Amaranthus palmeri is native to Mexico and the south-eastern parts of the USA, and is reported as alien in subtropical regions of the Old World. Previous records from Africa were from the northern parts of the continent. This species was first found in South Africa in March 2018 with further records in different regions of the country as well as in northern Botswana in March 2020. We consider it as naturalized weed which invades both ruderal and segetal plant communities. Mechanical control of A. palmeri plants may be effective to minimize its spreading, because at the flowering stage these tend to be taller compared to other amaranths. Those species of the genus alien in Africa are discussed in terms of their distribution and possible invasive status, particularly A. dubius and A. standleyanus.

Knowledge of invasive terrestrial gastropods species in Mexico, and their potential impacts, is practically unknown. We document in this study, the occurrence of the large invasive slug Arion vulgaris Moquin-Tandon, 1855 for the first time in Mexico and only the third time in North America. In addition, we also report Arion (Kobeltia) intermedius Normand, 1852 from seven localities demonstrating that the species is already well established in Mexico. To identify both species, a Maximum-Likelihood phylogenetic analysis was performed using partial sequences, alone or concatenated, of nicotinamide adenine dinucleotide dehydrogenase 1 (ND1) and cytochrome C oxidase 1 (COI) genes. In addition, we used the morphological characters reported in other studies of these species to confirm their taxonomic identity. The phylogenetic analysis performed with the concatenated ND1 and COI genes, showed that the Mexican sequences of A. vulgaris were grouped with the corresponding sequences of this species from Canada and European countries. In addition, attributes such as the shape and position of the ligula were useful to confirm the taxonomic identity of this species. On the other hand, the phylogenetic analysis using ND1 sequences alone clustered Mexican specimens of A. intermedius with sequences of this species from Spain and UK. Characters such as the body color pattern, prickles on the dorsum, as well as characters of the reproductive system of A. (K.) intermedius corroborated the taxonomic identity of Mexican specimens of this species.

The members of the heterobranch family Veronicellidae Gray, 1840 (commonly referred to as leatherleaf slugs) include some of the most widespread and agriculturally damaging invasive slugs. In a recent survey at Sagar Island of Sunderban Biosphere Reserve, four specimens hitherto unknown from the Reserve were collected. The specimens were identified as Laevicaulis haroldi Dundee, 1980, a native of South Africa. The first observation of this species in India was noted during 2005 in Maharashtra and recently from Uttar Pradesh. The current record from West Bengal affirmed this slug to be an invasive alien species in India. Categorized as IUCN-Endangered in its native range, this species might have a wider distribution in India. In addition, the current study underscores the need of identifying invasive alien species and quantifying their population dynamics in India.

Ants have historically not been recorded on the Faroe Islands. We report ants on the Faroe Islands for the first time, with all detections assumed to be recent accidental arrivals with human commerce. We detail thirteen detections of six ant species. The black garden ant Lasius niger has been found seven times since 1996, five times as established colonies. The red wood ant Formica rufa, Camponotus fallax and two detections of black garden ant Lasius niger were discovered in low numbers (1–4 individuals), and independent of any source of origin. No colonies of these species were ever found and the incursions are presumed to have died naturally. Pharaoh ant Monomorium pharaonis was discovered on a seafaring vessel and once in a private home. The incursion in the private home was eradicated but it is unknown what action was taken on the ship. Ghost ant Tapinoma melanocephalum was discovered on a fishing vessel and eradicated. Tapinoma ibericum was found in a pack of purchased fruits. We anticipate that ant incursions to the Faroe Islands will increase with increasing human commerce, and that the ability for some species to establish viable colonies will also increase.

Tuta absoluta (Meyrick) (Lepidoptera, Gelechiidae), a highly devastating and invasive pest attacking tomatoes either in greenhouses or in open fields, is currently spreading throughout many countries in Africa. Six major vegetable production areas in Kinshasa, Democratic Republic of Congo (DRC), were surveyed between October and November 2016 to report any possible occurrence of the invasive Tuta absoluta. Morphological identification of the sampled adult insect individuals was based on phenotypic characters using a stereomicroscope while molecular identification was carried out using polymerization chain reaction-based approaches targeting the mitochondrial cytochrome oxidase subunit I (COI) gene. Results showed that T. absoluta was found in a commercial tomato farm in Nsele area, while it was absent in the five other sampled sites. Phylogenetic analysis revealed that T. absoluta populations found in Nsele were genetically close to those from Tunisia and Kenya. This is the first report of T. absoluta occurrence and damage in tomatoes grown in DRC where effective and sustainable pest management programs against this invasive insect should be developed and implemented to avoid major crop yield and economic losses.

Tracking the invasion of Chrysomya albiceps (Wiedemann, 1819) (Diptera: Calliphoridae) in South America has multiple distribution gaps. In the present study, we describe the distribution change of this invasive blowfly through time in Chile, using combined methods of collection of occurrences to fill these distributional gaps. We reconstruct the current distribution with entomological collection data, literature, and citizen science. We found that the distribution of C. albiceps expanded only in the central zone of Chile from 2006 to 2011. However, from 2015, the species was recorded in northern Chile, more than 1300 km away from the first locality recorded, through samples and citizen science. We discuss the distribution change and the possible cause of its expansion in the country.

After more than 30 years from the first and only record of Amblycerus robiniae in Europe (Kecskemét, Hungary), two new established populations are reported. The new records came from Romania, 210–250 km away from the initial record, suggesting the possibility that the species was already established in Hungary and that it spread slowly to the south-east. Gleditsia triacanthos Linnaeus, 1753 seed pods were collected in order to detect the species and assess its abundance and frequency. The emerging adults were reared in laboratory conditions to collect information regarding its parasitoids and pest potential. Information regarding rearing, life cycle and biology of the species are also provided.

Ambrosia beetles, including Cyclorhipidion bodoanum, are frequently introduced into new areas through the international trade of wood and wood products. Cyclorhipidion bodoanum is native to eastern Siberia, the Korean Peninsula, Northeast China, Southeast Asia, and Japan but has been introduced into North America, and Europe. In Europe, it was first discovered in 1960 in Alsace, France, from where it has slowly spread to the north, southeast, and east. In 2020, C. bodoanum was captured in an ethanol-baited insect trap in the Bohemian Massif in the western Czech Republic. The locality is covered by a forest of well-spaced oak trees of various ages, a typical habitat for this beetle. The capture of C. bodoanum in the Bohemian Massif, which is geographically isolated from the rest of Central Europe, confirms that the species is spreading east. The species probably spread naturally from Germany, but the period of establishment is difficult to estimate. Although the spread seems to be slow i.e. the beetle required about 60 years to spread from the borders of France and Switzerland to Bohemia, C. bodoanum may have spread more quickly but remained undetected in the newly invaded areas.

Here we report new records of two invasive ambrosia beetles, Xyleborus affinis and X. ferrugineus, in mainland China. For X. affinis, 89 specimens were collected at 12 locations from five hosts (Eucalyptus robusta, Eucalyptus sp., Hevea brasiliensis, Schefflera octophylla and Sindora glabra) during 2014–2019. In 2019, there are only two samples of X. ferrugineus found in a dead log in Guangdong province. We suspected that both were likely introduced to China through international trade, and X. affinis may have arrived by natural dispersal. More investigation and research are needed to determine distribution, biology and ecology of these two Xyleborus species in China.

The impact of invasive species attacking economically important crops is often unpredictable, which is why information needs to be provided at the earliest stage of the attack. This is an incidence report of the fall armyworm, Spodoptera frugiperda (J.E. Smith, 1797) (Lepidoptera: Noctuidae), a new invasive species attacking maize in Malaysia. We found this devastating insect feeding on maize in Changlun, a district in the state of Kedah in northern Malaysia. Morphological examination on the collected specimens and plant damage symptoms due to larval feeding allowed us to confirm the presence of the pest. Hence, we confirm the presence of S. frugiperda in yet another country of South East Asia.

This paper describes the distribution and spread of the non-indigenous red alga Lophocladia lallemandii (Montagne) F. Schmitz along the coast of the Island of Ischia (Tyrrhenian Sea, Italy). Lophocladia lallemandii was monitored through surveys from July 2019 to January 2020 at the Capo Sant’Angelo (Ischia), where L. lallemandii was observed, but not reported, in the years preceding the invasion of the upper rocky infralittoral shore reported here. It is noteworthy that a large portion of the study area is included within one of the two “B no-take” zones of the Marine Protected Area of the “Regno di Nettuno” (“Neptune’s Realm”). During the surveys, the alga was first observed in the middle of July 2019 and totally disappeared by the middle of January 2020. Algal cover showed two peaks in August (55%) and November (58.5%). Fertile thalli (tetrasporophytes) of L. lallemandii were observed in all of the analysed samples. Thalli were not always strongly attached to the substrate or other algae and could often be easily detached by strong hydrodynamic conditions. These detached thalli were found laying on the bottom in dense turfs or floating or stranding on the beach. Noteworthy were the macroflora and fauna, the latter essentially composed by mollusks and amphipods, living among the branches of the alga, and various fishes hiding within the thick algal turf. These observations indicate that this alga may be a source of food and refuge for the native animal community of the upper rocky infralittoral zone.

The macroalgae Lophocladia lallemandii (Montagne) F. Schmitz and Sarconema filiforme (Sonder) Kylin and the spaghetti bryozoan Amathia verticillata (delle Chiaje, 1822) are here first reported in native seagrass beds in the Gulf of Gabès (southeastern Tunisia, Mediterranean Sea). Among them, the sighting of S. filiforme constitutes the first record of this species in Tunisia. The co-occurrence of these species was observed in the study area with variable abundances, and L. lallemandi appeared to impact the local seagrass meadows of Posidonia oceanica (Linnaeus) Delile. Further studies are needed to monitor the distribution of these non-native and cryptogenic taxa in Tunisia and to confirm or infirm the potential negative impacts of the non-indigenous macroalgae on local biota and seagrass beds.

There have been few surveys of intertidal invertebrates in San Francisco Bay, California, USA. Most prior intertidal surveys were limited spatially or taxonomically. This survey of the intertidal invertebrates of San Francisco Bay was conducted over 13 months between 1970 and 1971, generating what is now a legacy data set of invertebrate diversity. Specimens were hand collected at land access points at 34 sites around the Bay. In all 139 living species in 9 phyla were collected; 28.8% were introduced species, primarily from the Atlantic Ocean (62.5%) and the Northwest Pacific and Indo-West Pacific Oceans (30%).

Conrad’s false mussel Mytilopsis leucophaeata (Conrad, 1831) and the Asian date mussel Arcuatula senhousia (Benson, 1842) are highly invasive bivalves actively spreading in the Ponto-Caspian region, which includes the basins of the Black, Azov, and Caspian seas. This study provides new records of both species from this region and gives a synopsis of known information on their ecology, substrate preferences tolerance and adaptive potential to environmental factors such as salinity. Mytilopsis leucophaeata and A. senhousia are at different stages of colonization in the Ponto-Caspian region. While M. leucophaeata has become established in the region, approaching circumferential distribution in each sea basin, A. senhousia is in the initial phase of its dispersal. Although both species are distributed in estuarine and coastal areas, because of different salinity tolerances they are confined to zones of differing degrees of hydrological fluctuation: M. leucophaeata occurs in more estuarine conditions with fluctuating river discharges. Arcuatula senhousia avoids low salinity and is mainly absent near large rivers. In spite of this, A. senhousia generally prefers substrates of riverine origin (so called mixed sediments with prevalence of the soft fraction) and therefore its distribution reflects a compromise pattern with settlement occurring at the outer periphery of estuaries, whereas M. leucophaeata occupies areas with substantial freshwater influence. Unlike A. senhousia, M. leucophaeata usually occurs on hard substrates, however, our findings indicate that it is able to occupy other substrates in the absence of typical biotopes. Compared to A. senhousia, M. leucophaeata colonizes more diverse localities with a broader range of fluctuating conditions such as salinity and of substrate types. Both M. leucophaeata and A. senhousia in the Black Sea tend to settle on substrates that are not fully occupied by native byssus-attached bivalves.

An outbreak of the widely invasive mytilid mussel Perna perna is reported off Israel, long after its previously documented ephemeral occurrence in the mid-1960s. No contemporary populations are known east of the Gulf of Tunis, in the central Mediterranean Sea. Four molecular markers, the mitochondrial cytochrome c oxidase subunit I (COI), ribosomal 18S, 28S subunits (18S rRNA, 28S rRNA) and histone H3 have been used to validate samples identities. COI haplotype diversity suggests that the Israeli population is highly polymorphic, originating from multiple propagules. The present extensive beds in Haifa Bay, home to Haifa port, may point to vessel-transported introduction. The dense beds of P. perna may change intertidal habitats and their communities, and cause fouling of coastal infrastructure (e.g. marine outfalls, seawalls, jetties), as well as offshore infrastructure (e.g. offshore terminals, energy production platforms), and may incur heavy maintenance costs.

The golden crayfish, Faxonius luteus, was identified for the first time in the Black Hills of South Dakota. We collected specimens from three reservoirs and one stream in two adjacent watersheds. The species appears to be established with varying sizes and Form I and Form II males being observed. Records show the home range of F. luteus to be over 600 km east of the Black Hills. The lack of historic information on aquatic fauna in the area complicates determining what effects F. luteus may have on native and other non-native fauna in the area.

The occurrence of three exotic decapods is reported from the Lagoon of Bizerte (northern Tunisia) based on records gathered from local fishermen. These three species are the Atlantic blue crab Callinectes sapidus Rathbun, 1896, the blue swimming crab Portunus segnis (Forskål, 1775), and the Lessepsian shrimp Trachysalambria palaestinensis (Steinitz, 1932). Our sightings confirm the establishment of C. sapidus and P. segnis in the Lagoon of Bizerte and widen the known distribution of T. palaestinensis to northern Tunisia. The updated distribution maps of C. sapidus and P. segnis in the Mediterranean Sea confirm the rapid expansion and colonizing behaviour of these two invasive portunid species. Finally, the potential impacts of these two latter species on the local ecosystem were discussed.

A male Homarus americanus individual, commonly known as the American lobster, was caught by artisanal fishermen at Chalkidiki Peninsula, Greece, north-west Aegean Sea on 26 August 2019. The individual weighted 628.1 g and measured 96.7 mm in carapace length (CL) and 31.44 cm in total length (TL). The specimen was identified by both morphological and molecular means. This is the species’ first record from the eastern Mediterranean Sea and Greece, and only the second for the whole basin. However, several hypotheses for potential introduction vectors are discussed, as well as the potential implication to the regional lobster fishery.

This study delivers a continuous evidence of alien barramundi Lates calcarifer in the Northern Red Sea, a likely outcome of fish-cage escapees from the Saudi Arabian mariculture industry, located approx. 800 km to the south. Genetic mtDNA examinations provided solid evidence for an Australian ancestral origin. Debate for the ecological implications along with emphasis on needed biosecurity practices and management regulation are provided.

Fishes of the genus Abudefduf are increasingly being recorded in Mediterranean waters, with most of these occurrences being based on the sole inspection of underwater images or video footage. Here we present a critical review of these occurrences, taking into account the uncertainties related to the identification of the congeneric A. vaigiensis and A. saxatilis, and testing the validity of the external traits used so far to distinguish these two species. After a careful revision of the Mediterranean literature and based on the analyses of images mostly taken in their natural native environment, we highlight the possibility that major morphological characters previously used to distinguish A. saxatilis from A. vaigiensis are not consistent within the species and thus not sufficiently reliable for their discrimination. This also relates to the possible confusion of these two species with a third species A. troschelii, never reported in the Mediterranean Sea to date. Finally, new records of the genus Abudefduf are reported for the Adriatic Sea and Tunisian waters.

The proliferation of non-native species in the freshwater ecosystems of East Central Mexico is considered a primary threat to the integrity of local native community structure. However, a general understanding of consistent and predictable impacts of non-native species on native freshwater diversity is limited, in part, because of a lack of broad-scale studies including data from numerous localities across multiple drainages. In this study, we captured 85 neotropical fish belonging to nine species in the Alvarado Lagoon, Veracruz, southeast from the Gulf of Mexico. Of these, the presence of three non-native species was confirmed: the pantano cichlid Cincelichthys pearsei, the jaguar cichlid Parachromis managuensis and the vermiculated sailfin catfish Pterygoplichthys disjunctivus. The species settlement in the region is a consequence of aquaculture practices with food purpose and ornamental production.

Over the last decade, three alien snake species have been reported in three of the main islands of the Balearic Archipelago (Spain): Mallorca, Ibiza and Formentera. These introductions are considered a threat to the native biota and are associated with the nursery trade from the Iberian Peninsula. The Montpellier snake Malpolon monspessulanus (Hermann, 1809) was first reported in Mallorca in 2006. Since then, a significant number of observations and captures of this species have been reported around the natural park of s’Albufera de Mallorca. Most of these captures correspond to adult specimens, and the snout-vent length (SVL) values of the entire population ranged from 31.5 to 137.0 cm (n = 69). The observed operative sex ratio was 1.00:1.56 (males:females) and adult males reached larger sizes than adult females. In terms of reproductive biology, five adult females presented oviductal eggs. Finally, skeletal growth marks in the ectopterygoid bone were analyzed, giving results of age from 1 to 20 years old. The significant number of observations, the great sizes and ages reached by some individuals and the detection of gravid females could indicate that the population is well established, fully naturalized and threatening insular ecosystems. This naturalized population is the only insular population of M. monspessulanus located in the western Mediterranean. The proximity of the invasion event to sites of environmental relevance such as those included at Natura 2000 network and Ramsar wetland promotes the idea of assessing the impact of this alien species on native biodiversity. There is an urgent need of carrying out future control actions and implementing biosecurity measures in order to prevent new arrivals of this and other alien species into the Balearic Islands.

Alligator snapping turtles (Macrochelys temminckii Troost, 1835), Chelydridae, is native to the United States and is popular as a pet in many countries despite its large size and inclusions in CITES (Appendix III). On October 15, 2019, an alligator snapping turtle was found at the bottom of a stream in Gwangju, Republic of Korea. The turtle measured 310 mm in carapace length and weighed 7.6 kg. We presumed the shortest distance moved by this turtle was 1.54 km by stream or 1.26 km by land. This is the third record of an alligator snapping turtle in Korea. The first was reported in 2011 and the second in 2014. These repeated sightings of alligator snapping turtles suggest that more individuals are likely to be found in the wild in the Republic of Korea. We highlight the management problems of non-native species, including the alligator snapping turtle, starting with a lack of monitoring species that are imported into the country to inadequate surveys undertaken in the wild across the country.