Ladybird Harmonia Axyridis Research Articles

Identification of Peptides Implicated in Antibacterial Activity of Snow Crab Hepatopancreas Hydrolysates by a Bioassay-Guided Fractionation Approach Combined with Mass Spectrometry.

Snow crab (Chionoecetes opilio) by-products are a rich source of biomolecules, such as lipids, proteins, and chitin, which have not been extensively investigated. This study aims to identify antibacterial peptides to enhance the value of C. opilio by-products. After hydrolysis of different component parts using Protamex®, and concentration by solid-phase extraction, the resulting fractions were tested for antibacterial activity against Escherichia coli, Listeria innocua, and Vibrio parahaemolyticus. Hepatopancreas was the only tissue to display antibacterial activity detected using this protocol. Four fractions obtained with and without enzymatic hydrolysis of hepatopancreas followed by SPE C18 fractionation and elution with 50 and 80% acetonitrile demonstrated bacteriostatic activity against L. innocua HPB13, from concentrations of 0.30 to 43.05mg/mL of peptides/proteins. Eleven peptides sharing at least 80% amino acid homology with four antimicrobial peptides were identified by mass spectrometry. Two peptides had homology to crustin-like and yellowfin tuna GAPDH antimicrobial peptides belonging to the marine organisms Penaeus monodon and Thunnus albacares, respectively. Other peptide sequence homologies were also identified: Odorranain-C7 from the frog Odorrana grahami and a predicted antibacterial peptide in the Asian ladybeetle Harmonia axyridis. These active peptides may represent a novel group of bioactive peptides deserving further investigation as food preservatives.

Mitochondrial Polymorphism of Native and Invasive Populations of Harmonia axyridis (Coleoptera, Coccinellidae)

Ladybird Harmonia axyridis is a widespread polyphage and forms stable populations in East Asia and spreading invasive populations in Europe and other regions with temperate and subtropical climate. A characteristic of haplotype diversity of native and invasive populations of H. axyridis at the atp6 gene is given. The characteristic differences in the composition and quantitative ratio of mitochondrial haplotypes between the western and eastern groups of populations of the native range are revealed. The genetic structure of invasive populations is uniform across the whole range in Europe, from the Atlantic coast to the Black Sea coast of the Caucasus, which is indicative of the spread of H. axyridis invasive populations in Europe from one center. In Europe, the mitochondrial gene pool of invasive populations is formed by two major haplotypes. This mitochondrial haplotype composition remains unchanged in the process of the invasion expansion. The possible role of mixed origin of invasive populations of H. axyridis in the formation of the invasive ability is discussed.

The infection of Harmonia axyridis by a parasitic nematode is mediated by entomopathogenic bacteria and triggers sex-specific host immune responses

The harlequin ladybird Harmonia axyridis is native to Asia but has been introduced into many countries as a biological control agent. It is now considered an invasive pest, threatening the biodiversity of native ladybirds globally, in part because of its superior immune system. H. axyridis is infected and killed by the parasitic nematode Parasitylenchus bifurcatus, which could therefore be developed as a biological strategy to counter the spread of this insect pest. However, effective control requires an understanding of the tripartite relationship between H. axyridis, P. bifurcatus and their potential bacterial mutualists. Here we describe the isolation of two species of nematode-associated bacteria (Serratia marcescens and Providencia rettgeri) which were highly virulent against H. axyridis in survival experiments. In addition, contact between the nematodes and beetles led to the sex-specific modulation of multiple host immunity-related genes after 24 and 48 h, with many genes encoding antimicrobial peptides rapidly and stably repressed in females whereas the same genes were initially induced in males before suppression at the later time point. These data provide evidence that the female immune system responds much more strongly to the nematodes and provokes, in turn, a more robust invasion strategy involving the bacterial mutualists.

Spread of a model invasive alien species, the harlequin ladybird Harmonia axyridis in Britain and Ireland

Invasive alien species are widely recognized as one of the main threats to global biodiversity. Rapid flow of information on the occurrence of invasive alien species is critical to underpin effective action. Citizen science, i.e. the involvement of volunteers in science, provides an opportunity to improve the information available on invasive alien species. Here we describe the dataset created via a citizen science approach to track the spread of a well-studied invasive alien species, the harlequin ladybird Harmonia axyridis (Coleoptera: Coccinellidae) in Britain and Ireland. This dataset comprises 48 510 verified and validated spatio-temporal records of the occurrence of H. axyridis in Britain and Ireland, from first arrival in 2003, to the end of 2016. A clear and rapid spread of the species within Britain and Ireland is evident. A major reuse value of the dataset is in modelling the spread of an invasive species and applying this to other potential invasive alien species in order to predict and prevent their further spread.

May furtive predation provide enemy free space in ant-tended aphid colonies?

In furtive predation, a predator is able to exploit its prey without generating significant defensive behaviors from them. However, in aphidophagous guild, if furtive predator can benefit from dilution effects generated by the aphids, they also suffer from intraguild predation from more mobile and active-searching predators. In this context ant-tended aphid colonies might not only represent an important food source but also potentially an enemy-free space for furtive predators if they remain unharmed by ants while other active predators are being repelled. Here we use the furtive predator Aphidoletes aphidimyza and two distinct instars of an active-searching predator, the Asian ladybeetle Harmonia axyridis, to test hypotheses related to predator persistence within aphid colonies in presence of ants. Our results show that persistence rate over time of the furtive predator was not affected by ant presence while it was strongly reduced for both instars of the active-searching predator. Furthermore, when ran in paired trials within ant-tended aphid colonies, furtive predator persistence rate was significantly higher than for active-searching predators, with these latter always leaving the plants quicker. Finally, we tested the importance of predator mobility in detection susceptibility and aggressive responses in ants using mobile and immobile active-searching predators. While the number of antennal palpations was similar for both treatments indicating similar detection rate, the number of ant attacks was significantly higher on mobile individuals highlighting the importance of movement in triggering aggressive responses in ants. Overall our results indicate that furtive predation represents an efficient strategy to limit ant aggressions, while the exclusion of active-searching predators might create an enemy-free space for furtive predators within ant-tended aphid colonies.

Spiroplasma infection in Harmonia axyridis - Diversity and multiple infection.

The heritable endosymbiotic bacterium Spiroplasma is found in the harlequin ladybird Harmonia axyridis. The proportion of beetles infected with Spiroplasma in different native H. axyridis populations varies from 2% to 49%. We investigated the polymorphism of Spiroplasma strains in samples from individual beetles from Kyoto, Vladivostok, Troitsa Bay, Novosibirsk, and Gorno-Altaisk. To identify Spiroplasma strains, we analyzed nucleotide polymorphisms of the 16S rRNA gene and the ribosomal internal transcribed spacer (ITS1). The majority of infected beetles were infected with two or more Spiroplasma strains. We measured Spiroplasma density in beetles with different infection status using quantitative PCR. The abundance of Spiroplasma in samples with a single infection is an order of magnitude lower than in samples with multiple infections. Density dependent biological effects of Spiroplasma are discussed.

Functional responses and intraspecific competition in the ladybird Harmonia axyridis (Coleoptera: Coccinellidae) provided with Melanaphis sacchari (Homoptera: Aphididae) as prey

Functional responses at each developmental stage of predators and intraspecific competition associated with direct interactions among them provide insights into developing biological control strategies for pests. The functional responses of Harmonia axyridis (Pallas) at each developmental stage of Melanaphis sacchari (Zehntner) and intraspecific competition among predators were evaluated under laboratory conditions. The results showed that all stages of H. axyridis displayed a type II functional response to M. sacchari. Based on Holling's disc equation, the instantaneous searching rates were highest (a) and handling time was shortest (Th) of fourth instar larvae (a = 0.8818; Th = 3.9 min) and female adults (a = 0.9881; Th = 3.0 min) at larval and adult stages, respectively. The coefficients of mutual interference (m) assessed by the intraspecific competition equation were higher for fourth instar larvae (m = 0.4764) and female adults (m = 0.4183). The present study indicates that fourth instar and female adult were more effective stages of H. axyridis in the context of biological control but suitable predator densities need to be considered before natural enemy release.

Utilization of plant-derived food sources from annual flower strips by the invasive harlequin ladybird Harmonia axyridis

The ability to utilize plant-derived food sources and suboptimal prey when the main prey is scarce may enhance competitiveness and invasiveness of entomophagous species such as Harmonia axyridis. Alternative food sources are particularly abundant in flower strips and other agri-environment schemes to promote biodiversity and may thus also benefit the invasive species. We investigated the effects of alternative food sources on the development and reproduction of H. axyridis. Laboratory experiments demonstrated that larvae of H. axyridis developed into adults and produced offspring when reared solely on aphids, lepidopteran eggs or maize pollen but not when they were fed only lepidopteran caterpillars or buckwheat flowers. When fed a combination of the latter two suboptimal food sources, however, some H. axyridis larvae developed into fertile adults. Flowering plant species differed in their food quality to sustain ladybird survival and development when fed alone or in combination with suboptimal prey. Differences in food quality of flower species were confirmed in field-cage studies where newly emerged adults were exposed for six days to different plant species and their energetic compartments were analyzed subsequently. Overall Fagopyrum esculentum and Centaurea cyanus provided a higher food quality than Calendula arvensis in those experiments and mixing flower species did not provide an additional benefit. The results show that the harlequin ladybird can sustain itself not only on optimal prey, but also utilize alternative, animal- and plant-derived diets. This could provide H. axyridis a competitive advantage over those native ladybird species that depend on aphids for their reproduction.

Population-specific expression of antimicrobial peptides conferring pathogen resistance in the invasive ladybird Harmonia axyridis

The harlequin ladybird Harmonia axyridis has emerged as a model species in the context of invasion biology and possesses an expanded repertoire of antimicrobial peptides (AMPs). Here we measured the expression of 22 AMP genes in adult beetles from native and introduced populations, and from a biocontrol population, allowing us to compare populations differing in terms of invasive performance. Strikingly, we observed population-specific expression profiles for particular AMPs. Following an immune challenge, the genes for Coleoptericin1 (Col1), Coleoptericin-likeB and Defensin1 were induced up to several thousand times more strongly in the invasive populations compared to the native and biocontrol populations. To determine the role of Col1 in pathogen resistance, the corresponding gene was silenced by RNA interference (RNAi), causing higher mortality in beetles subsequently infected with the entomopathogen Pseudomonas entomophila. The RNAi-triggered susceptibility to this pathogen was reversed by the injection of a synthetic Col1 peptide. We show that a native population is more susceptible to P. entomomophila infection than an invasive population. This is the first study demonstrating population-specific differences in the immune system of an invasive species and suggests that rapid gene expression changes and a highly adaptive immune system could promote pathogen resistance and thereby invasive performance.

Finding of Parasitoids Phalacrotophora fasciata (Diptera: Phoridae) and Oomyzus scaposus (Hymenoptera: Eulophidae) in Pupas of Harmonia axyridis of the Crimea

New events of parasitization of pupas of Crimean ladybird Harmonia axyridis by native parasitoids Phalacrotophora fasciata and Oomyzus scaposus are described.

Distribution and Some Biological Features of Invasive Species Harmonia axyridis in the Crimea

We present data on the distribution of an invasive species Asian ladybird Harmonia axyridis in the Crimea, the presence in Crimean populations of different morphological types of H. axyridis, and the population ratio of the two most numerous species of Coccinellidae, namely, Harmonia axyridis and Adalia bipunctata, in connection with their possible competition.

The Influence of Diet and Population Density on Maturation of Females from Native and Invasive Populations of the Multicolored Asian Ladybird Harmonia axyridis (Pallas) (Coleoptera, Coccinellidae)

Population density can influence insect reproduction both directly and indirectly causing quantitative and qualitative changes in the feeding regime. We investigated the impact of diet and population density on reproductive maturation of females from native (Irkutsk) and invasive (Sochi) populations of the multicolored Asian ladybird Harmonia axyridis. During the study the beetles fed either on the green peach aphid, Myzus persicae, or on less suitable factitious food (eggs of the grain moth Sitotroga cerealella). Population density was determined by the number of females and males placed in a standard Petri dish. The experiments showed that feeding on the grain moth eggs (other conditions being equal) delayed maturation and increased the tendency to enter reproductive diapause in females from the native but not from the invasive population of H. axyridis. In addition, the preoviposition period increased with the number of females but decreased with the number of males in a dish, although these effects were observed only in individuals from the invasive population and their strength depended on the food of the beetles. Earlier we have demonstrated that the impact of the density-dependent factors on the larvae of the invasive population of H. axyridis was stronger than that on the larvae of the native population because the larvae of the invasive population have somewhat more aggressive interactions with competitors. In the present study, similar differences were revealed between females of these populations.

Behavioral and Immunological Features Promoting the Invasive Performance of the Harlequin Ladybird Harmonia axyridis

The harlequin ladybird Harmonia axyridis is now established as a model to test hypotheses explaining why some species become successfully invasive, while others, even closely related ones, do not. In this review, we evaluate behavioral and immunological features that may play a role in the invasive performance of this model species. We discuss the behavioral traits and associated semiochemicals that promote the invasive success of H. axyridis. In particular, we consider (1) the aggregative behavior and the particular role of long-chain hydrocarbons; (2) the importance of sex pheromones and non-volatile chemicals in mate location and selection; (3) the use of allelochemicals for prey location; and (4) the nature of chemicals that protect against natural enemies. We also highlight the superior immune system of H. axyridis, which encompasses a broader spectrum of antimicrobial peptides (and higher inducible expression levels) compared with native ladybird beetles such as Adalia bipunctata and Coccinella septempunctata. The chemical defense compound harmonine and the antimicrobial peptides are thought to confer resistance against the abundant microsporidia carried by H. axyridis. These parasites can infect and kill native ladybird species feeding on H. axyridis eggs or larvae, supporting the hypothesis that intraguild predation plays a role in the ability of H. axyridis to outcompete native ladybird species in newly-colonized areas.

Genetic Diversity of an Invasive Invertebrate in an Urban Environment, as Exemplified by the HarlequinLadybird HarmoniaAxyridis (Pallas, 1773)

Urbanised areas are capable of exerting a strong impact on the distribution of genetic diversity within populations of animals. Urban invertebrate species are currently either relicts from pre-urban ecosystems, or have immigrated during or following urbanisation. We analysed 10 microsatellite loci in 196 specimens of the harlequin ladybird (Harmonia axyridis), an invasive species in Poland sampled in three of the country's cities. Of Asiatic origin, this ladybird has been spreading through other continents, including Europe. Results showed that the Polish cities are being invaded by harlequin ladybirds that are uniform in terms of their genetic pool, with no significant genetic differentiation present between the urban populations investigated. Rapid spread and what are probably the large numbers of individuals colonising new areas allow this species to maintain high genetic diversity and avoid bottleneck effects. However, we suggest that urban populations differ in terms of genetic diversity. The highest genetic diversity characterises the most recently invaded area of Olsztyn in the north of Poland. Genetic data further suggest that this population could be still in an expansion phase. The earliest colonising population in Wroclaw exhibits signs of a Wahlund effect, suggesting that gene flow among local groups within this urban area could be disturbed or impaired. We conclude that, in the case of an urban population of the harlequin ladybird, successful colonisation is followed by the onset of a decline in genetic diversity, with isolation between local sampling sites appearing. Further studies are required, however, if this process is to be elucidated.

Predators and parasitoids of the harlequin ladybird, Harmonia axyridis, in its native range and invaded areas

The harlequin ladybird Harmonia axyridis (Coleoptera: Coccinellidae) has rapidly spread in several continents over the past 30 years and is considered an invasive alien species. The success of H. axyridis as an invader is often attributed to weak control by natural enemies. In this paper, we provide an overview of current knowledge on predators and parasitoids of H. axyridis. The common feature of predators and parasitoids is that they directly kill exploited organisms. Currently available data show that H. axyridis, displaying a variety of chemical, mechanical, and microbiological anti-predator defenses, is usually avoided by predators. However, some birds and invertebrates can eat this ladybird without harmful consequences. The primary defenses of H. axyridis against parasitoids include immune response and physiological and nutritional unsuitability for parasitoid development. These defenses are probably relatively efficient against most ladybird parasitoids, but not against flies of the genus Phalacrotophora. The latter are idiobiont parasitoids and hence can evade the host’s immune response. Indeed, rates of parasitism of H. axyridis by Phalacrotophora in the Palaearctic region (both in the native range in Asia and in Europe) are relatively high. While strong evidence for enemy release on the invasive populations of H. axyridis is lacking, several cases of parasitoid acquisition have been recorded in Europe, North America, and South America. We conclude that enemy release cannot be excluded as a possible mechanism contributing to the spread and increase of H. axyridis in the early stages of invasion, but adaptation of parasitoids may lead to novel associations which might offset previous effects of enemy release. However, further work is required to elucidate the population-level effects of such interactions.

Mating Status Influences Cold Tolerance and Subsequent Reproduction in the Invasive Ladybird Harmonia axyridis

Among arthropods, ability to survive cold conditions may be instrumental for species invading temperate or colder climatic zones. Cold tolerance can be influenced by multiple environmental and physiological factors. We experimentally investigated the effects of mating status (unmated, mated, or mated and reproductive) on cold tolerance of the invasive harlequin ladybird Harmonia axyridis and subsequent reproduction. We found that unmated adults survive cold better than mated ones. Among mated individuals, those that had not reproduced survived better than those that had reproduced. After cold stress, formerly unmated females were mated, and we evaluated ability to reproduce in females from all three treatments. Females that reproduced prior to cold stress were less likely to reproduce after cold stress than females from both other treatments. We discuss what these results mean for the proportion of unmated females in H. axyridis aggregates at overwintering sites. This study highlights the importance of investigating how physiological status can affect cold tolerance of invasive arthropods.

Harlequin ladybird Harmonia axyridis Pall. (Coleoptera, Coccinellidae) in Armenia

Information on the first finding (one specimen) in Armenia of an invasive species of beetle, harlequin ladybird Harmonia axyridis, is presented. Invasion from Georgia as a result of self-expansion or unintentional delivery is presumed.

First report of nematodes Parasitylenchus bifurcatus Poinar & Steenberg, 2012 parasitizing multicolored Asian lady beetle Harmonia axyridis (Pallas, 1773) in Slovenia

In years 2015 and 2016 around 200 specimens of ladybird species Harmonia axyridis were collected in Slovenia. Ladybirds were dissected and checked under stereomicroscope for presence of nematodes. Nematodes were discovered in samples of ladybirds H. axyridis collected at Brdo pri Lukovici and Trboje. The incidence of parasitized ladybirds was around 30 %. Nematodes were analysed morphometrically and the characteristic features of Parasitylenchus bifurcatus nematodes were observed: straight stylet lacking basal thickenings, a bursa and a forked tail tip in the vermiform females and juvenile males. The identity was confirmed with 18S rDNA region sequence (acc. no. LT629306 and LT629307) which showed high similarity (>99.9 % nucleotide identity) to the P. bifurcatus sequences in the public domain. This is a first report of P. bifurcatus nematode species found parasitizing ladybird Harmonia axyridis in Slovenia. The species compromises fecundity of its host and has therefore a potential to be used as a biological control agent to control high abundance of invasive H. axyridis ladybirds.

A "clean" alien species? Parasites of the invasive ladybird Harmonia axyridis (Coleoptera: Coccinellidae)

The multicoloured Asian ladybird Harmonia axyridis is an invasive insect that can negatively influence biodiversity and human economy in invaded areas. According to the enemy release hypothesis, invasive alien species are often little affected by parasites and other enemies. We studied the prevalence of common parasites of insects infesting and infecting H. axyridis in NW Poland. A large sample of 2351 individuals was collected and divided into two groups: 1180 beetles were dissected and examined for the presence of eugregarines, nematodes and Laboulbeniales fungi, and 751 were checked for phoretic mites. Our results show that H. axyridis is indeed parasitized infrequently. The prevalence of eugregarines and nematodes was very low (1.5% and 0.4%, respectively). No specimens of Laboulbeniales or phoretic mites were found. Our study indicates that in NW Poland H. axyridis is rarely infested or infected by parasites. This paper reports for the first time the infection of H. axyridis by the eugregarine Gregarina barbarara.

Evidence of indirect symbiont conferred protection against the predatory lady beetle Harmonia axyridis in the pea aphid

BackgroundDefensive symbionts can provide significant fitness advantages to their hosts. Facultative symbionts can protect several species of aphid from fungal pathogens, heat shock, and parasitism by parasitoid wasps. Previous work found that two of these facultative symbionts can also indirectly protect pea aphids from predation by the lady beetle Hippocampus convergens. When aphids reproduce asexually, there is extremely high relatedness among aphid clone-mates and often very limited dispersal. Under these conditions, symbionts may indirectly protect aphid clone-mates from predation by negatively affecting the survival of a predator after the consumption of aphids harboring the same vertically transmitted facultative symbionts. In this study, we wanted to determine whether this indirect protection extended to another lady beetle species, Harmonia axyridis.ResultsWe fed Ha. axyridis larvae aphids from one of four aphid sub-clonal symbiont lines which all originated from the same naturally symbiont free clonal aphid lineage. Three of the sub-clonal lines harbor different facultative symbionts that were introduced to the lines via microinjection. Therefore these sub-clonal lineages vary primarily in their symbiont composition, not their genetic background. We found that aphid facultative symbionts affected larval survival as well as pupal survival in their predator Ha. axyridis. Additionally, Ha. axyridis larvae fed aphids with the Regiella symbiont had significantly longer larval developmental times than beetle larvae fed other aphids, and females fed aphids with the Regiella symbiont as larvae weighed less as adults. These fitness effects were different from those previously found in another aphid predator Hi. convergens suggesting that the fitness effects may not be the same in different aphid predators.ConclusionsOverall, our findings suggest that some aphid symbionts may indirectly benefit their clonal aphid hosts by negatively impacting the development and survival of a lady beetle aphid predator Ha. axyridis. By directly affecting the survival of predatory lady beetles, aphid facultative symbionts may increase the survival of their clone-mates that are clustered nearby and have significant impacts across multiple trophic levels. We have now found evidence for multiple aphid facultative symbionts negatively impacting the survival of a second species of aphid predatory lady beetle. These same symbionts also protect their hosts from parasitism and fungal infections, though these fitness effects seem to depend on the aphid species, predator or parasitoid species, and symbiont type. This work further demonstrates that beneficial mutualisms depend upon complex interactions between a variety of players and should be studied in multiple ecologically relevant contexts.