DID CASTIARINA INSCULPTA (MIENA JEWEL BEETLE) RIDE ON THE SHEEP'S BACK?

Abstract

The Miena jewel beetle, Castairina insculpta, is a narrow range endemic, listed as being endangered under the Tasmanian Threatened Species Protection Act 1995. The species was originally described from a single female specimen collected from the Great Lake area (Carter 1934). Between then and 2010, only a further five specimens were found, all of which were dead. Until 2013 no records existed of live animals or a male of the species. In 2013 field naturalists observed for the first time multiple Castiarina insculpta of both sexes active across several locations south and west of Great Lake, the species being found on the composite (Asteraceae) shrub Ozothamnus hookeri (Bonham et al. 2013). The present article explores the likely factors contributing to the apparent population increase of Castiarina insculpta, hypothesizing that the expansion of Ozothamnus hookeri stands across the Central Plateau is the most probable explanation.

Full text

The Tasmanian Naturalist 136 (2014)
49
DID CASTIARINA INSCULPTA (MIENA JEWEL BEETLE)
RIDE ON THE SHEEP’S BACK?
Chris P. Spencer & Karen Richards
141 Valley Road, Collinsvale, Tasmania 7012, spenric@gmail.com
The Miena jewel beetle, Castiarina insculpta, is a narrow range endemic, listed as being
endangered under the Tasmanian Threatened Species Protection Act 1995. The species was
originally described from a single female specimen collected from the Great Lake area
(Carter 1934). Between then and 2010, only a further five female specimens were found, all
of which were dead. Until 2013 no records existed of live animals or a male of the species.
In 2013 field naturalists observed for the first time multiple Castiarina insculpta of both
sexes active across several locations south and west of Great Lake, the species being found
on the composite (Asteraceae) shrub Ozothamnus hookeri (Bonham et al. 2013). The present
article explores the likely factors contributing to the apparent population increase of
Castiarina insculpta, hypothesizing that the expansion of Ozothamnus hookeri stands across
the Central Plateau is the most probable explanation.
The past
The known range of Castiarina insculpta
(Plate 1) is contained wholly within the
upper region of the Central Plateau
landscape at elevations above 900 m and
confined to an area of approximately
620 km2 (Figure 1). Parts of this region
have been subjected to timber harvesting,
although this activity has generally been
concentrated in the mid to lower elevations,
as forest growth is greater in these areas and
the sawlog produced was of a much higher
grade (Shepherd 1973). Exploration of the
Great Lake catchment resource for
hydroelectricity generation began in 1911
(Shepherd 1973), while hunting, rabbit
trapping and snaring of wallaby and
possum also occurred across the plateau.
However, the major land use of the region
since European settlement in the 1820s has
been grazing (Jackson 1973).
Fossil pollen studies conducted at
Camerons Lagoon (Thomas & Hope 1994)
have revealed that on a regional basis
Liawenee Moor, home to Castiarina
insculpta, has remained a relatively stable
environmental unit for 8,000 years, while
also providing evidence of transformation
and change in the plant communities. The
most obvious of these changes was a
recognised slow trend towards increased
shrubbiness until about 165 years ago, after
which the trend accelerated (Thomas &
Hope 1994). Written accounts and oral
histories since European settlement support
the notion that the vegetation at Liawenee
Moor has degraded significantly over the
past 165 years from grassland to shrubby
grassland (Shepherd 1973; Thomas & Hope
1994).
Historically, grazing activity in the Central
Highlands was mostly concentrated on the
open grassy plains, much of which may
have been attributable to the Aboriginal
practice of burning (Ross 1830 and Plomley
1966 in Shepherd 1973) to promote green
growth, which encouraged greater
concentrations of grazing animals and
provided more successful hunting. Early
European settlers continued the practice of
burning and larger areas of scrub were
converted to unimproved pasture. Such
seasonal burning promoted fresh growth,
encouraging stock to eat the unpalatable
Poa tussocks (Jackson 1973, Kirkpatrick &
Bridle 2007). In the 1830s wool was

The Tasmanian Naturalist 136 (2014)
50
shipped to the United Kingdom stimulating
the growth of pastoralism that led to
increases in the number of land grants and
leases of Crown land on the Central Plateau
(Shepherd 1973). By the 1880s most of the
Central Plateau lake country grazing rights
were established as freehold or leasehold
and by century end flocks of sheep were
grazed on the plateau during summer (Scott
1955 in Jackson 1973).
Figure 1. Distribution of Castiarina insculpta (green points indicate collection sites; the inner blue
line a minimum convex polygon around all known sites; the outer line a nominal 2 km buffer)
In the late 19th century large numbers of
stock were transhumanced to the lake
country for summer grazing (approximately
350,000 sheep and 6,000 cattle) and small
flocks of sheep were overwintered in
favourable areas, including parts of the
upper region (Scott 1955 in Shepherd
1973). During the 20th century, the decline
in stock numbers summered in the upper
plateau coincided with a general
deterioration of the pasture. Owing to the
annual issuing of grazing licenses
established in 1965, which were renewed
without inspection of the leased land or any
regulation of stock numbers,
mismanagement of the land by the lessees
became evident (Shepherd 1973). Between
1923 and 1973, as the stocking rate per acre
decreased in areas where no land
improvement was carried out, a number of
properties were abandoned (Shepherd
1973). By 1971 the number of summer
grazed sheep in the upper plateau had
declined to 46,118 and cattle reduced to
5,100 (Shepherd 1973).

The Tasmanian Naturalist 136 (2014)
51
Plate 1. Present vegetation of Skittleball Plains
Plate 2. Present vegetation of Ellis Plains
 C. Spencer & K. Richards
 C. Spencer & K. Richards

The Tasmanian Naturalist 136 (2014)
52
Coinciding with land degradation
associated with the grazing practices,
rabbits were first recorded in the Tasmanian
Lake District around 1910, and by 1920
numbers of both rabbits and hares had
multiplied rapidly (Shepherd 1973). This
introduction, combined with grazing
pressure resulted in serious damage to the
inter-tussock flora (Jackson 1973).
Subsequently, dramatic changes to the
composition of plant communities have
resulted (Jackson 1973, Gibson &
Kirkpatrick 1989; Crowden 2005).
Denuding of the landscape has been
widespread and erosion of the thin skeletal
soil has prevented re-establishment of some
plant species due to the frequent and severe
burning, overstocking and presence of
rabbits, which reached plague proportions
during the period 1920 to 1953 (Jackson
1973; Shepherd 1973). The legacy of fires
on alpine vegetation communities has been
documented, indicating lengthy recovery
periods are necessary for some species
(Kirkpatrick et al. 2002). Bridle &
Kirkpatrick (1999), examining the effects
of grazing pressure on alpine vegetation,
demonstrated that sheep grazing has a far
greater impact on the plant composition of
alpine pastureland than rabbits and native
wildlife. Williams & Ashton (1987 in
Bridle & Kirkpatrick 1999) also stated that
a decrease in grazing pressure in disturbed
alpine environments leads to an increase in
shrub cover.
The present
Prior to 1900, Liawenee Moor and
Skittleball Plains supported tall tussock
grassland consisting of Poa species, with a
rich inter-tussock herb cover. Due to past
land management practices, both of these
areas changed remarkably (Jackson 1973).
With the cessation of grazing much of the
degraded former herb and tussock grassland
has become dominated by scrub containing
a high proportion of Ozothamnus hookeri.
This alpine species, a successional shrub, is
tolerant of the low nutrient soils, frost
heave, waterlogging and the species is able
to resprout after fire. It rapidly reaches
maturity and produces a prodigious amount
of wind-dispersed seed (Kirkpatrick et al.
2002), factors that contribute to its success.
Currently both Skittleball Plains and Ellis
Plains are clothed with an ocean of
Ozothamnus hookeri (Plates 1 & 2); areas
of Liawenee Moor also support some dense
stands of the plant. It is very likely that the
current Ozothamnus hookeri density is far
greater than ever since the last glacial
epoch; however, much of this area contains
single-aged cohorts of the species, some of
which may be nearing the end of the life
expectancy, estimated to be of 30-50 years
(Kirkpatrick et al. 2002). Over much of its
range, Ozothamnus hookeri occurs
concurrently with another widely
distributed Ozothamnus species
(Ozothamnus ericifolius) (Plates 3 & 4).
The two are similar in habit and flower over
approximately the same period; however, to
date Castiarina insculpta has only been
recorded utilising Ozothamnus hookeri.
Castiarina insculpta (Plate 5), are slow,
heavy fliers and activity is restricted to hot
weather with little or no wind; these
conditions prevail infrequently on the
Central Plateau, which must severely limit
the opportunity for the species to disperse.
Ozothamnus, known locally as ‘kerosene
bush’ due to its highly flammable nature,
burns fiercely but perhaps quickly and
some of the naked stems may not suffer
major scorching. With sparse ground cover
to generate intense heat, some larvae
approaching full-term may still be capable
of pupating in the dying stems; although,
any emergent beetles would need to fly to
the nearest flowering Ozothamnus hookeri
to feed, but providing the distance is not too
great they may survive and breed.

The Tasmanian Naturalist 136 (2014)
53
Plate 3. Ozothamnus hookeri
Plate 4. Ozothamnus ericifolius
 C. Spencer & K. Richards
 C. Spencer & K. Richards

The Tasmanian Naturalist 136 (2014)
54
Two co-occurring buprestids, Castiarina
wilsoni and Castiarina flavopicta have
been recorded by the authors feeding on
Ozothamnus ericifolius, but not on
Ozothamnus hookeri. These two
widespread and abundant species are
known to feed on the nectar of many genera
including Leptospermum, Hakea,
Helichrysum, Olearia, Bursaria,
Callistemon, Cassinia, Kunzea and
Baeckea. Another species, Castiarina
virginea which belongs to the Castiarina
rectifasciata species-group, along with
Castiarina insculpta (Barker 2006), has
also been observed (by the authors) feeding
on Ozothamnus hookeri. However, unlike
Castiarina insculpta, Castiarina virginea
has been reported to feed on Helichrysum
species, Bursaria and Cassinia (Cowie
2001).
The reported collection of a single
specimen of Castiarina insculpta from the
Great Lake area in 1934 (Carter 1934)
suggests the presence of Ozothamnus
hookeri at that time. Grazing still
continued, but land degradation was
becoming evident, consequently more
Ozothamnus hookeri is likely to have been
establishing. The initial collection of this
species by Critchley Parker occurred at a
time when the grazing pressure was
declining and presumably tracts of bare
‘degraded pasture’ were reverting back to
heath and shrubland where Ozothamnus
species dominated. Confirmation of the
increase in Ozothamnus hookeri at that time
is not possible given the vague collection
site data; however, it is conceivable that this
‘increasing habitat’ may have influenced
the radiation of Castiarina insculpta. This
theory is supported by the 2013 surveys
showing large concentrations of Castiarina
insculpta were located at Liawenee Moor,
Skittleball Plains and Ellis Plains, where
today there are extensive stands of
Ozothamnus hookeri.
It is unclear if the 2013 search effort was
any more intense than the previous surveys
(e.g. Smith et al. 2004): what is clear,
however, is that the historical search effort
was likely to have concentrated on a list of
possible food plants based on the known
feeding habits of other Castiarina species at
that time, a list that did not include
Ozothamnus hookeri or any of the
Ozothamnus or Helichrysum species
(Bryant & Jackson 1999; Cowie 2001;
Fernandez 2004). Further, the
recommended survey method adopted in
past surveys probably utilised a sweep net
as the preferred means of collecting
specimens: Cowie (2001) and Fernandez
(2004) reported that sweep netting was
necessary to collect flying or feeding adults.
In the authors’ experience, feeding
Castiarina species readily drop to the
ground as a defence strategy when
approached, and in consequence, they are
more successfully collected by hand, with
stealth and cunning. Irrespective of the
survey technique employed, Castiarina
insculpta numbers may fluctuate
significantly between years. Despite a
survey effort equal to 2013, in 2014 only a
single male specimen was observed by the
authors. During this period the flowering of
Ozothamnus hookeri was recorded to be of
intensity less than fifty percent that of the
previous year.
Castiarina larvae are root and stem borers
exclusive to native trees and shrubs;
references detailing aspects of the biology
and adult life expectancy of Australian
buprestids are infrequent (Barker 2006).
One published example, (McMillan 1950a
cited in Hawkeswood 2002) recorded that
the larvae of Melobasis sexiplagiata are
known to tunnel in Eucalyptus rudis and
“extend down the tree and the beetle can be
found at the bottom of these tunnels; the
adults overwinter from early June to late
September before emerging”. More often,
accounts are limited to observational

The Tasmanian Naturalist 136 (2014)
55
snapshots remaining as unpublished data.
For example, in Tasmania, teneral adults
and final instar larvae of Melobasis costata
have been found in large dead standing
Melaleuca ericifolia trunks (Spencer &
Fearn unpubl. data): teneral adults
occupying pupal chambers beneath surface
bark and the typically shaped larvae were
found within bores in the sapwood up to
1 cm deep immediately beneath the bark.
More detailed accounts of buprestid
ecology are recorded in international
literature, such as for the species Agrilus
planipennis (emerald ash borer) native to
the Asian region, which has been reported
to produce from 30-60 bright yellow eggs,
turning tawny brown before the larvae
eclose after around two weeks (Spence &
Smith 2011). Additionally, the larval cycle
of Anthaxia midas oberthuri, an Italian
buprestid, which feeds on Acer (maple)
species has been studied and found to
extend through two winters, oviposition
occurring in April/May, pupation taking
place in the following summer, the adult
ecloses after a couple of weeks and
emergence occurs in the following spring
(Izzillo 2010).
Stem characteristics of Ozothamnus
hookeri supporting Castiarina insculpta
emergence sites have been investigated by
the authors. Findings reveal emergence
sites occur in stems of 13-107 mm
diameter, but while multiple holes are
sometimes present in larger plants,
typically only a single site is found on a
stem, which is often dying. No preference
for shrub height or stem aspect was
observed, emergence sites occurring on
bushes supporting stems of sufficient
dimensions.
Given the information deficit of buprestid
life cycles, estimating the time frame of
Castiarina insculpta life history is
problematic. Larvae of differing age
cohorts have been observed and data
collected on stem characteristics, larval
tunnel and emergence hole dimensions
(Spencer & Richards, unpubl. data), but the
complete life cycle of Castiarina insculpta
has not yet been reliably established. Given
the variability in beetle numbers recorded
in 2013 and 2014, it is anticipated that the
life cycle will be a minimum of two or three
years duration and beetles resulting from
2013 oviposition are thus likely to emerge
in February 2015 or 2016. However, the
cycle may in fact be much longer, as in the
case of the North American species
Buprestis aurlenta, taking up to 25 years
(CSIRO 1970), or opportunistically linked
to periods of extreme flowering events.
The future
Into the future, disturbance including fire,
will remain imperative to the survival of
multi-aged populations of Ozothamnus
hookeri across the subalpine landscape, this
in turn should support a population of
Castiarina insculpta. The population
dynamics of Castiarina insculpta, though
not currently understood, is suspected to be
closely linked to flowering densities of
Ozothamnus hookeri and thus likely to
follow a pattern of boom and bust, as with
many other animals dependent on a single
host species. The vagaries of high altitude
weather are also likely to exert a strong
influence on the survival and dispersal of
adult Castiarina insculpta. Such impacts
may be seen in changes affecting the
flowering events of Ozothamnus hookeri or
weather patterns disrupting the breeding
opportunities or dispersal activity of the
beetle.
Recent land ownership changes may bring
about renewed grazing and perhaps burning
regimes to a large area presently supporting
advanced stands of Ozothamnus hookeri.
The current density of Ozothamnus hookeri
across the range of Castiarina insculpta
provides a bountiful supply of both blossom
and stems of sufficient diameter for

The Tasmanian Naturalist 136 (2014)
56
breeding. Given the survival requirements
of Ozothamnus hookeri it is evident that a
level of disturbance is necessary to
maintain the species in the landscape.
While new grazing and burning activity is
likely to negatively impact upon Castiarina
insculpta in the short-term, correctly
managed, it may pose a long-term benefit.
Management of State reserves and
conservation areas in conjunction with
private landowners is critical to the survival
of both host plant and beetle. Successful
management for these species will need to
ensure that a landscape-level approach is
applied to maintain a mosaic supporting
stands of different aged Ozothamnus
hookeri. To encourage regeneration it will
be necessary to implement a low-level
disturbance regime using controlled low
intensity burning or other mechanisms.
Minimising distance between regenerating
and senescing Ozothamnus hookeri stands
will further assist in beetle dispersal.
ACKNOWLEDGEMENTS
The authors would like to thank the Inland
Fisheries Service for granting access to land
and providing accommodation, Jamie
Kirkpatrick for encouragement and advice
on aspects of the physiology of
Ozothamnus, and Richard Schahinger for
offering useful comments on an early draft
of this article.
REFERENCES
Barker, S. (2006). Castiarina: Australia’s
Richest Jewel Beetle Genus. Australian
Biological Resources Study, Canberra.
Bonham, K., Richards, K., Spencer, C.P.,
Grove, S., Reid, C., Byrne, K., Hird, D. &
Throssell, A. (2013). Observations of the
Miena jewel beetle Castiarina insculpta
(Carter, 1934) in the summer of 2012–13.
The Tasmanian Naturalist 135: 104–109.
Bryant, S.L. & Jackson, J. (1999).
Tasmania’s Threatened Fauna
Handbook: What, Where and How to
Protect Tasmania’s Threatened Animals.
Threatened Species Unit, Parks and
Wildlife Service, Hobart.
Bridle, K.L. & Kirkpatrick, J.B. (1999).
Comparative effects of stock and wild
vertebrate herbivore grazing on treeless
sub-alpine vegetation, Eastern Central
Plateau, Tasmania. Australian Journal of
Botany 47: 817–834.
Carter, H.J. (1934). Australian and New
Guinea Coleoptera. Notes and new
species. No. III. Proceedings of the
Linnean Society of New South Wales
598: 252–269.
Cowie, D. (2001). Jewel Beetles of
Tasmania: a Field Naturalist’s Guide.
Tasmanian Field Naturalists Club, Inc.,
Hobart.
Crowden, R. K. (1999). Alpine vegetation.
IN: Vegetation of Tasmania (Eds.
J.B. Reid, R.S. Hill, M.J. Brown & M.J.
Hovenden). Australian Biological
Resources Study, Hobart.
CSIRO (1970). The Insects of Australia:
A Textbook for Students and Research
Workers. Melbourne University Press,
Melbourne.
Fernandez, K. (2004). Miena Jewel Beetle,
Castiarina insculpta Preliminary Survey
Report October 2004 for the Threatened
Species Unit, DPIWE. Department of
Primary Industries and Water, Hobart.
Gibson, N. & Kirkpatrick, J.B. (1989).
Effects of the cessation of grazing on the
grasslands and grassy woodlands of the
Central Plateau, Tasmania. Australian
Journal of Botany 37: 55–63.
Hawkeswood, T.J. (2002). A review of the
biology and host plants of Australian
Buprestidae (Coleoptera) known to breed
in Eucalyptus species (Myrtaceae).
Journal of the Entomological Research
Society 4(2): 31–58.
Izzillo, F. (2010). New faunistic records of
jewel beetles from southern Italy and

The Tasmanian Naturalist 136 (2014)
57
Sardinia (Coleoptera: Buprestidae).
Biodiversity Journal 1(1-4): 3–6.
Jackson, W. D. (1973). Vegetation of the
Central Plateau. IN: The Lake Country of
Tasmania (Ed. M.R. Banks). Royal
Society of Tasmania, Hobart.
Kirkpatrick, J.B., Bridle, K.L. & Wild, A.S.
(2002). Succession after fire in alpine
vegetation on Mount Wellington,
Tasmania. Australian Journal of Botany
50: 145–154.
Kirkpatrick, J. & Bridle, K. (2007) (eds.)
People, Sheep and Nature Conservation:
The Tasmanian Experience. CSIRO
Publishing, Collingwood.
Shepherd, R. R. (1973). Land use on the
Central Plateau with special reference to
the grazing industry. IN: The Lake
Country of Tasmania (Ed. M.R. Banks).
Royal Society of Tasmania, Hobart.
Smith, B.J., Reid, C. & Gordon, T. (2004).
Rediscovery of the Miena jewel beetle
(Castiarina insculpta Carter, 1934),
formally listed as extinct. The Tasmanian
Naturalist 126: 31–34.
Spence, D. & Smith, J. (2011). Emerald
Ash Borer: A Potential Future Threat to
Ash Trees in Florida. University of
Florida. http://edis.ifas.ufl.edu.
Thomas, I. & Hope, G. (1994). An example
of Holocene vegetation stability from
Camerons Lagoon, a near treeline site on
the Central Plateau, Tasmania. Australian
Journal of Ecology 19: 150–158.
Plate 5. Female Castiarina insculpta feeding on Ozothamnus hookeri
 C. Spencer & K. Richards