Worst Invasive Species Research Articles

Regional differences in clonal Japanese knotweed revealed by chemometrics-linked attenuated total reflection Fourier-transform infrared spectroscopy

BackgroundJapanese knotweed (R. japonica var japonica) is one of the world’s 100 worst invasive species, causing crop losses, damage to infrastructure, and erosion of ecosystem services. In the UK, this species is an all-female clone, which spreads by vegetative reproduction. Despite this genetic continuity, Japanese knotweed can colonise a wide variety of environmental habitats. However, little is known about the phenotypic plasticity responsible for the ability of Japanese knotweed to invade and thrive in such diverse habitats. We have used attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy, in which the spectral fingerprint generated allows subtle differences in composition to be clearly visualized, to examine regional differences in clonal Japanese knotweed.ResultsWe have shown distinct differences in the spectral fingerprint region (1800–900 cm− 1) of Japanese knotweed from three different regions in the UK that were sufficient to successfully identify plants from different geographical regions with high accuracy using support vector machine (SVM) chemometrics.ConclusionsThese differences were not correlated with environmental variations between regions, raising the possibility that epigenetic modifications may contribute to the phenotypic plasticity responsible for the ability of R. japonica to invade and thrive in such diverse habitats.

State of Blue Crab Callinectes Sapidus in the Lagoon of Orikum in Albania

Callinectes sapidus Rathbun, 1896, or as it is otherwise called blue crab, is an invasive species, which was reported for the first time to the Mediterranean Sea in 1949. It has been spread and adapted well to almost the entire Mediterranean and during the recent years even along the coast of the Adriatic Sea. Today it is considered as one of the worst invasive marine species in this region, with an impact on both biodiversity and socio-economic aspects. After a preliminary study on the distribution of blue crab in the Albanian coast, the aim of this study is to provide data on the presence and abundance of this species and to evaluate the population structure by measuring biometric parameters in the lagoon of Orikum. Blue crab observations and collections are conducted almost every month during the period 2012, 2014 and 2015 in the Orikum lagoon. Based on standard method of biometric parameters, measurements of weight, height and width of individuals collected during the study period in the Orikum lagoon were performed. During the study period questionnaires were distributed to local fishermen to collect information on the presence of the blue crab, asses its condition and its possible impact on other populations in the Orikum lagoon.

Whitefly (Bemisia tabaci) Management Program for Ornamental Plants

Bemisia tabaci (Gennadius), commonly known as silverleaf whitefly, is a polyphagous pest and listed as one of the world’s 100 worst invasive species. It is known to feed on more than 1000 plant species and vector over 120 plant-damaging viruses. This publication provides a management program for nursery and ornamental plant growers to aid in their efforts to minimize selection for insecticide resistance irrespective of whitefly biotype while helping to achieve top-quality plant materials.

Development and characterization of microsatellite markers in the small Indian mongoose (Urva auropunctata).

The small Indian mongoose (Urva auropunctata) is one of the world's worst invasive alien species and eradication programs are ongoing worldwide. The development of individual and sex identification markers will improve their management. We searched for novel mongoose microsatellite markers using genome-wide screening and identified 115,265 tetra-nucleotide repeat loci. Of 96 loci tested, 17 were genotyped in 28 mongooses from the Okinawa population. The genetic diversity analysis showed that the average expected and observed heterozygosity and number of alleles were 0.55, 0.56, and 2.94, respectively. Of 17 loci, one deviated from Hardy-Weinberg equilibrium and six loci pairs were likely linked to each other. However, we succeed in identifying all individuals using all of the microsatellite loci. The novel sex identification markers worked successfully in a test using sex known samples. Our novel microsatellite and sex identification markers should be useful in studies of individual identification and population genetics of the mongoose.

Filling the gap on Italian records of an invasive species

Callinectes sapidus is considered one of the worst invasive species in the Mediterranean Sea. After its first observation in 1948, the species has colonized several Mediterranean areas. In this work, we report the first records of the species in Latium and Campania (northern-central and central Tyrrhenian Sea respectively), filling a gap in its distribution along the Italian coasts. We also provide a review of Italian records.

Composition and diversity of gut microbiota in Pomacea canaliculata in sexes and between developmental stages

BackgroundThe apple snail, Pomacea canaliculata, is one of the world’s 100 worst invasive alien species and vector of some pathogens relevant to human health.MethodsOn account of the importance of gut microbiota to the host animals, we compared the communities of the intestinal microbiota from P. canaliculata collected at different developmental stages (juvenile and adult) and different sexes by using high-throughput sequencing.ResultsThe core bacteria phyla of P. canaliculata gut microbiota included Tenericutes (at an average relative abundance of 45.7 %), Firmicutes (27.85 %), Proteobacteria (11.86 %), Actinobacteria (4.45 %), and Cyanobacteria (3.61 %). The female group possessed the highest richness values, whereas the male group possessed the lowest bacterial richness and diversity compared with the female and juvenile group. Both the developmental stages and sexes had important effects on the composition of the intestinal microbiota of P. canaliculata. By LEfSe analysis, microbes from the phyla Proteobacteria and Actinobacteria were enriched in the female group, phylum Bacteroidetes was enriched in the male group, family Mycoplasmataceae and genus Leuconostoc were enriched in the juvenile group. PICRUSt analysis predicted twenty-four metabolic functions in all samples, including general function prediction, amino acid transport and metabolism, transcription, replication, recombination and repair, carbohydrate transport and metabolism, etc.ConclusionsThis study provided a general understanding of the diversity characteristics of intestinal microbial communities of P. canaliculata, and indicated that developmental stage and gender could both influence the intestinal microbes of P. canaliculata. Further study may focus on the interaction between the gut microbiota and their host.

Community narratives and local impacts of invasion in the Eastern Cape: A critical invasion ethnography of black wattle

Since 1995, the South African government has spearheaded a national invasive species campaign known as the Working for Water Program with the dual objectives of invasive species eradication and rural development. This national narrative on invasive species reflects a politicized research agenda and a wealth of material resources directed toward eradication, yet does not accurately portray the reality of invasion at the village level. In particular, Acacia mearnsii de Wild, or the black wattle tree, is classified as one of the worst invasive species in South Africa and a primary target for Working for Water, yet represents an important livelihood resource for rural communities and impacts community members differentially. To better understand these local rural realties, I use a critical invasion science approach to interrogate the local experiences and narratives of black wattle invasion in a rural pastoral community in the Eastern Cape. Within this community, local understandings and impacts of black wattle are nuanced, spatially variable, and reflect complex knowledge politics and political economies. As invasion research moves to incorporate the human and local dimension of invasion for improved policy, it is imperative to fully consider this differentiation of perspectives and impacts within the local community.

Influence of selected biogenic amines on development and demographic parameters of a temperate population of Cinara (Cupressobium) cupressi (Hemiptera, Aphididae)

Cinara (Cupressobium) cupressi, the cypress aphid, is a serious pest of Cupressus spp. and other Cupressaceae, considered to be one of the world’s 100 worst invasive alien species. The potential influence of selected biogenic amines (tryptamine, tyramine, putrescine, and cadaverine) on development and demographic parameters of a temperate population of the cypress aphid was investigated under laboratory conditions. Within parthenogenetic generations, the use of biogenic amines resulted in a significant reduction in the total fecundity and the average daily fecundity both in the fundatrix (F0) and the fundatrigeniae (F1), whereas this influence in the F5 generation was insignificant. In all parthenogenetic generations treated with amines, the dissected female abdomen contained a greater number of mature embryos compared to control samples. Cadaverine caused marked changes in the body length of all viviparous generations studied and a significant reduction in the number of developing embryos, compared to the control sample. The use of biogenic amines did not significantly affect the number of eggs produced by oviparous females but had an impact on their lifespan. Our results indicate that biogenic amines application may disrupt feeding behavior and thus leads to reduced fecundity, consistent with the observation of reduced embryo production. Consequently, bioamines can be used as an alternative agents to control this important pest species.

Pathogenic fungi associated with Ageratina adenophora (Spreng.) King & H. Rob and Parthenium hysterophorus L. in Nepal

This study was carried out in Kathmandu valley, Nepal to document the fungal pathogens associated with the worst invasive species Ageratina adenophora and Parthenium hysterophorus . Pathogen infected leaves were collected in the fields and were cultured in the PDA media. The pathogenic fungi were isolated and identified. Eleven fungal pathogens, namely Alternaria sp., Fusarium sp., Cercospora partheniicola , Colletotrichum capsici , Curvularia sp., Passalora ageratinae , Chaetomium anguipilium , Cladosporium cladosporoides, and Puccinia abrupta var. partheniicola were found on Parthenium hysterophorus . In contrast, Passalora ageretinae and Cladosporium cladosporoides were found on Ageratina adenophora . Curvularia lunata was seen on both the invasive plant species.

Ingestion of Poisonous Eggs of the Invasive Apple Snail Pomacea canaliculata Adversely Affects Bullfrog Lithobathes catesbeianus Intestine Morphophysiology

The poisonous eggs of Pomacea canaliculata hardly have any predators. This invasive snail, listed among 100 of the worst invasive species, is a serious crop pest and a vector of human parasitic diseases. Females lay eggs in pink-reddish masses, the colour presumably a warning of their chemical defenses. Egg ingestion alters rodent gastrointestinal tracts and is lethal if injected, but its effect on other taxa is unknown. Here we explored the toxic effects of Pomacea canaliculata eggs on the bullfrog Lithobathes catesbeianus (Anura, Ranidae).Juvenile bullfrogs were gavaged with egg extracts and their digestive tract analyzed after 24 h and 48 h using histological, immunohistochemical and lectin-histochemical techniques. Toxicity was also evaluated by intraperitoneal injection of egg extract.Egg extract ingestion adversely affected the small intestine of the bullfrogs. Short term (24 h) effects included large, reversible changes of the intestinal wall, villi morphology, and changes in the glycosylation patterns of enterocytes. The mucosal area increased and infiltration of inflammatory cells, mainly eosinophils and macrophages, were observed together with a weak hemorrhage. Most of these changes reversed after 48 h. In addition, intraperitoneal injection of egg extract was nontoxic to bullfrog juveniles and no lethality or behavioral changes were observed, a remarkable difference from the effect on rodents.Overall, these results indicate that toxins of apple snail eggs reversibly modify gut morphology, which may alter bullfrog physiology, limiting their ability to absorb egg nutrients. This study extends the known targets of the apple snail egg defenses against predation to amphibians.

Globalization and the anthropogenic spread of invasive social insects.

Social insects are among the worst invasive species and a better understanding of their anthropogenic spread is needed. I highlight recent research demonstrating that social insects have been dispersed since the early beginnings of globalized trade and in particular after the Industrial Revolution, following two waves of globalization. Many species have complex invasion histories, with multiple independent introduction events and frequent secondary spread. The major source and recipient regions differ markedly across ants, wasps, termites and bees, probably linked to their different introduction pathways. At a more local scale, anthropogenic factors such as irrigation, urbanization or the presence of railways facilitate invasions. In the future, social insect invasions could further accelerate due to intensifying global trade and novel introduction pathways.

Hybridization and invasiveness in social insects - The good, the bad and the hybrid.

Hybridization may help drive biological invasions by reducing Allee effects, increasing genetic variation, and generating novel adaptive genotypes/phenotypes. Social insects (ants, bees, wasps, and termites) are among the world's worst invasive species. In this review, we study the relationship between hybridization and invasiveness in social insects. We examine three types of hybridization based on the reproductive characteristics of first-generation hybrids. We discuss several examples of the association between hybridization and invasiveness, which are predominantly found in bees and termites. However, hybridization also occurs in several non-invasive species, and highly invasive species are not consistently associated with hybridization events, indicating that hybridization is not a main driver of invasiveness in social insects. We discuss why hybridization is not more commonly seen in invasive social insects.

Determination of insecticide resistance in Bemisia tabaci (Hemiptera: Aleyrodidae) populations from Punjab, Pakistan

The whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is one of the most important crop pest among the 100 worst invasive species which threatens agriculture worldwide and poses a serious threat to global food security. The control of B. tabaci depends on the insecticide applications in Pakistan, therefore, monitoring of insecticide resistance is essential for achieving control and for managing resistance. In current study, the field populations of B. tabaci from three crops (cotton, okra and tomato) were collected in five districts (Bahawalpur, Lodhran, Multan, Vehari and Faisalabad) of Punjab, Pakistan in 2017, 2018 and 2019. A leaf- dip bioassay was used to determine the resistance of these populations to five insecticides (Diafenthiuron, spirotetramat, deltamethrin, abamectin and nitenpyram). A very low to low level of resistance to nitenpyram, spirotetramat, and abamectin, whereas moderate to high level of resistance to diafenthiuron and deltamethrin were detected in all populations of B. tabaci compared with the laboratory susceptible strain. The resistance ratios ranged 16.37 to 26.07-fold for diafenthiuron, 52.76 to 73.85-fold for deltamethrin, 3.85 to 7.79-fold for nitenpyram, 3.62 to 13.75-fold for spirotetramat and 5.19 to 9.09-fold for abamectin. The presented results will be helpful to make decision on the proper usage of insecticides against whitefly control and to reduce the development of insecticide resistance.

One of the world’s worst invasive species, Clarias batrachus (Actinopterygii: Siluriformes: Clariidae), has arrived and established a population in Turkey

One of the world’s worst invasive species, Clarias batrachus (Actinopterygii: Siluriformes: Clariidae), has arrived and established a population in Turkey

Identifying prey of the Javan mongoose (Urva javanica) in Java from fecal samples using next-generation sequencing

The Javan mongoose (Urva javanica) is a mesopredator native to Java island that has been rarely studied. The limited information raises questions as to its ecological roles, particularly in terms of its effects on agriculture and biodiversity. These questions are critical as its congeneric species, the small Indian mongoose, has been listed among the 100 worst invasive species. To disclose its ecological function, a new approach that is capable of revealing the diet of the Javan mongoose at the species level is required. We conducted this study to identify the prey species of the Javan mongoose using next-generation sequencing methodology. Our study was conducted in a forested area of the southern mountains of Java, Indonesia. We collected fecal samples during the dry season of March–October 2018, extracting DNA using a QIAamp Fast DNA Stool Mini Kit. We performed Illumina sequencing using a 133 bp mini-barcode of the Cytochrome Oxidase I gene. Our rigorous analysis found 17 species, 14 genera, and 12 families of vertebrates and invertebrates in the mongoose feces. The greater bandicoot rat (Bandicota indica) and the domestic chicken (Gallus gallus) made up the primary diet of the Javan mongoose. Cricket, ant, moth, and fly species were also found in the feces. In effect, our results suggested that this species has a relatively diverse diet, one that includes mammals, birds, amphibians, snakes, fish, and many invertebrates. It confirms that the Javan mongoose has an opportunistic diet, which is most likely related to the availability of putative prey.

Cuticle-associated bacteria can inhibit crayfish pathogen Aphanomyces astaci: Opening the perspective of biocontrol in astaciculture

Pathogenic oomycete Aphanomyces astaci, the causative agent of crayfish plague, is listed among the world's 100 worst invasive alien species due to its fast spread and detrimental impact on native European crayfish populations, as well as losses in crayfish aquaculture. During the infection process, A. astaci mycelium invades the host through its cuticle where it interacts with the resident epibiotic bacteria. Since host microbial communities may have an important role in the defense against pathogens, in this study we aimed to i) identify the epibiotic bacterial isolates from the cuticle of two commercially relevant crayfish – the signal crayfish Pacifastacus leniusculus and the narrow-clawed crayfish Pontastacus leptodactylus, and ii) distinguish those that can inhibit the growth of A. astaci mycelium. Results of 16S rRNA gene sequencing and MALDI–TOF mass spectrometry revealed that the majority of collected isolates belonged to the phylum Proteobacteria (69%), followed by Bacteroidetes (17%) and Firmicutes (8%). Using the in vitro plate assays, we tested the potential of the isolates to inhibit A. astaci mycelial growth and classified them as inhibitors (33%) or non-inhibitors (67%). More than half of the identified inhibitors (56%) belonged to the genus Pseudomonas. Our results represent the first step in the understanding of interactions between A. astaci and epibiotic bacteria on the crayfish cuticle and open the perspective for testing in vivo the application of selected bacterial inoculums for crayfish plague prevention and/or treatment. The development of such A. astaci biocontrol measures is urgently needed in astaciculture.

Rural households\u2019 perception on the effects of Prosopis juliflora invasion: The case of Amibara District of Afar National Regional State, Ethiopia

In Ethiopia, Prosopis juliflora (P. juliflora) becomes one of the worst invasive alien species threatening the livelihood and thus food security of pastoral and agro-pastoral communities. However, up to the present, there have been few studies on the social aspects of the problem. This study explores households’ perceptions about the effects of P. juliflora invasions in Amibara district of Afar National Regional State, Ethiopia. The study used cross-sectional data collected from 130 randomly selected households based on probability proportional to household size. To measure households’ perceptions, a perception index was constructed based on a five-point Likert scale, and a two-limit tobit regression model was used to determine factors affecting households’ perception. The abundance of P. juliflora was perceived to have increased since its introduction in the study area, mainly due to the mobility of dispersal agents and the species’ ability to resist the harsh environment. Between the time when the first trees were planted and today, households’ mean perception about the effect of P. juliflora invasion has experienced a significant shift; whilst initially some 78% of the sampled households were in favour of the tree species, today, less than 1% still favour the tree and some 90% disfavour it. Empirical evidence indicates that gender, market distance, extension service and livelihood strategy had a significant negative influence whilst proximity to the bush land had a significant positive effect on households’ perceptions about the effects of P. juliflora invasion. Almost all sampled households had applied some form of control measure on their individually own land, including uprooting of seedlings or cutting and burning of trees. We recommend that government bodies should, in collaboration with other stakeholders, design P. juliflora management programmes, which take into account the households’ interests, demographic and socio-economic characteristics and institutional settings.

Who's afraid of the big bad boar? Assessing the effect of wild boar presence on the occurrence and activity patterns of other mammals.

Wild boar are considered one the world's worst invasive species and linked to biodiversity loss, competition for resources, predation of native species, and habitat modifications. In this study, we use camera traps to evaluate whether the invasive wild boar had an effect on the medium-sized mammal community of a protected area in southern Brazil. Based on photographic records, we evaluated whether the presence and relative abundance of wild boar was associated with a decrease in diversity or change in activity of medium-sized mammals. All comparisons were made between samples where wild boar were present or absent. The records of each camera during a season were considered a sample. The wild boar was the fourth most common species in the study area being present in 7.8% of the photographic records. The species richness of mammals was not negatively affected by the occurrence of wild boar and most common species did not exhibit changes in the daily activity pattern. However, we recorded an increase in the time elapsed between an observation of wild boar and the record of the next species relative to the average latency period observed among other mammalian species. This average latency period was similar to that observed in the case of large predators such as Puma, and its increase could be reflective partly of the avoidance of native species to wild boar. Nevertheless, our results show that the effect of invasive wild boar on the mammal community is not large as expected.

Comparison of long-term energy efficiency and microbial community dynamics of different reactors in response to increased loadings of water hyacinth juice

Water hyacinth is considered to be among the worst invasive weed species globally, causing detrimental environmental and social problems worldwide. It rapidly grows, and therefore has significant potential as a resource. Due to its high moisture content (approximately 95%), the by-product obtained by dehydrating water hyacinth yields a considerable amount of water hyacinth juice (WHJ). In this study, we performed a comparative assessment of long-term energy efficiency, maximum treatment capacity limits, and microbial community dynamics of modified internal circulation (MIC) and up-flow anaerobic sludge blanket (UASB) reactors in response to increasing loadings of WHJ. The MIC reactor exhibited a higher energy recovery rate and stronger performance compared with the UASB reactor. The optimal organic loading rates of the MIC and UASB reactors were 17.93 and 8.85 kg chemical oxygen demand (COD)/m3/d, with methane conversion rates of 0.21 and 0.15 m3 CH4/kg COD, respectively. Furthermore, the engineering costs and project floor space required by the MIC reactor are less than those in the case of the UASB reactor. The high-throughput sequencing analysis indicated that the dominant phyla (e.g. Firmicutes and Bacteroidetes) were more abundant using the MIC reactor than with the UASB reactor, which may indicate WHJ degradation efficiency. Both reactors had similar predominant methanogens, suggesting that acetoclastic methanogenesis was the predominant metabolic pathway of methane formation. The results of this study provide new insights into the sustainable management of water hyacinth as a resource by establishing a regional ecosystem with biogas engineering applications.

Status and impacts of invasive alien plant species in Parsa National Park, central Nepal

Extent of plant invasions has been expected to be low in protected areas such as national parks due to low anthropogenic activities and high wilderness. However, recent researches across the world have revealed that plant invasions can be severe in the national parks with negative impacts on the protected species and ecosystems. Unfortunately, the status of plant invasions in the national parks of Nepal is mostly unknown. In this study, we sampled at seven locations inside the Parsa National Park (PNP) to document diversity and abundance of invasive alien plant species (IAPS) and their impacts on tree regeneration. Altogether, 130 quadrats of 10 m × 10 m were sampled. We recorded 14 IAPS in the PNP. Three of the IAPS (Chromolana odorata, Lantana camara and Mikania micrantha) were among the 100 of the world’s worst invasive alien species. C. odorata was found to be the most frequent IAPS with the highest cover. The frequency and cover of the IAPS were higher at the sites close to the settlements than at the sites away from the settlements. The species richness of the IAPS was also higher at the sites closer to the settlements than away. The sapling density of the tree species was found to have declined with the increasing cover of the IAPS suggesting that the IAPS had negatively affected tree regeneration. Our data revealed that the PNP has already witnessed massive plant invasions with widespread occurrence of three of the world’s worst invasive species. Therefore, it is high time to integrate management of invasive alien species in the management plan of the park.