A study of inter- and intrasubject variability in seven-day weighed dietary intakes with particular emphasis on trace elements

In this study of inter- and intrasubject variance of trace element (TE) dietary intake data, 14 female university students recorded weighed, self-selected food intakes for seven consecutive days, starting on a randomly selected day of the week. Daily intakes of energy, dietary fiber, macronutrients, 7 vitamins, and Fe, Zn, Cu, Mn, and Se were calculated using food composition tables and literature values. Analysis of variance showed a significant weekend effect for energy and TE intakes that was reduced when data were expressed on the basis of nutrient densities. No day of the working week or training effect was noted for energy or any nutrient. The ratios of the inter- to intrasubject coefficient of variation for all the nutrients were surprisingly constant. However, the overall coefficients of variation—Fe, 36.5%; Zn, 45.7%; Cu, 43.7%; Mn, 58.2%, and Se, 52.7%—were markedly lower than for vitamin A (109.0%), Vitamin D (117.1%), and linoleic acid (82.2%), but slightly higher than those for energy (27.2%) and carbohydrate (30.1%). The widespread distribution of TE in the diets results in comparable reliability for dietary studies of TE and macronutrients. The 95% confidence intervals for mean individual TE intakes ranged from 25% (Zn) to 40% (Se). These relatively large uncertainties make it essential that any assessment of the significance of correlations between dietary TE intakes and biochemical indices takes into account the intra-individual variation associated with both variables.     

THE CLADISTICS OF IDEAS (LEPIDOPTERA, DANAINAE)

Abstract— Males of Idea tambusisiana , previously unstudied, lack the only known unequivocal synapomorphy associating the constituent members of Idea . Further cladistic analyses were performed on an expanded data matrix containing two characters alternatively coded in binary and multistate form. Two topologies were obtained of which one, in which I. tambusisiana remains internal to the genus, is accepted following consideration of information content and assessment of the supporting character states. A character analysis is also performed in which the problem of ambiguous charater state assignments to the internal nodes of the cladogram is examined. Biogeographic implications of the results are discussed with respect to areas of endemism in southeast Asia, the origin of Sulawesi (Celebes), and vicariance/dispersal models intended to explain the distribution of Idea species in relation to the Makassar Strait.     

Indigenous tropical ecology

Two major works on the ecology of Sumatra and Sulawesi two of the world's great tropical islands, have appeared relatively recently. These volumes represent the rarest of genres in tropical ecology: works of indigenous origin with an indigenous audience in mind. An examination of these exciting books prompts us to examine a wider literature on tropical ecology.     

The variability of the hepatitis B virus genome: statistical analysis and biological implications

A statistical analysis of the nucleotide sequence variability in 14 published hepatitis B virus (HBV) genomes was carried out using parametric and nonparametric methods. A parametric statistical model revealed that the different regions of the genome differed significantly in their variability. The conclusion was supported by a nonparametric kernel-density model of the HBV genome. Genes S, C, and P, region X, the precore region, and the pre-S2/pre-S1 regions were ranked in order of increasing variability. In many instances, conserved regions of the genome identified with sequences of known function in HBV biology. However, other characterized regions (such as pre-S) showed much variability despite the involvement of their encoded peptides in specific functions. Point mutations that may result in the formation of stop codons and amino acid changes may affect the clinical picture of HBV infection and may be reflected in atypical serological patterns.      

Quantifying the distribution and abundance of an animals resource using aerial photography

Summary Infra-red aerial photography was used on two occasions to map the abundance and dispersion of milkweeds (Asclepias spp.). The scale at which the aerial photographs could be interpreted showed that milkweeds occur in large contiguous areas or patches. These patches are abundant, the number in any size-class declining exponentially with increasing size. Analysis of the maps using various dispersion indices and spatial autocorrelation statistic showed that patches have a clumped dispersion. Large patches tend to be surrounded by smaller sized patches. The scales at which clumping occurred indicated a close association between milkweeds and the degree of disturbance of the natural environment by human activities. The utility of resource mapping using aerial photography is demonstrated.     

A meta-analysis of the effects of galling insects on host plant secondary metabolites

The idea that galling insects actively manipulate host plant chemistry has been previously documented but has not been quantified across a range of galler and host plant taxa. We present the first quantitative review of the relationship between insect galling and levels of secondary metabolites in host plants. Using meta-analytic techniques, we examined this relationship across 40 galler and host plant species combinations. We found that galling insects are associated with significantly higher levels of tannins and phenolics; however, no difference was found for volatiles. Hymenoptera, Diptera and Hemiptera were associated with higher levels of secondary metabolites; however, only Hymenoptera was significant. The climatic zone of the study area did not explain significant differences in gall-induced secondary metabolites. Overall the results show that the ability of galling insects to manipulate host plant secondary chemistry is widespread across insect and plant taxa. The evolutionary success of galling insects may be in part due to this unique ability.     

Invertebrates and the complexity of tropical ecosystems

It has been estimated that there are seven million terrestrial arthropod species on Earth consisting of 6.1 million species of insects, 1.5 million of which are beetles. Tropical forests hold a majority of these species, yet few such places have been adequately sampled for alpha diversity, and there remains even more uncertainty about beta diversity. From an ecological point of view, it is the functional role of organisms within ecosystems that is the particular focus. It has been customary to classify invertebrates within ecosystems in terms of their trophic roles, but it is also useful to consider their roles in networks. In broad terms, we can classify these networks on the grounds of their basal resources. Those based directly on the photosynthetic products of plants are so-called “green” food webs, and those based on dead and dying plant material are “brown” food webs. Here, we principally discuss the diversity and functional roles of the invertebrates in tropical terrestrial ecosystems. New sampling and analytical techniques, an expanded set of focal taxa, and an enhanced concern with interactions and processes hold the promise of a productive future for invertebrate studies in the tropics. These will not only add to general understanding of the dynamics of tropical ecosystems but will also provide powerful tools for monitoring and responding to environmental change.     

Field sampling is biased against small-ranged species of high conservation value: a case study on the sphingid moths of East Africa

The range size of species co-occurring in local assemblages is a pivotal variable in assessments of a site’s conservation value. Assemblages featuring many small-ranged species are given more priority than assemblages consisting mainly of wide-ranging species. However, the assembly of relevant information can be challenging and local range size distributions of tropical invertebrates are rarely available for conservation planning. We present such data for sphingid moths in East Africa, a highly diverse region of high conservation value. We compare geographic range size distributions based on field samples with predictions from modelled range map data. Using this system as a case study, we provide evidence for a systematic sampling bias when inferring average local range sizes from field data. Unseen species (i.e., species present but missed in local sampling) are often those with small ranges (hence, of high conservation value). Using an elevational gradient, we illustrate how this bias can lead to false, counterintuitive assessments of environmental effects on local range size distributions. Furthermore, with particular reference to sphingid moths in the study region, we show that current protected areas appear unrelated to the spatial distribution of species richness or average geographic range sizes at a local scale. We discuss the need to treat field sampled data with caution and in concert with other data sources such as probabilistic models.