Literature review: Impact of Chilean needle grass ... - Weeds Australia
Literature review: Impact of Chilean needle grass ... - Weeds Australia
Literature review: Impact of Chilean needle grass ... - Weeds Australia
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Other <strong>grass</strong>land insects <strong>of</strong> conservation significance include Tropiderus childreni Gray (Phasmatodea: Bacteriidae), SA, Vic,<br />
NSW, savannah, mallee, <strong>grass</strong>, reportedly threatened by urbanisation in the Adelaide Hills (Hill and Michaelis 1988); Anisynta<br />
albovenata Waterhouse (Lepidoptera: Hesperiidae), SA, WA, NSW, associated with Austrostipa, reportedly threatened by<br />
roadworks, clearing and overgrazing (Hill and Michaelis 1988); Oriexenica kershawi kanunda Tindale (Lepidoptera: Satyriinae)<br />
<strong>of</strong> SA and Vic , associated with open <strong>grass</strong>land, reportedly threatened by fire at Canunda National Park (Hill and Michaelis<br />
1988); Trapezites lutea (Tepper) (Lepidoptera: Hesperiidae) <strong>of</strong> SA and Vic found on Lomandra dura threatened by fire and<br />
drought in SA (Hill and Michaelis 1988).<br />
Xathorhoini, Larentiinae, Geometridae<br />
McQuillan (1999) reported on studies on the Xanthorhoini, a tribe <strong>of</strong> small, colourful, largely diurnal Geometridae (Lepidoptera)<br />
with high diversity and endemicity in <strong>Australia</strong>n <strong>grass</strong>lands. Members <strong>of</strong> the subfamily Larentiinae are “numerous <strong>of</strong> the<br />
tablelands and mountains <strong>of</strong> sout-eastern <strong>Australia</strong> and Tasmania” (Common 1990 p. 375). The tribe is represented in <strong>Australia</strong><br />
by about 20 spp. <strong>of</strong> Xanthorhoe Hűbner, mostly found in the south (Common 1990, but only 13 spp. listed by Nielsen et al.<br />
1996), many species <strong>of</strong> Chrysolarentia Butler, three species <strong>of</strong> Acodia Rosenstock, one <strong>of</strong> Austrocidaria Dugdale, eight <strong>of</strong><br />
Epyaxa Meyrick and two <strong>of</strong> Visiana Swinhoe (Nielsen et al. 1996). Adults <strong>of</strong> many Chrysolarentia spp. are “common in summer<br />
at the higher altitudes on the tablelands and mountains” <strong>of</strong> southern NSW, Victoria and Tasmania (Common 1990, as Euphyia<br />
Hűbner). Larval Xanthorhoini are sluggish and nocturnal and most species appear to be stenophagous on a small number <strong>of</strong> lowgrowing<br />
annual native herbs, including species <strong>of</strong> Hydrocotyle, Geranium and Acaena (McQuillan 1999). McFarland (1988)<br />
recorded details <strong>of</strong> the habitats and diets <strong>of</strong> X. actinipha (Lower) and X. vicissata (Guenée) which both consumed Medicago<br />
polymorpha L. in captivity. No <strong>Australia</strong>n Geometridae are known to consume <strong>grass</strong>es or any other monocots (McFarland 1988).<br />
The studies <strong>of</strong> McQuillan (1999), in Tasmanian <strong>grass</strong>lands mainly dominated by Poa labillardieri or other Poa spp., Themeda<br />
triandra, exotic <strong>grass</strong>es, Gymnoschoenus sphaerocephalus (R.Br.) (Cyperaceae) or other Cyperaceae and Restionaceae, found<br />
that species richness increased with altitude, rainfall and greater sedge-content, and declined in areas with greater <strong>grass</strong><br />
dominance, livestock grazing and weediness. Site species richness was lowest in highly modified <strong>grass</strong>lands and reached a<br />
maximum <strong>of</strong> 15 in unmodified <strong>grass</strong>lands and sedgelands, and 25 spp. were detected overall. Many species survived in small<br />
remnant <strong>grass</strong>land patches. Some species required <strong>grass</strong> tussocks for shelter in the adult stage and used tussocks as pheromonal<br />
‘calling’ and mating sites.<br />
Synemon spp., Sun Moths (Lepidoptera: Castniidae)<br />
The <strong>Australia</strong>n Castniidae or sun-moths consist <strong>of</strong> 20 (Douglas 2003b), 22 (Douglas and Marriott 2003) or 24 (Douglas 2000,<br />
Edwards 1996 1997a) named species and 22 (Douglas 2003b) or possibly 21 or more unnamed species <strong>of</strong> the endemic genus<br />
Synemon Doubleday (Edwards 1997a, Douglas and Marriott 2003). Douglas (2003a) provided a brief bibliography for the<br />
family. Adults normally fly only in bright sunshine (Edwards 1997a, Douglas 2003b), hence the common name, and resemble<br />
butterflies, having broad wings, clubbed antennae and usually bright colours (Douglas 2000). Females have very long,<br />
retractable ovipositors and deposit eggs underground between foodplant and soil or on the base <strong>of</strong> the tillers <strong>of</strong> the foodplant<br />
(Common and Edwards 1981, Edwards 1994, Dunn 1996, Douglas 2000). There is pronounced sexual dimorphism <strong>of</strong> adults, e.g.<br />
the the sexes <strong>of</strong> S. plana Walker were described as separate species in 1854 and 1874 and their identity was not recognised until<br />
1926 (Edwards 1994).<br />
The larvae <strong>of</strong> different species feed inside the rhizomes <strong>of</strong> Lomandra spp. (Xanthorrhoaeaceae), Ecdeiocolea sp.<br />
(Ecdeiocoleaceae), in the tillers and then against the rhizomes <strong>of</strong> Lepidosperma viscidum R.Br. (Cyperaceae) or in tunnels<br />
entirely undergound, on the roots <strong>of</strong> <strong>grass</strong>es (Poaceae) or other sedges (Cyperaceae) (Common and Edwards 1981, Edwards<br />
1994, Dunn 1996, Douglas 2000, Douglas and Marriott 2003). Douglas (1999) also mentions unnamed Juncaceae as larval food<br />
plants. Most species are found in areas with sandy or light textured soils (Edwards 1994). Final instar larvae pupate in their<br />
feeding gallery and the pupa works its way upwards to protrude from the ground or the foodplant to enable adult emergence<br />
(Edwards 1994, Douglas 2000). The whole life cycle occupies 1-3 years (Common and Edwards 1981, Edwards 1994, Douglas<br />
2000, Endersby and Koehler 2006) so the adults present in any one year may represent only a small proportion <strong>of</strong> the population<br />
(Edwards 1994). All species are localised in their occurrence and the adult flight period is brief (Dunn 1996), “as short as a<br />
fortnight” (Edwards 1997b). Adults are usually present in only small areas (hundreds <strong>of</strong> square metres) (Dear 1996).<br />
Determination <strong>of</strong> what plant is actually eaten is a vexed question for some species. Edwards (1994) stated that digging the roots<br />
to find pupae “is the surest method … Finding protruding pupal shells within and between tussocks is the next most reliable”,<br />
female oviposition probing is unreliable as a foodplant indicator, although local distribution <strong>of</strong> adults, particularly females, is<br />
indicative. None <strong>of</strong> these methods establish actual feeding relationships. Nevertheless the appear to be the basis for the food<br />
plant relationships recorded, until recently with little criticism, in the literature. Determination <strong>of</strong> the actual food <strong>of</strong> the larvae is<br />
difficult and requires a clear protocol to indicate the various levels <strong>of</strong> uncertainty inolved (Edwards 1997a)<br />
The literature records species <strong>of</strong> Austrodanthonia as known or probable foodplants for five species found in Victoria including A.<br />
setacea (R.Br.) H.P. Linder and A. laevis (Vickery) H.P. Linder (Marriott 2004), while A. carphoides and A. auriculata are also<br />
probable food plants (Dear 1996) as well as Austrostipa sp. (Marriott 2004). Food plants <strong>of</strong> Queensland Synemon spp. include<br />
the <strong>grass</strong>es Chrysopogon sp. and Thellungia advena (Edwards 1997a).<br />
Recently Braby and Dunford (2006) identified N. neesiana and red-leg <strong>grass</strong> Bothrichloa macra as probable larval food plants<br />
for the Golden Sun Moth S. plana on the basis <strong>of</strong> the location and distribution <strong>of</strong> empty pupal cases (protruding from or beside<br />
tussocks) in ACT <strong>grass</strong>lands. Despite Edwards’ reliance on this method himself (e.g. Edwards 1994) he disputes this attribution<br />
(pers. comm. October 2006) believing it more likely that the moth has bred on undetected Austrodanthonia or in plants no longer<br />
visible above ground at the site, the juvenile stages being prolonged. More recently Gilmore et al. (2008) reported female<br />
oviposition on N. neesiana and pupal cases amongst a dense N. neesiana sward at Greenvale, Victoria. Gilmore et al. (2008) also<br />
reported oviposition on Austrostipa spp. and Microlaena stipoides. Edwards (1994) suggested that S. plana larvae may consume<br />
a mixture <strong>of</strong> roots, rhizomes and culm bases.<br />
S. plana is one <strong>of</strong> the few invertebrate taxa that have been used as flagship taxa for <strong>grass</strong>land invertebrate conservation in<br />
<strong>Australia</strong> (New 2000) and is ranked as critically endangered in <strong>Australia</strong> (Endersby and Koehler 2006, Gilmore et al. 2008). It<br />
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