Characterization of polymorphic microsatellite markers for the Carnaby's cockatoo (Calyptorhynchus latirostris) and related black cockatoo species

Microsatellite loci were isolated from Carnaby's black cockatoo (Calyptorhynchus latirostris: Aves), a highly valued, endangered, and endemic species of bird from Western Australia. This study describes three dinucleotide and one tetranucleotide microsatellite loci for which the primers produced clear and polymorphic amplification patterns with between two and nine alleles and moderate levels of variability. Two additional dinucleotide markers which were monomorphic in the Carnaby's cockatoo were able to amplify and were polymorphic in two other species of black cockatoo, greatly increasing the utility of these markers.     

Novel strategies for assessing and managing the risks posed by invasive alien species to global crop production and biodiversity

International actions to combat the threat posed by invasive alien species (IAS) to crops and biodiversity have intensified in recent years. The formulation of 15 guiding principles on IAS by the Convention on Biological Diversity (CBD) stimulated the International Plant Protection Convention (IPPC) to review its role in protecting biodiversity. IPPC standards now demonstrate clearly that the risks posed by any organism that is directly or indirectly injurious to cultivated or uncultivated plants can be assessed and managed under the IPPC. Since the IPPC, unlike the CBD, constitutes an international legal instrument recognised by the World Trade Organization, greater protection from the introduction of IAS is now available. However, phytosanitary measures can only be enacted if they can be justified by risk analysis and we outline some novel strategies to improve the assessment and management of the risks posed by IAS, highlighting some of the key challenges which remain.     

Current status of the Drosophila melanogaster species-group (Diptera)

Abstract. The Drosphila melanogaster species-group, established by Sturtevant (1942) for fourteen species, is now known to contain 115 described species here divided into twelve named subgroups (including one newly proposed), as well as further undescribed species. Three of the species, melanogaster, simulans and ananassae , are cosmopolitan; two others, kikkawai and malerkotliana , are widespread in the southern hemisphere, the latter apparently a recent introduction to South America. The greatest numbers of species otherwise occur in the Oriental region with smaller numbers in the Ethiopian, eastern Palaearctic and Australian regions and in several islands of the South Pacific. D.rajasekari and D.raychaudhurii are synonymized with D.biamipes;also D.andamanensis Parshad & Singh is synonymized with D.andamanensis Gupta & Raychaudhuri.     

Why are there few algae on snail shells? The effects of grazing,nutrients and shell chemistry on the algae on shells of Helisoma trivolvis

1. Freshwater snails often lack visible growths of algae on their shells. We tested three possible mechanisms that may account for this (grazing, snail-derived nutrients and chemical defences), using the ramshorn snail Helisoma trivolvis .
2. The experiments were carried out in floating plastic enclosures in a pond and comprised seven treatments. Grazing treatments were: a lone snail (ungrazed, as self-grazing does not occur), Helisoma with conspecifics, Helisoma with the co-occurring pond snail Physa sp., empty shells with Helisoma , and ungrazed empty shells. Nutrient effects were possible in all treatments with occupied shells (lone snail; Helisoma with conspecifics, and with Physa ) versus absent in other treatments. Testing for chemical defences compared algae on fresh empty shells, weathered shells (outer organic periostracum layer absent) and boiled fresh shells (with denaturization of susceptible proteins).
3. Diatoms dominated algal assemblages on snail shells. Although the upright diatom Gomphonema gracile was abundant on all shells, it was dominant on the shells of snails housed with other snail grazers (either Helisoma or Physa ).
4. Only the lone snail (nutrients but no grazing) showed higher algal biomass, so presumably any nutrient effect in the treatments with grazers was masked. Both Helisoma and Physa were observed apparently grazing on Helisoma shells, and consequently algal biomass in multi-snail treatments was similar to that on empty shells. Scanning electron microscopy revealed that algal density was highest near the aperture of live snails, but not empty shells; this is consistent with a nutrient addition effect. There was no evidence of chemical defences against algal growth.
5. In soft-bottomed freshwater habitats with abundant snails, shells of living snails provide nutrient-augmented substrata that may indirectly boost overall snail production.     

On Arborescence in Gahnia clarkei and Gahnia sieberiana

Specimens of Gahnia sieberiana from Brisbane, Queensland, andof Gahnia clarkei from near Orbost, Victoria, were collectedand examined both morphologically and anatomically. The speciesgrow in wet areas and are of interest because they representthe largest arborescent species known in the Cyperaceae. Stemdiameters up to 120 mm and stems up to 10 m long have been observed.Such long stems tend to be supported by nearby vegetation. Althoughfresh stems are tough and woody, they are brittle. Branchingof the stems is sympodial, and numerous branches are producedby plants growing in exposed habitats. There is less branchingin plants from shaded habitats. Basal shoots may also occur.Adventitious roots develop basally on most plants, but withG. sieberiana, some adventitious roots form near the shoot apexand grow in and around leaf bases. Anatomical features of interestare an endodermoid layer composed of sclereids with elongate,undulated, outer tangential walls that are lignified and suberized,short vessel elements with horizontal to oblique simple perforationplates, and relatively short sclereids surrounding vessel elementsin the vascular bundles. Some vascular bundles are bipolar.The presence of short vessel elements here is in marked contrastto the longer tracheary elements in other arborescent monocotyledons. Arborescence, stem anatomy, Cyperaceae, Gahnia, saw sedge, Monocotyledon, bipolar bundles, morphology, endodermoid layer     

Rearing temperature influences flavivirus vector competence of mosquitoes

Culex annulirostris Skuse mosquitoes (Brisbane strain) were reared at 20 degrees C or 27 degrees C and the adult females were experimentally infected by feeding Murray Valley encephalitis virus (MVE). They were then maintained (a) in the insectary at 20 degrees C, after rearing at either 20 degrees C or 27 degrees C; (b) at ambient outdoor temperatures, range 12.2-28.9 degrees C, mean 19.6 degrees C; or (c) at 27 degrees C after rearing at 27 degrees C. There was no significant difference in rates of MVE infection or transmission when mosquitoes were reared and maintained constantly at 20 degrees C or 27 degrees C. However, for females kept at reduced temperature (i.e. mean = 19.6 degrees C or 20 degrees C after rearing at 27 degrees C), the infection and transmission rates of MVE were significantly reduced (2 x 8 replicates). This investigation illustrates that vector competence is depressed by decreasing temperatures for adult mosquitoes compared with those they experienced during development. Similar patterns were evident with previously published work on Japanese and St Louis encephalitis, dengue and yellow fever. The process appears to be reversible, i.e. increased temperature raises virus infection and transmission rates. It is concluded that, without incubation at warmer temperatures, flavivirus recovery from overwintering mosquitoes will be negatively biased.     

Microhabitat selection and life cycle patterns of two Rhyacophila species (Trichoptera: Rhyacophilidae) in southern Ontario streams

SUMMARY.

• 1 Two species of predatory caddisfly larvae—Rhyacophila fuscula (Walker) and R. melita Ross—have overlapping longitudinal distributions in southern Ontario streams.
• 2 The populations were studied at sites in areas of overlap (sympatry) and allopatry to determine what resources were partitioned, and if partitioning varied in the zones of overlap.
• 3 Life cycle and species size variation resulted in substantial physical differences between these univoltine species for most months of the year.
• 4 In May, when larvae of both species were not significantly different in size, a detailed microhabitat field study found no difference in microhabitat use between allopatric populations of R. fuscula and R. melita. Microhabitat selection by R. fuscula remained constant at sympatric sites but R. melita showed a significant change resulting in reduced microhabitat overlap with R. fuscula.

     

Paracrystalline Arrays in the Mitochondria of the Peritrichous Ciliate Carchesium polypinum1,2

SYNOPSIS Intramitochondrial inclusions of a paracrystalline nature were observed in the peritrichous ciliate Carchesium polypinum This ciliate was found growing in the effluent of a sewage treatment plant. When paracrystalline inclusions were present, there was one per mitochondrion. A variety of profiles was encountered, all presumably of the same structure. Cross-sections revealed packed, spherical masses of 100-150 A diameter with dense walls 30-40 A thick and a variety of core densities. In more longitudinal sections the paracrystalline array appeared as long. electron-dense, finely filamentous elements oriented in parallel arrays and regularly spaced with a diameter of 60-100 A. Mitochondria tended to cluster, and between closely apposed mitochondria a dense, amorphous material was present. Numerous bud-like processes projected from mitochondria. Structural evidence, particularly the arrangement and core densities of these arrays, suggests a filamentous type of viral infection.     

Aral Sea Ostracoda as environmental indicators

Fluctuations in the level and chemistry during its history have played a major part in shaping the floral and faunal communities of the Aral Sea. Of the eleven species of Ostracoda (Crustacea) known to have been living in the Aral Sea in 1960, only one survives today due to the anthropogenically induced salinity increase of the past three decades. The origins of a mixed fresh- and brackish-water ostracod fauna are discussed, and it is concluded that some of the major faunal elements must have reached the Aral Sea Basin during a past high water level phase when connection existed with the Caspian Sea. The taxonomic position of key taxa is clarified, and the major elements of the pre-1960 Aral Sea ostracod fauna are illustrated from Holocene sequences. Aral Sea, Ostracoda, Holocene, palaeolimnology.