Origin and evolution of Parthenogenetic reproduction in the grasshopper Maraba virgo (Eumastacidae: Morabinae)

1968 ◽  
Vol 16 (4) ◽  
pp. 647 ◽  
Author(s):  
MJD White ◽  
GC Webb

The virgo group of morabine grasshoppers includes the parthenogenetic, all. female species virgo from western New South Wales and north-western Victoria, together with four bisexual species from arid regions of Western Australia. The karyotypes of three of these bisexual species are compared with that of virgo and the origin of the various kinds of genetic heterozygosity found in the latter is discussed. It has been shown by tritiated thymidine autoradiography that virgo, in addition to being heterozygous for various structural rearrangements, is a permanent heterozygote for certain late-replicating DNA segments in the AB and CD chromosomes. The total amount of DNA per diploid nucleus is slightly lower in virgo than in its bisexual relatives. It is probable that the evolution of the virgo karyotype under conditions of parthenogenetic reproduction has involved inactivation of some segments (as suggested by late-labelling) and actual deletion of others. There have been two different X-autosome fusions in the phylogeny of the virgo group (one in the ancestry of virgo itself), two fusions between autosomes, and a translocation (or dissociation plus fusion). A numerical system to designate these and other chromosomal rearrangements in the morabine grasshoppers is put forward.

2008 ◽  
Vol 21 (4) ◽  
pp. 271 ◽  
Author(s):  
Robyn L. Giles ◽  
Andrew N. Drinnan ◽  
Neville G. Walsh

Specimens of Phebalium glandulosum Hook. subsp. glandulosum representing the entire geographic range of the subspecies were examined for morphological and anatomical variation. Phenetic patterns were identified with the pattern analysis package PATN, and three distinct groups were identified. One group consists of plants from inland areas of New South Wales, north-western Victoria, and the Yorke and Eyre Peninsulas of South Australia; a second group consists of plants collected from alongside the Snowy River in eastern Victoria and south-eastern New South Wales; and a third group consists of plants from Queensland and northern New South Wales. The climate analysis program BIOCLIM was used to compare climate variables across the geographic range, and showed clear climatic separation in support of the phenetic analysis. The three groups are formally recognised here as distinct subspecies. Plants from Queensland and the Bourke region of northern New South Wales belong to the typical subspecies; plants from north-western Victoria, central New South Wales, and the Yorke and Eyre Peninsulas of South Australia form a cohesive assemblage and are recognised as a new subspecies P. glandulosum subsp. macrocalyx; and plants from the Snowy River in far eastern Victoria and the Southern Tablelands of New South Wales form a distinct and isolated group recognised as a new subspecies P. glandulosum subsp. riparium. These new subspecies are formally described, and an identification key and summaries distinguishing all six subspecies of P. glandulosum are presented.


1981 ◽  
Vol 71 (3) ◽  
pp. 449-466 ◽  
Author(s):  
V. A. Drake ◽  
K. F. Helm ◽  
J. L. Readshaw ◽  
D. G. Reid

AbstractAn entomological radar was used to observe insect flight activity at a coastal locality in north-western Tasmania during the spring of 1973. Insects were regularly observed to take off at dusk, and local movements from nearby islands were detected on several occasions. Large-scale southward movements of insects across Bass Strait were also observed and were found to be associated with the warm anticyclonic airflows which occur ahead of a cold front. Light-trap catches indicated that the insects were noctuid moths, with Persectania ewingii (Westw.), Heliothis punctiger Wllgr. and Agrotis munda Wlk. dominant. The movements appear to have originated mainly in Victoria and south-eastern South Australia, but it is tentatively suggested that the ultimate source of the moths was in the region stretching westwards from north-western Victoria and south-western New South Wales towards the shores of the Spencer Gulf, South Australia.


2006 ◽  
Vol 285 (1-2) ◽  
pp. 245-255 ◽  
Author(s):  
M. T. McHenry ◽  
B. R. Wilson ◽  
J. M. Lemon ◽  
D. E. Donnelly ◽  
I. G. Growns

2004 ◽  
Vol 17 (3) ◽  
pp. 327 ◽  
Author(s):  
Trisha L. Downing ◽  
Marco F. Duretto ◽  
Pauline Y. Ladiges

A morphological study of herbarium and field-collected specimens, using phenetic techniques of agglomerative classification, ordination and minimum spanning trees, and covering the geographic range of the Holly Grevillea, G.�ilicifolia (R.Br.) R.Br. sensu lato, has resulted in the recognition of three species and four subspecies. The taxa are based on leaf form, noted by previous authors to be highly variable between populations. The taxa recognised here are G.�ilicifolia, G.�ilicifolia subsp. ilicifolia (typical, kite-shaped leaf form), G.�ilicifolia subsp. lobata (F.Muell.) T.L.Downing comb. et stat. nov. (oak-shaped leaf form), G.�dilatata (R.Br.) T.L.Downing comb. et stat. nov. (fan-shaped leaf form), G.�angustiloba (F.Muell.) T.L.Downing comb. et stat. nov., G.�angustiloba subsp. angustiloba (narrow-lobed leaf form) and G.�angustiloba subsp. wirregaensis T.L.Downing subsp. nov. (very narrow-lobed leaf form). The rank of subspecies is used where there are some intermediate plants between forms. Grevillea ilicifolia subsp. ilicifolia is the most widespread taxon and occurs in South Australia, western Victoria and in two localities in New South Wales. Grevillea angustiloba subsp. wirregaensis has the most restricted range, occurring in semi-arid regions near Wirrega in South Australia. Grevillea dilatata is largely endemic to Kangaroo Island, South Australia.


1954 ◽  
Vol 5 (3) ◽  
pp. 422 ◽  
Author(s):  
EG Hallsworth ◽  
FR Gibbons ◽  
TH Lemerle

A study has been made of the nitrogen, organic carbon, phosphate, and pH levels of the wheat soils of north-western New South Wales, and the cultivation practices adopted. They are found generally to be high in both total and available phosphate, and particularly high figures for available phosphate, over 1000 p.p.m., were found in limited areas. The nitrogen levels of the virgin chernozemic soils are distinctly higher than those of the red-brown earths and red solodic soils, but soils of all groups show a decline with cultivation, which is most rapid in the first 10 years. The introduction of periods under lucerne raises the nitrogen level, but the wheat/grazed fallow or wheat/grazing oats appear to cause the same nitrogen losses as are encountered under continuous wheat, in spite of the prevalence of stubble burning which inevitably accompanies this practice. The average yields of wheat on the chernozemic soils are distinctly higher than those obtained on the red-brown earths and red solodic soils, on some of which nitrogen appears to be limiting.


1971 ◽  
Vol 16 (1) ◽  
pp. 29 ◽  
Author(s):  
PT Bailey ◽  
PN Martensz ◽  
RD Barker

1998 ◽  
Vol 38 (6) ◽  
pp. 555 ◽  
Author(s):  
A. M. Bowman ◽  
D. M. Hebb ◽  
D. J. Munnich ◽  
J. Brockwell

Summary. Populations of Rhizobium meliloti in self-mulching clay soils (Vertisols) at 48 sites on 27 properties in north-western New South Wales were classified according to number and ability to fix nitrogen with several species of Medicago. Rhizobia were counted using serial dilution, nodulation frequency, plant infection tests. Abilities of the soil populations to fix nitrogen were determined in the laboratory with whole-soil inoculation of Medicago seedlings in test tubes with shoots exposed to the atmosphere and roots within the tubes under bacteriological control, and in the field using a technique based on the natural abundance of 15N in the soil. The majority of soils contained >1000 cells of R. meliloti per gram. The major component of those populations fixed nitrogen with lucerne (Medicago sativa) and some components of some soils also fixed nitrogen with M. polymorpha, M. scutellata, M. littoralis, M. tornata, M. laciniata and Trigonella suavissima. However, a number of soils were located which contained few if any rhizobia effective in nitrogen fixation with M. polymorpha. Overall, the effectiveness of nitrogen fixation of the naturally occurring populations of R. meliloti in association with M. polymorpha, M. scutellata, M. littoralis and M. tornata was only 46% of the effectiveness of standard strains. At one particular site, where 10 lines of annual Medicago spp. were growing experimentally, fixed nitrogen as a proportion of shoot nitrogen averaged only 28%. At that site, there were no effective rhizobia for M. scutellata and it was wholly dependent on the soil as the source of its nitrogen. The results are discussed in relation to the need for a substantial input of legume nitrogen for restoring the natural fertility of self-mulching clay soils in degraded wheat lands of north-western New South Wales. It is suggested that lucerne, or perhaps other perennial Medicago spp., might fill this role better than annual medics such as M. polymorpha and M. scutellata that are more dependent than lucerne on specific strains of R. meliloti to meet their requirements for symbiotic nitrogen fixation.


1997 ◽  
Vol 3 (3) ◽  
pp. 235 ◽  
Author(s):  
Jack Baker

The Eastern Bristlebird Dasyornis brachypterus is a threatened passerine, endemic to southeastern Australia. It is a cryptic, ground dwelling, semi-flightless inhabitant of dense, fire-prone vegetation and is usually only detected by its calls. The disjunct distribution suggests that they were once more numerous and their population continuous from southern Queensland to western Victoria. Their decline has been documented in historic and recent times. Habitat loss, nest desertion and fire have been implicated in the decline and extinction of local populations. Strongholds for the species are Barren Grounds Nature Reserve and Bherwerre Peninsula, 100 and 150 km south of Sydney respectively. At Barren Grounds, in the absence of recent fire, there were significant increases in the population between 1992 and 1996. There was a trend of increasing Eastern Bristlebird density with increasing fire-age of habitat and average density plateauing at two birds per 5 ha, 10 years after fire. At Nadgee, a coastal Nature Reserve on the New South Wales/Victorian border, the population appears to be recovering very slowly from severe wildfires in 1972 and 1980. At the beginning of 1996 there were less than 2 000 individual Eastern Bristlebirds occupying an area of approximately 100 km2. For the management of Eastern Bristlebirds, habitat manipulation using prescribed fire should not be undertaken unless site-specific population monitoring data demonstrate that it would be beneficial. Concentrations of Eastern Bristlebirds and potential fire refuges should be protected from unplanned fire. For prescription burns, potential escape routes need to be planned for Eastern Bristlebirds. The threatened status should be changed from Vulnerable to Endangered.


1996 ◽  
Vol 18 (1) ◽  
pp. 179 ◽  
Author(s):  
MH Campbell ◽  
AM Bowman ◽  
WD Bellotti ◽  
DJ Munich ◽  
HI Nicol

The recruitment of Astrebla lappacea was studied from 1986 to 1995 in a pasture in north-western NSW where the density of plants had declined from 1 to 3 plants/m2 in 1970 to 0.023 plants/m2 in 1986. Three treatments were imposed: ungrazed-sprayed-slashed, where annual weeds were treated with herbicides and slashing to reduce competition during recruitment; ungrazed-only; and grazed-only. The seed bank of A. lappacea was measured on four occasions and densities of A. lappacea plants determined after major rainfall events mainly in summer and autumn. On the ungrazed treatments the seed bank of A. lappacea increased from 0 in 1988 to 908, 898 and 286 germinable seed/m2 in, respectively, 1992, 1993 and 1995. Flowering and seedling recruitment occurred each year from 1988 to 1995 but seedlings only survived to become mature plants from the 1988 and 1992 recruitments. The major reason for the death of seedlings was dry conditions in the latter half of the year (1 10 to 135 mm of raid6 months). Frosts and competition from Brassicaceae weeds (mainly Raphistrum rugosum) in winter and spring also contributed to death of seedlings. Recruitment of seedlings and their survival to mature plants was higher on the ungrazed-sprayed-slashed treatment than on the other treatments. Recruitment and survival on the ungrazed-only treatment occurred because Brassicaceae weeds did not establish when recruiting rains fell in summer. Plant densit increased from 0.023 plants/m2 in 1986 to, respectively, 0.86, 0.64 Y and 0.004 mature plantdm and 7.88, 6.37, 0.10 seedlings/m2 on the ungrazed-sprayed-slashed, ungrazed-only and grazed-only treatments in 1995. On the grazed-only treatment the methods used to detect seeds revealed none in the soil during the experiment. However, some seeds were present because there was a low level of recruitment none of which survived to mature plants. The number of mature plants declined from 0.023 to 0.004/m2 indicating that under the present grazing system the complete elimination of A. lappacea from pastures in north-western NSW is possible if some form of managed recruitment is not devised.


1974 ◽  
Vol 1 (1) ◽  
pp. 17 ◽  
Author(s):  
BS Parker ◽  
K Myers

Aerial surveys can be used to measure the distribution of rabbit warrens over large areas of arid and semiarid Australia. Clumped patterns of distribution of rabbit warrens found by ground surveys are also detected in aerial surveys, which further show that the highest density of warrens occurs in habitats containing shales or other fine-grained rocks overlain by recent sediments, or those closely related to drainage systems. A good picture of rabbit distribution is obtained when about 25% of the area has been overed by the aircraft. * Part IV, Aust. J. Zool., 1971, 19, 355–70.


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