Relationships between morphology, genetics and geography in the cave fruit bat Eonycteris spelaea (Dobson, 1871) from Indonesia

Morphological and genetic analyses of Eonycteris spelaea from 15 islands along the Banda Arc, from Sumatra to Timor and including Kalimantan and Sulawesi, revealed considerable divergence between islands and geographical patterning. On the basis of both morphology and genetics, the populations on the large islands of Greater Sunda (Sumatra, Java, Kalimantan and Sulawesi) are generally distinct from one another and from those on the islands in Nusa Tenggara (Lombok to Timor), which form a more cohesive cluster. These differences may be the result of the Nusa Tenggara populations having been colonized more recently than those on the Greater Sunda, and probably from a single source. All biological measures of the relationships between island populations are positively associated with the extent of the sea-crossing between them, indicating the sea is an important barrier to movement. Multivariate analyses show the presence of a marked trend for body size to increase from west to east. However, individuals from Kalimantan are not consistent with this trend, being smaller than predicted, and on the two outer Banda Arc islands of Sumba and Timor animals are a little larger than predicted from the longitudinal trend. These differences could be due to the relative isolation of these populations or differing environmental conditions. There is also a negative relationship between body size and island area, but this is confounded by the longitudinal trend. No significant longitudinal trends in the genetic data were detected and the trend in body size may be an adaptive response to an environmental cline that is known to occur in this region.  © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 79, 511–522.     

Changes in soil carbon and nitrogen properties and microbial communities in relation to growth of Pinus radiata and Nothofagus fusca trees after 6 years at ambient and elevated atmospheric CO2

Increasing atmospheric CO₂ concentration can influence the growth and chemical composition of many plant species, and thereby affect soil organic matter pools and nutrient fluxes. Here, we examine the effects of ambient (initially 362 μL L^?1) and elevated (654 μL L^?1) CO₂ in open‐top chambers on the growth after 6 years of two temperate evergreen forest species: an exotic, Pinus radiata D. Don, and a native, Nothofagus fusca (Hook. F.) Oerst. (red beech). We also examine associated effects on selected carbon (C) and nitrogen (N) properties in litter and mineral soil, and on microbial properties in rhizosphere and hyphosphere soil. The soil was a weakly developed sand that had a low initial C concentration of about 1.0 g kg^?1 at both 0–100 and 100–300 mm depths; in the N. fusca system, it was initially overlaid with about 50 mm of forest floor litter (predominantly FH material) taken from a Nothofagus forest. A slow‐release fertilizer was added during the early stages of plant growth; subsequent foliage analyses indicated that N was not limiting. After 6 years, stem diameters, foliage N concentrations and C/N ratios of both species were indistinguishable (P>0.10) in the two CO₂ treatments. Although total C contents in mineral soil at 0–100 mm depth had increased significantly (P<0.001) after 6 years growth of P. radiata, averaging 80±0.20 g m^?2 yr^?1, they were not significantly influenced by elevated CO₂. However, CO₂‐C production in litter, and CO₂‐C production, microbial C, and microbial C/N ratios in mineral soil (0–100 mm depth) under P. radiata were significantly higher under elevated than ambient CO₂. CO₂‐C production, microbial C, and numbers of bacteria (but not fungi) were also significantly higher under elevated CO₂ in hyphosphere soil, but not in rhizosphere soil. Under N. fusca, some incorporation of the overlaid litter into the mineral soil had probably occurred; except for CO₂‐C production and microbial C in hyphosphere soil, none of the biochemical properties or microbial counts increased significantly under elevated CO₂. Net mineral‐N production, and generally the potential utilization of different substrates by microbial communities, were not significantly influenced by elevated CO₂ under either tree species. Physiological profiles of the microbial communities did, however, differ significantly between rhizosphere and hyphosphere samples and between samples under P. radiata and N. fusca. Overall, results support the concept that a major effect on soil properties after prolonged exposure of trees to elevated CO₂ is an increase in the amounts, and mineralization rate, of labile organic components.     

A Companion to the Anthropology of American Indians

A Companion to the Anthropology of American Indians . Thomas Biolsi, ed. Williston, VT: Blackwell Publishers, 2004. 567 pp.     

Vector specificity of barley yellow dwarf virus serotypes and variants in southwestern Idaho

Plants with symptoms of barley yellow dwarf virus (BYDV) obtained in infection feeding assays of aphids collected in the field in Idaho between 1986 and 1988 were tested for virus transmissibility by possible aphid vectors. Isolates obtained during 1987–1988 were also tested with a range of polyclonal antisera which distinguished PAV, MAV, SGV, RPV and RMV serotypes. In 1989 some Idaho (ID) BYDV isolates, maintained as standards for comparison, were serotyped and tested for aphid transmissibility, using 11 species of aphids. There was not always the expected correspondence between serotype and vector specificity for ID isolates. For isolates obtained from field-collected Rhopalosiphum padi, vector transmissibility and serotype corresponded with previous reports; however, 44% of isolates which were serotyped as RMV were also transmissible by species other than Rhopalosiphum maidis. Similarly, the transmissibility of the ID laboratory standards did not always conform to the reported vector specificity of serotypes. The laboratory ID-MAV culture was transmitted by Metopolophium dirhodum and Myzus persicae as well as by Sitobion avenae. The laboratory ID-SGV culture was transmitted by R. padi and 5. avenae as well as by Schizaphis graminum. The ID-RPV culture was transmitted by S. graminum and Rhopalosiphum insertum as well as R. padi. Both of two laboratory ID-RMV cultures were transmissible by R. insertum and R. padi transmitted one of them. The results indicate that, for isolates collected in Idaho, vector specificity cannot be assumed from their serotypes.     

Caching behaviour of Red Squirrels Sciurus vulgaris under conditions of high food availability

Members of the genus Sciurus store seed when plentiful by scatterhoarding. Such caches are impossible to defend and vulnerable to both interspecific and intraspecific competitors. In view of the delicate position held by Red Squirrels Sciurus vulgaris L. in Britain it is of value to extend to this species studies of the methods whereby such competition is reduced. Caching behaviour in a population of Red Squirrels living in a protected reserve and receiving supplementary food was studied for 18 months. Two main aspects were investigated; their ability to find caches they had not made, and their efforts to reduce competition for caches they did make. Stapanian & Smith (1978) predicted that caches are made at an optimal density and that the entire 360d? arc around a resource is used. This study upheld this second prediction but not the first for the population of Red Squirrels in question. In addition, it is suggested that caching cannot be considered to be permanent under conditions of surplus food.     

THE RELATIVE IMPORTANCE OF SHORT- AND LONG-RANGE MOVEMENT OF FLYING APHIDS

1. Aphids are notorious pests of world agriculture. Even so, uncertainty persists as to their capacity for successful aerial dispersal. Evidence exists that, under some conditions, aphids can be wind-borne over long distances, i.e. hundreds of kilometers over desert or sea. It has been argued, in the recent past, that this phenomenon may be part of a strategy to locate fresh host plants in new distant areas. However, the proportion of these insects successfully colonizing new hosts is unknown. 2. Other work using meteorological backtracking has also indicated long-distance movement, but the accuracy of such predictions is dubious unless the altitude of transport is known. Mark-releaseecapture experiments with such small insects have limited potential due to large dilution effects. Static ‘snap-shots’ of demographic population densities, using suction traps, cannot accurately distinguish local aerial density fluxes and population movements from a distance. However, genetic and physiological markers may provide more direct information on population mixing; for example, some allozyme studies have shown a limited level of inter-population gene flow. 3. Under suitable conditions, aphids take off, maintain flight and alight in response to the appropriate visual and olfactory cues. Undoubtedly successful long-distance movement occurs from time to time, but its ecological relevance may have been overstated in the past. It may be selectively disadvantageous for aphids to move from areas containing their host plants. In contrast, it is advantageous for aphids to maximise their chances of survival and reproductive success by landing on suitable plant hosts at the earliest opportunity. 4. The clonal nature of aphids (a single genotype may comprise vast numbers of individuals) means that there may be advantages to phenotypic variation between individuals in the readiness to move. Recent evidence indicates that such a variation exists in the duration of the behavioural migratory phase, the initial period of maiden flight when host-plant cues are ignored and when landing is inhibited. 5. The relative biological importance of short- us. long-distance movements is reassessed with reference to plant virus epidemiology and the spread of new genotypes, e.g. insecticide resistance. It is concluded that the biological relevance of short-distance movements have a much greater impact on population and genotype distribution than long-distance movements, which may be comparatively infrequent.     

Midgut lectin activity and sugar specificity in teneral and fed tsetse

Abstract. . Midgut infection rates of Trypanosoma congolense in Glossina palpalis palpalis and of Trypanosoma brucei rhodesiense in Glossina pallidipes are potentiated by the addition of D+ glucosamine to the infective feed, but not to the levels of super-infection reported for G. m. morsitans. G. p. palpalis and G.pallidipes are shown to possess two trypanocidal molecules: a glucosyl lectin which can be inhibited by D+ glucosamine and a galactosyl molecule inhibited by D+ galactose. Addition of both D+ glucosamine and D+ galactose to the teneral infective feed promotes super-infection of the midguts of G.p.palpalis. The glucosyl lectin is specific for rabbit erythrocytes and is present in guts of fed G.m.morsitans and G.p.palpalis , titres of lectin activity do not increase substantially after the second bloodmeal. The galactosyl specific molecule does not show any erythrocyte specificity, although haemolytic activity is observed only in G.p.palpalis and not in G.m.morsitans. The presence of two trypanocidal molecules in some species of tsetse may account for the innate refractoriness of these flies to trypanosome infection.
As D+ glucosamine also inhibits the killing of procyclic trypanosomes taken as an infective feed, it is suggested that the midgut lectin is normally responsible for the agglutination of trypanosomes in the fly midgut by binding to the pro-cyclic surface coat, prior to establishment in the ecto-peritrophic space.     

Analysis of the UV-Induced Melanogenesis and Growth Arrest of Human Melanocytes

Cultured human melanocytes derived from different skin types responded to frequent treatment with ultraviolet (UV) light with increased melanin synthesis, decreased proliferation, and morphologic signs of aging. These effects were augmented by increased frequency of irradiation with 15.5 mJ/cm² UV light. Stimulation of melanogenesis by UV light involved an increase in tyrosinase activity, without any change in the amounts of either tyrosinase or tyrosinase-related protein (TRP)-1, and a decrease in the amount of TRP-2, as determined by Western blot analysis. These results are different from the mechanisms by which other melanogenic agents, such as cholera toxin and isobutyl methylxanthine, stimulated melanogenesis, whereby the amounts of tyrosinase, TRP-1 and TRP-2 were increased. The decrease in the amount of TRP-2 might be significant in that it might alter the properties of the newly synthesized melanin. The UV irradiation protocol that was followed blocked melanocytes in G₂-M phase of the cell cycle without compromising cellular viability. Following three rounds of UV irradiation, melanocytes could recover from the growth arrest and resume proliferation. Treatment with 0.1 μM α-melanocyte stimulating hormone (α-MSH) postirradiation enhanced the melanogenic effect of UV light and stimulated the melanocytes to proliferate. The effects of α-MSH on the UV induced responses and their implications on photocarcinogenesis are being further investigated. Analyzing the mechanisms by which UV light exposure affects normal melanocytes might lead to a better understanding of how these cells undergo malignant transformation, and why individuals with different skin types differ in their susceptibility to skin cancers.     

Extraintestinal Development of Caryospora simplex (Apicomplexa: Eimeriidae) in Experimentally Infected Mice,Mus musculus1

Developmental stages of Caryospora simplex were found in connective tissue of the cheek, tongue, and nose of Swiss-Webster and C57 BL/6 mice (Mus musculus) from 8 through 70 days after oral inoculation with 50,000 or 250,000 oocysts, or 60,000 free sporocysts of the same species obtained from an Ottoman viper, Vipera xanthina xanthina. The earliest developmental stages were seen on day 8 post-inoculation (PI) and consisted of two types of meronts and gamonts (undifferentiated sexual stages). Gamonts, microgametocytes, macrogametes, and unsporulated oocysts were found on days 10 and 12 PI. Fully sporulated, thin-walled oocysts containing eight sporozoites surrounded by a thin sporocyst membrane were first seen 12 days PI. Monozoic cysts (caryocysts) were first seen 12 days PI and appeared fully viable throughout the duration of the study, 70 days PI. Four mice injected intra-peritoneally with 150,000 free sporozoites and killed 12 days PI contained unsporulated and sporulated oocysts in connective tissues of the cheek, tongue, and nose, suggesting that sporozoites may be carried to the site of infection via the lymphatic/circulatory system. Four cotton rats, Sigmodon hispidus, inoculated orally with 250,000 oocysts all had unsporulated and sporulated oocysts of C. simplex in connective tissue of the cheek, tongue, and nose when killed on day 12 PI, indicating extraintestinal development in the secondary host is not species specific. This is the first report of a heteroxenous coccidium with both asexual and sexual development in the primary (predator) and secondary (prey) hosts.