Thirty years of slug control using the parasitic nematode Phasmarhabditis hermaphrodita and beyond.

Several slug species are highly pestiferous and threaten global sustainable agriculture. Current control methods rely heavily on metaldehyde pellets, which are often ineffective, harm nontarget organisms and have been banned in some countries. A viable alternative is the parasitic nematode Phasmarhabditis hermaphrodita (and recently P.

A parasitic nematode induces dysbiosis in susceptible but not resistant gastropod hosts.

Animals' gut microbiomes affect a wide array of biological processes including immunity and protection from pathogens. However, how the microbiome changes due to infection by parasites is still largely unknown, as is how the microbiome changes in hosts that differ in their susceptibility to parasites. To investigate this, we exposed two slug species of differing susceptibility to the parasitic nematode Phasmarhabditis hermaphrodita (Deroceras reticulatum is highly susceptible and Ambigolimax valentianus resistant to the nematode) and profiled the gut microbiota after 7 and 14 days.

Avoidance and attraction behaviour of slugs exposed to parasitic nematodes.

Avoidance of pathogens and parasites is the first line of defense to survive. Several slug species avoid the parasitic nematode Phasmarhabditis hermaphrodita to reduce infection however, there is nothing known about whether slugs avoid other members of the Phasmarhabditis genus. I exposed two slug species (Deroceras invadens and Limax maculatus) to Phasmarhabditis californica and P.

Microbiome Analysis of Malacopathogenic Nematodes Suggests No Evidence of a Single Bacterial Symbiont Responsible for Gastropod Mortality.

Nematodes and bacteria are prevalent in soil ecosystems, and some have evolved symbiotic relationships. In some cases, symbionts carry out highly specialized functions: a prime example being entomopathogenic nematodes (EPNs), which vector bacteria ( or ) into insect hosts, killing them to provide a food source for the nematodes. It is thought that the commercially available malacopathogenic (kills slugs and snails) biocontrol nematode vectors a bacterium () into slugs to kill them.

Phylogenetic evidence for the invasion of a commercialized European Phasmarhabditis hermaphrodita lineage into North America and New Zealand.

Biological control (biocontrol) as a component of pest management strategies reduces reliance on synthetic chemicals, and seemingly offers a natural approach that minimizes environmental impact. However, introducing a new organism to new environments as a classical biocontrol agent can have broad and unanticipated biodiversity effects and conservation consequences. Nematodes are currently used in a variety of commercial biocontrol applications, including the use of Phasmarhabditis hermaphrodita as an agent targeting pest slug and snail species.

Pathogenicity of wild and commercial Phasmarhabditis hermaphrodita exposed to the pestiferous slug Deroceras invadens.

Many terrestrial gastropods are pestiferous and pose a significant threat to agriculture, horticulture and floriculture. They are usually controlled by metaldehyde based pellets but an alternative control method is the slug parasitic nematode Phasmarhabditis hermaphrodita, which has been formulated into a biological control agent (Nemaslug®) for use by farmers and gardeners to kill certain pestiferous slug species in 4-21 days. The current strain of P.

A nematode that can manipulate the behaviour of slugs.

The ability of parasites to manipulate the behaviour of their hosts has evolved multiple times, and has a clear fitness benefit to the parasite in terms of facilitating growth, reproduction and transfer to suitable hosts. The mechanisms by which these behavioural changes are induced are poorly understood, but in many cases parasite manipulation of serotonergic signalling in the host brain is implicated. Here we report that Phasmarhabditis hermaphrodita, a parasite of terrestrial gastropod molluscs, can alter the behaviour of slugs.

Genome-Wide RNAi Screens in C. elegans to Identify Genes Influencing Lifespan and Innate Immunity.

RNA interference is a rapid, inexpensive, and highly effective tool used to inhibit gene function. In C. elegans, whole genome screens have been used to identify genes involved with numerous traits including aging and innate immunity.

A functional genomic screen for evolutionarily conserved genes required for lifespan and immunity in germline-deficient C. elegans.

The reproductive system regulates lifespan in insects, nematodes and vertebrates. In Caenorhabditis elegans removal of germline increases lifespan by 60% which is dependent upon insulin signaling, nuclear hormone signaling, autophagy and fat metabolism and their microRNA-regulators. Germline-deficient C.

System wide analysis of the evolution of innate immunity in the nematode model species Caenorhabditis elegans and Pristionchus pacificus.

The evolution of genetic mechanisms used to combat bacterial infections is critical for the survival of animals and plants, yet how these genes evolved to produce a robust defense system is poorly understood. Studies of the nematode Caenorhabditis elegans have uncovered a plethora of genetic regulators and effectors responsible for surviving pathogens. However, comparative studies utilizing other free-living nematodes and therefore providing an insight into the evolution of innate immunity have been lacking.

Genome-wide analysis of germline signaling genes regulating longevity and innate immunity in the nematode Pristionchus pacificus.

Removal of the reproductive system of many animals including fish, flies, nematodes, mice and humans can increase lifespan through mechanisms largely unknown. The abrogation of the germline in Caenorhabditis elegans increases longevity by 60% due to a signal emitted from the somatic gonad. Apart from increased longevity, germline-less C.

The importance of being regular: Caenorhabditis elegans and Pristionchus pacificus defecation mutants are hypersusceptible to bacterial pathogens.

Bacterial pathogens have shaped the evolution and survival of organisms throughout history, but little is known about the evolution of virulence mechanisms and the counteracting defence strategies of host species. The nematode model organisms, Caenorhabditis elegans and Pristionchus pacificus, feed on a wealth of bacteria in their natural soil environment, some of which can cause mortality. Previously, we have shown that these nematodes differ in their susceptibility to a range of human and insect pathogenic bacteria, with P.

A subset of naturally isolated Bacillus strains show extreme virulence to the free-living nematodes Caenorhabditis elegans and Pristionchus pacificus.

The main food source of free-living nematodes in the soil environment is bacteria, which can affect nematode development, fecundity and survival. In order to occupy a reliable source of bacterial food, some nematodes have formed specific relationships with an array of invertebrate hosts (where bacteria proliferate once the hosts dies), thus forming a tritrophic system of nematode, bacteria and insect or other invertebrates. We isolated 768 Bacillus strains from soil (from Germany and the UK), horse dung and dung beetles and fed them to the genetically tractable free-living nematodes Caenorhabditis elegans and Pristionchus pacificus to isolate nematocidal strains.

Quantitative assessment of the nematode fauna present on Geotrupes dung beetles reveals species-rich communities with a heterogeneous distribution.

Pristionchus spp. nematodes exhibit several traits that might serve as pre-adaptations to parasitism. Under harsh environmental conditions, these nematodes can arrest development and form dauer larvae.

The slug parasitic nematode Phasmarhabditis hermaphrodita associates with complex and variable bacterial assemblages that do not affect its virulence.

Phasmarhabditis hermaphrodita is a nematode parasite of slugs that is commercially reared in monoxenic culture with the bacterium Moraxella osloensis and sold as a biological molluscicide. However, its bacterial associations when reared in vivo in slugs are unknown. We show that when reared in vivo in slugs, P.

Chemoattraction and host preference of the gastropod parasitic nematode Phasmarhabditis hermaphrodita.

Phasmarhabditis hermaphrodita is a parasitic nematode that has been formulated into a biological control agent for slugs. The nematode responds to slug-associated cues such as mucus and feces in order to locate potential hosts. We assessed the olfactory response of P.

Isolation of naturally associated bacteria of necromenic Pristionchus nematodes and fitness consequences.

Nematodes and bacteria are major components of the soil ecosystem. Many nematodes use bacteria for food, whereas others evolved specialized bacterial interactions ranging from mutualism to parasitism. Little is known about the biological mechanisms by which nematode-bacterial interactions are achieved, largely because in the laboratory nematodes are often cultured under artificial conditions.

Assessment of the olfactory response to chemicals or bacteria in pristionchus nematodes.

INTRODUCTIONIn the soil environment, nematodes must rely on a number of host-specific chemical cues in order to find potential beetle hosts. They must also discriminate among different food choices (i.e.

Isolation of pristionchus nematodes from beetles.

INTRODUCTIONIn this procedure, nematodes disembark from a beetle carcass and feed on Escherichia coli OP50. The nematodes are then monitored for a few days and identified using simple morphological characteristics. This method is rapid, easy, and biased for Pristionchus species.

Pristionchus pacificus: A Genetic Model System for the Study of Evolutionary Developmental Biology and the Evolution of Complex Life-History Traits.

INTRODUCTIONPristionchus pacificus is a nematode that has been established as a model system for evolutionary developmental biology. Initially, P. pacificus was used as a convenient nematode with which to compare the processes of vulva and gonad development as well as sex determination to Caenorhabditis elegans, one of the best-studied animal models.

Biological control of terrestrial molluscs using Phasmarhabditis hermaphrodita--progress and prospects.

Phasmarhabditis hermaphrodita Schneider (Nematoda: Rhabditidae) is a nematode that parasitises a wide range of slug and snail species. It has been formulated into a biological control agent (Nemaslug) and was commercialised in 1994. It is now available in fourteen European countries.

Susceptibility and immune response of Deroceras reticulatum, Milax gagates and Limax pseudoflavus exposed to the slug parasitic nematode Phasmarhabditis hermaphrodita.

We exposed three slug species (Deroceras reticulatum (Müller), Milax gagates (Draparnaud) and Limax pseudoflavus L.) to the parasitic nematode Phasmarhabditis hermaphrodita Schneider. P.