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Literature review: Impact of Chilean needle grass ... - Weeds Australia

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Nevertheless, based largely on Northern Hemisphere knowledge, the basic insect phytophage assemblage, for the smallest<br />

<strong>grass</strong>es, consists <strong>of</strong> one species each <strong>of</strong> Eurytomidae (Hymenoptera), Cecidomyiidae (Diptera) and Pseudococcidae (Hemiptera)<br />

(Tscharntke and Greiler 1995). The large, cosmopolitan Common Reed, Phragmites australis (Cav.) Trin. ex Steud., is the most<br />

speciose host known, attacked by c. 100 insect species (Tscharntke and Greiler 1995) and has a total <strong>of</strong> over 160 associated<br />

arthropods, approximately half <strong>of</strong> which are endophages (Witt and McConnachie 2004). Its diverse flora may be largely a result<br />

<strong>of</strong> a long evolutionary history, it being a “Palaeogenic relict” belonging to the”most ancient <strong>of</strong> modern <strong>grass</strong>es” the Arundineae<br />

(Tsvelev 1984 p. 59) and its broad geographical distribution. The phytophage complement is dependent on many factors, but<br />

larger faunas are associated with wider geographical range, large size, predictable occurrence and perenniality (Lawton and<br />

Schroder 1977). More than 24 arthropod species have been identified as potential biological control agents for the intertidal <strong>grass</strong><br />

Spartina alternifolia Lois. in the USA, while Calamagrostis epigejos (L.) has 10 endophagous arthropod species (Witt and<br />

McConnachie 2004).<br />

Isoptera (Termites)<br />

Drepanotermes <strong>grass</strong>-harvesting termites are a conspicuous feature <strong>of</strong> arid <strong>Australia</strong> but are not found in the <strong>grass</strong>lands <strong>of</strong><br />

temperate south-eastern <strong>Australia</strong> (Watson 1982), where most <strong>grass</strong>es appear to escape termite attack.<br />

Coleoptera<br />

Unlike on dicotyledonous groups, beetles (Coleoptera) are generally relatively depauperate on <strong>grass</strong>es. Only 8 spp. are known<br />

from Phragmites australis and only 2 <strong>of</strong> 24 apparent specialists on Spartina alternifolia are beetles (Witt and McConnachie<br />

2004). Coleoptera are “relatively abundant” on smaller <strong>grass</strong>es including Sporobolus spp. and Nassella trichotoma, but are<br />

mostly pollen feeders (Witt and McConnachie 2004).<br />

Thysanoptera<br />

Thrips (Thysanoptera) are common inhabitants <strong>of</strong> <strong>grass</strong>es. Chirothrips species breed only in the flowers <strong>of</strong> <strong>grass</strong>es and can<br />

reduce seed production and limit <strong>grass</strong> regeneration (Mound and Palmer 1972). Six species are recorded in <strong>Australia</strong>, all<br />

introductions. Native thrips <strong>of</strong> <strong>grass</strong> flowers are species <strong>of</strong> Odontothripella. Other species associated with Poeaceae flowers<br />

include Caliothrips striatopterus (Kobus), common in <strong>grass</strong> flowers in Queensland, Haplothrips froggatti Hood common in<br />

subtropical <strong>Australia</strong>, Desmothrips reedi Mound and D. tenicornis (Bagnall). Many other species are associated with <strong>grass</strong>es<br />

including Phibalothripis longiceps (Karny), leaf tissue-feeding species related to Anaphothrips, usually found in leaf funnels,<br />

Podothrips species predatory on coccoids at the base <strong>of</strong> <strong>grass</strong>es in the tropics, and species found in the bases <strong>of</strong> <strong>grass</strong> tussocks<br />

that feed on fungi (Mound and Palmer 1972). Desmothrips reedi (Aelothripidae)lives at the base <strong>of</strong> <strong>grass</strong>es, Moundothrips and<br />

Phibalothrips (Thripidae) live on <strong>grass</strong>es and Odontothripella are found on <strong>grass</strong> flowers (Mound and Heming 1991) including<br />

O. compta Pitkin, O. reedi Pitkin and O. unidentata Pitkin (Pitkin 1972). Introduced Limothrips is common on <strong>grass</strong>es in cooler<br />

areas <strong>of</strong> southern <strong>Australia</strong> <strong>of</strong>ten living on leaves, the introduced Aptinothrips rufus is abundant on <strong>grass</strong>es and Haplothrips<br />

(Phlaeothripidae) live in <strong>grass</strong> flowers (Mound and Heming 1991), five species (H. anceps Hood, H. angustus Hood, H. gowdeyi<br />

(Franklin), H. froggatti Hood and H. pallescens (Hood)) apparently breeding there, one species living in the base <strong>of</strong> tussocks,<br />

and other species including Antillothrips cingulatus (Hood), Apterygothrips australis Pitkin and Podothrips xanthopus Hood<br />

living on or amongst <strong>grass</strong>es, the latter probably predatory on small arthropods such as coccids, mites or other thrips (Pitkin<br />

1973).<br />

Diptera<br />

True flies are relatively more common on Poaceae than on dicotyledons, notably gall midges Cecidomyiidae, leafminer flies<br />

Agromyzidae and <strong>grass</strong> flies Chloropidae. On a world basis, many stem-boring and stem-galling Diptera on <strong>grass</strong>es have narrow<br />

host ranges (Witt and McConnachie 2004).<br />

Many cecidomyiid species appear to be monophagous at species level (Witt and McConnachie 2004). The <strong>Australia</strong>n<br />

cecidomyiid fauna is extremely poorly known (Harris 1979, Gagné 2007, R. Adair and R. Gagné pers. comms.) but several<br />

species belonging to three genera, Contarinia, Lasioptera and Geromyia have been recorded from <strong>grass</strong>es, largely in northern<br />

<strong>Australia</strong> (Harris 1979). Larval Cecidomyiidae feed in the inflorescence, inside the culms, or under leaf sheaths <strong>of</strong>ten near the<br />

base <strong>of</strong> the plant. The Contarinia spp. inhabit inflorescences and seed heads, and include C. brevipalpis Harris which attacks<br />

Eragrostis brownii (Nees) Kunth, C. dichanthii Harris which attacks Dichanthium spp. including D. sericeum (R.Br.) A. Camus,<br />

and undescribed species on Heteropogon contortus (L.) P. Beauv. ex Roem.and Schult. and Themeda triandra (Harris 1979).<br />

There are “probably hundreds” <strong>of</strong> undescribed <strong>Australia</strong>n species (Harris 1979 p. 168). Lasioptera species are found on<br />

inflorescences <strong>of</strong> <strong>grass</strong>es including Panicum, Setaria, Bothriochloa and Heteropogon, while the single Geromyia species is<br />

“probably restricted to Setaria” (Harris 1979 p. 164). No Cecidomyiidae species are known from Austrostipa or Austrodanthonia<br />

spp. It is highly likely that exploration <strong>of</strong> the temperate <strong>Australia</strong>n fauna will reveal many species that inhabit native <strong>grass</strong>lands<br />

and attack <strong>grass</strong>es (Adair and Gagné pers. comms.). The biology <strong>of</strong> a New Zealand species that feeds on developing seeds <strong>of</strong><br />

New Zealand ‘snow-tussocks’ Chionochloa spp. has been described by Kolesik et al. (2007). The larvae do not form galls but<br />

overwinter in the floret after feeding on developing seeds. The species appears to be the main seed predator driving mast seeding<br />

<strong>of</strong> these <strong>grass</strong>es, destroying up to 60% <strong>of</strong> florets (Kolesik et al. 2007, Kelly et al. 2008).<br />

Agromyzidae has relatively high host plant specificity with most species specific to a single plant genus or family, Asteraceae<br />

hosting the greatest number <strong>of</strong> species, and polyphagy (across plant families) being rare (Spencer 1977). Larvae may be leaf<br />

miners, internal feeders throughout the plant or selective feeders in roots, stems or flowers (Ferrar 1987, Spencer 1989). Adults<br />

feed on plant sap via punctures in the tissue made by the female (Ferrar 1987). No <strong>Australia</strong>n Agromyzidae are known from<br />

Stipeae (Spencer 1977), but members <strong>of</strong> the family are recorded from other <strong>grass</strong>es in <strong>Australia</strong>. Spencer (1977) listed<br />

Pseudonapomyza ?spinosa Spencer from Urochloa subquadripara (Trin.) R.D. Webster at Darwin, NT (as Agromyza sp. on<br />

Brachiaria miliformis (Presl.) Chase in Kleinschmidt 1965), P. spinosa from the introduced Eleusine indica (L.) Gaertn. and<br />

Agromyza sp. from Oplismenus compositus (L.) Beauv., while Kleinschmidt (1965) also listed Cerodontha australis Malloch<br />

from Poa annua L. and Pseudonapomyza spicata (Malloch), a “common <strong>grass</strong>-mining species”, probably <strong>of</strong> exotic origin, from<br />

Eleusine indica. Elsewhere in the world P. spinosa attacks wheat and barley and “other wild <strong>grass</strong>es certainly serve as hosts”<br />

(Spencer 1977). U. subquadripara is widespread in NSW, but not in areas <strong>of</strong> temperate <strong>grass</strong>land, the common weed E. indica is<br />

154

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