The life – history of the peach silver mite,Aculus fockeui (Acari: Eriophyidae) in Egypt

The peach silver mite Aculus fockeui (Nalepa and Trouessart) successfully developed from egg to adult stage when reared on a nectarine or peach leaflet attached with soft lateral divided branch dipped in test tube at different constant temperatures and 70% r.h. The effect of temperature on the development, reproduction and population growth was investigated. Below 20°C all activity ceased and by 33°C the adult began to slow down and cease all activity. At least of 34% of the generation time was spent in the egg stage at 29°C. Adult longevity decreased with increasing temperature. Fecundity was highest at 29°C with 43.16 eggs per female. Life table parameters showed that the population of A. fockeui on nectarine leaves multiplied 30.04 times in a generation time of 18.49 days at 29°C, while the population on peach leaves increased 13.87 times in a generation time of 19.18 days under the same conditions.     

Is there a future for wild grapevine (Vitis vinifera subsp. silvestris) in the Rhine Valley?

The wild grapevine, Vitis vinifera L. subsp. silvestris (Gmelin) Hegi, is considered to be an endangered taxon in Europe, mainly as a consequence of the introduction of pathogens from North America and of the destruction of its habitat. In the Rhine Valley, nearly all populations disappeared due to river management, the intensi.cation of forestry, and the introduction of phylloxera. After a growing awareness of the need to preserve endangered forest ecosystems, attempts to reintroduce wild grapevine in the Rhine Valley were performed, particularly in the French nature reserves Erstein and Offendorf since 1992. However, regular surveys of the plants indicate the rapid decline of the populations. In 2002, we proposed to summarise the knowledge accumulated after 10 years of experiments. Results indicate that from the initial 91 individuals planted in 1992, only 14 survived in 2002 (2 in Erstein, 12 in Offendorf). The failure of the experiment may be explained by several factors: unsuitable sites (too shady, absence of support for the young plants), absence of monitoring, vandalism or predation. According to these results and recent knowledge of the ecology of the plant and of vines in general, new transplantation experiments are proposed in which the plants will be monitored during their establishment in the forests. The success of this second transplant (50 plants per reserve) will be enhanced by restoration projects of the Rhine River dynamics, with partial re-.ooding. Floods should help to avoid, or at least to reduce, pest and disease expansion on future adult plants.     

Effects of Shading on the Synthesis of Volatile Organic Compounds in ‘Marselan’ Grape Berries (Vitis vinifera L.)

Journal of Plant Growth Regulation - Light is a vital environmental factor that can affect the synthesis of volatile organic compounds (VOCs) in grape berries. However, the mechanism through which...     

‘Candidatus Tisiphia’ is a widespread Rickettsiaceae symbiont in the mosquito Anopheles plumbeus (Diptera: Culicidae)

Symbiotic bacteria can alter host biology by providing protection from natural enemies, or alter reproduction or vectoral competence. Symbiont-linked control of vector-borne disease in Anopheles has been hampered by a lack of symbioses that can establish stable vertical transmission in the host. Previous screening found the symbiont ‘Candidatus Tisiphia’ in Anopheles plumbeus, an aggressive biter and potential secondary vector of malaria parasites and West Nile virus. We screened samples collected over 10-years across Germany and used climate databases to assess environmental influence on incidence. We observed a 95% infection rate, and that the frequency of infection did not fluctuate with broad environmental factors. Maternal inheritance is indicated by presence in the ovaries through FISH microscopy. Finally, we assembled a high-quality 1.6 Mbp draft genome of ‘Ca. Tisiphia’ to explore its phylogeny and potential metabolic competence. The infection is closely related to strains found in Culicoides biting midges and shows similar patterns of metabolism, providing no evidence of the capacity to synthesize B-vitamins. This infection offers avenues for onward research in anopheline mosquito symbioses. Additionally, it provides future opportunity to study the impact of ‘Ca. Tisiphia’ on natural and transinfected hosts, especially in relation to reproductive fitness and vectorial competence and capacity.     

Somatic embryogenesis from stamen filaments in grapevine (Vitis vinifera L. cv. Mencía): changes in ploidy level and nuclear DNA content

Somatic embryogenesis was induced from stamen filaments and an embryogenic suspension culture was established in the grapevine cultivar Mencía using thidiazuron and 2,4-dichlorophenoxyacetic acid. Four combinations of each growth regulator were assessed for somatic embryo induction in a basal medium containing Nitsch and Nitsch salts and Murashige and Skoog vitamins, and an embryogenic suspension was established in liquid medium containing 1 μM 2,4-dichlorophenoxyacetic acid plus 4.5 μM thidiazuron. By using thidiazuron instead of benzyladenine, induction rates were improved over those previously reported for this cultivar and were relatively high compared with previous results in other cultivars. Three combinations of indole-3-acetic acid and benzyladenine and two inoculum levels were tested in a differentiation medium containing activated charcoal. The size of the inoculum affected the developmental stage of the somatic embryos, whereas the type of growth regulator did not. Both the germination and plant conversion rates were high (87.8% and 88.2%, respectively). An analysis of plant ploidy levels by flow cytometry revealed that 5.6% of the somatic embryo-derived plants were tetraploid. The mean nuclear DNA content of the diploid somatic embryo-derived plants was, on average, 6.7% lower than that of diploid field-grown plants, indicating that this protocol produces low levels of somaclonal variation. The results obtained here indicate that such variations in grapevine can occur both through changes in the ploidy level and by loss of genetic material during somatic embryogenesis.     

Neoseiulus idaeus (Acari: Phytoseiidae) as a potential biocontrol agent of the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae) in papaya: performance on different prey stage – host plant combinations

Development, reproduction, and life table parameters of the phytoseiid mite Neoseiulus idaeus Denmark & Muma preying on various stages of Tetranychus urticae Koch fed on papaya or snap bean plant were studied at 25 ± 2°C, 77 ± 2% RH and 12L:12D photoperiod. Most characteristics of the predator, including the duration of the immature stages, preoviposition and oviposition periods, and female longevity did not differ significantly among the different food combinations. During the adult stage, N. idaeus females survived up to 14 days. The net reproductive rate, the mean generation time, and the intrinsic rate of natural increase of N. idaeus were very similar on all T. urticae stage – host plant combinations, ranging from 5.15 to 6.61 females, 10.15 to 12.62 days, and 0.150 to 0.168, respectively. These results indicate that T. urticae reared either on papaya or snap bean is an adequate prey for the development and reproduction of N. idaeus. Moreover, the current findings demonstrate that the host plant of T. urticae did not affect the predator. The implications of these results for the success of N. idaeus as a biological control agent of T. urticae in papaya orchards are discussed.     

Detection of ‘Candidatus Cardinium’ Bacteria from the Haploid Host Brevipalpus Californicus (Acari: Tenuipalpidae) and Effect on the Host

Brevipalpus californicus (Banks) was infected with ‘Candidatus Cardinium’ bacteria (Cardinium). Tetracycline-treated females produced many male progeny even though untreated females produced only female progeny. B. californicus appears to be feminized by Cardinium. The values for net reproduction rate (R₀), generation time (T) and intrinsic rate of natural increase (r_m) calculated for B. californicus were 7.48/day, 31.45 days and 0.064/day, respectively. The comparison of infected females with uninfected males and other closely related species, indicated that Cardinium does not have a negative effect on the fitness of B. californicus.     

The use of AFLP and SSR molecular markers to decipher homonyms and synonyms in grapevine cultivars: the case of the varietal group known as ’’Schiave’’

’’Schiave’’ collectively refers to grapevine cultivars presently grown on the Southern and Northern slopes of the Eastern Alps and bearing different names (Schiava, Trollinger, Rossara, Rossola, Geschlafene, Gansfüsser, Urban and others). Their common origin has been suggested by historic, linguistic and ampelographic considerations. This hypothesis has now been assayed by using more direct approaches based on AFLP and SSR analysis. The present paper shows: (1), that AFLP and SSR give comparable results when used to study genomic similarity among the Schiave grapevine cultivars, and (2) that ’’Schiave’’ is used to group grapevine cultivars that are genetically heterogeneous. In fact, a dendrogram constructed from an AFLP analysis of the 33 best-known Schiave (or correlated) cultivars, shows different, and in some cases relevant, degrees of genomic dissimilarity. The analysed cultivars cluster into at least five taxonomic groups with specific geographic distribution along the valleys of Valtellina, Bergamo and Brescia and those of South Tyrol and Swabia. It is concluded that the common definition ’’Schiave’’ refers to a similar cultivation practice in contiguous regions rather than to a common genetic background. Received: 16 February 2000 / Accepted: 10 May 2000     

Genetic variation at storage protein-coding loci of common wheat (cv ‘Chinese Spring’) induced by nitrosoethylurea and by the cultivation of immature embryos in vitro

Electrophoretic patterns of seed storage proteins, the high-molecular-weight glutenins and gliadins, were studied in 468 plants of the common wheat cultivar Chinese Spring regenerated from callus culture of immature embryos, in 115 plants grown from seeds treated with nitrosoethylurea and in 260 control plants. From 5 to 21 single grains were analysed from each plant. In these three groups, the frequency of inherited mutations causing the loss of all proteins controlled by a locus (null-mutations, probably caused by a chromosomal deficiency) was 0.69%, 2.07%, and 0.05% per locus (the differences were statistically significant), respectively, while that of mutations causing the loss of a single protein band was 0.11%, 0.33%, and 0.05%, respectively. The loss of all of the gliadins controlled by Gli-B1 or GH-B2 (mutations were probably caused by a deletion of satellites of the corresponding chromosomes), was significantly higher than the loss of gliadins controlled by genomes A and D. Gene mutations altering the electrophoretic mobility of a single protein band in the pattern were found only in the second group of plants (0.44%). Therefore, chemical mutagenesis which produced not only more mutations than cultivation of immature wheat embryos in vitro, but also a higher ratio of mutations that altered DNA sequences, can be considered as an easier and comparatively more promising way for obtaining new improved variants of loci controlling biochemical characteristics in wheat. Somaclonal variation, on the other hand, was probably mainly caused by chromosomal abnormalities and could therefore hardly be considered as a useful tool in wheat breeding.     

New Genera and Species of ‘Giant’ Ostracods (Crustacea: Cyprididae) from Australia

Two new genera of giant ostracods Lacrimicypris n. gen. and Repandocypris n. gen. from Australia are described and eight new species:L. kumbar n. sp., R. austinensis n. sp., R. gleneagles n. sp., Mytilocypris coolcalalaya n. sp., Australocypris bennetti n. sp., A. beaumonti n. sp., A. mongerensis n. sp. and Caboncypris kondininensis n. sp. The number of known Australian genera and species of giant ostracods are now 6 and 21, respectively. Keys to genera and species are provided: all species can be distinguished using the hemipenis and male first leg. The usefulness of the bursa copulatrix as a species-level taxonomic character is highlighted. Most of the species described in this paper occur in salt lakes and existing ecological information on Western Australian species, as well as the distributions of all species, are summarized. Western Australia has a particularly rich halobiont fauna but current explanations relating richness of the halobiont fauna to the widespread occurrence of salt lakes appear incomplete. Australocypris bennetti is unusual in that it is frequently found at pH < 4. Its morphology differs slightly in acidic and alkaline waters.     

Altered physiology in worker honey bees (Hymenoptera: Apidae) infested with the mite Varroa destructor (Acari: Varroidae): a factor in colony loss during overwintering?

The ectoparasitic mite Varroa destructor (Anderson & Trueman) is the most destructive pest of the honey bee, Apis mellifera L., in Europe and the United States. In temperate zones, the main losses of colonies from the mites occur during colony overwintering. To obtain a deeper knowledge of this phenomenon, we studied the mites' impact on the vitellogenin titer, the total protein stores in the hemolymph, the hemocyte characteristics, and the ecdysteroid titer of adult honey bees. These physiological characteristics are indicators of long-time survival and endocrine function, and we show that they change if bees have been infested by mites during the pupal stage. Compared with noninfested workers, adult bees infested as pupae do not fully develop physiological features typical of long-lived wintering bees. Management procedures designed to kill V. destructor in late autumn may thus fail to prevent losses of colonies because many of the adult bees are no longer able to survive until spring. Beekeepers in temperate climates should therefore combine late autumn management strategies with treatment protocols that keep the mite population at low levels before and during the period when the winter bees emerge.     

Manipulating national identity: the strategic use of rhetoric by supporters and opponents of the ‘Cronulla riots’ in Australia

This research explores the role of opinion-based groups in understanding responses to racist violence such as the 2005 Cronulla riots in Australia. Traditionally, explanations of collective action in social psychology and sociology focus on conflict between broad social categories. We propose that the responses to the riots can be understood not only as inter-group conflict between Muslims and non-Muslims, or an in-group argument amongst non-Muslims, but as a bona fide inter-group conflict between supporters and opponents of the riots. We argue that these groups use rhetoric in attempts to claim dominant status within society by aligning their identities with positively valued social categories such as ethnicities and national identities. The analysis of rhetoric from the groups supporting and opposing the riots demonstrates consistent, albeit contested, attempts to align support for the riot with the Australian national category in conflict with countervailing attempts to align opposition to the riot with the same national category.     

Oocyte maturation in the sloth’s giant tick Amblyomma varium (Acari: Ixodidae) in an ecological context

The sloth’s giant tick Amblyomma varium Koch, which is a neotropical species that inhabits tropical rainforests, is the largest tick reported to date. The adult stage of this tick parasitizes mammals from the families Bradypodidae and Magalonychidae (Xenarthra) nearly exclusively. This study aimed to describe morphological and histological features of the reproductive system and the oocyte maturation process of this tick species. The ovary of A. varium is a long single tubular organ that is horseshoe-shaped, winding and arranged in the posterior part of the body. Two oviducts are connected to the ovary on each side; these thicken at certain region forming the uterus (common oviduct), followed by a muscular connecting tube, vagina and genital aperture. A large number of oocytes at different stages of development are attached to the ovary wall by the pedicel, as they reach maturity they are released into the ovary lumen and from there to the genital aperture. These oocytes develop simultaneously and asynchronically along the ovary. Amblyomma varium oocytes were classified into five development stages (i.e., I–V), and specific characteristics were observed; the processes of yolk and chorion deposition begin early in oocytes stage II, and oocytes V exhibit a very thick chorion and eggs of a large size. These characteristics are likely adaptations that enhance the survival and the reproductive success of this extremely host-specific tick, which is limited to a particular environment.     

‘The vain speculation disillusioned by the sense’: the Italian painter Agostino Scilla (1629–1700) called ‘The Discoloured’, and the correct interpretation of fossils as ‘lithified organisms’ that once lived in the sea

The search for the true nature and origin of fossils gave rise, starting about the beginning of the sixteenth century and throughout the seventeenth century, to a heated debate between the supporters of the inorganic nature of these objects and proponents of an interpretation of fossils as ex-vivi. Among the latter, a key figure is the Italian painter Agostino Scilla (1629–1700), who represents one of the first naturalists who was able to accumulate substantial evidence to support the interpretation of fossils as once-living marine organisms. The world view of Scilla and his real contribution to paleontology are here analysed and contextualised, taking into account the state of knowledge characterising the time of his activities. Scilla was not only a pioneer in the field of paleontology, but he prepared the groundwork for the achievement of milestone geological concepts such as actualism, taphonomy and recognition of internal and external moulds (in the instance of non-representation of original hard parts); Scilla deserves further recognition as one of the first to attempt sedimentological interpretation of rocky bodies observed directly in the field.     

Correction to: Species of Monogenoidea infecting the gill lamellae of the common silver-biddy Gerres oyena (Forsskål) and the common silver belly Gerres subfasciatus Cuvier (Perciformes: Gerreidae) in Moreton Bay,Queensland, Australia

Systematic Parasitology - During registration of specimens of Protogyrodactylus scalmophorus and Protogyrodactylus ichthyocercus for the Queensland Museum, it was noticed that the collection sites...     

Don't Blame the ‘Bio’ — Blame the ‘Ethics’: Varieties of (bio) ethics and the challenge of pluralism

We tend to think that the difficulties in bioethics spring from the novel and alarming issues that arise due to discoveries in the new biosciences and biotechnologies. But many of the crucial difficulties in bioethics arise from the assumption we make about ethics. This paper offers a brief overview of bioethics, and relates ethical 'principlism' to 'ethical fundamentalism.' It then reviews some alternative approaches that have emerged during the second phase of bioethics and argues for a neo-Aristotelian approach. Misconceptions about ethical principles and ethical reasoning not only distort our views of the business of bioethics, but they also prevent us from facing up to the formidable problems posed by ethical pluralism in so-called liberal societies.     

Plant and animal communities in brackish supra-littoral pools (‘dobben’) in the northern part of the Netherlands

Fifty brackish supra-littoral pools bordering the Waddenzee were studied. The structure of plant communities (Potamogeton pectinatus L., Ranunculus baudotii Godr. and Zannichellia pedunculata Rchb.) is discussed in relation to water level fluctuations, chlorinity and water transparency. Chlorinity tolerances of the macrophytes (7 species) are discussed. The macrofauna was studied semi-quantitatively. The aquatic Coleoptera had the greatest diversity (24 species). A distinct relationship between the number of Coleoptera species and the percentage of macrophyte coverage was found. The distribution patterns of the most frequent species with respect to chlorinity categories are shown in histograms. The number of aquatic Heteroptera species is also discussed in relation to chlorinity and vegetation coverage. Less important macrofaunal groups (the Crustacea, Mollusca and Odonata) occurred in low species numbers.