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New Zealand beech bud-mite: Acalitus morrisoni

By N A Martin (2017)

Classification

Phylum:
Arthropoda
Class:
Arachnida
Subclass:
Acari
Order:
Trombidiformes
Suborder:
Prostigmata
Superfamily:
Eriophyoidea
Family:
Eriophyidae
Subfamily:
Eriophyinae
Tribe:
Aceriini
Scientific Name:
Acalitus morrisoni Manson 1970
  • Drawing of side view of New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). The adult mite is very tiny, 0.138-0.186 mm long. Image: Dave Manson © Drawing published in Fauna of New Zealand 1984, vol. 5, fig. 86
    Drawing of side view of New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). The adult mite is very tiny, 0.138-0.186 mm long. Image: Dave Manson © Drawing published in Fauna of New Zealand 1984, vol. 5, fig. 86
  • New and old bud galls on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Tim Holmes © Plant & Food Research
    New and old bud galls on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Tim Holmes © Plant & Food Research
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Common Names

New Zealand beech bud-mite, Nothofagus big bud mite
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Biostatus and Distribution

This endemic gall mite is found in the North and South Islands of New Zealand on its host plants, southern beech trees in the genus Fuscospora (Nothofagaceae), black beech, hard beech, mountain beech and red beech. Feeding by the mites induces enlarged buds. The northern most populations of Fuscospora species are in Auckland, in forest remnants on the north side of the Waitemata harbour.

Conservation status: Widespread, not threatened.

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Life Stages and Annual Cycle

This gall mite is very tiny. Adult mites are about 0.138-0.186 mm long. The adult mite is like a tiny white cow’s horn with two pairs of legs at the wide end of the horn. Adult female mites lay tiny spherical eggs. The larva that hatches from an egg looks like a tiny adult. The mite larva moults (changes skin) into a nymph. There is one nymphal stage that also looks like a small adult. The last juvenile stage moults into an adult mite. There are males and females.

Walking
The mite uses its legs for walking, but it can also hold on to the plant with the tip of its abdomen, which acts as a sucker.

Feeding and inducing the gall
The mites have pointed mouth parts that puncture the surface cells of young leaves and gall tissue from which they suck up the cell sap. During feeding, the mites may inject saliva into the plant. When mites feed in a leaf bud, the cells of the bud scales in the immediate area multiply forming a hairy spongy tissue in which the mites live and breed. The bud scales also grow bigger forming a large round bud. The enlarged bud protects the gall mites from predators and adverse weather.

Dispersal to new stems and new plants
When the plant grows new shoots, adult female mites disperse to these and their feeding induces the formation of new galls. It is presumed mites walk from the old bud galls to new buds.

When this gall mite colonises new plants or branches, it is unlikely that mites walk all the way. It is believed that most mites are dispersed by wind. Some species of mite climb to prominent places on plants and stand waiting for a gust of wind to take them away.

  • Two halves of a bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the white spongy tissue in which the mites live.  Image: Tim Holmes © Plant & Food Research
    Two halves of a bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the white spongy tissue in which the mites live. Image: Tim Holmes © Plant & Food Research
  • Section through a bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live.  Image: Tim Holmes © Plant & Food Research
    Section through a bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live. Image: Tim Holmes © Plant & Food Research
  • Section through a bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live. Image: Tim Holmes © Plant & Food Research
    Section through a bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live. Image: Tim Holmes © Plant & Food Research
  • Section through a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live.  Image: Tim Holmes © Plant & Food Research
    Section through a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live. Image: Tim Holmes © Plant & Food Research
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Recognition

This mite requires special procedures and taxonomic knowledge to identify specimens. However, its presence on a plant can be recognised by plant damage symptoms. This species of mite is the only one known to induce large bud galls on trees in the genus Fuscospora (Nothofagaceae) species in New Zealand. Bud galls on other species of plant are caused by other species of mite or other insects.

  • Large bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Tim Holmes © Plant & Food Research
    Large bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Tim Holmes © Plant & Food Research
  • Old bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Tim Holmes © Plant & Food Research
    Old bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Tim Holmes © Plant & Food Research
  • Large bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Tim Holmes © Plant & Food Research
    Large bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Tim Holmes © Plant & Food Research
  • Large bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the bud scales being pushed apart at the top of the gall.  Image: Tim Holmes © Plant & Food Research
    Large bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the bud scales being pushed apart at the top of the gall. Image: Tim Holmes © Plant & Food Research
  • Large bud gall on mountain beech, Fuscospora cliffortioides (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Nicholas A. Martin © Plant & Food Research
    Large bud gall on mountain beech, Fuscospora cliffortioides (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Nicholas A. Martin © Plant & Food Research
  • Large bud gall on black beech, Fuscospora solandri (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Nicholas A. Martin © Plant & Food Research
    Large bud gall on black beech, Fuscospora solandri (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Nicholas A. Martin © Plant & Food Research
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Natural Enemies

No natural enemies of this mite have been recorded, but predatory mites may feed on these mites.

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Host Plants

New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), lives in enlarged buds on four species of Fuscospora (Nothofagaceae) growing in New Zealand. Mites feeding in young leaf buds induce the cells of the bud scales in the area to multiply forming hairy spongy tissue in which the mites live and breed. The bud scales also grow bigger forming a large round bud in contrast to the normal narrow pointed buds. The mites appear to colonise a terminal bud in the current year’s new growth. The enlarged bud has a short wide stem with what appears to be scars of bud scales. This indicates that as the mite colony grows and new bud scales grow as the outer scales die and fall off.

Table: Host plants of the New Zealand beech bud-mite, Acalitus morrisoni (Acari: Prostigmata: Eriophyidae) from Plant-SyNZ database (26 February 2017). The reliability score shows the quality of evidence for the host association (1-10, 10=high).
Common Name(s)Scientific NameFamilyReliability IndexBiostatus
Mountain beech, Tawhai raurikiFuscospora cliffortioides (Hook.f.) Heenan & SmissenNothofagaceae10endemic
Red beech, Hutu, Hututawai, Raunui, Tawai, TawhaiFuscospora fusca (Hook.f.) Heenan & SmissenNothofagaceae10endemic
Black beech, Tawhai raurikiFuscospora solandri (Hook.f.) Heenan & SmissenNothofagaceae10endemic
Hard beech, Hutu, Hututawai, Tawhai raunuiFuscospora truncata (Colenso) Heenan & SmissenNothofagaceae10endemic
  • Large bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Tim Holmes © Plant & Food Research
    Large bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Tim Holmes © Plant & Food Research
  • Large bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Tim Holmes © Plant & Food Research
    Large bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Tim Holmes © Plant & Food Research
  • Section through a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Tim Holmes © Plant & Food Research
    Section through a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Tim Holmes © Plant & Food Research
  • Old bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Tim Holmes © Plant & Food Research
    Old bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Tim Holmes © Plant & Food Research
  • Section through a bud gall on Hard beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the white spongy tissue in which the mites live.  Image: Tim Holmes © Plant & Food Research
    Section through a bud gall on Hard beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the white spongy tissue in which the mites live. Image: Tim Holmes © Plant & Food Research
  • Large bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the bud scales being pushed apart at the top of the gall.  Image: Tim Holmes © Plant & Food Research
    Large bud gall on Red beech, Fuscospora fusca (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the bud scales being pushed apart at the top of the gall. Image: Tim Holmes © Plant & Food Research
  • Large bud gall on mountain beech, Fuscospora cliffortioides (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Nicholas A. Martin © Plant & Food Research
    Large bud gall on mountain beech, Fuscospora cliffortioides (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Nicholas A. Martin © Plant & Food Research
  • Large bud gall on mountain beech, Fuscospora cliffortioides (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Nicholas A. Martin © Plant & Food Research
    Large bud gall on mountain beech, Fuscospora cliffortioides (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Nicholas A. Martin © Plant & Food Research
  • Large bud gall on black beech, Fuscospora solandri (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae).  Image: Nicholas A. Martin © Plant & Food Research
    Large bud gall on black beech, Fuscospora solandri (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae). Image: Nicholas A. Martin © Plant & Food Research
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Additional Information

Eriophyid gall mites belong to the super family Eryiophyoidea. These mites have several unusual features. For example, though most mites have four pairs of legs like spiders, Eriophyoid mites have only two pairs of legs. Many of these mites can induce host plants to form galls, some of which may be very complex. Some species of these mites can transmit plant viruses that may cause plant diseases and plant death.

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Information Sources

Manson DCM 1984. Eriophyinae (Arachnida: Acari: Eriophyoidea). Fauna of New Zealand 5: 1-123.

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Acknowledgements

The New Zealand Plant & Food Research Institute Limited (Plant & Food Research) for permission to use photographs.

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Other Images

  • Section through a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live.  Image: Tim Holmes © Plant & Food Research
    Section through a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live. Image: Tim Holmes © Plant & Food Research
  • Section through a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live.  Image: Tim Holmes © Plant & Food Research
    Section through a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live. Image: Tim Holmes © Plant & Food Research
  • Outer scales partly removed from a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live.  Image: Tim Holmes © Plant & Food Research
    Outer scales partly removed from a bud gall on Hard beech, Fuscospora truncata (Nothofagaceae) induced by New Zealand beech bud-mite, Acalitus morrisoni (Acari: Eriophyidae), note the spongy tissue in which the mites live. Image: Tim Holmes © Plant & Food Research
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Suggested Citation

Martin NA. 2017. New Zealand beech bud-mite - Acalitus morrisoni. Interesting Insects and other Invertebrates. New Zealand Arthropod Factsheet Series Number 75. http://nzacfactsheets.landcareresearch.co.nz/Index.html. Date Accessed. ISSN 1179-643X.

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