Influence of temperature and food availability on the ecological energetics of the giant scallop Placopecten magellanicus

Summary Gonad output, reproductive effort and residual reproductive value are greater in scallops (Placopecten magellanicus) from shallow water, where conditions are more favourable, than in scallops from deep water. Variation between years in these fitness correlates is also greater in shallow water scallops. High reproductive effort is associated with a greater reproductive cost, although in general reproduction in this species appears to be restrained, and only in older individuals from shallow water is there evidence of reckless reproductive behaviour. Reproductive effort increases as the animal grows older, but residual reproductive value is a maximum at age 4 years, after which it decreases with age owing to greater mortality. Localities vary in their suitability for scallop growth and reproduction, and at one Newfoundland site conditions in shallow water (10 m) are better than those in deep water (31 m). Scallops from the former have a greater fitness than those from the latter. The energy costs of reproduction have implications for life history variability in P. magellanicus, although for a considerable part of its lifetime the scallop is able to maximise gamete production in response to environmental factors (especially the food supply) without trading off reproduction against growth or maintenance.     

Optimal body size and an animal's diet

Within many animal taxa there is a trend for the species of larger body size to eat food of lower caloric value. For example, most large extant lizards are herbivorous. Reasonable arguments based on energetic considerations are often invoked to explain this trend, yet, while these factors set limits to feasible body size, they do not in themselves mathematically produce optimum body sizes. A simple optimization model is developed here which considers food search, capture, and eating rates and the metabolic cost of these activities for animals of different sizes. The optimization criterion is defined as the net caloric gain a consumer accrues per day. This model does produce an optimum intermediate body size which increases with food quality - not the reverse. This discrepancy is accounted for, however, because the model also predicts that body size should be even more sensitive to increases in food abundance. In nature, many poor quality foods are also relatively abundant foods, hence the consumers eating them may maximize their daily energetic profit by evolving a relatively large body size. Optimum consumer body size also decreases with increases in consumer metabolic rate and prey speed.     

Metabolic engineering of an alternative pathway for ascorbic acid biosynthesis in plants

Plants and most animals can synthesize their own L-ascorbic acid (vitamin C), but a mutation in the L-gulono--lactone oxidase gene in the primate lineage makes it necessary for humans to acquire this vital compound from their diet. Despite the fact that plants and animals synthesize ascorbic acid via different pathways, transgenic tobacco and lettuce plants expressing a rat cDNA encoding L-gulono--lactone oxidase accumulated up to seven times more ascorbic acid than untransformed plants. These results demonstrate that basal levels of ascorbic acid in plants can be significantly increased by expressing a single gene from the animal pathway.     

The smallest but fastest: Ecophysiological characteristics of traps of aquatic carnivorous Utricularia

Aquatic Utricularia species usually grow in standing, nutrient-poor humic waters. They take up all necessary nutrients either directly from the water by rootless shoots or from animal prey by traps. The traps are hollow bladders, 1–6 mm long with elastic walls and have a mobile trap door. The inner part of the trap is densely lined with quadrifid and bifid glands and these are involved in the secretion of digestive enzymes, resorption of nutrients and pumping out the water. The traps capture small aquatic animals but they also host a community of microorganisms considered as commensals. How do these perfect traps function, kill and digest their prey? How do they provide ATP energy for their demanding physiological functions? What are the nature of the interactions between the traps and the mutualistic microorganisms living inside as commensals? In this mini review, all of these questions are considered from an ecophysiologist''s point of view, based on the most recent literature data and unpublished results. A new concept on the role of the commensal community for the plants is presented.Key words: aquatic carnivorous plants, bladderwort, bladders, firing, resetting, enzyme secretion, water pumping, microbial commensals     

Zur Brutbiologie des Seggenrohrs?ngers(Acrocephalus paludicola)

Zusammenfassung In der vorliegenden Arbeit werden Beobachtungen ausgewertet, die in den letzten Jahren in einer Seggenrohrsängerpopulation der Mark Brandenburg gesammelt wurden. Brutbiotop ist eine Großseggenwiese. und haben getrennte Reviere, wobei sich -Reviere, -Reviere und auch - und -Reviere zum Teil sehr erheblich überlagern. Keinem konnte ein bestimmtes zugeordnet werden, sie leben also in Keinehe. versuchen, aus der Nestnähe zu vertreiben. Aggressive Handlungen zwischen benachbarten konnten nicht festgestellt werden. Ihre Singflüge unterscheiden sich von denen der Schilfrohrsänger. 28 Eier maßen im Durchschnitt 17,76×13,14 mm. Nur die brüten und Füttern. Die durchschnittliche Fütterungsfrequenz liegt bei 19,7 Fütterungen pro Stunde, die tägliche Aktivitätszeit der ist im Juli etwa 1 Stunde kürzer als im Juni. 13–14 Tage nach dem Schlüpfen verlassen die Jungen das Nest. In der Nestlingsnahrung ist bei Julibruten der hohe Heuschreckenanteil auffällig. Nachdem die Jungen selbständig sind, streunen sie im Brutbiotop umher. Zweitbruten sind sehr wahrscheinlich, konnten aber noch nicht nachgewiesen werden.

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Summary Observations made during the last years on a population of the Aquatic Warbler (Acrocephalus paludicola) in Brandenburg, Germany, gave the following results:In a sedge meadow, withCarex elata the dominant species, males and females ofAcrocephalus paludicola held separate territories, those of males as well of females sometimes considerably overlapping territories held by other individuals of the same or the opposite sex. In no case a certain male could be considered as having formed a firm pair bond with a certain female: on the contrary, the relations between the sexes were very loose, and probably the birds are even promiscuous. Females try to chase away males from the neighbourhood of their nests. Aggressiveness between neighbouring males has not been observed. The display flights of the males are different from those of the Sedge Warbler(A. schoenobaenus). 28 eggs measure on the average 17,76×13,14 mm. Females alone incubate and feed the young, at an average rate of 19,7 times per hour. The young leave the nest 13–14 days after hatching. Young reared in July are fed a great amount of grasshoppers. Second broods probably occur, but could not be proved.

     

The use of nitrogen fertiliser in agriculture. Where do we go practically and ecolotically?

Nitrogen fertilisers were produced in 72 countries in 1982, total world capacity being 99 mt of N, having been 50 mt in 1970. Consumption was 31.8 mt in 1970, rising to 60.3 mt in 1980 (Av. annual growth rate 7%). Forecasts suggest N use of 90 mt in 1990 rising to between 111–134 mt by the year 2000.The large amount of N added to only some 11% of the earth's land surface as fertilisers, coupled with concurrent increases in biological N fixation, mainly by grain legumes, is bound to result in increases in the total N content of soils, waters, crop residues and municipal wastes. The need to use N to produce sufficient food and fibre for the 7 billion humans must be set against the need to maintain a good and safe environment. Nitrate levels are increasing in both surface and ground water supplies. The amount of ammonia and oxides of nitrogen in the atmosphere produced by volatilisation and denitrification from soils and animal excreta is also rising. Such increases may have detrimental environmental effects to human health and to the ecology of downstream or polluted non-agricultural ecosystems though the severity and extent of these effects requires verification. As yet, there is little hard evidence of direct damage to human health due to high levels of nitrate in diet or of NH₃ and NO_x in the atmosphere, but effects on natural and forest ecosystems in some areas are proven.With this background, strategies are examined which should help to increase the efficiency with which N is utilised by crops and animals and so decrease losses of nitrogen from farmland.These include the selection of optimum N fertiliser practices based on knowledge of plant requirements, soil N supply, and the use of carefully chosen times, methods and forms of N fertiliser application. Other technological approaches such as use of slow release fertilisers, chemicals that inhibit certain biological transfers of N in soils and amendments added to N fertilisers, to soils or to animal excreta to alter their chemical properties could be developed. Greater use of legumes and enhanced levels of N₂-fixation may also help to lessen the need for N fertiliser.To achieve further improvement in the ways of using N in agriculture, more precise knowledge is needed of the dynamics of nitrogen turnover in soils, of translocation and assimilation in plants, and of interactive flows between soil, plants and animals, and the atmosphere. Only with full understanding of the many biological processes that affect N in ecosystems obtained by multidisciplinary research will it be possible to determine the guidelines for environmentally kind, socially acceptable and economically sound management of nitrogen utilisation in agriculture.     

Age-related accumulation of lysosomes and other cytological features in active thyroid follicles of the CBA mouse

Summary This study attempts to elucidate the mechanism through which lysosomal accumulation occurs with age in the epithelial cells of the thyroid gland and especially in the active follicles of the aging mouse thyroid. Thyroid morphology and function in old CBA (at least 24 months of age) male mice were compared with those in young (2 months of age) animals. The effects of different intake of iodine were tested and compared in both cohorts, each of which was divided into three groups: (i) low iodine group, (ii) moderate iodine group, and (iii) high iodine group. As expected, the present work confirmed the well-known accumulation with age of cold follicles coexisting with active follicles in the old mouse thyroid. Attention has been focused on the active follicles whose follicular cells contained in their cytoplasm a large number of pleomorphic dense bodies. The lysosomal nature of these bodies, referred to as secondary lysosomes, was confirmed by histochemistry; however, they displayed variability in acid phosphatase staining. In old animals, regardless of the type of iodine regimen, the ratio between relative follicular volume and relative colloid volume as determined by morphometry remained unchanged. Ultrastructurally, the relative volume occupied by secondary lysosomes in active follicles was always higher than in the young groups. Autoradiographic studies with ¹²⁵I revealed that a large part of the radioactivity was located in secondary lysosomes of thyroid cells in active follicels of old mice when radioiodine was injected 3 weeks before death. Two different types of vacuoles were present in a non-negligible number of thyrocytes of the active follicles in aged cohorts. The first type was made up of grossly dilated rough endoplasmic cisternae, the second corresponded to intracytoplasmic microfollicular vacuoles. Both aspects have been described in conditions of chronic stimulation. It is concluded (1) that different intake of iodine for 6 weeks does not modulate the thyroid morphology in old mice; (2) that in the thyrocytes of the active follicles in old mice accumulation of secondary lysosomes occurs due to a slowdown of turnover; and (3) that the follicular cells of active follicles feature morphological aspects suggesting a hyperactive state compensating the lack of hormone production in the cold follicles.     

Prey availability affects territory size,but not territorial display behavior,in green anole lizards

The availability of food resources can affect the size and shape of territories, as well as the behaviors used to defend territories, in a variety of animal taxa. However, individuals within a population may respond differently to variation in food availability if the benefits of territoriality vary among those individuals. For example, benefits to territoriality may differ for animals of differing sizes, because larger individuals may require greater territory size to acquire required resources, or territorial behavior may differ between the sexes if males and females defend different resources in their territories. In this study, we tested whether arthropod abundance and biomass were associated with natural variation in territory size and defense in insectivorous green anole lizards, Anolis carolinensis. Our results showed that both male and female lizards had smaller territories in a habitat with greater prey biomass than lizards in habitats with less available prey, but the rates of aggressive behaviors used to defend territories did not differ among these habitats. Further, we did not find a relationship between body size and territory size, and the sexes did not differ in their relationships between food availability and territory size or behavioral defense. Together, these results suggest that differences in food availability influenced male and female territorial strategies similarly, and that territory size may be more strongly associated with variation in food resources than social display behavior. Thus, anole investment in the behavioral defense of a territory may not vary with territory quality.     

Stable isotopic survey of the role of macrophytes in the carbon flow of aquatic foodwebs

Whether aquatic animals rely primarily for sustenance upon vascular macrophytes or attached algae has been often debated. A compilation of carbon isotope data from the literature for coastal seagrass meadows, estuarine salt marshes, and freshwater lakes and rivers indicates that animal ¹³C values more closely approximate those of attached algae than they do those of vascular plants. This empirical synthesis supports results from individual studies in suggesting that macrophytes are unlikely to play an exclusive and direct dietary role in aquatic foodwebs.     

Cellular immunity in an annelid (Nereis diversicolor,Polychaeta): production of melanin by a subpopulation of granulocytes

Summary We attempted to identify the nature and origin of the pigment produced by the marine worm Nereis diversicolor in order to isolate, in inert brown capsules, foreign objects introduced into its body cavity. This brown pigment, characterized by cytochemical techniques, could be a melanin. The activity of the enzyme phenoloxidase responsible for melanin biosynthesis was detected by enzyme cytochemistry techniques in vacuoles and the Golgi apparatus of coelomocytes activated by the presence of foreign bodies. Morphological techniques combined with a monoclonal immunological probe enabled us to establish that the G₂ granulocytes contain both the precursor of the pigment in dense bodies and the capacity for phenoloxidase synthesis when activated to encapsulate foreign bodies. The G₂ granulocyte may therefore be compared to a melanocyte in which melanin is not stored as in mammals, but immediately extruded following synthesis in the form of a thick fluid.Abbreviations ACTH adrenocorticotropic hormone - Dopa L-3,4 dihydroxyphenylalanine - FITC fluorescein isothiocyanate - G ₁, G ₂, G ₃ granulocyte of types 1, 2, 3 - MSH melanocyte-stimulating hormone - proPo prophenoloxidase     

Development and fate of the secretory granules of juxtaglomerular epithelioid cells

Summary The development and fate of the secretory granules in murine, rat and human juxtaglomerular epithelioid cells were examined using ultrastructural and immunocytochemical methods. The formation of mature renin granules occurs by fusion of rhomboid protogranules followed by coalescence of their paracrystalline contents, and by the fusion of roundish juvenile granules having an amorphous internum. Protogranules with paracrystalline contents are prominent in animals with stimulated renin synthesis, indicating an overcharge in processing and/or packaging of the secretory product, renin, under these conditions. Various similarities between lysosomes/multivesicular bodies (MVBs) and juvenile renin granules have been observed. With the exception of small MVBs, no renin-negative organelles that could be regarded as lysosomes were found in epithelioid cells of mice and rats. Therefore, we suggest that renin granules are modified lysosomes. Immunocytochemical findings indicate that juvenile secretory granules of epithelioid cells represent the converting and activating compartment for prorenin. Endocytosed foreign tracers such as HRP or cationized ferritin are preferentially internalized by juvenile renin granules, which hence appear to be outstanding by their fusogeneity. Consequently, juvenile granules are probably responsible for the secretion of prorenin, and mature granules for that of active renin.These studies were supported by the German Research Foundation within the Forschergruppe Niere/Heidelberg     

Feeding selectivity in relation to territory size in a herbivorous reef fish

Summary Territory size in the herbivorous reef fish, Parma victoriae, (Pisces: Pomacentridae) is primarily determined by local density patterns and is independent of changes in food levels (Norman and Jones 1984). However, while individual readily expand territories in response to having their neighbours removed, they appear not to increase total food consumption. Individuals with large territories may benefit from improved food quality. Here we test the hypothesis that expanded territories increase access to preferred food types.A preliminary comparison of the relative proportions of algal species consumed and those present in the field indicated that feeding was highly selective. Strong feeding preferences were indicated by a field cafeteria experiment, in which algal species were presented to individuals in equal amounts. Selectivity indices calculated from diet and availability measures were positively correlated with the feeding preference rankings.Individuals examined from two territory size categories (<10 m² and > 10 m²) did not exhibit significant differences in feeding prefernces. However, they differed greatly in terms of the makeup of their diets. Higher ranking algae such as Champia zostricola and Rhodoglossum sp. were consumed in greater proportions on large territories. Algal abundances within territories also differed for the two groups. Some of the less abundant, high ranking food species were found in greater quantities per unit area on large territories. The differences in diet were not solely explained by changes in availability. The appropriate comparison showed that whereas individuals on large territories fed in a highly selective manner, those on small territories consumed algae in proportion to their availability. A neighbour removal experiment supported the hypothesis that territory expansion results in an increase in the consumption of preferred algal species.     

The importance of a relative shortage of food in animal ecology

Summary It is proposed that for many if not most animals — both herbivore and carnivore, vertebrate and invertebrate — the single most important factor limiting their abundance is a relative shortage of nitrogenous food for the very young. Any component of the environment of a plant, by varying the amount of adequately nutritious plant tissue available to herbivores, may consequently affect the abundance of food through all subsequent trophic levels; in this regard weather may be important more often than is immediately obvious.The hypothesis proposes that animals live in a variably inadequate environment wherein many are born but few survive, and leads to a concept of populations being limited from below rather than controlled from above. And it may lead to a reappraisal of the role of predation, competition and social and territorial behaviour as factors likely to influence the numbers of animals in the environment, the response of pests to manipulation of populations of their food plants by Man, and the likely effectiveness of agents of biological control.     

Effects of suspensoids (turbidity) on penetration of solar radiation in aquatic ecosystems

In mainland Australia and in southern Africa, the aridity of the climate and sparse vegetative cover increase the susceptibility of the soils to erosion, and as a consequence surface waters are usually turbid. The inanimate suspensoids in such waters, the tripton fraction of the limnologist, are responsible for virtually all the light scattering, and also, by virtue of the yellow-brown humic materials adsorbed on their surface, for a substantial part of the light absorption. Spectral absorption data for suspensoids in terms of theirin situ absorption coefficient values, and the contribution of suspensoids to absorption of photosynthetically available radiation (PAR) are given for certain Australian water bodies.To understand the effect of suspensoids on attenuation of the solar flux with depth, the scattering coefficient must also be known, and this can be determined from the nephelometric turbidity or from up- and down-welling irradiance measurements. The effect of particle size on scattering efficiency is discussed.An equation expressing the vertical attenuation coefficient for downward irradiance as a function of absorption coefficient, scattering coefficient and solar altitude is presented, and is used to explore the effects of absorption due to dissolved colour and suspensoids, and the effects of scattering by suspensoids, on the penetration of PAR.Suspensoids, by increasing the rate of attenuation of the solar flux with depth, can greatly diminish the euphotic depth of a water body, with a consequent decrease in the ratio of the euphotic to the mixed depth: thus turbidity can reduce productivity of a water body substantially below that which might be expected on the basis of nutrient availability. Shallow turbid waters of low intrinsic colour can, however, be highly productive. By diminishing the depth of the layer within which solar energy is dissipated as heat, suspensoids can greatly modify the hydrodynamic behaviour of water bodies, and this also has far-reaching ecological consequences.Suspensoids drastically impair the visual clarity of water, a fact of major significance for the aquatic fauna, as well of aesthetic significance for humanity. The reciprocal of the Secchi depth is more correctly thought of as a guide to the vertical contrast attenuation coefficient rather than to the vertical attenuation coefficient for irradiance. The reflectivity of a water body, being at any wavelength proportional to the backscattering coefficient divided by the absorption coefficient, is highly dependent on the concentration, and optical character, of the suspensoids present. This has implications not only for the appearance (colour, muddiness) of the water to an observer, but also for the remote sensing of water composition by air- or satellite-borne radiometric sensors.     

Measuring the Arousal Space of a Sit-and-Wait Predator: A Comparison of Predictive Models

The present study set out to compare two predictive models, Holling (1966) and Hardman and Turnbull (1980), to describe the arousal space for the aquatic sit-and-wait predator, Ranatra dispar. When tested in the horizontal plane the fit of Holling's model was good, although a better fit was achieved by using the untransformed angle of prey to body axis term . The second, multiple regression model, gave smaller residuals for low food deprivation periods but larger for longer periods. In the vertical plane the Holling model was unsatisfactory. It is suggested that the changes in number and size of ommatidia from dorsal to ventral region of the eye is largely responsible. A multiple regression model is described that predicts the arousal field of R. dispar in the vertical plane. It is suggested that the general applicability of such models to other visual predators is restricted if apparent hunger effects are not included in their development.     

Distribution of the genus Leptospira in soil and water

The distribution of the aerobic spirochetes Leptospira in surface waters, soil, and aquatic animals was investigated. Isolates from water and soil exhibited physiological characteristics common to members of the "biflexa complex," none were capable of infecting experimental animals, and leptospires could not be isolated from the eight genera of aquatic animals examined. The isolation frequencies from surface waters were: stream, 100%; lake, 65%; spring, 28%; bog lake, 5%; and marsh, 0%. With the exception of the stream, more isolations were obtained from the soil adjacent to the water than from the water. Leptospires were most frequently associated with soils of high moisture and organic matter content.     

Morphometrics of the callitrichid forelimb: A case study in size and shape

Mosimann and colleagues formulated a technique that distinguishes between size and shape, based on the concept of geometric similarity and the distinction between log size-and-shape and log shape variables. We extend these formulations in an examination of the forelimb of three callitrichid species (adultSaguinus oedipus, Saguinus fuscicollis, andCallithrix jacchus). We employ principal components analysis to explore the relationship between variance explained by size-and-shape versus shape alone. Independence of shape vectors is examined via correlation analysis. Then we use log shape data to construct intersample (species means) and total sample (between all paris of individuals) matrices of average taxonomic distances. These distance matrices are subjected to cluster analysis and principal coordinate ordinations. Results of principal components analysis suggest that after isometric size is removed, there remains sufficient shape information to discriminate among the three taxa. Careful examination and quantification of the relationships between shape and size suggest that size information (e.g., geometric mean) is fundamental for understanding shape differences within and among callitrichid species; in other words, most aspects of forelimb shape are significantly correlated with size. Contrary to conventional wisdom, we also demonstrate that such correlations are not spurious. Ordinations and clustering of log shape distance matrices (based on means and individuals) support the notion that, despite differences in size, the two tamarins are more similar in shape than either is toC. jacchus (despite size similarity betweenS. fuscicollis andC. jacchus). Although shape variation in the forelimb of calliirichids may have a functional component, the phylogenetic signal remains strong and serves to group individuals accordingly.     

Deployment of a threshold activated pump sampler in an industrial shock load impact study

Shock loading of toxic substances into natural waterways is apervasive practice which has substantial impacts on their biota.This paper describes the effects of shock (pulse) pollution loadingfrom two major industries on a river and wetland system in southernOntario, Canada. The assessment of shock loading frequencyindicated that sporadic discharges of polluted water occurred onaverage once every other day during the 38 days of monitoring inthe period April, 1986 to November, 1987.To estimate the frequency and intensity of the shock loads, anautomatic pump sampler that was activated by a thresholdconductivity was constructed and deployed. Samples were withdrawnfrom the river when the specific conductivity of the streamexceeded a threshold value of two times background. Backgroundspecific conductivity ranged between 200–250 S cm^-1The impact of these shock load discharges on a downstream aquaticplant community in a Class One (Provincially Significant) wetlandwas examined. The area of Thompsons Creek upstream of the CyanamidChemical Company displayed a normal complement of aquatic organismswhile downstream of the companys main discharges for a distance ofnearly 2 km, the stream was barren of nearly all aquatic life.A reef-like structure in which nickel, chromium, and lead reachedrespectively 2900, 2100 and 2210 mg kg^-1 dry weight ofsediment was located in the Welland River near the outfall of theAtlas-Mansfield storm sewer adjacent to the Atlas Specialty SteelsCompany. The average flow rate at the outfall of theAtlas-Mansfield storm sewer into the Welland River wasapproximately 28400 m³ day-¹ in 1986 (MOE 1987). Asmall area referred to as the Atlas reef because of the high ironconcentrations giving the sediments a cement-like condition, wasdevoid of all higher aquatic plants.     

Photosynthetic metabolism of an antarctic diatom and its physiological responses to fluctuations in light

Summary The short-term incorporation of NaH¹⁴CO₃ (10 to 60 s) into photosynthetic products has been studied in the antarctic diatom Nitzschia turgiduloides. It appears that there are two pathways of inorganic carbon assimilation: the C₃ pathway (Calvin cycle) principally, on which are superimposed -carboxylation reactions. Photorespiration, which contributes to decrease the net photosynthesis rate, has also been reported. With regard to these results the antarctic diatom was not different from the temperate one. However, the antarctic diatom presents some distinctive features. -carboxylation reactions which are probably favoured in Antarctic waters because of the high nitrate or ammonium concentrations, and also because they are more economical in terms of energy, are enhanced at the expense of the Calvin cycle reactions. On the other hand, the photorespiration rate is lower than that observed in temperate species, leading to an enhancement of net photosynthesis rate; this seems to occur principally by the more advantageous tartronic semialdehyde pathway. These two features are more pronounced for cells grown under light: dark cycles, particularly a 2:2 hour regime, as compared to continuous light. By contrast to the temperate species Skeletonema costatum, changes in the light regime modifies not only the relative amount of inorganic carbon assimilated by the C₃ or the -carboxylation pathways, but also the total amount of CO₂ incorporated per g Chl a. The productivity is highest in 2:2 regime, which simulates conditions of vertical mixing encountered in Antarctic Ocean more than does a 12:12 regime. This finding corroborates the view that the antarctic diatom is well adapted to its environment, although its production is not optimal compared to that of the temperate species grown under the same conditions of irradiance and temperature. Whether this is a genetic adaptation needs to be examined.     

Ontology and cultural politics: Aboriginal versus European Australians

Conclusion Nevertheless, in the remote parts of the Western Desert the Aboriginal people remain Aboriginal in thought and experience. They exploit the advantages which the Euraustralians offer, while remaining committed to their way of life. European-Australians water their trees, carry water to the camps, collect the Aboriginals' firewood, repair their automobiles, cook meals for the children and old people, and clean the few Aboriginal houses which exist; their wages are paid by the Australian government.If anything, strategic contact with European civilization has increased the amount of time available for traditional Aboriginal ceremonies, as well as the number of Aboriginals who can transport themselves to the ceremonies. Euraustralian residents are outraged about the amount of time Aboriginals spend corroborreein'. The Secretary of the West Swan Progress Association, a Euraustralian community group. claims that the Aboriginals are becoming a law unto themselves, and this offends the moral-legalistic sense of order which Euraustralians assert in their cultural political struggle with Aboriginals. Today, the cultural politics is being carried on with renewed vigor, and the outcome is by no means certain.A Catholic missionary, at the end of his career with Aboriginals made perhaps the most astute comment I have heard about the Aboriginal undergoing modernization.Ken Liberman has been the Western Desert Research Officer for the Western Australian Museum for the past two years. Currently, he and his wife, Ms A.Z. Parker, are community organizers employed by the Aboriginal Council at Docker River, Northern Territory, Australia.