Australasian Arachnology 77

23 Pages·2007·0.36 MB·English

by  Volker W. Framenau

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Australasian Arachnology No. 77 Page 2
THE AUSTRALASIAN ARTICLES
ARACHNOLOGICAL
SOCIETY The newsletter depends on your
contributions! We encourage articles on a
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arachnids of the Australasian region. events or behavioural observations.

MEMBERSHIP Please send articles to the editor:

Membership is open to amateurs, Volker Framenau
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Australasian Arachnology No. 77 Page 3
EDITORIAL Lynne Forster
17 King St
Sandy Bay, Tas 7005
You could easily call this new issue of Australia
Australasian Arachnology a special ‘mite [email protected]
edition. Putting this newsletter together, I
learned a lot about mites, and this is what
Bruce Halliday, the authors of our feature Change of Address
article apparently had in mind. Thanks
Bruce, for this great introduction to mite Karen Edward
systematics and biology! I will upload this School of Animal Biology
article onto our website soon to make it University of Western Australia
available for a wider audience Crawley, WA 6009
(www.australasian-arachnology.org). Australia
[email protected]
I have not received any articles for the next
issue, so please sharpen your pencils and Sydney Jordan
send some articles for Australasian 21 Undara Ave
Arachnology 78 which is scheduled for Buddina, Qld 4575
release in September. Australia
[email protected]
I have not quite packed my bags yet for
Brazil, but I am looking forward to catching ----------------------------
up with many of our readers at this year’s
17th International Congress of Arachnology LIBRARY
in São Pedro
UPDATE
(http://www.ib.usp.br/~ricrocha/ISA17/ISA1

7.htm).
Our librarian Jean-Claude Herremans
Cheers, Volker received reprints of publications from
Helen Smith, Wilson Lourenco, and Herb

Levi (via Laura Leipensperger). Thanks a
lot to Helen, Wilson and Herb!
MEMBERSHIP
All our members should consider
UPDATES
donating reprints of their publications to
our library, which is an important source
New Members
of information for our members without
Tenille Nielson access to a professional library!
39 Gregory Terrace
I will include an updated list of our
Kuranda, Qld 4881
library holdings in one of the next
Australia
newsletters and will hopefully be able to
[email protected]
upload this list onto our website at some

stage as well.
Australasian Arachnology No. 77 Page 4
than those devoted to arachnology. This
Mites are arachnids too
is a reflection of the fact that mites have
much in common with insects, especially
Bruce Halliday, CSIRO Entomology, as pests of cultivated plants and crops.
GPO Box 1700, Canberra ACT 2601, The purpose of this general article is to
[email protected] make mites more accessible to
arachnologists who do not have specialist
Introduction knowledge of acarology.

Almost all arachnids are predators. The
only group of arachnids that has managed Classification of the Acari
to break out of the predatory habit on a
large scale is the mites, which have Mites are the smallest arachnids in terms
diversified into an extraordinary range of of body size (although the biggest mites
niches. Many are still predatory, but there are bigger than the smallest spiders).
are also thousands of species of plant Adults of most species of mites are in the
feeders, fungivores, saprophytes, pollen range 300–800 micrometres in body
and nectar feeders, microbial filter length. Mites are also distinguished from
feeders, and internal and external other arachnids by the complete absence
parasites on a wide range of vertebrates of body segmentation, and by the
and invertebrates. Others have a complex fundamental organisation of the body.
life cycle, in which parasitism and There is no division of the body into
predation occur at different life stages cephalothorax and abdomen. Instead, the
within a species, and others are mouthparts and associated sensory
omnivorous. Mites occur in soil and structures form a discrete anterior
decomposing organic matter, in fresh structure known as the gnathosoma. All
water and sea water, high in the air, deep the rest of the animal's anatomical
in the oceans, on and in the bodies of structures, including leg bases, central
other animals, and on plants of all kinds. nervous system, ocelli when present, and
This ecological diversity has been reproductive and digestive systems, are
accompanied by a bewildering degree of all fused into a single unsegmented body
morphological diversity. Their called the opisthosoma.
diversification has in turn been reinforced
Many systems of higher classi-
by their small body size, which allows
fication have been used for the mites,
them to occupy minute spaces, and
and many different names have been
makes it necessary to use specialised
used for the higher taxa of mites at all
techniques for their observation and
levels. In the most modern classification,
taxonomic study. All of these factors
the mites are placed in the class Acari,
conspire to create an artificial division
within which there are two superorders.
between acarologists and other
The superorder Parasitiformes includes
arachnologists, to the extent that mites
order Opilioacarida, order Holothyrida,
have their own literature, their own
order Ixodida, and order Mesostigmata.
anatomical terminology, and their own
The superorder Acariformes includes
national and international conferences.
order Trombidiformes and order
One of the outcomes of this division is
Sarcoptiformes (Walter 2006; Krantz and
that research papers on mites are more
Walter 2007).
likely to be found in entomology journals
Australasian Arachnology No. 77 Page 5
The order Opilioacarida includes a Australia, all in the family Allothyridae
single family of large mites ( ≥ 1 mm) that (van der Hammen 1983), but many other
have many character states that are undescribed species have been collected
considered to be ancestral (Krantz 1978). and await study.
They are widespread but rare in semi-arid
There are about 80 known species of
climates, where they are found under
ticks, order Ixodida, in Australia (Roberts
stones. An unidentified species has been
1970; Keirans et al. 1994, 1996). They are
collected in Kakadu National Park, where
all blood-feeding parasites of mammals,
it feeds on mites and insects, as well as
reptiles and birds, and are characterised
fungal hyphae and pollen (Walter and
by mouthparts with a large number of
Proctor 1998).
backward-directed hooks that are inserted
into the host for feeding. The best known
Australian species is the paralysis tick
Ixodes holocyclus , which can be
dangerous to the health of humans and
dogs (Anonymous 2003).
The order Mesostigmata (e.g. Fig. 1)
includes about 80 families of relatively
large mites with adult body lengths in the
range 300–3000 m m. They are
characterised by a series of leathery
sclerotised plates that cover the body, and
by a pair of laterally-placed stigmata,
which are the external openings of the
tracheal system. Most are predatory, while
a few also feed on pollen and nectar.
They occur in a wide range of habitats,
including soil and litter, but are also
Fig. 1: Species of Asca (Mesostigmata:
abundant in dung, carrion, compost, and
Ascidae) are recognised by the pair of
in the nests of vertebrates. Many are
prominent horns or protuberances on
beneficial, contributing to the control of
the posterior margin of the body.
insect and mite pests. Notable among
About 80 species occur in leaf litter
these is the arboreal family Phytoseiidae,
and moss world-wide, where they prey
which are widely used in the control of
on mites, insect eggs and larvae, and
spider mites that damage crop plants
nematodes
(Gerson et al. 2003). Many families are
Photograph: D.E. Walter
parasites of vertebrates, including families
The order Holothyrida includes large such as the Dermanyssidae and Macro-
mites (≥ 2 mm) with a heavily sclerotised nyssidae, which parasitise domesticated
and highly-arched body, which feed animals and can attack humans
readily on dead arthropods (Walter and (Southcott 1976). Many families have
Proctor 1998). The order includes about associations with insects. These
25 species in three familes, and has a relationships vary from simple phoresy for
Gondwanan distribution. Only three the purpose of dispersal, to much closer
species have been described from relationships in which the mite has
specialised morphological and be-
Australasian Arachnology No. 77 Page 6
havioural adaptations at different stages the predatory families Bdellidae and
of the life cycle that are involved in its Cunaxidae, whose members have been
interaction with its insect carrier. Sexual used as biological control agents of mite
dimorphism is common, in the general pests in pastures and horticulture (Gerson
arrangement of body sclerites, in et al . 2003). The superfamily
modification of the legs of the male which Eriophyoidea includes thousands of
are used in fighting, and in structures on species of plant parasites, many of which
the male chelicerae that are used in are important crop pests, either through
sperm transfer. the damage they cause directly, or
through their role as vectors of plant
viruses. The cohort Anystina includes
beneficial predatory species among its 6
families. The cohort Parasitengona
includes hundreds of species, most of
which have a complex life cycle in which
the larval stage is a parasite and later
stages are free-living predators. Larval
Trombiculidae are parasites of
vertebrates, commonly known as
chiggers, the Australian fauna of which
has been catalogued by Domrow and
Lester (1985). Several families including
Fig. 2: Stereotydeus (Prostigmata: Erythraeidae and Trombidiidae have
Penthalodidae) is a genus of brightly larvae that are parasitic on insects, and
coloured and ornamented mites found terrestrial adults that are often called red
in moss and leaf litter in the Southern velvet mites. Only a handful of species
Hemisphere, including Antarctica. have been reared in captivity to allow the
Little is known of their biology, but they adults and larvae to be correlated. A
are believed to be predatory. further group of families is collectively
Photograph: D.E. Walter known as “water mites” or Hydracarina.
The larvae of these groups are mostly
The order Trombidiformes , also parasites of aquatic insects, and the
known as Prostigmata (e.g. Fig. 2), is the adults are often large brightly coloured
most diverse of the major mite groups, in mites that can be found swimming in fresh
terms of the number of species it water. Harvey (1998) reviewed the
contains, and in the range of Australian fauna, which includes over 400
morphological and behavioural variation known species spread over 24 families. A
they display. They are called Prostigmata further important group of Prostigmata
because the stigmata are usually located includes the spider mites of the family
at the base of the mouthparts, or on the Tetranychidae. These are damaging pests
anterior margin of the opisthosoma. The of crop plants, especially in horticulture,
cohort Eupodina includes the family but the Australian fauna has never been
Penthalaeidae, in which the redlegged systematically studied. The cohort
earth mite Halotydeus destructor and blue Heterostigmata includes about 12 families
oat mite Penthleus major are serious of small to minute mites, many of which
pests of crops and pastures in southern have close associations with insects. The
Australia. The same cohort also includes existence of intra-species polymorphism
Australasian Arachnology No. 77 Page 7
and often bizarre morphologies has meant for dispersal. The Astigmata also includes
that the taxonomy of these groups is very hundreds of species of feather mites that
unstable, even at the family level. A occur on birds, but the Australian fauna of
diverse range of families of Prostigmata these groups has never been studied in
that are parasites of vertebrates have any depth. Domrow (1992) catalogued
been catalogued by Domrow (1991). 204 species of Astigmata in 24 families
that parasitise Australian vertebrates or
The order Sarcoptiformes includes
occur on their bodies. These include the
over 130 families of soil mites in the
mites that cause such diseases as
suborder Oribatida, commonly known as
scabies (Sarcoptes scabiei), scaly leg of
oribatids. These are mostly slow-moving,
chickens (Knemidokoptes mutans ) and
heavily sclerotised mites that are most
several types of mange in domestic
abundant and diverse in the upper layers
animals (e. g. the ear mite of dogs and
of the soil and the associated organic
cats, Otodectes cynotis).
litter. They feed on dead plant material

and the associated microfungi, and most
The Australian mite fauna
have very robust heavily sclerotised
chelicerae, adapted for crushing fungal A recent review estimated that there are
mycelium. Their role in feeding on 48,000 named and described species of
decaying plant material means that they mites world-wide (Halliday et al. 2000),
are very important in maintaining and and extrapolated that number to speculate
enhancing soil fertility, and they have that over half a million species of mites
been the subject of a substantial exist in total. In Australia, 2,871 described
ecological literature for that reason. A few species in 304 families had been
species are beneficial in more direct documented to April 2000 (Halliday
ways, contributing to the control of pest 2001a), and the total number of species
mites, nematodes, and weeds. Others are that exist is likely to exceed 20,000
themselves pests that damage crop plants (Halliday 2001b). Significant habitats such
(Colloff and Halliday 1998). Some act as as the rainforest canopy remain largely
intermediate vectors of tapeworm unexplored, and diverse faunas await
parasites of livestock (Denegri 1993). The discovery there (Walter et al. 1998). Major
Australian fauna was catalogued by groups have never been studied in a
Colloff and Halliday (1998), who listed 340 systematic way, and are likely to contain
described species. large numbers of undescribed species.
Conspicuous among these are the feather
The order Sarcoptiformes also
mites, with possibly 2,000 unknown
includes the cohort Astigmata, which until
Australian species, the plant parasites of
recently has been given equal rank with
the family Eriophyidae, with posssibly
the Oribatida. The Astigmata includes the
5,000 unknown species, and the
common flour mites and cheese mites
Halacaridae (Prostigmata) and Uropodina
that infest stored food and which damage
(Mesostigmata), each of which is likely to
stored grain on an industrial scale, the
yield hundreds of species (Halliday
house dust mites that cause allergy and
2001b). A single expedition by a single
asthma in humans, and a wide range of
acarologist revealed 200 new species of
fungivorous and saprophytic species in
aquatic mites (Cook 1986), and similar
soil. Many of these species have a
results are likely when serious attention is
specialised immature form known as the
hypopus, which attaches itself to insects
Australasian Arachnology No. 77 Page 8
paid to other groups that have previously 1998), Nothogynidae (Walter and Krantz
been neglected. 1999), Saltiseiidae (Walter 2000), and
Uronyssidae and Teranyssidae (Halliday
There are no general estimates of the
2006).
level of endemism in the Australian mite

fauna. Colloff and Halliday (1998)
Acarology in Australia
documented 340 species of Australian
Oribatida, including 256 that were The history of the science of acarology in
described from Australian type localities Australia has been reviewed in some
and had not been recorded elsewhere. depth (Southcott 1982; Halliday 2001b).
Many distinctive elements of the The main trends have been research on
Australian mite fauna are found in those agricultural pest mites and their natural
mite groups that have intimate enemies, on mite parasites of vertebrates,
associations with other components of our including humans and domesticated
flora and fauna. The mites parasitic on animals, on mites that have various types
vertebrates have been catalogued in of association with Australian insects, and
detail (Domrow 1988, 1991, 1992; on the native mite fauna in agricultural
Domrow and Lester 1985), and all these and forest soils.
parasitic groups include species and
There is no single comprehensive mite
genera that are found only on Australian
collection in Australia. Instead, there are
native vertebrate hosts. The ticks were the
collections in a number of institutions
subject of a monograph by Roberts
where the research effort has historically
(1970), but new species are still being
been concentrated. The South
found on native vertebrates (e.g. Keirans
et al. 1994, 1996). The same is likely to Australian Museum in Adelaide has had
apply to the Australian feather mites, the longest history of research in truly
which are almost completely unstudied. Australian mite taxonomy. Research there
Plant-parasitic groups that have some began with the work of Stanley Hirst, who
degree of host specificity are also likely to was publishing from about 1912 to 1930,
include many endemic species and on a very wide range of mite groups.
genera, especially the Eriophyidae and Herbert Womersley worked in the South
Tetranychidae. Among the free-living Australian Museum from 1933 to 1962
groups in forest litter, Australia has a rich (Southcott 1964). His work includes
and distinctive fauna of Holothyrina and important publications on chiggers
predatory Mesostigmata that have not (Trombiculidae), including the vector of
been adequately studied. The Uropodina scrub typhus; on other parasites of
are now being examined closely for the vertebrates; on beneficial predatory
first time, and are yielding many surprises groups; on pasture pest mites and their
(e.g. Błoszyk et al. 2005; Dylewska et al. natural enemies; and on the families of
2006). Mesostigmata that dominate the fauna of
soil and forest litter in this country. No
The rapid rate of change in the modern study of Australian taxonomic
classification of Australian mites is clearly acarology is complete without constant
demonstrated by the fact that new families reference to Womersley’s publications
are still being described. Recent and collections. Acarology at the South
examples are Eriorhynchidae (Qin and Australian Museum continued with Ron
Halliday 1997), Heatherellidae (Walter Southcott, who published hundreds of
1997), Dasythyreidae (Walter and Gerson papers from about 1945 to 1999 on a
Australasian Arachnology No. 77 Page 9
wide range of subjects. He is best known with many other groups of insects, but
for his major works on trombidiform mites, only a minority of these have been
especially the Erythraeidae (Southcott documented. There is a representative
1961), Trombidiidae (Southcott 1986) and collection of marine mites of the family
Microtrombidiidae (Southcott 1994). The Halacaridae (e.g. Otto 1994, 1999d), and
Adelaide tradition was continued by David some families of oribatids are represented
Lee, who published important revisionary (Niedbala 1987; Niedbala and Colloff
work on Mesostigmata (e.g. Lee 1970) 1997). There is a large collection of ticks,
and Oribatida (e.g. Lee 1992, 1993). most importantly those documented by
Roberts (1970). The mite fauna of forest
The Agricultural Scientific
litter is huge and diverse, and a few
Collections Unit at the New South
preliminary studies of ANIC collections of
Wales Department of Primary these groups have appeared (Halliday
Industries, Orange Agricultural 1997; Halliday et al. 1998). The collection
Institute, Orange NSW, has an important also houses hundreds of unsorted
collection of predatory Phytoseiidae samples of fauna from forest litter and
created by Eberhard Schicha (Schicha other habitats, and these contain very rich
1987; Schicha and Corpuz-Raros 1992), collections of mites that await study.
which includes many type specimens.
There are also collections of other groups The Queensland Museum in
of plant mites including Tenuipalpidae, Brisbane houses a collection of
Tetranychidae and Pygmephoridae. approximately 16,000 slides and 2,500
These are now being supplemented by a vials of mites. By far the most significant
growing collection of plant parasites of the portion of this collection is Bob Domrow’s
family Eriophyidae (Knihinicki and Boczek collection of about 13,000 slides and
2002, 2003). 1,000 tubes of mites from mammals, birds
and reptiles, which was originally housed
The mite collection in the Australian at the Queensland Institute of Medical
National Insect Collection in Canberra, Research. Only a small portion of these
has grown as a result of a series of slides have been registered, and even
research projects on mite and insect pests fewer databased. The remainder of the
and their natural enemies. A long term collection comprises about 1,000 vials of
program of research on red-legged earth mixed mites (mostly from pitfall trap
mites has included taxonomic studies of samples), 500 vials of ticks, and another
the pest and its relatives (Qin and Halliday 3,000 slides that have a strong focus on
1996a, 1996b, 1997), and families of the Trigynaspida, Podapolipidae and
predatory mites that occur in the same Tetranychidae (e.g. Seeman and Nahrung
habitats, especially Anystidae and 2005). The Entomology section also holds
Bdellidae (Wallace and Mahon 1973, a collection of 1,270 Berleseates, mostly
1976; Otto 1999a, 1999b, 1999c; Halliday from the wet forests of coastal
2005). The result was the formation of Queensland, which are a rich source of
large collections of plant-feeding and unstudied mites.
predatory mites from pastures, both from
The University of Queensland Insect
Australia and overseas. The ANIC also
includes large collections of mites Collection houses a very substantial
associated with dung and dung beetles collection of mites, which was largely built
(e.g. Wallace 1986; Halliday 2000) and up through the efforts of Dave Walter.
Most of the major families are
Australasian Arachnology No. 77 Page 10
represented, with strength in soil and litter The Western Australian Museum in
Mesostigmata, predatory Phytoseiidae Perth has strong collections of mites in a
(Beard 2001), plant-feeding spider mites range of families. There is an important
(Tetranychidae) and false spider mites collection of types of mites parasitic on
(Tenuipalpidae), and some of the lesser vertebrates, mostly described in a series
known families of Prostigmata, including of papers that appeared in Records of the
aquatic families. There is also a good Western Australian Museum in 1978–
range of Oribatid families, and both free- 1981, under the general title Parasites of
living and parasitic Astigmata. About 25% Western Australia (e.g. Fain and
of the collection has been catalogued in Lukoschus 1979, 1981). There is also a
the UQIC database. An outline of this large collection of marine mites of the
catalogue is available at family Halacaridae, especially the species
http://www.sib.uq.edu.au/acarina- from Rottnest Island (e.g. Bartsch 1993,
catalogue, and contains links to a number 1994), a collection of water mites from
of spectacular mite images. Western Australia (Harvey 1988, 1996), a
good collection of ticks, and a large
The Museum of Victoria mite
quantity of unsorted mite material.
collection in Melbourne includes a

substantial collection of water mites from
Further reading
Victoria. It includes types and identified
material (Harvey 1990a; Harvey and Cook There are several excellent modern
1988), as well as unidentified water mites textbooks of acarology. Evans (1992) is a
from multidisciplinary surveys of river comprehensive review of mite anatomy,
faunas. There are also significant holdings morphology, and behaviour, with detailed
of unidentified and sorted and unsorted coverage of the structure and function of
mites from soils in a range of Victorian the integument, musculature, circulatory,
forests and woodlands, collected in pitfall respiratory and sensory systems, feeding,
traps during biodiversity and digestion, physiology, reproduction and
environmental management surveys. mating, and development and dispersal.
There is also a summary of classification,
Acarology at the Australian Museum
with keys to higher taxa down to the
(Sydney) began with Rainbow (1906), the
superfamily level. Walter and Proctor
first attempt to produce an overview of the
(1999) thoroughly explores the
Australian mite fauna, and some of
evolutionary origin of mites, the
Rainbow's types are still in the collection.
morphology and systematics of the major
The tick collection there includes types of
mite groups, and the life cycles,
some species described by Roberts,
development, behaviour, reproduction,
among others (e.g. Roberts 1960). There
habitat and ecological relationships of
is also a collection of water mites,
mites, and uses mites as models to
including some described by Harvey
demonstrate a wide range of phenomena
(1987, 1990a, b), but the collection is
in evolutionary biology. The most detailed
dominated by oribatids described by
textbook of mite taxonomy is Krantz
Glenn Hunt (Hunt 1996a, b; Hunt and Lee
(1978), which provides keys down to the
1995). The slide collection is supported by
family level for all groups. Each family
substantial holdings of non-type and
study includes information on biology and
unidentified mite accessional material.
behaviour, evolutionary relationships and
including bulk samples from pitfall and
economic importance, and a taxonomic
litter collecting.