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Kerrie A. Davies - One of the best experts on this subject based on the ideXlab platform.
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First record of Fergusonina (Diptera: Fergusoninidae) and associated Fergusobia (Tylenchida: Neotylenchidae) forming galls on Leptospermum (Myrtaceae) in Australia, with descriptions of new species
Insect Systematics & Evolution, 2018Co-Authors: Kerrie A. Davies, Gary S. Taylor, Jeffrey R. Makinson, Robin J. AdairAbstract:A new species of fly, Fergusonina madidum Taylor sp.n. (Diptera: Fergusoninidae) from Leptospermum madidum A.R. Bean in far north Queensland and a new species of nematode, Fergusobia leptospermum Davies sp.n. (Tylenchida: Neotylenchidae) from L. laevigatum (Gaertn.) F. Muell. in southern Victoria, Australia are described. These represent the first species of the Fergusonina fly/ Fergusobia nematode mutualism to be described from the genus Leptospermum (Myrtaceae). Fergusonina madidum sp.n. forms lateral and terminal multilocular shoot bud galls enclosed in subterminal leaflets. It can be distinguished from all other species of Fergusonina by the lack of dorsal setae on abdominal segment 7 of the female. Unlike most described species of Fergusonina it also lacks the posterior cross vein m-cu in the wing. It shares this character with F. giblindavisi Taylor and F. thomasi Taylor from flower bud galls on Corymbia , but both these species are large and abdominal segment 7 of females is densely setose. Its larva is unknown but from the morphology of puparia the dorsal shield comprises 3 broad transverse bands comprising lateral rows of raised ridge-like sclerotised spicules. Its associated species of nematode is not known. Fergusobia leptospermum sp.n. is associated with cryptic lateral and terminal usually unilocular shoot bud galls. It is characterised by the combination of an open to tight C-shaped parthenogenetic female having a small ‘a’ ratio, with a short but sturdy stylet, flat anterior end; huge dorsal pharyngeal gland, reproductive system with a relatively long uterus, and a sub-conoid tail with a broadly rounded tip; a C-shaped infective female with an almost hemispherical tail tip which may or may not be ventrally hooked; and an open C-shaped male with angular spicules and peloderan bursa arising near the anterior end, and a relatively long (c’ = 2.2–3.2) sub-conoid tail with a bluntly to broadly rounded tip. Its status as a distinct species is confirmed by molecular analyses. Its associated species of fly is known only from several larvae and a puparium, and remains undescribed. The dorsal shield of this Fergusonina species comprises 7 broad bands, the first six having heavily sclerotised raised ridges and the seventh with a medial field of weak spicules. The widely separated collection localities, together with the large number of species in Leptospermum suggest that the mutualism is likely to be speciose and occupy a broad geographic range on this host.
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Nematodes from galls on Myrtaceae. VIII. Fergusobia from small galls on shoot buds, with descriptions of four new species
Zootaxa, 2014Co-Authors: Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Faerlie Bartholomaeus, W. Kelley ThomasAbstract:Small shoot bud galls induced by the Fergusobia (Nematoda: Neotylenchidae)/Fergusonina (Diptera: Fergusoninidae) mutualism occur on various Eucalyptus spp. Four new species of Fergusobia, collected from small shoot bud galls on Eucalyptus camaldulensis, E. gomphocephala and E. leucoxylon, are described. Fergusobia gomphocephalae Davies n. sp. is morphologically characterized by a combination of a small C-shaped parthenogenetic female with a variable, conoid tail, a small C-shaped infective female with a hemispherical tail tip, and an arcuate or J-shaped male with a broad tail, angular spicule and short peloderan bursa. Fergusobia leucoxylonae Davies n. sp. has a C-shaped parthenogenetic female with a conoid tail with a narrowly rounded tip, an arcuate infective female with a broadly rounded tail tip, and an almost straight to barely J-shaped male with angular (not heavily sclerotised) spicule and short bursa. Fergusobia schmidti Davies & Bartholomaeus n. sp. has an arcuate to open C-shaped parthenogenetic female with a relatively large body diameter, relatively long stylet and small tail with a broadly rounded tail tip, an open C-shaped infective female with a broadly rounded to hemispherical tail tip, and an arcuate to barely J-shaped male with spicules angular at about 33% of their length and peloderan bursa arising at about half body length. Fergusobia sporangae Davies n. sp. has an arcuate to open C-shaped parthenogenetic female with a relatively long stylet and a broadly rounded tail tip, an arcuate infective female with a short tail with a broadly rounded to hemispherical tip, and an arcuate to barely J-shaped male with angular (not heavily sclerotised) spicule and short peloderan bursa. Various forms of small shoot bud galls are described. From phylogenetic analyses based on sequences of the D2/D3 expansion segment of the large subunit rRNA gene, the four new species belong to two sister clades of Fergusobia. The larval shield morphology of their associated fly species and possible genetic relationships are discussed.
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Nematodes from galls on Myrtaceae. VI. Fergusobia from galls on Angophora in Australia, with description of F. colbrani n. sp. and key.
Zootaxa, 2014Co-Authors: Kerrie A. Davies, Gary S. Taylor, Leigh A. Nelson, David K. Yeates, Robin M. Giblin-davisAbstract:Collection data and biological information is presented on the Fergusobia (Nematoda: Neotylenchidae)/ Fergusonina (Diptera: Fergusoninidae) mutualism inducing galls on Angophora in Australia. Three species and two morphospecies have been recognised. Fergusobia colbrani Davies n. sp. is described from soft spheroid leaf galls on Angophora floribunda. It is characterised by a combination of morphological characters including a small C-shaped parthenogenetic female with a short broadly conoid tail, an arcuate infective female with an almost hemispherical tail tip, and an arcuate to barely J-shaped male with an angular spicule having a notched tip and mid-length leptoderan bursa. A key to the species and morphospecies of nematodes collected from Angophora is presented. Possible relationships of these organisms are discussed based on evidence from the nematode morphology, gall forms, and the morphology of the dorsal shield of the associated Fergusonina fly larvae.
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An emerging example of tritrophic coevolution between flies (Diptera: Fergusoninidae) and nematodes (Nematoda: Neotylenchidae) on Myrtaceae host plants
Biological Journal of the Linnean Society, 2014Co-Authors: Leigh A. Nelson, Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Sonja J. Scheffer, Matthew F. Purcell, Andrew H. Thornhill, David K. YeatesAbstract:A unique obligate mutualism occurs between species of Fergusonina Malloch flies (Diptera: Fergusoninidae) and nematodes of the genus Fergusobia Currie (Nematoda: Neotylenchidae). These mutualists together form different types of galls on Myrtaceae, mainly in Australia. The galling association is species-specific, and each mutualism in turn displays host specificity. This tritrophic system represents a compelling arena to test hypotheses about coevolution between the host plants, parasitic nematodes and the fergusoninid flies, and the evolution of these intimate mutualisms. We have a basic knowledge of the interactions between the host plant, fly and nematode in this system, but a more sophisticated understanding will require a much more intensive and coordinated research effort. Summaries of the known Fergusonina/Fergusobia species associations and gall type terminology are presented. This paper identifies the key advantages of the system and questions to be addressed, and proposes a number of predictions about the evolutionary dynamics of the system given our understanding of the biology of the mutualists. Future research will profitably focus on (1) gall cecidogenesis and phenology, (2) the interaction between the fly larva and the nematode in the gall, and between the adult female fly and the parasitic nematode, (3) the means by which the fly and nematode life cycles are coordinated, (4) a targeted search of groups in the plant family Myrtaceae that have not yet been identified as gall hosts, and (5) establishment and comparison of the phylogenetic relationships of the host plants, fly species and nematodes. Recently derived phylogenies and divergence time estimation studies of the Diptera and the Myrtaceae show that the fly family Fergusoninidae is less than half the age of the Myrtaceae, discounting the hypothesis of cospeciation and coradiation of the fly/nematode mutualism and the plants at the broadest levels. However, cospeciation may have occurred at shallower levels in the phylogeny, following the establishment of the fly/nematode mutualism on the Myrtaceae.
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sex limited association of fergusobia nematodes with female fergusonina flies in a unique australasian mutualism nematoda Neotylenchidae diptera fergusoninidae
Australian Journal of Entomology, 2013Co-Authors: Sonja J. Scheffer, Kerrie A. Davies, Gary S. Taylor, Leigh A. Nelson, Matthew L. Lewis, Robin M Giblindavis, David K. YeatesAbstract:All known species of Fergusonina flies (Fergusoninidae) participate in an obligate mutualism with Fergusobia nematodes (Neotylenchidae). From dissections, it is believed that all female third-instar larvae, pupae and adult female flies carry nematodes internally, while male adults and larvae do not. This observation of sex-limited association was tested using a molecular diagnostic approach. Nematode-specific primers were used for polymerase chain reaction amplification of a portion of the mitochondrial cytochrome oxidase I gene in order to screen DNA extractions from flies for the presence of nematode DNA. Consistent with evidence from dissections, nearly all extractions from adult female flies were positive for nematode DNA, while all DNA extractions from adult male flies were negative. Nearly half of late-instar larvae screened showed evidence of nematode DNA, consistent with the hypothesis that nematodes are only present within females. This paper is the first to use a molecular method to confirm this phenomenon within the Fergusonina/Fergusobia system.
Gary S. Taylor - One of the best experts on this subject based on the ideXlab platform.
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First record of Fergusonina (Diptera: Fergusoninidae) and associated Fergusobia (Tylenchida: Neotylenchidae) forming galls on Leptospermum (Myrtaceae) in Australia, with descriptions of new species
Insect Systematics & Evolution, 2018Co-Authors: Kerrie A. Davies, Gary S. Taylor, Jeffrey R. Makinson, Robin J. AdairAbstract:A new species of fly, Fergusonina madidum Taylor sp.n. (Diptera: Fergusoninidae) from Leptospermum madidum A.R. Bean in far north Queensland and a new species of nematode, Fergusobia leptospermum Davies sp.n. (Tylenchida: Neotylenchidae) from L. laevigatum (Gaertn.) F. Muell. in southern Victoria, Australia are described. These represent the first species of the Fergusonina fly/ Fergusobia nematode mutualism to be described from the genus Leptospermum (Myrtaceae). Fergusonina madidum sp.n. forms lateral and terminal multilocular shoot bud galls enclosed in subterminal leaflets. It can be distinguished from all other species of Fergusonina by the lack of dorsal setae on abdominal segment 7 of the female. Unlike most described species of Fergusonina it also lacks the posterior cross vein m-cu in the wing. It shares this character with F. giblindavisi Taylor and F. thomasi Taylor from flower bud galls on Corymbia , but both these species are large and abdominal segment 7 of females is densely setose. Its larva is unknown but from the morphology of puparia the dorsal shield comprises 3 broad transverse bands comprising lateral rows of raised ridge-like sclerotised spicules. Its associated species of nematode is not known. Fergusobia leptospermum sp.n. is associated with cryptic lateral and terminal usually unilocular shoot bud galls. It is characterised by the combination of an open to tight C-shaped parthenogenetic female having a small ‘a’ ratio, with a short but sturdy stylet, flat anterior end; huge dorsal pharyngeal gland, reproductive system with a relatively long uterus, and a sub-conoid tail with a broadly rounded tip; a C-shaped infective female with an almost hemispherical tail tip which may or may not be ventrally hooked; and an open C-shaped male with angular spicules and peloderan bursa arising near the anterior end, and a relatively long (c’ = 2.2–3.2) sub-conoid tail with a bluntly to broadly rounded tip. Its status as a distinct species is confirmed by molecular analyses. Its associated species of fly is known only from several larvae and a puparium, and remains undescribed. The dorsal shield of this Fergusonina species comprises 7 broad bands, the first six having heavily sclerotised raised ridges and the seventh with a medial field of weak spicules. The widely separated collection localities, together with the large number of species in Leptospermum suggest that the mutualism is likely to be speciose and occupy a broad geographic range on this host.
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Nematodes from galls on Myrtaceae. VIII. Fergusobia from small galls on shoot buds, with descriptions of four new species
Zootaxa, 2014Co-Authors: Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Faerlie Bartholomaeus, W. Kelley ThomasAbstract:Small shoot bud galls induced by the Fergusobia (Nematoda: Neotylenchidae)/Fergusonina (Diptera: Fergusoninidae) mutualism occur on various Eucalyptus spp. Four new species of Fergusobia, collected from small shoot bud galls on Eucalyptus camaldulensis, E. gomphocephala and E. leucoxylon, are described. Fergusobia gomphocephalae Davies n. sp. is morphologically characterized by a combination of a small C-shaped parthenogenetic female with a variable, conoid tail, a small C-shaped infective female with a hemispherical tail tip, and an arcuate or J-shaped male with a broad tail, angular spicule and short peloderan bursa. Fergusobia leucoxylonae Davies n. sp. has a C-shaped parthenogenetic female with a conoid tail with a narrowly rounded tip, an arcuate infective female with a broadly rounded tail tip, and an almost straight to barely J-shaped male with angular (not heavily sclerotised) spicule and short bursa. Fergusobia schmidti Davies & Bartholomaeus n. sp. has an arcuate to open C-shaped parthenogenetic female with a relatively large body diameter, relatively long stylet and small tail with a broadly rounded tail tip, an open C-shaped infective female with a broadly rounded to hemispherical tail tip, and an arcuate to barely J-shaped male with spicules angular at about 33% of their length and peloderan bursa arising at about half body length. Fergusobia sporangae Davies n. sp. has an arcuate to open C-shaped parthenogenetic female with a relatively long stylet and a broadly rounded tail tip, an arcuate infective female with a short tail with a broadly rounded to hemispherical tip, and an arcuate to barely J-shaped male with angular (not heavily sclerotised) spicule and short peloderan bursa. Various forms of small shoot bud galls are described. From phylogenetic analyses based on sequences of the D2/D3 expansion segment of the large subunit rRNA gene, the four new species belong to two sister clades of Fergusobia. The larval shield morphology of their associated fly species and possible genetic relationships are discussed.
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Nematodes from galls on Myrtaceae. VI. Fergusobia from galls on Angophora in Australia, with description of F. colbrani n. sp. and key.
Zootaxa, 2014Co-Authors: Kerrie A. Davies, Gary S. Taylor, Leigh A. Nelson, David K. Yeates, Robin M. Giblin-davisAbstract:Collection data and biological information is presented on the Fergusobia (Nematoda: Neotylenchidae)/ Fergusonina (Diptera: Fergusoninidae) mutualism inducing galls on Angophora in Australia. Three species and two morphospecies have been recognised. Fergusobia colbrani Davies n. sp. is described from soft spheroid leaf galls on Angophora floribunda. It is characterised by a combination of morphological characters including a small C-shaped parthenogenetic female with a short broadly conoid tail, an arcuate infective female with an almost hemispherical tail tip, and an arcuate to barely J-shaped male with an angular spicule having a notched tip and mid-length leptoderan bursa. A key to the species and morphospecies of nematodes collected from Angophora is presented. Possible relationships of these organisms are discussed based on evidence from the nematode morphology, gall forms, and the morphology of the dorsal shield of the associated Fergusonina fly larvae.
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An emerging example of tritrophic coevolution between flies (Diptera: Fergusoninidae) and nematodes (Nematoda: Neotylenchidae) on Myrtaceae host plants
Biological Journal of the Linnean Society, 2014Co-Authors: Leigh A. Nelson, Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Sonja J. Scheffer, Matthew F. Purcell, Andrew H. Thornhill, David K. YeatesAbstract:A unique obligate mutualism occurs between species of Fergusonina Malloch flies (Diptera: Fergusoninidae) and nematodes of the genus Fergusobia Currie (Nematoda: Neotylenchidae). These mutualists together form different types of galls on Myrtaceae, mainly in Australia. The galling association is species-specific, and each mutualism in turn displays host specificity. This tritrophic system represents a compelling arena to test hypotheses about coevolution between the host plants, parasitic nematodes and the fergusoninid flies, and the evolution of these intimate mutualisms. We have a basic knowledge of the interactions between the host plant, fly and nematode in this system, but a more sophisticated understanding will require a much more intensive and coordinated research effort. Summaries of the known Fergusonina/Fergusobia species associations and gall type terminology are presented. This paper identifies the key advantages of the system and questions to be addressed, and proposes a number of predictions about the evolutionary dynamics of the system given our understanding of the biology of the mutualists. Future research will profitably focus on (1) gall cecidogenesis and phenology, (2) the interaction between the fly larva and the nematode in the gall, and between the adult female fly and the parasitic nematode, (3) the means by which the fly and nematode life cycles are coordinated, (4) a targeted search of groups in the plant family Myrtaceae that have not yet been identified as gall hosts, and (5) establishment and comparison of the phylogenetic relationships of the host plants, fly species and nematodes. Recently derived phylogenies and divergence time estimation studies of the Diptera and the Myrtaceae show that the fly family Fergusoninidae is less than half the age of the Myrtaceae, discounting the hypothesis of cospeciation and coradiation of the fly/nematode mutualism and the plants at the broadest levels. However, cospeciation may have occurred at shallower levels in the phylogeny, following the establishment of the fly/nematode mutualism on the Myrtaceae.
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sex limited association of fergusobia nematodes with female fergusonina flies in a unique australasian mutualism nematoda Neotylenchidae diptera fergusoninidae
Australian Journal of Entomology, 2013Co-Authors: Sonja J. Scheffer, Kerrie A. Davies, Gary S. Taylor, Leigh A. Nelson, Matthew L. Lewis, Robin M Giblindavis, David K. YeatesAbstract:All known species of Fergusonina flies (Fergusoninidae) participate in an obligate mutualism with Fergusobia nematodes (Neotylenchidae). From dissections, it is believed that all female third-instar larvae, pupae and adult female flies carry nematodes internally, while male adults and larvae do not. This observation of sex-limited association was tested using a molecular diagnostic approach. Nematode-specific primers were used for polymerase chain reaction amplification of a portion of the mitochondrial cytochrome oxidase I gene in order to screen DNA extractions from flies for the presence of nematode DNA. Consistent with evidence from dissections, nearly all extractions from adult female flies were positive for nematode DNA, while all DNA extractions from adult male flies were negative. Nearly half of late-instar larvae screened showed evidence of nematode DNA, consistent with the hypothesis that nematodes are only present within females. This paper is the first to use a molecular method to confirm this phenomenon within the Fergusonina/Fergusobia system.
David K. Yeates - One of the best experts on this subject based on the ideXlab platform.
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Nematodes from galls on Myrtaceae. VI. Fergusobia from galls on Angophora in Australia, with description of F. colbrani n. sp. and key.
Zootaxa, 2014Co-Authors: Kerrie A. Davies, Gary S. Taylor, Leigh A. Nelson, David K. Yeates, Robin M. Giblin-davisAbstract:Collection data and biological information is presented on the Fergusobia (Nematoda: Neotylenchidae)/ Fergusonina (Diptera: Fergusoninidae) mutualism inducing galls on Angophora in Australia. Three species and two morphospecies have been recognised. Fergusobia colbrani Davies n. sp. is described from soft spheroid leaf galls on Angophora floribunda. It is characterised by a combination of morphological characters including a small C-shaped parthenogenetic female with a short broadly conoid tail, an arcuate infective female with an almost hemispherical tail tip, and an arcuate to barely J-shaped male with an angular spicule having a notched tip and mid-length leptoderan bursa. A key to the species and morphospecies of nematodes collected from Angophora is presented. Possible relationships of these organisms are discussed based on evidence from the nematode morphology, gall forms, and the morphology of the dorsal shield of the associated Fergusonina fly larvae.
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An emerging example of tritrophic coevolution between flies (Diptera: Fergusoninidae) and nematodes (Nematoda: Neotylenchidae) on Myrtaceae host plants
Biological Journal of the Linnean Society, 2014Co-Authors: Leigh A. Nelson, Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Sonja J. Scheffer, Matthew F. Purcell, Andrew H. Thornhill, David K. YeatesAbstract:A unique obligate mutualism occurs between species of Fergusonina Malloch flies (Diptera: Fergusoninidae) and nematodes of the genus Fergusobia Currie (Nematoda: Neotylenchidae). These mutualists together form different types of galls on Myrtaceae, mainly in Australia. The galling association is species-specific, and each mutualism in turn displays host specificity. This tritrophic system represents a compelling arena to test hypotheses about coevolution between the host plants, parasitic nematodes and the fergusoninid flies, and the evolution of these intimate mutualisms. We have a basic knowledge of the interactions between the host plant, fly and nematode in this system, but a more sophisticated understanding will require a much more intensive and coordinated research effort. Summaries of the known Fergusonina/Fergusobia species associations and gall type terminology are presented. This paper identifies the key advantages of the system and questions to be addressed, and proposes a number of predictions about the evolutionary dynamics of the system given our understanding of the biology of the mutualists. Future research will profitably focus on (1) gall cecidogenesis and phenology, (2) the interaction between the fly larva and the nematode in the gall, and between the adult female fly and the parasitic nematode, (3) the means by which the fly and nematode life cycles are coordinated, (4) a targeted search of groups in the plant family Myrtaceae that have not yet been identified as gall hosts, and (5) establishment and comparison of the phylogenetic relationships of the host plants, fly species and nematodes. Recently derived phylogenies and divergence time estimation studies of the Diptera and the Myrtaceae show that the fly family Fergusoninidae is less than half the age of the Myrtaceae, discounting the hypothesis of cospeciation and coradiation of the fly/nematode mutualism and the plants at the broadest levels. However, cospeciation may have occurred at shallower levels in the phylogeny, following the establishment of the fly/nematode mutualism on the Myrtaceae.
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sex limited association of fergusobia nematodes with female fergusonina flies in a unique australasian mutualism nematoda Neotylenchidae diptera fergusoninidae
Australian Journal of Entomology, 2013Co-Authors: Sonja J. Scheffer, Kerrie A. Davies, Gary S. Taylor, Leigh A. Nelson, Matthew L. Lewis, Robin M Giblindavis, David K. YeatesAbstract:All known species of Fergusonina flies (Fergusoninidae) participate in an obligate mutualism with Fergusobia nematodes (Neotylenchidae). From dissections, it is believed that all female third-instar larvae, pupae and adult female flies carry nematodes internally, while male adults and larvae do not. This observation of sex-limited association was tested using a molecular diagnostic approach. Nematode-specific primers were used for polymerase chain reaction amplification of a portion of the mitochondrial cytochrome oxidase I gene in order to screen DNA extractions from flies for the presence of nematode DNA. Consistent with evidence from dissections, nearly all extractions from adult female flies were positive for nematode DNA, while all DNA extractions from adult male flies were negative. Nearly half of late-instar larvae screened showed evidence of nematode DNA, consistent with the hypothesis that nematodes are only present within females. This paper is the first to use a molecular method to confirm this phenomenon within the Fergusonina/Fergusobia system.
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Sex‐limited association of Fergusobia nematodes with female Fergusonina flies in a unique Australasian mutualism (Nematoda: Neotylenchidae; Diptera: Fergusoninidae)
Australian Journal of Entomology, 2012Co-Authors: Sonja J. Scheffer, Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Leigh A. Nelson, Matthew L. Lewis, David K. YeatesAbstract:All known species of Fergusonina flies (Fergusoninidae) participate in an obligate mutualism with Fergusobia nematodes (Neotylenchidae). From dissections, it is believed that all female third-instar larvae, pupae and adult female flies carry nematodes internally, while male adults and larvae do not. This observation of sex-limited association was tested using a molecular diagnostic approach. Nematode-specific primers were used for polymerase chain reaction amplification of a portion of the mitochondrial cytochrome oxidase I gene in order to screen DNA extractions from flies for the presence of nematode DNA. Consistent with evidence from dissections, nearly all extractions from adult female flies were positive for nematode DNA, while all DNA extractions from adult male flies were negative. Nearly half of late-instar larvae screened showed evidence of nematode DNA, consistent with the hypothesis that nematodes are only present within females. This paper is the first to use a molecular method to confirm this phenomenon within the Fergusonina/Fergusobia system.
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The complete mitochondrial genome of the gall-forming fly, Fergusonina taylori Nelson and Yeates (Diptera: Fergusoninidae)
Mitochondrial DNA, 2011Co-Authors: Leigh A. Nelson, Stephen L. Cameron, David K. YeatesAbstract:The monogeneric family Fergusoninidae consists of gall-forming flies that, together with Fergusobia (Tylenchida: Neotylenchidae) nematodes, form the only known mutualistic association between insects and nematodes. In this study, the entire 16,000 bp mitochondrial genome of Fergusonina taylori Nelson and Yeates was sequenced. The circular genome contains one encoding region including 27 genes and one non-coding A þT-rich region. The arrangement of the proteincoding, ribosomal RNA (rRNA) and transfer RNA (tRNA) genes was the same as that found in the ancestral insect. Nucleotide composition is highly A þ T biased. All of the protein initiation codons are ATN, except for nad1 which begins with TTT. All 22 tRNA anticodons of F. taylori match those observed in Drosophila yakuba, and all form the typical cloverleaf structure except for tRNA-Ser (AGN) which lacks a dihydrouridine (DHU) arm. Secondary structural features of the rRNA genes of Fergusonina are similar to those proposed for other insects, with minor modifications. The mitochondrial genome of Fergusonina presented here may prove valuable for resolving the sister group to the Fergusoninidae, and expands the available mtDNA data sources for acalyptrates overall.
Leigh A. Nelson - One of the best experts on this subject based on the ideXlab platform.
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Nematodes from galls on Myrtaceae. VI. Fergusobia from galls on Angophora in Australia, with description of F. colbrani n. sp. and key.
Zootaxa, 2014Co-Authors: Kerrie A. Davies, Gary S. Taylor, Leigh A. Nelson, David K. Yeates, Robin M. Giblin-davisAbstract:Collection data and biological information is presented on the Fergusobia (Nematoda: Neotylenchidae)/ Fergusonina (Diptera: Fergusoninidae) mutualism inducing galls on Angophora in Australia. Three species and two morphospecies have been recognised. Fergusobia colbrani Davies n. sp. is described from soft spheroid leaf galls on Angophora floribunda. It is characterised by a combination of morphological characters including a small C-shaped parthenogenetic female with a short broadly conoid tail, an arcuate infective female with an almost hemispherical tail tip, and an arcuate to barely J-shaped male with an angular spicule having a notched tip and mid-length leptoderan bursa. A key to the species and morphospecies of nematodes collected from Angophora is presented. Possible relationships of these organisms are discussed based on evidence from the nematode morphology, gall forms, and the morphology of the dorsal shield of the associated Fergusonina fly larvae.
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An emerging example of tritrophic coevolution between flies (Diptera: Fergusoninidae) and nematodes (Nematoda: Neotylenchidae) on Myrtaceae host plants
Biological Journal of the Linnean Society, 2014Co-Authors: Leigh A. Nelson, Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Sonja J. Scheffer, Matthew F. Purcell, Andrew H. Thornhill, David K. YeatesAbstract:A unique obligate mutualism occurs between species of Fergusonina Malloch flies (Diptera: Fergusoninidae) and nematodes of the genus Fergusobia Currie (Nematoda: Neotylenchidae). These mutualists together form different types of galls on Myrtaceae, mainly in Australia. The galling association is species-specific, and each mutualism in turn displays host specificity. This tritrophic system represents a compelling arena to test hypotheses about coevolution between the host plants, parasitic nematodes and the fergusoninid flies, and the evolution of these intimate mutualisms. We have a basic knowledge of the interactions between the host plant, fly and nematode in this system, but a more sophisticated understanding will require a much more intensive and coordinated research effort. Summaries of the known Fergusonina/Fergusobia species associations and gall type terminology are presented. This paper identifies the key advantages of the system and questions to be addressed, and proposes a number of predictions about the evolutionary dynamics of the system given our understanding of the biology of the mutualists. Future research will profitably focus on (1) gall cecidogenesis and phenology, (2) the interaction between the fly larva and the nematode in the gall, and between the adult female fly and the parasitic nematode, (3) the means by which the fly and nematode life cycles are coordinated, (4) a targeted search of groups in the plant family Myrtaceae that have not yet been identified as gall hosts, and (5) establishment and comparison of the phylogenetic relationships of the host plants, fly species and nematodes. Recently derived phylogenies and divergence time estimation studies of the Diptera and the Myrtaceae show that the fly family Fergusoninidae is less than half the age of the Myrtaceae, discounting the hypothesis of cospeciation and coradiation of the fly/nematode mutualism and the plants at the broadest levels. However, cospeciation may have occurred at shallower levels in the phylogeny, following the establishment of the fly/nematode mutualism on the Myrtaceae.
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sex limited association of fergusobia nematodes with female fergusonina flies in a unique australasian mutualism nematoda Neotylenchidae diptera fergusoninidae
Australian Journal of Entomology, 2013Co-Authors: Sonja J. Scheffer, Kerrie A. Davies, Gary S. Taylor, Leigh A. Nelson, Matthew L. Lewis, Robin M Giblindavis, David K. YeatesAbstract:All known species of Fergusonina flies (Fergusoninidae) participate in an obligate mutualism with Fergusobia nematodes (Neotylenchidae). From dissections, it is believed that all female third-instar larvae, pupae and adult female flies carry nematodes internally, while male adults and larvae do not. This observation of sex-limited association was tested using a molecular diagnostic approach. Nematode-specific primers were used for polymerase chain reaction amplification of a portion of the mitochondrial cytochrome oxidase I gene in order to screen DNA extractions from flies for the presence of nematode DNA. Consistent with evidence from dissections, nearly all extractions from adult female flies were positive for nematode DNA, while all DNA extractions from adult male flies were negative. Nearly half of late-instar larvae screened showed evidence of nematode DNA, consistent with the hypothesis that nematodes are only present within females. This paper is the first to use a molecular method to confirm this phenomenon within the Fergusonina/Fergusobia system.
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Sex‐limited association of Fergusobia nematodes with female Fergusonina flies in a unique Australasian mutualism (Nematoda: Neotylenchidae; Diptera: Fergusoninidae)
Australian Journal of Entomology, 2012Co-Authors: Sonja J. Scheffer, Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Leigh A. Nelson, Matthew L. Lewis, David K. YeatesAbstract:All known species of Fergusonina flies (Fergusoninidae) participate in an obligate mutualism with Fergusobia nematodes (Neotylenchidae). From dissections, it is believed that all female third-instar larvae, pupae and adult female flies carry nematodes internally, while male adults and larvae do not. This observation of sex-limited association was tested using a molecular diagnostic approach. Nematode-specific primers were used for polymerase chain reaction amplification of a portion of the mitochondrial cytochrome oxidase I gene in order to screen DNA extractions from flies for the presence of nematode DNA. Consistent with evidence from dissections, nearly all extractions from adult female flies were positive for nematode DNA, while all DNA extractions from adult male flies were negative. Nearly half of late-instar larvae screened showed evidence of nematode DNA, consistent with the hypothesis that nematodes are only present within females. This paper is the first to use a molecular method to confirm this phenomenon within the Fergusonina/Fergusobia system.
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The complete mitochondrial genome of the gall-forming fly, Fergusonina taylori Nelson and Yeates (Diptera: Fergusoninidae)
Mitochondrial DNA, 2011Co-Authors: Leigh A. Nelson, Stephen L. Cameron, David K. YeatesAbstract:The monogeneric family Fergusoninidae consists of gall-forming flies that, together with Fergusobia (Tylenchida: Neotylenchidae) nematodes, form the only known mutualistic association between insects and nematodes. In this study, the entire 16,000 bp mitochondrial genome of Fergusonina taylori Nelson and Yeates was sequenced. The circular genome contains one encoding region including 27 genes and one non-coding A þT-rich region. The arrangement of the proteincoding, ribosomal RNA (rRNA) and transfer RNA (tRNA) genes was the same as that found in the ancestral insect. Nucleotide composition is highly A þ T biased. All of the protein initiation codons are ATN, except for nad1 which begins with TTT. All 22 tRNA anticodons of F. taylori match those observed in Drosophila yakuba, and all form the typical cloverleaf structure except for tRNA-Ser (AGN) which lacks a dihydrouridine (DHU) arm. Secondary structural features of the rRNA genes of Fergusonina are similar to those proposed for other insects, with minor modifications. The mitochondrial genome of Fergusonina presented here may prove valuable for resolving the sister group to the Fergusoninidae, and expands the available mtDNA data sources for acalyptrates overall.
Sonja J. Scheffer - One of the best experts on this subject based on the ideXlab platform.
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An emerging example of tritrophic coevolution between flies (Diptera: Fergusoninidae) and nematodes (Nematoda: Neotylenchidae) on Myrtaceae host plants
Biological Journal of the Linnean Society, 2014Co-Authors: Leigh A. Nelson, Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Sonja J. Scheffer, Matthew F. Purcell, Andrew H. Thornhill, David K. YeatesAbstract:A unique obligate mutualism occurs between species of Fergusonina Malloch flies (Diptera: Fergusoninidae) and nematodes of the genus Fergusobia Currie (Nematoda: Neotylenchidae). These mutualists together form different types of galls on Myrtaceae, mainly in Australia. The galling association is species-specific, and each mutualism in turn displays host specificity. This tritrophic system represents a compelling arena to test hypotheses about coevolution between the host plants, parasitic nematodes and the fergusoninid flies, and the evolution of these intimate mutualisms. We have a basic knowledge of the interactions between the host plant, fly and nematode in this system, but a more sophisticated understanding will require a much more intensive and coordinated research effort. Summaries of the known Fergusonina/Fergusobia species associations and gall type terminology are presented. This paper identifies the key advantages of the system and questions to be addressed, and proposes a number of predictions about the evolutionary dynamics of the system given our understanding of the biology of the mutualists. Future research will profitably focus on (1) gall cecidogenesis and phenology, (2) the interaction between the fly larva and the nematode in the gall, and between the adult female fly and the parasitic nematode, (3) the means by which the fly and nematode life cycles are coordinated, (4) a targeted search of groups in the plant family Myrtaceae that have not yet been identified as gall hosts, and (5) establishment and comparison of the phylogenetic relationships of the host plants, fly species and nematodes. Recently derived phylogenies and divergence time estimation studies of the Diptera and the Myrtaceae show that the fly family Fergusoninidae is less than half the age of the Myrtaceae, discounting the hypothesis of cospeciation and coradiation of the fly/nematode mutualism and the plants at the broadest levels. However, cospeciation may have occurred at shallower levels in the phylogeny, following the establishment of the fly/nematode mutualism on the Myrtaceae.
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The release and unsuccessful establishment of the Melaleuca biological control agent Fergusonina turneri and its mutualistic nematode Fergusobia quinquenerviae
BioControl, 2013Co-Authors: Paul D. Pratt, Robin M. Giblin-davis, Sonja J. Scheffer, Scott Blackwood, Susan A. Wright, Matthew Purcell, Min B. Rayamajhi, Philip W. Tipping, Ted D. CenterAbstract:The Australian tree Melaleuca quinquenervia is an invasive weed in wetland systems of Florida, USA. A biological control program targeting M. quinquenervia resulted in the simultaneous release of the gall-fly Fergusonina turneri and the nematode Fergusobia quinquenerviae . Fergusonina (Diptera: Fergusoninidae) flies are gall formers that exploit plants in the Myrtaceae through a mutualistic association with nematodes in the genus Fergusobia (Tylenchida: Neotylenchidae). With a limited number of founding individuals, a risk-spreading release strategy was employed in 2005 by liberating a total of 1996 adult flies across seven locations in southern Florida. However, all release efforts failed to establish a viable population at any of the sites despite variation in location. In an effort to increase founding population size and improve phenological synchrony, 1,432 individual flies and associated nematodes were released within a single M. quinquenervia stand during the early winter months of 2006–2007. The population of F. turneri and F. quinquenerviae persisted at the field site for between two and three generations and, in accordance with the ca. 2-month generation time, emergence of F generation flies peaked in March, May and July 2007. Population growth rate increased with each succeeding generation up to the F_3, after which the population went extinct. Both the F_1 and F_2 generations expanded spatially when compared to the distribution of their respective parental generations. The field population failed to spread after the F_2 generation, with F_3 generation galls found entirely within the spatial distribution of F_2 galls. The release of F. turneri and F. quinquenerviae represent the first obligate mutualism used in weed biological control. Factors contributing to the failure of these species to establish are discussed.
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sex limited association of fergusobia nematodes with female fergusonina flies in a unique australasian mutualism nematoda Neotylenchidae diptera fergusoninidae
Australian Journal of Entomology, 2013Co-Authors: Sonja J. Scheffer, Kerrie A. Davies, Gary S. Taylor, Leigh A. Nelson, Matthew L. Lewis, Robin M Giblindavis, David K. YeatesAbstract:All known species of Fergusonina flies (Fergusoninidae) participate in an obligate mutualism with Fergusobia nematodes (Neotylenchidae). From dissections, it is believed that all female third-instar larvae, pupae and adult female flies carry nematodes internally, while male adults and larvae do not. This observation of sex-limited association was tested using a molecular diagnostic approach. Nematode-specific primers were used for polymerase chain reaction amplification of a portion of the mitochondrial cytochrome oxidase I gene in order to screen DNA extractions from flies for the presence of nematode DNA. Consistent with evidence from dissections, nearly all extractions from adult female flies were positive for nematode DNA, while all DNA extractions from adult male flies were negative. Nearly half of late-instar larvae screened showed evidence of nematode DNA, consistent with the hypothesis that nematodes are only present within females. This paper is the first to use a molecular method to confirm this phenomenon within the Fergusonina/Fergusobia system.
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Sex‐limited association of Fergusobia nematodes with female Fergusonina flies in a unique Australasian mutualism (Nematoda: Neotylenchidae; Diptera: Fergusoninidae)
Australian Journal of Entomology, 2012Co-Authors: Sonja J. Scheffer, Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Leigh A. Nelson, Matthew L. Lewis, David K. YeatesAbstract:All known species of Fergusonina flies (Fergusoninidae) participate in an obligate mutualism with Fergusobia nematodes (Neotylenchidae). From dissections, it is believed that all female third-instar larvae, pupae and adult female flies carry nematodes internally, while male adults and larvae do not. This observation of sex-limited association was tested using a molecular diagnostic approach. Nematode-specific primers were used for polymerase chain reaction amplification of a portion of the mitochondrial cytochrome oxidase I gene in order to screen DNA extractions from flies for the presence of nematode DNA. Consistent with evidence from dissections, nearly all extractions from adult female flies were positive for nematode DNA, while all DNA extractions from adult male flies were negative. Nearly half of late-instar larvae screened showed evidence of nematode DNA, consistent with the hypothesis that nematodes are only present within females. This paper is the first to use a molecular method to confirm this phenomenon within the Fergusonina/Fergusobia system.
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The nematode genus Fergusobia (Nematoda: Neotylenchidae): molecular phylogeny, descriptions of clades and associated galls, host plants and Fergusonina fly larvae
Zootaxa, 2010Co-Authors: Kerrie A. Davies, Robin M. Giblin-davis, Gary S. Taylor, Sonja J. Scheffer, W. Kelley ThomasAbstract:Collection data and biological information is presented on the genus Fergusobia (Nematoda: Neotylenchidae) from Australasia, India and The Philippines, an emended diagnosis of the genus is presented, and its putative phylogeny is discussed based on molecular and morphological evidence. About 20 clades have been found, and are outlined, including information on nematode and fly morphology; plant host species and distribution. Fly morphology, particularly the structure of the dorsal shield of third stage larvae, is congruent with the clades of nematodes, suggesting coevolution. However, little evidence of coevolution between the fly/nematode association and their host plants is apparent: host-switching appears to have been common, although host-specificity is stringent among most clades. A key to the species and morphospecies of nematodes collected from Corymbia, Angophora, Metrosideros, Syzygium, narrow-leaved Melaleuca, and Eucalyptus is presented.