish as eatable seafood among consumers may effectively reduce the lionfish population, alleviating its impact on marine ecosystems. The primary goal of this article is to assess lionfish’s market potential and determine an effective policy instrument to nudge consumers’ preference for lionfish. Discrete choice experiments are used to elicit consumer preferences for seafood dishes. In addition, we use a split-sample approach to test the effects of providing information about the ecological benefit of eating lionfish. Results indicate that consumer willingness-to-pays for other fish species were substantially higher than that of lionfish, even with the information treatment.

An online survey was distributed to South Dakota stakeholders to understand how noxious weeds are currently being managed. The response rate was 26%; 129 stakeholders completed the survey of the 491 stakeholders who opened the survey. Eighty percent of respondents stated noxious weeds were a problem. Canada thistle [Cirsium arvense (L.) Scop.], leafy spurge (Euphorbia esula L.), and absinth wormwood (Artemisia absinthium L.) were the most common and troublesome, but all statewide noxious weeds were reported. The most common singular response to manage noxious weeds was herbicides alone (25%), but respondents utilized two (27%) to three (24%) other tactics as well. Most respondents (47%) were somewhat satisfied with management tactics, while others were completely satisfied (9%), neither satisfied nor dissatisfied (20%), somewhat unsatisfied (11%), or very unsatisfied (15%). A covariate analysis showed that the more management tactics individual stakeholders utilized, the less satisfied they were with control (P < 0.0001). The most common barrier of adopting new tactics was effectiveness (26%) followed by a combination of effectiveness + current production practices + cost + labor (13%). An additional covariate analysis showed that the increase in management tactics increased the barriers of adoption (P = 0.04) and increasing the number of barriers of adoption resulted in stakeholders being dissatisfied with control (P = 0.0003). Overall, the results of the survey suggest that statewide noxious weeds remain a problem, and multiple tactics are used to manage these weeds. However, Cooperative extension efforts need to address how to use current management and implement new management strategies to increase effectiveness.

Invasive common reed [Phragmites australis (Cav.) Trin. ex Steud. ssp. australis] has established and dominated Ontario wetlands for decades. The detrimental effects of P. australis invasions on wetland habitats have demanded intervention through aggressive suppression efforts. However, constraints in available control methods to suppress P. australis have led to persistent invasions. To improve P. australis management in wetlands, we investigated remotely piloted aircraft systems (RPASs) as a precision tool for herbicide application. We applied an imazapyr-based herbicide (240 g ai L−1) with a spray-equipped RPAS at selected test sites, marking the first-ever application of its kind in Canada. We then (1) evaluated the efficacy of RPAS-based herbicide application to P. australis and (2) examined the plant community changes 1 yr after the initial herbicide application. We found a >99% reduction in live P. australis stems, along with reductions in species richness (33%), Shannon-Weiner diversity (73%), Simpson’s reciprocal diversity (50%), and Pielou’s evenness (73%) in the year following herbicide application. Plant community changes varied by field site; one wetland underwent a secondary invasion by European frog-bit (Hydrocharis morsus-ranae L.) while the other was dominated by the native spotted jewelweed (Impatiens capensis Meerb.), highlighting the complexities of plant community succession following herbicide application in biodiverse wetlands.

The Manapany day gecko Phelsuma inexpectata is a Critically Endangered species endemic to Réunion Island in the Indian Ocean. Studying its geographical distribution and its evolution is important for developing effective biodiversity conservation strategies. We evaluated past and current distributions of P. inexpectata using records from 2008–2020 and through recent, intensive field surveys (230 person-days, 2020–2022). We found that its past distribution has declined by more than 28% (5.12 ha), from 19.44 ha to 14.32 ha. In natural habitats, the distribution of P. inexpectata has been strongly affected, declining by c. 45%, but we identified new areas of occurrence (10.72 ha) through field surveys. Most of these new areas (79%) were found in anthropogenic habitats where the species had not been documented before. The current distribution of P. inexpectata covers c. 24 ha, of which 75% is located in urban areas such as gardens and green urban spaces. Moreover, our field survey showed that at least 10% of its range is now colonized by the invasive gold-dust day gecko Phelsuma laticauda. This survey provides an essential baseline for tracking the future distribution of this threatened species and its potential invasive competitor, and for monitoring how changes to its habitat affect the distribution of P. inexpectata.

Island-endemic arthropods are understudied species and likely to be highly threatened with extinction. Analysis of IUCN Red List assessments can be used to highlight important microhabitats requiring conservation for the effective management of island-endemic arthropod biodiversity. We synthesized information on the 296 island-endemic arthropod species assessed as Critically Endangered as of April 2024, the geography of the islands to which they are endemic, and the broad threats they face. These species comprised 33 taxonomic orders, across which an average of 53% of species were limited entirely to tiny, confined areas of habitat: caves, high elevation areas, isolated pools or sea stacks. These micro-refugia are most utilized by crustaceans and least utilized by myriapods. Caves and pools are the most important habitats on temperate islands where habitat degradation threatens crustaceans. On small tropical islands where arachnids and hexapods are threatened by invasive species, refugia are mostly in high elevation areas. Sea stacks appear to be effective refugia from invasive species only for threatened island-endemics with notable long-distance dispersal adaptation. None of the refugia appear effective in sustaining arthropod species immediately threatened by climate change. Using the interaction between arthropod life history, habitat and threats, it is possible to generalize micro-refugia that (1) should be immediately targeted for management, and (2) could yield undescribed or presumed-extinct species. Prioritizing such refugia for management and research can guide efficient expenditure of local capacity. In our case study, on Ascension Island, micro-refugia for seven endemic arthropods covered < 0.1% of the island's total area.

Johnsongrass [Sorghum halepense (L.) Pers.], an invasive tallgrass, actively inhabits grassland ecosystems of North America. The grasslands ecoregions of the Southern Great Plains are particularly susceptible to S. halepense invasion and dominance because of its preferential growth in continental climate zones coupled with its ability to readily colonize recent disturbances associated with declining livestock grazing and anthropogenic energy and housing development. Controlling S. halepense via chemical or mechanical inputs can reduce this plant species’ abundance temporarily, but are typically followed by S. halepense reestablishment. Sorghum halepense does, however, provide high-quality forage and appears to withstand the frequent drought and flooding events associated with climate change in Southern Great Plains ecosystems. In this review, the benefits and drawbacks of S. halepense in Southern Great Plains grassland ecosystems are discussed and areas where research on this species could be expanded are identified.

Understanding the interactive effects of temperature and diet on insect life cycles is crucial for effective pest management. Here, the influence of different temperatures and diets on the life cycle of Conogethes punctiferalis was investigated using the age-stage, two-sex life table analysis. The results support the hypothesis that temperature and diets (maize, apple, and artificial diet) significantly influence the entire life cycle performance of C. punctiferalis. The duration of larval development was significantly prolonged, whereas adult lifespan was shortened and showed lower reproductive capacity on apple and artificial diet than maize. The total pre-oviposition period was longer on apples than on maize and artificial diet at both temperatures (20, 26°C). The highest r (0.113 d−1), λ (1.128 d−1), R0 (57.213), and GRR (75.54) of C. punctiferalis were found on maize at 26°C, while the highest T (45.062) was found on apples. Similar results were obtained in the age-specific survival curves (sxj), fecundity (mx), maternity (lxmx), and reproductive value (vxj) of YPM on different host plants when exposed to 20°C. These findings highlight the need for further research into the complex interactions between temperature, diet, and insect life history traits to develop effective pest management strategies and enhance our understanding of insect ecology in agroecosystems.

Several Elaeagnus species (autumn olive [Elaeagnus umbellata Thunb.], Russian olive [Elaeagnus angustifolia L.], and thorny olive [Elaeagnus pungens Thunb.]) are invasive in North America. Elaeagnus pungens is prevalent throughout much of the southeastern United States, commonly overtaking wooded and natural areas, bottomlands, and roadsides. While many management methods, including several herbicide treatments, have been evaluated, the efficacy of these methods can vary based on the size and density of the target plants. Further, personal communication with land managers revealed a lack of information that incorporated application effort, duration, and associated cost into treatment efficacy and usefulness. We evaluated three herbicide application methods using the free acid formulation of triclopyr in an E. pungens–infested forest in South Carolina, USA, to determine the effectiveness of each application method. We estimated pretreatment E. pungens biomass and destructively harvested all live material posttreatment to obtain actual biomass values. Foliar herbicide application was ineffective, but both cut stump and basal bark application nearly eliminated E. pungens in the treatment plots. The basal bark application took slightly more time to complete than cut stump treatments but was described as less physically demanding by applicators. Based on treatment efficacy and time required, the basal bark application method seems most prudent for controlling E. pungens in these areas. These results will help land managers more effectively use their resources for invasive woody plant control.

Non-native plants negatively impact ecosystems via a variety of mechanisms, including in forested riparian areas. Japanese knotweed [Polygonum cuspidatum Siebold & Zucc.] and its hybrids (referred to as Polygonum spp. hereafter) are widely spread throughout North America and can impact flora and fauna of riparian habitats. Thus, information improving our ability to understand and predict the potential spread and colonization of Polygonum spp. is valuable. One dispersal mechanism is hydrochory (i.e., dispersal by water), including the downstream dispersal of viable stems that can facilitate rapid invasion within a watershed. We used passive integrated transponder (PIT) telemetry in experimental releases of Polygonum spp. stems to track the downstream transport of Polygonum spp. in a small (second-order) stream in northern New Hampshire, USA, in the summers of 2021 and 2022. A total of 180 (90 each year) Polygonum spp. stems were released at three sites within the stream reach, with 185 (∼98%) being recaptured at least once, with a total of 686 recaptures. Individual relocated stems moved a maximum distance of 30 to 875 m downstream in 2021 and 13 to 1,233 m in 2022 during regular flows; however, a high-streamflow event in July 2021 flushed out all remaining stems downstream of the study area. Generalized additive mixed models (GAMMs) identified site-specific differences in stem movement rates and a general reduction in movement rates with increased duration of time elapsed since post-release. In general, Polygonum spp. stems moved farther downstream in sites with lower channel sinuosity, although other fine-scale habitat factors (e.g., water depth, habitat type, and presence of wood and debris jams) likely contribute to the ability for Polygonum spp. to further disperse or otherwise be retained within the channel. Thus, stream morphology and stream flow are likely to affect where Polygonum spp. stems will be retained and potentially reestablish. Predictive tools identifying areas of higher probability of hydrochory-based dispersal could help to focus removal efforts when employed or to identify riparian habitats at highest risk for spread.

Urban areas are increasingly recognized as important centers of biodiversity. Nonetheless, invasive species can reduce this biodiversity, and cities can be hubs for alien plant invasions, highlighting the need to monitor urban biodiversity and problematic alien species. The goal of our study was to assess the distribution of wild chervil [Anthriscus sylvestris (L.) Hoffm.] and anise [Myrrhis odorata (L.) Scop.] in green spaces of Reykjavík, Iceland. This information is necessary to implement the city’s biodiversity strategy regarding invasive species. Both of these alien plants are spreading throughout Iceland, and Reykjavík’s high-latitude location (≥63°N) and remoteness make it an ideal case study to assess alien plant introductions and invasions in subarctic urban areas. We surveyed four green spaces (Laugarnes, Vatnsmýri, Elliðaárdalur, and Ægisiða) from May to October 2017 using AllTrailsPro and ArcGIS mobile applications. ANOVA and Bonferroni correction (post hoc test) were used to compare the distribution and patch sizes of A. sylvestris and M. odorata among the study sites. We found that A. sylvestris covered at least 10% (15.5 ha) of the total area surveyed (158 ha), while M. odorata only covered ≤1 ha. Both plants were abundant near buildings, pathways, riversides, and streams, and they are expanding their distribution in Reykjavík’s green spaces. While A. sylvestris is clearly more established and widespread with larger patches (>100 m2), the distribution of M. odorata is more localized, occurring mainly in smaller patches (<100 m2). We recommend long-term monitoring to further assess M. odorata’s invasive potential, as well as testing and adopting integrated weed management strategies via adaptive management to control the distribution of A. sylvestris and that of other problematic alien plants. These actions, which are applicable to other subarctic cities, will help foster more proactive management encouraging urban biodiversity.

Common cattail is a perennial weed that naturally occurs in wet or saturated soils, such as in marshes, lakes, ponds, irrigation and drainage canals, and streams, throughout North America. Recently, common cattail has become an important problem for the drill-seeded rice systems in the Sacramento–San Joaquin River Delta of northern California. This research was conducted in 2022 and 2023 at three sites near Stockton, CA, to evaluate the efficacy of florpyrauxifen-benzyl, a newly registered auxin-mimic herbicide, to control common cattail in drill-seeded rice. Florpyrauxifen-benzyl was applied alone at 40 g ai ha–1 and 80 g ha–1 on 0- to 1-m-tall and 1- to 2-m-tall common cattail and in a sequential application of florpyrauxifen-benzyl at 40 g ha–1 followed by 40 g ha–1 between 14-d intervals on 0- to 1-m-tall and 1- to 2-m-tall common cattail. Triclopyr, another auxin-mimic rice herbicide widely used in California, was applied alone at 420 g ae ha–1 on 0- to 1-m-tall common cattail for comparison. Triclopyr was also applied in combination with florpyrauxifen-benzyl at 40 g ha–1 at the 0- to 1-m growth stage. The injury symptoms on common cattail started within 3 d after treatment (DAT) for the florpyrauxifen-benzyl + triclopyr mixture treatment and within 7 DAT for all other florpyrauxifen-benzyl applied treatments. All florpyrauxifen-benzyl treatments controlled 100% of common cattail at 28 DAT regardless of application rate and timing. Common cattail height and dry biomass at 28 DAT were lower for all treatments compared to the nontreated control. While the common cattail control was excellent for all florpyrauxifen-benzyl applications, rice injury was minimal. This research indicates that common cattail up to 2 m tall can be effectively and rapidly controlled in rice fields with florpyrauxifen-benzyl at 40 g ha–1.

One of the most prominent problems related to biological invasions is the variation of local species composition, which often leads to ex novo interspecific interactions. Here, we explored and analysed the native species composition of gall inducers and their associated parasitoids and inquilines in Spanish areas invaded by Dryocosmus kuriphilus Yasumatsu 1951 (Hymenoptera: Cynipidae), an invasive pest of chestnut trees. After a quantitative description of these species' assemblages, we analysed through bipartite networks the level of the trophic specialisation of parasitoids and inquilines when considering either the host taxonomic identity, the host plant species or the host gall morphological type. We sampled galls of D. kuriphilus and native species of Cynipidae in different Spanish areas, including those where the exotic parasitoid Torymus sinensis Kamijo 1982 (Hymenoptera: Torymidae) had been released for D. kuriphilus biological control. The results indicate that the native parasitoids recruited by D. kuriphilus come almost exclusively from native communities on Quercus galls, except for one species from Rosa. Galls of D. kuriphilus had the second most diverse species composition; despite this species assemblage arose ex novo in less than a decade. The bipartite networks resulted more specialised when considering host plant taxa than when gall types and the host taxa were accounted. In such trophic webs, there were few parasitoid/inquiline specialist and many generalist species, which agrees with the rapid recruitment by D. kuriphilus. Higher parasitoid species richness in D. kuriphilus galls is likely due to their being a largely unexploited available resource for the native natural enemies of cynipid wasps.