Rev: 11/01/2022

  Classification Biology and Ecology
Morphology and Anatomy Life Cycle
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          Fergusobia Currie, 1937

Type species: Anguillulina (Fergusobia) tumifaciens Currie 1937

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Morphology and Anatomy:


  • Tylenchid stylet
  • Esophageal glands very large, occupying 50-70% of body width and up to 50% of body length.
  • Females monodelphic, prodelphic
  • Males monorchic; bursa peloderan, membranous, difficult to see; no gubernaculum.




Body size range for the species of this genus in the database - Click:
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Although the biology of this genus, and in fact, the whole family Neotylenchidae, is poorly known, represenatives of the family are considered to have alternartive life cycles, probably depending on resource availability, one that is fungus- or plant-feeding generation and another that is parasitic in the insect haemocoel (Siddiqi, 2000).

The relationship between flies of the genus Fergusonina and nematodes of the genus Fergusobia Currie, 1937 is considered mutualistic.The flies with the associated nematodes induce multilocular shoot bud galls, also also distinguished as terminal and axial leaf bud galls (Davies et al., 2013). The galls are especially evident in trees on the genus Eucalyptus and other trees of the family Myrtaceae. Several species of Fergusobia have been recorded and each combination of fly species and nematode species seems to result in a specific gall morphology (Davies et al., 2013).

Pre-parasitic stages of the nematode infect larvae and pupae of the flies and develop into parasitic females which are found in the haemocoel of adult flies. Males are usually found in the galled plant tissue.


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Biology and Ecology:

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Life Cycle:

The mutualistic association between flies of the genus Fergusonina and nematodes of the genus Fergusobia Currie (Tylenchida: Neotylenchidae) leads to the formation of galls of various forms (flower bud, axial leaf bud, apical (or terminal) leaf bud, leaf and stem galls) on plants in the family Myrtaceae.

Several life forms can be recognized: parthenogenetic females and males occur in plant tissue. Pre-parasitic forms occur in plant galls and enter larvae and pupae of flies.

Parasitic forms in the adult fly haemocoel.  Esophagus and intestine degenerate, cuticle may be lacking, ovary long and convoluted.

The life cycle is complex but, in simplified form,  is as follows:

Fly eggs and juvenile nematodes are oviposited in the undifferentiated meristematic tissue of a plant.  Gall formation is induced, presumably intitiated by secretions from the nematodes.. Fly larvae hatch from eggs and pass through tthree instars befoer pupating. Nematode eggs oviposited by the flies hatch to juveniles that develop, while feeding on plant tissue, into parthenogenetic female adults.  The parthenogenetic females produce juveniles that develop into and amphimictic generation of males and females. Mating occurs and the resulting eggs develop to pre-parasitic females that penetrate the tissues of the third instar fly larvae.  As the adult flies emerge from the pupae, the parasitic adult nematodes occupy the haemocoel as parasites.  They deposit eggs which develop into juveniles that congregate around the fly ovipositer so that they are deposited with fly eggs into new plant tissue (Davies et al., 2013; Nelson et al., 2014; Taylor and Davies, 2010)..

Fergusobia life cycle

Life cycles of Fergusonina flies and Fergusobia nematodes (from Nelson et al., 2014).. 


For Ecophysiological Parameters for this genus, click 
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Ecosystem Functions and Services:


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Currie, G.A. 1937.  Galls on Eucalyptus trees. A new type of association between flies and nematodes. Proceedings Linnaean
Society of New South Wales, 62, 147–174.

Davies, K.A., Giblin-Davis, R.M., Ye, W., Wita, L., Taylor, G.S., Thomas, W.K. 2013. Nematodes from galls on Myrtaceae. V. Fergusobia from large multilocular shoot bud galls from Angophora and Eucalyptus in Australia, with descriptions of six new species. Zootaxa 3741:101-140.

Nelson, L., Davies, K., Scheffer, S., Taylor, G., P, M., Giblin-Davis, R.,  Thornhill, A., Yeates, D. D. 2014.. An emerging example of tritrophic coevolution between flies (Diptera: Fergusoninidae) and nematodes (Nematoda: Neotylenchidae) on Myrtaceae host plants. Biological Journal of the Linnean Society. 111. 10.1111/bij.12237.

Siddiqi, M. R. 2000. Tylenchida: Parasites of plants and insects, 2nd ed. Wallingford: CABI Publishing.

Taylor, G.S. and Davies, K.A. 2010. The gall fly, Fergusoninalockharti Tonnoir (Diptera: Fergusoninidae) and description of its associated nematode, Fergusobiabrittenae sp. nov. (Tylenchida: Neotylenchidae), Journal of Natural History, 44:15-16, 927-957, DOI: 10.1080/00222930903383545

Wood, F.H. 1973. Nematode feeding relationships: Feeding relationships of soil-dwelling nematodes. Soil Riol. Biochem. 5: 593-601.

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Copyright © 1999 by Howard Ferris.
Revised: November 01, 2022.