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J. Jaenike – One of the best experts on this subject based on the ideXlab platform.

    Evolution; international journal of organic evolution, 2003
    Co-Authors: Steve J. Perlman, J. Jaenike


    Surprisingly little is known about what determines a parasite’s host range, which is essential in enabling us to predict the fate of novel infections. In this study, we evaluate the importance of both host and parasite phylogeny in determining the ability of parasites to infect novel host species. Using experimental lab assays, we infected 24 taxonomically diverse species of Drosophila flies (Diptera: Drosophilidae) with five different nematode species (Ty- lenchida: Allantonematidae: Howardula, Parasitylenchus), and measured parasite infection success, growth, and effects on female host fecundity (i.e., virulence). These nematodes are obligate parasites of mushroom-feeding Drosophila, particularly quinaria and testacea group species, often with severe fitness consequences on their hosts. We show that the potential host ranges of the nematodes are much larger than their actual ranges, even for parasites with only one known host species in nature. Novel hosts that are distantly related from the native host are much less likely to be infected, but among more closely related hosts, there is much variation in susceptibility. Potential host ranges differ greatly between the related parasite species. All nematode species that successfully infected novel hosts produced infective juveniles in these hosts. Most novel infections did not result in significant reductions in the fecundity of female hosts, with one exception: the host specialist Parasitylenchus nearcticus sterilized all quinaria group hosts, only one of which is a host in nature. The large potential host ranges of these parasites, in combination with the high potential for host colonization due to shared mushroom breeding sites, explain the widespread host switching observed in comparisons of nematode and Drosophila phylogenies.

  • Associations between mycophagous Drosophila and their Howardula nematode parasites: a worldwide phylogenetic shuffle.
    Molecular ecology, 2002
    Co-Authors: Steve J. Perlman, Greg S. Spicer, Dewayne Shoemaker, J. Jaenike


    Little is known about what determines patterns of host association of horizontally transmitted parasites over evolutionary timescales. We examine the evolution of associations between mushroom-feeding Drosophila flies (Diptera: Drosophilidae), particularly in the quinaria and testacea species groups, and their horizontally transmitted Howardula nematode parasites (Tylenchida: Allantonematidae). Howardula species were identified by molecular characterization of nematodes collected from wild-caught flies. In addition, DNA sequence data is used to infer the phylogenetic relationships of both host Drosophila (mtDNA: COI, II, III) and their Howardula parasites (rDNA: 18S, ITS1; mtDNA: COI). Host and parasite phylogenies are not congruent, with patterns of host association resulting from frequent and sometimes rapid host colonizations. Drosophila -parasitic Howardula are not monophyletic, and host switches have occurred between Drosophila and distantly related mycophagous sphaerocerid flies. There is evidence for some phylogenetic association between parasites and hosts, with some nematode clades associated with certain host lineages. Overall, these host associations are highly dynamic, and appear to be driven by a combination of repeated opportunities for host colonization due to shared breeding sites and large potential host ranges of the nematodes.

  • Howardula neocosmis sp.n. parasitizing North American Drosophila (Diptera: Drosophilidae) with a listing of the species of Howardula Cobb, 1921 (Tylenchida: Allantonematidae)
    Fundamental and applied nematology, 1998
    Co-Authors: G. O. Poinar, J. Jaenike, Dew. D. Shoemaker


    Description est donnee d’Howardula neocosmis sp. n. (Tylenchida : Allantonematidae) parasite de Drosophila acutilabella Stalker (Diptera : Drosophilidae) provenant de Floride, USA et de D. suboccidentalis Spencer provenant de Colombie Britannique, Canada. Ces deux souches representent le premier Howardula decrit sur des drosophiles nord-americaines. Des notes sur la biologie de ce parasite et une liste des especes du genre Howardula Cobb sont presentees.

George Poinar – One of the best experts on this subject based on the ideXlab platform.

  • Proparasitylenchus californicus n. sp. (Tylenchida: Allantonematidae), parasitic in the intertidal rove beetle Tarphiota geniculata (Mäklin) (Coleoptera: Staphylinidae) in California, USA
    Systematic Parasitology, 2015
    Co-Authors: George Poinar, Nicole Datlen, Magaly Espinoza, John Mclaughlin


    A new nematode species, Proparasitylenchus californicus n. sp., is described from the intertidal rove beetle Tarphiota geniculata (Mäklin) (Coleoptera: Staphylinidae) in California, USA. The new species differs from European representatives of the genus by possessing a cleft stylet in both sexes. The parasitic female is ovoviviparous and produces numerous juveniles that moult twice in the beetle host, then exit and moult twice to the adult stage in the environment. After mating, the free-living fertilised females enter a new host. Heavy infections sterilise the beetles. This is the first record of the genus Proparasitylenchus Wachek, 1955 in the New World and the first allantonematid parasite of a marine, intertidal beetle.

  • Natural parasitism of Metaparasitylenchus hypothenemi (Tylenchida: Allantonematidae) on the coffee berry borer in Chiapas, Mexico
    Biocontrol Science and Technology, 2015
    Co-Authors: Jeanneth Pérez, Alfredo Castillo, George Poinar, Francisco Infante, Fernando E. Vega


    We assessed the parasitism of Metaparasitylenchus hypothenemi on its host, the coffee berry borer, in 20 coffee plantations of Mexico. A total of 23,568 adult borers were dissected, with 179 of the…

  • SHORT COMMUNICATION Natural parasitism of Metaparasitylenchus hypothenemi (Tylenchida: Allantonematidae) on the coffee berry borer in Chiapas, Mexico
    , 2015
    Co-Authors: Jeanneth Pérez, Alfredo Castillo, George Poinar, Francisco Infante, Fernando E. Vega


    The parasitic nematode Metaparasitylenchus hypothenemi (Tylenchida: Allantonematidae) was first reported infecting the coffee berry borer (Hypothenemus hampei (Ferrari); Coleoptera: Curculionidae: Scolytinae) in coffee plantations of Chiapas, Mexico (Castillo, Infante, Barrera, Carta, & Vega, 2002), and was later described as a new species (Poinar, Vega, Castillo, Chavez, & Infante, 2004). This discovery was noteworthy because it increased the limited number of natural enemies attacking the coffee berry borer, the main insect pest of coffee worldwide (Vega, Infante, Castillo, & Jaramillo, 2009; Vega, Infante, & Johnson, 2015), and revealed the presence of endemic populations of a biological control agent in an area where the insect had been introduced. Even though several papers have reported on commercially available entomopathogenic nematodes (Steinernema or Heterorhabditis) infecting the coffee berry borer in the laboratory (Allard & Moore, 1989; Castillo & MarbanMendoza, 1996; Lara, Lopez-Nunez, & Bustillo, 2004; Benavides, Quintero, & Lopez, 2010; Manton, Hollingsworth, & Cabos, 2012), only one other record of a nematode attacking the insect under natural conditions exists: Panagrolaimus sp. (Rhabditida: Panagrolamidae) parasitizing adult coffee berry borers in India (Varaprasad, Balasubramanian, Diwakar, & Rao, 1994). M. hypothenemi infects larvae, pupae and adult stages of the coffee berry borer, causing partial or complete sterilisation of adult females (Poinar et al., 2004). In this study, we assessed the natural parasitism and distribution of M. hypothenemi in coffee plantation in the state of Chiapas, Mexico, in order to elucidate its role in the biological control of the coffee berry borer.

G. O. Poinar – One of the best experts on this subject based on the ideXlab platform.

  • FlIndam. app!. Nemawl., 1997,20 (2),187-190 Parasitylenchus nearcticus sp. n. (Tylenchida: Allantonematidae) parasitizing Drosophila (Diptera: Drosophilidae) in North America
    , 2015
    Co-Authors: G. O. Poinar, I. Dombeck


    Summary- Parasitylenchus nearclicus sp. n. (Tylenchida: Allantonematidae) is described as a parasite of Drosophila recen

  • Parasitylenchus bifurcatus n. sp. (Tylenchida: Allantonematidae) parasitizing Harmonia axyridis (Coleoptera: Coccinellidae)
    Parasites & Vectors, 2012
    Co-Authors: G. O. Poinar, Tove Steenberg


    Background The harlequin ladybird, Harmonia axyridis Pallas (Coleoptera: Coccinellidae) is native to central and eastern Asia and was purposely introduced into Europe to control aphids. While it proved to be a good biological control agent, its rapid spread and buildup of large populations made it a nuisance, since it overwinters in homes, emits unpleasant odors, stains fabrics, occasionally bites humans and feeds on apples, pears and grapes. Aside from the above, the ravenous appetite of H. axyridis results in their consumption of harmless native insects, including even other ladybird beetles. A study of the natural enemies of H. axyridis in Denmark revealed the presence of nematodes. The present study describes this nematode parasite and discusses aspects of its development and ecology. Methods Adult harlequin ladybird beetles were collected from March to November from four localities in Copenhagen on different plant species. In addition, groups of last-instar larvae and pupae (n = 50) were examined for the presence of nematodes. Living and recently dead nematodes were removed from adult H. axyridis in 0.5% saline solution, the nematodes were then heat killed (at 75C), fixed in 5% formalin and transferred to glycerin on slides for further examination and measurements. Results A new species of Allantonematidae (Tylenchida), Parasitylenchus bifurcatus n. sp., is described from adults of the harlequin ladybird, Harmonia axyridis in Denmark. The new species is characterized by a straight stylet lacking basal thickenings, a bursa and a forked tail tip in the vermiform (infective) females and juvenile males. The new species is compared with P. coccinellinae previously described from ladybird beetles in France. Parasitism resulted in depletion of the fat body and partial or complete atrophy of the reproductive organs of the beetles. Infections occurred throughout the year with rates of parasitism reaching up to 35%. The rate increased to 60% when field-collected ladybirds were incubated for 30 days in the laboratory. Conclusions The production of subsequent generations within the host with only the fertilized females (not the males) leaving the hosts and the absence of parasitism of the larvae and pupae is an impressive developmental modification of P. bifurcatus . It is proposed that the vermiform (infective) females pass from one adult host to another when the beetles are hibernating or in assemblage groups. Rates of parasitism show that P. bifurcatus could be a significant biological control agent of H. axyridis .

  • Halophilanema prolata n. gen., n. sp. (Nematoda: Allantonematidae), a parasite of the intertidal bug, Saldula laticollis (Reuter)(Hemiptera: Saldidae) on the Oregon coast
    Parasites & Vectors, 2012
    Co-Authors: G. O. Poinar


    Background It is rare to find terrestrial nematode lineages parasitizing arthropods inhabiting the intertidal or littoral zone of the oceans. During an ecological study along the Oregon dunes, an allantonematid nematode (Tylenchomorpha: Allantonematidae) was discovered parasitizing the intertidal shore bug, Saldula laticollis (Reuter)(Hemiptera: Saldidae). This shore bug is adapted to an intertidal environment and can survive short periods of submergence during high tides. The present study describes the nematode parasite and discusses aspects of its development, ecology and evolution. Methods Adults and last instar nymphs of S. laticollis (Hemiptera: Saldidae) were collected from the high intertidal zone among clumps of Juncus L. (Juncaceae) plants at Waldport, Oregon on October 3, 2011. The bugs were dissected in 1% saline solution and the nematodes killed in 1% Ringers solution and immediately fixed in 5% formalin (at 20°C). Third stage juveniles removed from infected hosts were maintained in 1% saline solution until they matured to the adult stage, molted and mated. Results Halophilanema prolata n. gen., n. sp. (Nematoda: Allantonematidae) is described from last instar nymphs and adults of the intertidal bug, Saldula laticollis on the Oregon coast. The new genus can be distinguished from other genera in the Allantonematidae by a stylet lacking basal knobs in both sexes, an excretory pore located behind the nerve ring, ribbed spicules, a gubernaculum, the absence of a bursa and the elongate-tubular shape of the ovoviviparous parasitic females. Studies of the organogenesis of Halophilanema showed development to third stage juveniles in the uterus of parasitic females. Maturation to the free-living adults and mating occurred in the environment. The incidence of infection of S. laticollis ranged from 0% to 85% depending on the microhabitat in the intertidal zone. Conclusions Based on the habitat and morphological characters, it is proposed that Halophilanema adapted a parasitic existence fairly recently, evolutionarily speaking. It was probably a free-living intertidal or shore nematode that fed on microorganisms, especially fungi, in the intertidal habitat and became parasitic after saldids entered the environment. Halophilanema represents the first described nematode parasite of an intertidal insect.