Non-native Habitats Research Articles

Invasive Apple Snail Diets in Native vs. Non-Native Habitats Defined by SIAR (Stable Isotope Analysis in R)

Invasive apple snails adversely impact the ecological function of non-native habitats, resulting in eutrophication as well as reduced biodiversity, which diminishes ecosystem goods and services, thereby [negatively] impacting human well-being. The onus here is to define the diet of an invasive apple snail (Pomacea canaliculata) in native (Maldonado, Uruguay) versus non-native habitats (Hangzhou, China, and Oahu, HI, USA). Diets for apple snails, in five sites, within both native and non-native habitats were defined via SIAR (Stable Isotope Analysis in R) with δ13C and δ15N stable isotope data collected therein. SIAR models indicate P. canaliculata shift diet from generalist (where myriad plant species comprise relatively small proportions of overall diet) to a specialist diet (where plants species constitute much larger proportions of said diet). What may be more telling is that in (anthropogenically disturbed) portions of the native habitat, and progressively more so in non-native habitats, invasive apple snail diets are increasingly composed of aquatic plants. The inherent and pronounced dietary differences amongst pristine and anthropogenically disturbed native habitats, as well as non-native habitats, provide a mechanism that may elucidate the variable ecological impacts of invasive apple snails within native and non-native habitats.

Soil bacterial assemblage responses to wildfire in low elevation southern California habitats.

Understanding how wildfires and modification in plant assemblages interact to influence soil bacteria assemblages is a crucial step in understanding how these disturbances may influence ecosystem structure and function. Here, we resampled soil from three study sites previously surveyed in spring 2016 and 2017 and compared soil bacterial assemblages prior to and six months after (spring 2019) the 2018 Woolsey Fire in the Santa Monica Mountain National Recreation Area using Illumina sequencing of the 16S rRNA gene. All sites harbored both native California sage scrub and a non-native (grassland or forbland) habitat, allowing us to examine how fire influenced bacterial assemblages in common southern California habitats. Most results contrasted with our a-priori hypotheses: (1) richness and diversity increased following the fire, (2) heat/drought resistant and sensitive bacteria did not show consistent and differing patterns by increasing and decreasing, respectively, in relative abundance after the fire, and (3) bacterial assemblage structure was only minimally impacted by fire, with no differences being found between 2017 (pre-fire) and 2019 (post-fire) in three of the six habitats sampled. As sage scrub and non-native grasslands consistently harbored unique bacterial assemblages both before and following the fire, modifications in plant compositions will likely have legacy effects on these soils that persist even after a fire. Combined, our results demonstrate that bacterial assemblages in southern California habitats are minimally affected by fire. Because direct impacts of fire are limited, but indirect impacts, e.g., modifications in plant compositions, are significant, plant restoration efforts following a fire should strive to revegetate sage scrub areas to prevent legacy changes in bacterial composition.

Analysis of preferred habitats of needlegrass (Hesperostipa spartea) and spotted knapweed (Centaurea biebersteinii) in the Crex Meadows State Wildlife Area

Invasive species threaten the health of native species by establishing in non-native habitats and outcompeting native species. The Crex Meadows State Wildlife Area (CMSWA) is 30,000 acres of native prairie and waterfowl habitat that is dedicated to the management of waterfowl and barrens habitat. Invasive species present in this area are inhibiting this management. Needlegrass (Hesperostipa spartea) and spotted knapweed (Centaurea biebersteinii) are two species that thrive in the CMSWA. Needlegrass is native to this area and is a key species for reintroduction, while spotted knapweed is an invasive species. The objective of this study was to document and analyze the locations of both species to determine if they prefer the same habitat types and identify possible sites of reintroduction for needlegrass and areas of vulnerability to invasion by spotted knapweed. Locations of both species were recorded and, using MaxEnt a species distribution model, the key environmental predictors of the locations of both species were identified. Results show that needlegrass habitat suitability was highest within 500 m of the nearest road, in the south-central and north-central areas of the CMSWA, away from the nearest major road, in sand/gravel, and igneous, metamorphic, and volcanic bedrock. Habitat suitability for spotted knapweed was highest at a slope of 20 degrees or steeper, within 500 m of the nearest road, in the southern part of the CMSWA, and at an elevation of 950 feet and greater. These results can help with management of both species on this property and beyond.

Testing the acoustic adaptation hypothesis with vocalizations from three mongoose species

Acoustic signals degrade and attenuate as they propagate through the environment, thus transmitting information with lower efficiency. The acoustic adaptation hypothesis (AAH) states that selection should shape the vocalizations of a species to maximize transmission through their habitat. A specific prediction of the AAH is that vocalizations will transmit better when emitted in their native habitat versus non-native habitats. We tested this prediction using vocalizations of three mongoose species that dwell in structurally different habitats: banded mongooses, Mungos mungo , dwarf mongooses, Helogale parvula , and meerkats, Suricata suricatta . Representative vocalizations of the three species were broadcast and rerecorded in each habitat at six distances from the source. Rerecorded vocalizations were compared to nondegraded calls through spectrogram correlation. Using generalized linear mixed models, we then quantified the differences in transmission fidelity of each species' vocalizations. Overall, we found partial support for the AAH within the mongoose family: habitat type strongly affected sound transmission, but depending on the species, vocalizations did not always transmit best in their native habitat, suggesting various degrees of acoustic adaptation. Vegetation cover within habitat type was also found to have a significant influence on the transmission properties of vocalizations. In addition, we found evidence that by changing their behaviour, either by producing vocalizations at different amplitudes or by choosing a specific calling location, mongooses can reduce sound degradation and attenuation over distance, thereby enhancing their communication efficiency. Our work highlights how habitat features may be key determinants of vocalization structure in mongooses, and is generalizable to other species living in similar conditions. It also suggests that, given a species and habitat, other selective pressures might prevail and limit acoustic adaptation in animal communication systems. Finally, our study provides insights into how mammals can adjust their vocal behaviour to compensate for environmental constraints on the transmission of their vocalizations. • We tested the acoustic adaptation hypothesis in social mongooses' vocalizations. • Propagation experiments showed partial support for acoustic adaptations in mongooses. • Vegetation cover and habitat type significantly influenced sound propagation. • Behavioural adjustments allow mongooses to optimize efficient sound transmission. • Factors other than acoustic adaptations likely also shape mongoose vocalizations.

Luciferase Immunosorbent Assay Based on Multiple E Antigens for the Detection of Chikungunya Virus-Specific IgG Antibodies.

ABSTRACTIn recent years, the chikungunya virus (CHIKV) has continued to spread from local epidemics to nonnative habitats until eventually reaching pandemic status. Nonendemic areas such as China have also emerged as potential epidemic areas of CHIKV. Serological detection of CHIKV is the key to diagnosing and controlling the prevalence of this virus. In this study, we review the progress of the serological detection of the envelope (E) protein in CHIKV, and we provide a novel research assay and ideas for the serological detection of CHIKV. The luciferase immunosorbent assay (LISA) does not require species-specific labeled secondary antibodies for detection, making it universally suitable for tracking samples from various animals or carriers. At present, most research on CHIKV antigen detection technology tends to combine two or more proteins to avoid the decrease in detection ability caused by antigen mutation. Our results indicate that two or more kinds of CHIKV E antigens combined with LISA detection can improve the detection rate of anti-CHIKV immunoglobulin G (IgG) antibodies in CHIKV-infected patient sera and detect antibodies in the early stage of infection accurately and sensitively. After 235 days of infection, the anti-CHIKV IgG antibodies could still be detected in CHIKV-infected patients. All serum samples were tested with a detection rate of 100% after combining various recombinant CHIKV E antigens. Our proposed CHIKV-specific LISA could be a useful tool for serum diagnosis of CHIKV infection and serum epidemic research in areas where CHIKV is endemic, which would help to manage potential epidemics in the future.IMPORTANCE At present, chikungunya virus (CHIKV) is still circulating in some parts of the world, and mutated strains have emerged, making it easier for the virus to spread among humans. With the continuous variation of CHIKV, its antigen variation leads to the decline of detection ability. In addition, the risk of transmission of CHIKV in areas where CHIKV is not endemic, such as China, has increased dramatically, which compels us to enhance the detection capacity of CHIKV and continuously monitor CHIKV antibody levels in the population. Real-time quantitative PCR (RT-PCR) detection technology will not be reliable when the infection time is chronic or in subclinical infection due to decreases in virus concentration, and an antibody detection technology must be adopted. In this study, multiple CHIKV envelope (E) antigens were used to detect anti-CHIKV IgG antibodies in serum for the first time. The new assay is characterized by convenient operation, high detection rate, and high sensitivity and has significance for early warning and monitoring. Moreover, it contributes to the prevention and control of CHIKV.

A detailed time series of hourly circumference variations in Pinuspinea L. in Chile

Key messageThe dataset provides digital dendrometer measurements on stem circumference of irrigated and non-irrigated Pinus pinea trees. Data were obtained in a xeric non-native habitat of central Chile. Forest mensuration was hourly collected from six adult trees during a growth year. This data can be re-used to perform different studies, including growth and tree water status temporal correlations, climate-growth relationships, and to compare stone pine stands growing in native and non-native habitats. Such studies could facilitate decisions for the species management and contribute to the understanding of its growth dynamics in a climate change context, providing valuable information for a climate-smart forestry. Dataset access is at https://doi.org/10.5281/zenodo.6010567. Associated metadata are available at metadata-afs.nancy.inra.fr/geonetwork/srv/fre/catalog.search#/metadata/bcea7f69-2cf1-444b-8e5b-e9feb23683db

Short-term stem diameter variations in irrigated and non-irrigated stone pine (Pinus pinea L.) trees in a xeric non-native environment

Irrigation of adult stone pine trees growing in a xeric non-native habitat had positive effects not only in stem diameter growth but also in tree response to climatic variability. Stone pine is a key species from Mediterranean Europe increasingly planted in South America. The knowledge about irrigation impact on short-term stem diameter dynamics is still limited in non-native arid areas. To improve our understanding of the effect of irrigation on (1) stem diameter changes of stone pine trees in a drought-prone environment in Chile and (2) the sensitivity of the species to weather conditions. We studied daily stem diameter changes in irrigated and non-irrigated 31-year-old stone pine trees during a growing season with below average precipitation in Chile. Short-term diameter changes were recorded using high-resolution dendrometers. The detrended daily stem diameter changes, expressing tree water status, were correlated with weather variability in both irrigated and non-irrigated trees. The growth period lasted longer and the cumulative sum of daily changes increased by 130% in irrigated trees. Moreover, a similar correlation of tree water status with climatic variables was found in non-irrigated, with the exception of precipitation. Irrigation increased stone pine productivity in this xeric environment and reduced the correlations between daily stem diameter variations and local climatic variability.

Non-native plant drives the spatial dynamics of its herbivores: the case of black locust (Robinia pseudoacacia) in Europe

Non-native plants typically benefit from enemy release following their naturalization in non-native habitats. However, over time, herbivorous insects specializing on such plants may invade from the native range and thereby diminish the benefits of enemy release that these plants may experience. In this study, we compare rates of invasion spread across Europe of three North American insect folivores: the Lepidoptera leaf minersMacrosaccus robiniellaandParectopa robiniella, and the gall midgeObolodiplosis robiniae, that specialize onRobinia pseudoacacia. This tree species is one of the most widespread non-native trees in Europe. We find that spread rates vary among the three species and that some of this variation can be explained by differences in their life history traits. We also report that geographical variation in spread rates are influenced by distribution ofRobinia pseudoacacia, human population and temperature, thoughRobinia pseudoacaciaoccurrence had the greatest influence. The importance of host tree occurrence on invasion speed can be explained by the general importance of hosts on the population growth and spread of invading species.

Self-Compatibility and Reproductive Success of Oenothera drummondii subsp. drummondii: Is It Similar between Native and Non-Native Populations?

The mating system of plants widely distributed can change in native range but also in non-native habitats. Oenothera drummondii, native to the coastal dunes of the Gulf of Mexico, has been introduced to Europe, Africa, Asia and Oceania. Hand self- and cross-pollination were performed to determine compatibility and to compare fruit set, fruit weight, seed set and germination characteristics from natives and non-natives populations and a comprehensive integral reproductive success index (IRSI) was built. Oenothera drummondii exhibited high self-compatibility and mixed reproductive systems in all populations. Characteristics of fruits and seeds from self- and cross-pollination varied within and between native and non-native populations and some had a positive clinal variation in the native range. The IRSI was sensitive to changes of fruit set, seed set and final germination of both self- and cross-pollination, showing differences between native populations. Differences in characteristics of fruits and seeds in the native and non-native ranges suggest the occurrence of distinct selection factors. The mixed reproductive system of O. drummondii suggests it can take advantage of local visitors in the native range, but also can provide advantages for the establishment at non-native sites giving the opportunity to interact with local flower visitors.

Synergistic effects of habitat configuration and land-use intensity shape the structure of bird assemblages in human-modified landscapes across three major neotropical biomes

Maximizing biodiversity persistence in heterogeneous human-modified landscapes is hindered by the complex interactions between habitat quality and configuration of native and non-native habitats. Here we examined these complex interactions considering avian diversity across 26 sampling sites, each of which comprised of three sampling points located across a gradient of disturbance: core native habitat fragment, fragment edge, and non-native adjacent matrix. The 78 sampling points were further nested within three neotropical biomes—Amazonia, Cerrado and Pantanal—in central-western Brazil. Matrix type consisted of cattle pastures in the Amazon and teak plantations in the Pantanal and Cerrado. We considered the interactive effects of (1) disturbance-context: fragment core, edge and adjacent matrix, (2) matrix type: tree plantation or cattle pastures, both subject to varying land-use intensity, and (3) native habitat configuration (fragment size, shape and isolation) on bird species richness, abundance and composition. Based on point-count surveys, we recorded 210 bird species. Bird species richness and abundance declined across the disturbance gradient, while genus composition only differed within the adjacent matrix, particularly cattle-pastures. The effect of native habitat area was positive but only detected at fragment edges. Overall bird diversity increased at sites characterized by higher availability of either relict trees within pasture landscapes or old-growth trees within teak plantation landscapes. The core of native fragments played a primary role in ensuring the persistence of bird diversity, regardless of fragment size. In contrast to pastures, tree plantations likely harbour a higher proportion of forest-dependent species while bird diversity can be further enhanced by reduced management intensity in both matrix types. Strategies to maximize avian persistence should not only include retaining native habitats, but also maximizing the size of core native habitats. Likewise, more structurally complex matrix types should be encouraged while maintaining low levels of land-use intensity.

Western conifer seed bug (Leptoglossus occidentalis) challenging stone pine cropping in the Southern Hemisphere

Stone pine edible seeds are highly appreciated and increasingly demanded. However, kernel yield (percentage of total weight corresponding to kernel) has halved in European producing countries largely due to the attack of the invasive seed-feeding insect Leptoglossus occidentalis. In the Southern Hemisphere, where new stone pine plantations have shown positive results in terms of growth, cone production and health, the exotic seed pest L. occidentalis was first detected in 2017 in Chile, with observed changes and damages having been subsequently reported. The objective of this study was to assess cone and seed traits, and kernel-per-cone yield in P. pinea in Chile before and after the detection of the regional presence of L. occidentalis in 2017. Cone, seed and kernel traits were assessed in seven plantations from central Chile from 2010 to 2015 (before L. occidentalis arrival) and from 2018 to 2019 (after the pest arrival). For the kernels, three types of insect damage were quantified: type I (endosperm/embryo damage), type II (endosperm elimination) and type III (empty seeds). Results showed an average kernel yield of 4.0 ± 0.1%, with no differences between periods. However, in Mulchén, a significant decrease was recorded in cone weight, seed weight and kernels per cone. Regarding kernel analysis, significant increases in damage types I and II were found in all plantations after 2017. Cone assignment to weight categories showed that type I (partially damaged kernel) was the most frequent (58.6%) damage in heavy cones (>550 g), and damage type II was frequent in cones of <350 g in weight (51.4%). Thus, it is necessary to monitor the advance of the insect and its effects on stone pine cropping in non-native habitats. Given that in the southern area of Latin America stone pine is grown in managed plantations, biological and/or chemical control might be applied to limit the negative impact of L. occidentalis.

Stock composition of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) encountered in marine and estuarine environments on the U.S. Atlantic Coast

Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) is a large, anadromous fish native to the Atlantic Coast of North America. Although this species once supported important fisheries, centuries of exploitation and habitat degradation have resulted in dramatic declines, presumed extirpation in some rivers, and ultimately listing under the U.S. Endangered Species Act (ESA). Under the ESA, Atlantic sturgeon are listed as five separate Distinct Population Segments (DPSs), which form the basis for federal management. Despite state and federal protections Atlantic sturgeon still face significant threats to their recovery, including fisheries bycatch mortality, marine construction, dredging, dams, and vessel strikes. However, because subadult and adult Atlantic sturgeon migrate extensively across estuarine and marine environments and frequently form mixed-stock aggregations in non-natal habitats, it can be difficult to determine how these threats impact specific populations and DPSs. To better understand ontogenetic shifts in habitat use and stock-specific exposure to anthropogenic threats, we performed a mixed-stock analysis of 1704 Atlantic sturgeon encountered across the U.S. Atlantic Coast. Collections made north of Cape Cod, MA and south of Cape Hatteras, NC were dominated by individuals from regional stocks; however, we found extensive stock mixing in the mid-Atlantic region, particularly in coastal environments where individuals from all five DPSs were commonly observed. Subadults and adults that were encountered in offshore environments had moved, on average, 277 km from their natal source; however, 23% were sampled over 500 km from their natal river suggesting long-distance movements are relatively common in these age classes. Overall, our work highlights that Atlantic sturgeon populations are vulnerable to threats over vast areas and emphasizes the need for continued genetic monitoring to track recovery progress.

Botany is the root and the future of invasion biology.

Botany is the root and the future of invasion biology.

¿Las plantas exóticas leñosas dependen de los polinizadores para reproducirse? Un estudio de caso en las Sierras de la Ventana (Argentina)

Most of the flowering plants depend on pollinators, in different degrees, for their reproduction. The degree of pollinator dependence is especially important in exotic plants because it could determine their colonization success in new locations. The objective of this study was to determine the degree of pollinator dependence in five exotic entomophilous plant species in a Pampean grassland located in Sierra de Ventana. It was determined if the differences in dependency are related to the geographic location and the phylogeny of plant species. The plants species were Spartium junceum, Genista monspessulana, Prunus mahaleb, Rosa rubiginosa and Rubus ulmifolius. Sampling was carried out in the Ernesto Tornquist Provincial Park and in surrounding areas (Buenos Aires Province). During the flowering peak of each species and in different sites, two treatments were undertaken in pre-bagged flowers: self-pollination and cross-pollination. Also, others pre-bagged flowers were left without pollination as control. Later, the probability of fruit develop and seed set under the two treatments and the control were assessed. Finally, the results of this study were compared with studies carried out in other regions (except for R. ulmifolius). The studied plant species showed a varied response to pollinator dependence, from very dependent species, such as S. junceum, G. monspessulana and P. mahaleb, to low dependent species such as R. rubiginosa y R. ulmifolius. Our results indicate that pollinator dependence can be variable in plants species that are colonizing non-native habitats. Furthermore, there are variations in the degree of pollinator dependency according to the geographical area, except for R. rubiginosa, showing that the geographical location can influence the dependence on pollinators for woody plants.

Enhancing Pinus pinea cone production by grafting in a non-native habitat

Pinus pinea is an interesting species for its valued pine nuts. Despite the high demand for this nut, the species is mostly harvested from natural forests, because the time elapsed until the trees come into production hinders advances toward a more intensive cultivation. The grafting technique has been used to favor an earlier production in native Mediterranean habitats. In Chile, stone pine has been recently included in orchards. The objective of this study was to assess the initial performance in terms of growth, entry into production and cone yield of three grafting trials of the species established in Chile; two of the trials included nursery-grafted plants and the other, in situ grafting of P. pinea on a 3-year-old P. radiata plantation. An earlier entry into production and a higher number of female strobili and 1-year-old conelets (up to 2.9 times) were found in nursery-grafted plants compared with control seedlings. Growth was higher in trees in situ grafted onto radiata pine than in seedlings; eight years after grafting, the trees had achieved reproductive maturity, 67% had on average three cones per tree, and the presence of female strobili and 1-year-old conelets was 6.6 and 15.6 times higher than in seedlings, respectively. Radiata pine could be a feasible rootstock for either in-nursery or in situ stone pine grafting. Grafting accelerated stone pine entry into production, showing to be an effective tool for stone pine propagation and cropping.

Mediterranean Pinus pinea L. nuts from Southern Hemisphere provenances

Stone pine nuts, the most expensive dry fruit worldwide, have been characterized mostly for the main producer countries, located in the Northern Hemisphere. A proximate composition analysis of pine nuts harvested from seven areas located in the Southern Hemisphere (Argentina, Australia, Chile and New Zealand) was performed. Pine nuts showed significant differences in dietary fiber and minerals, probably due to the different climate and environmental conditions, confirming the species’ plasticity and adaptability. Australian pine nuts showed a different profile, with the highest values for protein, lipids and ashes, and the lowest for dietary fiber. Studied pine nuts showed values comparable to the ones reported for the species in its native habitat. Results confirmed that high-quality Mediterranean pine nuts might be produced in the areas included in this study, with practical implications for stone pine cropping in non-native habitats and for the later marketing of pine nuts.

High regenerative capacity is a general feature within colonial dendrophylliid corals (Anthozoa, Scleractinia).

The regenerative capacity of cnidarians plays an essential role in the maintenance and restoration of coral reef ecosystems by allowing faster recovery from disturbances and more efficient small-scale dispersal. However, in the case of invasive species, this property may contribute to their dispersal and success in nonnative habitats. Given that four Indo-Pacific members of the coral genus Tubastraea have invaded the Atlantic, here we evaluated the ability of three of these species (Tubastraea coccinea, Tubastraea diaphana, and Tubastraea micranthus) to regenerate from fragments of undifferentiated coral tissue to fully functional polyps in response to differences in food supply and fragment size. For comparative purposes, another colonial dendrophylliid (Dendrophyllia sp.) was included in the analyses. All dendrophylliids displayed regenerative ability and high survival rates that were independent of whether or not food was supplied or fragment size. However, regeneration rates varied between species and were influenced by fragment size. Temporal expression of key genes of the regenerative process (Wnt and FGF) was profiled during whole-body regeneration of T. coccinea, suggesting a remarkable regenerative ability of T. coccinea that points to its potential use as a laboratory model for the investigation of regeneration in colonial calcified anthozoans.

Non-native regal demoiselle, Neopomacentrus cyanomos, presence, abundance, and habitat factors in the North-Central Gulf of Mexico

Non-native regal demoiselle, Neopomacentrus cyanomos, presence, abundance, and habitat factors in the North-Central Gulf of Mexico

Recruitment dynamics of non-native largemouth bass within the Sacramento–San Joaquin Delta

Largemouth bass (LMB; Micropterus salmoides) recruitment is limited by a critical developmental period during early life stages, but this mechanism may be less important within non-native habitats. We conducted boat electrofishing surveys in four tidal lakes of California’s Sacramento–San Joaquin Delta (SSJD) from 2010 to 2011 to describe introduced LMB recruitment dynamics. We evaluated growth, proximate composition, and health indices of young-of-the-year (YOY) LMB among tidal lakes and developed an integrated count model to determine how factors known to affect LMB recruitment shape SSJD population structure. Our results show a mismatch among growth, nutrition, and YOY abundance, where the tidal lake with the most abundant and fastest-growing LMB had the poorest nutritional status. The warm winter water temperatures and lack of a hatching-cohort growth advantage suggests overwinter starvation plays a less important role in SSJD LMB recruitment than in many native LMB habitats. Collectively, our results suggest that habitat characteristics (submerged aquatic vegetation) and not overwinter mortality shapes SSJD LMB population structure, a mechanism consistent with contemporary hypotheses about the altered fish community structure of the SSJD.

The association of the non-indigenous spider crab Pyromaia tuberculata with the jellyfish Catostylus tagi as a potential spread mechanism in European waters

The presence of non-indigenous species outside their home range attracts growing attention by the scientific community, as well as policy makers and common citizens. However, dispersal pathways of most non-indigenous species remain poorly understood. The association between non-indigenous and indigenous species may facilitate dispersal in non-native habitats. Identifying such associations is therefore paramount, but few studies have addressed this issue to date. The present work reports the association between the non-indigenous spider crab Pyromaia tuberculata, morphologically and molecularly identified, with the autochthonous scyphomedusa Catostylus tagi in European waters. This is the first time this widespread invasive brachyuran crab is described associated with jellyfish. In the laboratory, P. tuberculata was observed feeding on the gonadal tissues of its cnidarian host, although this behaviour needs to be confirmed in the wild. The association between P. tuberculata and C. tagi raises awareness on how the dispersal potential of this non-indigenous species may be significantly enhanced. As recommended by the Marine Strategy Framework Directive, it is important to include P. tuberculata in the European monitoring programmes of non-indigenous species. Future studies should continue to investigate the prevalence of this specific association, as well as other associations between jellyfish and non-indigenous fauna, as an early warning initiative. Researchers may benefit from ongoing citizen science projects to gather data on this overlooked pathway for dispersal of non-indigenous species.