South-eastern Mainland Australia Research Articles

Life cycles and distribution of atherinids in the marine and estuarine waters of southern Australia

New and published data have been collated for the biology and distribution of atherinid species abundant in the coastal saline waters of Australia below 30°S. This information has been used to determine whether these species typically spawn at sea or pass through the whole of their life cycle in estuaries, and in one case, also lagoons and saline lakes. Length-frequency data, gonadosomatic indices and distribution records indicate that in south-eastern AustraliaCraterocephalus honoriae andAtherinosoma microstoma typically reach total lengths less than 90 mm, have a one-year life cycle and breed within estuaries. This parallels the situation recently described forAtherinosoma elongata, Atherinosoma wallacei andAllanetta mugiloides in south-western Australia (Princeet al., 1982a; Prince & Potter, 1983). The marine speciesAtherinosoma presbyteroides, which reaches a similar size and has a one year life cycle in both south-western and south-eastern mainland Australia, only enters estuaries in large numbers in the former region. WhileAtherinomorus ogilbyi is also found in estuaries and typically breeds at sea, it reaches total lengths as great as 189 mm and has a longer life thanA. presbyteroides. The limited data forAtherinason esox andAtherinason hepsetoides demonstrate that both these marine atherinids can attain total lengths of 139 and 108 mm respectively and live for longer than a year but do not enter estuaries in large numbers. The latter species is unique amongst southern Australian atherinids in having a distribution which extends into deeper water. It is suggested that landlocking may have played a role in the evolution and success of the estuarine mode of lifesensu stricto ofA. wallacei, A. elongata, A. microstoma, A. honoriae andA. mugiloides in southern Australian waters.

Silicified wood of Early MioceneNothofagus, Acaciaand Myrtaceae (aff.EucalyptusB) from the upper Lachlan valley, New South Wales

Three specimens of silicified wood, two transported and one probably in situ, have been found in association with Early Miocene basaltic lavas in the upper Lachlan valley, N.S.W. On the basis of their preserved structure, the three specimens have been identified as belonging to Nothofagus, Acacia, and the family Myrtaceae, respectively. The specimen of Nothofagus (one of the transported specimens) constitutes the first identification of a macrofossil of this genus from this interval in southeastern mainland Australia, while its conjunction with the myrtaceous specimens (one probably in situ) may indicate vegetation zonation according to elevation, as proposed on pollen evidence from Kiandra. Such zonation is not demanded by the upper Lachlan evidence, however, but if it is favoured, reconstruction of the Early Miocene geography of the upper Lachlan constrains the maximum elevation above the locality of the myrtaceous fossils to be 350 m.

A taxonomic revision of the Australian autumn gum moth genus Mnesampela Guest (Lepidoptera: Geometridae, Ennominae)

AbstractThe taxonomy and biology of the ennomine genus Mnesampela Guest is reviewed. Several species are well known in southern Australia as defoliators of gumtrees (Eucalyptus spp.) in cultivation. Seven species are recorded in the genus: privata (Guenée) (= inordinata Walker), comarcha Guest ( = comarcha Meyrick), lenaea Meyrick, heliochrysa (Lower), and three new species: athertonensis from the Atherton Tableland of north-eastern Quccnsland, kunama from high altitudes in south-eastern mainland Australia, and arida from the subinterior of southern Australia. A key to the species is provided and all species and their genitalia are descrihed and illustrated. Details of the immature stages, foodplants, flight periods, and distribution of the various species are also recorded. One new synonymy is established and two lectotypes are designated.

The life histories of many of the stoneflies (Plecoptera) of south-eastern mainland Australia

Collections of stonefly nymphs and adults were made at monthly intervals in 11 streams in Victoria throughout a year, and these were supplemented by collections from other streams. By following seasonal changes in the size distribution of the nymphs, and the occurrence of adults and cast skins, and by determining the length of development of the eggs under simulated stream conditions, the life cycles of 27 species were worked out in detail, and some information was obtained on a further seven species. The 34 species include representatives of all the four families that occur in Australia, and for several species the cycle was worked out in two or more streams. It is concluded that the life cycles in Australian species are generally much less rigid than those found in the northern hemisphere, and that they provide evidence of great adaptability to an uncertain climate. Each species therefore tends to occupy a broader ecological niche than do northern hemisphere ones and this possibly accounts fcr the relatively small number of species that are found in south-eastern Australia.

Low volume concentrate spraying for the control of the field cricket (Teleogryllus commodus)

The field cricket, Teleogryllus commodus (Walker) is an important pest of black cracking soils of south-eastern mainland Australia and of New Zealand. Insecticidal control was unsatisfactory until dieldrin was introduced. Residue problems associated with the use of dieldrin on pastures led to a revival of investigations into alternative treatments. The low volume concentrate application of technical malathion by aircraft gave rapid and effective control when applied late in the season. As little as 6.5 fl oz of 96 per cent malathion, estimated to cost no more than $1.20 an acre, including application costs, reduced cricket populations by 94-95 per cent two to six days after spraying, providing quick, convenient, and economical control and avoiding undesirable insecticide residues. Further trials will be necessary to determine suitable applications earlier in the season.