An ecological study of an Australian dung beetle, Onthophagus granulatus Boheman (Coleoptera: Scarabaeidae), using physiological age-grading techniques

1981 ◽  
Vol 71 (1) ◽  
pp. 137-152 ◽  
Author(s):  
M. Tyndale-Biscoe ◽  
M. M. H. Wallace ◽  
J. M. Walker
Keyword(s):  
Ecological Study ◽  
Summer Rainfall ◽  
Dung Beetle ◽  
Early Summer ◽  
Physiological Age ◽  
Brood Production ◽  
Factors Affecting ◽  
Eastern Australia ◽  
Age Grading ◽  
Threshold Of Development

The distribution and seasonal activity of Onthophagus granulatus Boh. was studied at two sites in eastern Australia. It is a univoltine species, with peaks of activity in spring and early summer. Breeding cycles and periods of stress were demonstrated by the proportions of newly emerged, nulliparous and parous beetles and those resorbing oocytes. The optimum temperature for brood production was 25°C. The threshold of development was 11·3°C, and 495 day-degrees C were required for development from egg to adult. Dung quality and drought were important factors affecting survival and brood production in the field. The distribution of the species in south-eastern Australia is limited by summer rainfall and temperature.

Physiological age-grading in females of the dung beetle Euoniticellus intermedius (Reiche) (Coleoptera: Scarabaeidae)

1978 ◽  
Vol 68 (2) ◽  
pp. 207-217 ◽  
Author(s):  
Marina Tyndale-Biscoe
Keyword(s):  
Fat Body ◽  
Dung Beetle ◽  
Oocyte Development ◽  
Physiological Age ◽  
Maturation Period ◽  
Brood Production ◽  
Yellow Body ◽  
Age Grading

AbstractNewly emerged females of Euoniticellus intermedius (Reiche) have no differentiated oocytes in their single ovariole. The eggs mature sequentially during the maturation period, and at 27°C the first egg is laid 4–8 days after emergence. The rate of oviposition increases with temperature between 18 and 32°C. The threshold for oviposition is 19·6°C, and one egg is produced for every four day-degrees above this threshold. Most females can be sorted into the nulliparous or one of three parous categories, covering the period from emergence to the time when between 75 and 127 eggs have been deposited, on the basis of the quantity of yellow body in the ovariole. The hardness of the cuticle, the degree of oocyte development, and the presence or absence of fat-body in the abdomen can be used to subdivide the nulliparous category into three parts and to recognise old or ‘spent’ beetles. The degree of wear on the tibial teeth gives an age estimate that is independent of nutritionally induced delays and with which the ovarian age can be compared. Actual age cannot be estimated in field-caught-beetles, however, since many factors besides temperature alter the rate of brood production.

An ecological study of an attempt at biological control of Noogoora burr (Xanthium strumarium)

1974 ◽  
Vol 25 (2) ◽  
pp. 275 ◽  
Author(s):  
AJ Wapshere
Keyword(s):  
Biological Control ◽  
Egg Production ◽  
Ecological Study ◽  
Plant Density ◽  
Summer Rainfall ◽  
Growth Conditions ◽  
Xanthium Strumarium ◽  
Eastern Australia ◽  
Number Of Stems ◽  
Verbal Model

The recent introduction of two cerambycids, Mecas saturnina and Nupserha vexator, for the biological control of Noogoora burr, Xanthium strumarium, a weed of sheep pastures in subtropical eastern Australia, has led to the development of a verbal model of the effect of these introductions on the populations of the weed. The model takes into account the dependence of X. strumarium on late spring and summer rainfall, the overwinter survival and germinability of the burrs, and the effect of plant density and growth conditions oil the number of stems and burr production per plant. The fact that only one cerambycid survives in each rootstock, no matter how many stems are attacked, and the small estimated reduction in burrs per plant produced by an individual cerambycid larva (15 for N. vexator, 35 for M. saturnina), indicated that successful biocontrol depended on high cerambycid populations. On taking into account the egg production of each cerambycid, it was concluded that, although high beetle populations could develop in dense, strongly growing X. strumarium stands in coastal and subcoastal regions, they would cause only minor reductions in plant density. They would be more effective against poorly growing stands and at sites with low overwinter burr survival, provided that stands occur consistently each year. These conclusions are dependent on the adaptability of the cerambycids to the climates of the Noogoora burr-infested region. a factor not considered.

The sensitivity of Australian animals to 1080 poison. I. Intraspecific variation and factors affecting acute toxicity

1981 ◽  
Vol 8 (2) ◽  
pp. 369 ◽  
Author(s):  
J. C. Mcilroy
Keyword(s):  
Acute Toxicity ◽  
Intraspecific Variation ◽  
Factors Affecting ◽  
Eastern Australia ◽  
Vertebrate Pests ◽  
Breeding Condition ◽  
Different Populations ◽  
Males And Females

The calculated sensitivity (LD50) of a species to 1080 poison (sodium fluoroacetate), used for control of vertebrate pests, is affected by the experimental procedures employed. Variation can be minimized if the most obvious sources are avoided, as described in this paper. Very young mammals and female waterfowl in breeding condition may be more sensitive to 1080 than other members of their populations. No other substantial differences in sensitivity were found between males and females, immatures and adults, or within and between different populations of six species of birds and mammals in eastern Australia.

The Southern Oscillation Index as a predictor of seasonal rainfall in the arable areas of the inland Australian subtropics

1993 ◽  
Vol 44 (6) ◽  
pp. 1337 ◽  
Author(s):  
JS Russell ◽  
IM McLeod ◽  
MB Dale ◽  
TR Valentine
Keyword(s):  
Southern Oscillation Index ◽  
Southern Oscillation ◽  
Linear Trend ◽  
Summer Rainfall ◽  
Seasonal Rainfall ◽  
Four Seasons ◽  
Eastern Australia ◽  
Australian Continent ◽  
Ace Algorithm ◽  
Linear Trends

A detailed study has been carried out in four regions in the subtropics of Eastern Australia to determine the relationship between the Southern Oscillation Index (SOI) and subsequent seasonal rainfall. The period studied was from 1915 to 1991 for 3-monthly periods of spring (SON), summer (DJF), autumn (MAM) and winter (JJA). The 3-monthly prior SOI values were plotted against seasonal rainfall of the four regions and four seasons. These data were widely scattered but with a linear trend showing increased seasonal rainfall as the SOI increased. Linear trends were plotted for each season and region. Comparisons were made between the use of the ACE algorithm, which transforms the SOI and rainfall data, and the use of linear trends. Polynomials were used to calculate equations for each region and season, but only spring and summer produced satisfactory ACE functions. Estimates were made of spring and summer rainfall relative to prior SOI values for each region. While the SOI as a predictor of rainfall broadly estimates spring and summer rainfall, this variable has limited usefulness on its own. One of the options available with the ACE program is that additional independent variables can be added as required. Current research suggests that sea surface temperature data from specific ocean areas surrounding the Australian continent is the most useful additional variable at present. However the complexity of such an analysis is greatly increased.

Factors affecting the response ofLongitarsus jacobaeae(Coleoptera: Chrysomelidae) to upwind plant odours

1996 ◽  
Vol 86 (3) ◽  
pp. 307-313
Author(s):  
Zhi-Qiang Zhang ◽  
Peter B. McEvoy
Keyword(s):  
Wind Tunnel ◽  
Host Plants ◽  
Local Density ◽  
Flea Beetle ◽  
Late Summer ◽  
Developmental State ◽  
Early Summer ◽  
Directed Movement ◽  
Factors Affecting ◽  
Plant Odours

AbstractFactors (developmental state, starvation time, host local density and host distance from insects) affecting the response of the ragwort flea beetle,Longitarsus jacobaeae(Waterhouse), to upwind plants of tansy ragwort,Senecio jacobaeae(Compositae), were examined in a wind tunnel. There was seasonal variation in beetle response to host odours. Individuals collected during spring and early summer (6 May to 14 July 1993) showed directed movement toward the upwind plants. However, individuals collected in mid-summer (23 July 1993) showed no significant response to upwind host plants and walked randomly in the wind tunnel. Individuals collected during late summer to autumn (4 August to 23 October 1994) once again showed response to upwind plants, whereas those collected in winter (January 1994) walked randomly in the wind tunnel. The absence of beetle response to plant odours coincided with potential summer aestivation and winter ‘hibernation’. For spring and early summer beetles that responded to plant odours, the strength of the response did not change significantly with the number of plants (1, 2, 4 or 6) presented upwind in the tunnel nor with the starvation time (2, 6, 10, 12, 24 or 36 h) of the tested beetles, and these patterns were consistent for male and female beetles. Individuals responded to plants from a distance of 60 and 300 cm. The speed of movement, similar for males and females, increased slightly asL. jacobaeaeoriented more directly toward host plants.

Population biology of Microlaena stipoides in a south-eastern Australian pasture

2014 ◽  
Vol 65 (8) ◽  
pp. 767 ◽  
Author(s):  
M. L. Mitchell ◽  
J. M. Virgona ◽  
J. L. Jacobs ◽  
D. R. Kemp
Keyword(s):  
Seed Predation ◽  
Population Biology ◽  
Seedling Recruitment ◽  
Perennial Grass ◽  
Early Summer ◽  
Seed Rain ◽  
Perennial Grasses ◽  
South Eastern ◽  
Eastern Australia ◽  
Microlaena Stipoides

Microlaena (Microlaena stipoides var. stipoides (Labill.) R.Br.) is a C3 perennial grass that is native to areas of south-eastern Australia. In this region, perennial grasses are important for the grazing industries because of their extended growing season and persistence over several years. This series of experiments focused on the population biology of Microlaena by studying the phenology (when seed was set), seed rain (how much seed was produced and where it fell), seed germination, germinable seedbank, seed predation and seedling recruitment in a pasture. Experiments were conducted at Chiltern, in north-eastern Victoria, on an existing native grass pasture dominated by Microlaena. Seed yields were substantial (mean 800 seeds m–2), with seed rain occurring over December–May. Microlaena has two distinct periods of high seed rain, in early summer and in early autumn. Seed predation is high. Within a 24-h period during peak seed production, up to 30% of Microlaena seed was removed from a pasture, primarily by ants. Microlaena seedlings recruited throughout an open paddock; however, seedling density was low (5 seedlings m–2). Microlaena represented only low numbers in the seedbank (0.01–0.05% of total); hence, any seedlings of Microlaena that germinate from the seedbank would face immense competition from other species. Management strategies for Microlaena-dominant pastures need to focus on the maintenance of existing plants.

The influence of supplementary feeding on growth and fertility of beef heifers grazing natural pastures

1968 ◽  
Vol 8 (33) ◽  
pp. 425 ◽  
Author(s):  
EJ Sparke ◽  
DR Lamond
Keyword(s):  
New South ◽  
Age Groups ◽  
Summer Rainfall ◽  
Early Summer ◽  
Protein Supplementation ◽  
Low Fertility ◽  
Winter Period ◽  
Target Weight ◽  
South Wales ◽  
North Eastern

This paper reports an experiment examining the effect of age and protein supplementation on growth and fertility of Shorthorn-Devon cross heifers grazing natural pastures in the summer rainfall, subtropical environment of the Upper Clarence valley, north-eastern New South Wales. Heifers born over the period October to January 1963-64 were weaned in June 1964 and allotted at random within age groups (by month of birth) to a supplemented or non-supplemented treatment. The supplemented heifers were given linseed meal during the dry winter period each year from 1964 to 1966 inclusive (May-June to September-October). They were weighed each month and joined with bulls in the early summer of 1965 (2 years) and 1966 (3 years). They were examined for pregnancy in the autumn, and their calves were identified at birth. Supplemented heifers gained weight throughout and non-supplemented heifers generally lost weight in the winter periods. At two years fertility was closely related to liveweight at joining in supplemented heifers, but not in others. Heifers born in January gave the poorest reproductive performance, as the two supplemented ones that became pregnant in 1965 died at calving, and two-thirds of the non-supplemented ones were still empty after joining as 3-year-olds. The advantage of high 2-year-old fertility gained by heifers born in October and November, due to their greater size at joining, was partly offset by low fertility when lactating the following year. It is concluded that a decision as to whether a heifer should be supplemented during a period of nutritional stress prior to joining ought to be based on the probability of her reaching a prescribed target weight at joining as a result of receiving the supplement. The target weight for lactating heifers was at least 100 Ib higher than for dry hdfers. The results also indicate specific areas for further research.

Post-fire ephemerals and spinifex-fuelled fires: a decision model for bilby habitat management in the Tanami Desert, Australia

2007 ◽  
Vol 16 (6) ◽  
pp. 741 ◽  
Author(s):  
Richard Southgate ◽  
Susan Carthew
Keyword(s):  
Habitat Suitability ◽  
Decision Model ◽  
Habitat Management ◽  
Fire History ◽  
Spatial Databases ◽  
Ground Cover ◽  
Weather Conditions ◽  
Early Summer ◽  
Annual Rainfall ◽  
Factors Affecting

Seed from post-fire ephemeral plants like Yakirra australiense can form an important component of the diet of the bilby, a threatened arid-dwelling bandicoot. An investigation was conducted to determine the factors affecting the production of Yakirra and fire reoccurrence in the Tanami Desert. A simple decision model was produced to assist managers decide where and when to burn and what to expect regarding Yakirra australiense growth following fire and rainfall. The information used in the model may be derived from existing spatial databases that document rainfall and fire history and could be used to map broad-scale temporal change in total vegetation cover and components of habitat suitability for the bilby. The season and magnitude of rainfall and time-since-fire were the most important variables in the production of Yakirra seed. Rainfall >300 mm within a 2-month period of intense-complete burns could result in >5% Yakirra cover, and >100 mm was required for >1% cover. Negligible Yakirra cover occurred in adjacent long-unburnt plots. Total ground cover and spinifex cover varied substantially in relation to mean annual rainfall, but not in relation to substrate type. Long-unburnt spinifex cover was mostly too sparse to carry a fire in the southern part of the Tanami and the growth of non-spinifex vegetation would be necessary to boost fuel loads sufficiently to carry a fire. Generally, more than 41% cover was required to carry a fire but this was also dependent on weather conditions. Managers should aim to burn in late spring or early summer to improve Yakirra production. Fire management to enhance habitat suitability for the bilby would be of most benefit in the northern part of the Tanami Desert where growth rate of vegetation is greater and there is little existing fire age heterogeneity.

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