Preliminary observations on the distribution and abundance of seaweed flies (Diptera: Coelopidae) on beaches in the Gosford district of New South Wales,Australia

Abstract Thirteen species of the family Coelopidae occur in beach wrack on Australian coasts, predominantly at temperate latitudes. Four species (This canus, Chaetocoelopa sydneyensis (Schin.), Amma blancheae and Dasycoelopa australis Mall.) can be caught on beaches in the Gosford district, New South Wales. Seasonal changes in the distribution of coelopid species may be linked with seasonal weather variations. Field and laboratory data on the commonest and most abundant species, T. canus, suggest that variations in adult abundance could be due to fluctuations in high tide level governing the rate of the coelopid life cycle. Local weather conditions and human influences may modify the effects of the high tides.     

The effect of the taxon and geographic range size of host eucalypt species on the species richness of gall-forming insects

Abstract This field study was designed to test whether the taxonomic group and geographic range size of a host plant species, usually found to influence insect species richness in other parts of the world, affected the number of gall species on Australian eucalypts. We assessed the local and regional species richness of gall-forming insects on five pairs of closely related eucalypt species. One pair belonged to the subgenus Corymbia, one to Monocalyptus, and three to different sections of Symphyomyrtus. Each eucalypt pair comprised a large and a small geographic range species. Species pairs were from coastal or inland regions of eastern Australia. The total number of gall species on eucalypt species with large geographic ranges was greater than on eucalypt species with small ranges, but only after the strong effect of eucalypt taxonomic grouping was taken into account. There was no relationship between the geographic range size of eucalypt species and the size of local assemblages of gall species, but the variation in insect species composition between local sites was higher on eucalypt species with large ranges than on those with small ranges. Thus the effect of host plant range size on insect species richness was due to greater differentiation between more widespread locations, rather than to greater local species richness. This study confirms the role of the geographic range size of a host plant in the determination of insect species richness and provides evidence for the importance of the taxon of a host plant.     

Developmental stress in wild-living Drosophilids inferred from biometry: metric and meristic traits react differently to heterogeneous environmental conditions

Abstract.  1. During their development in natural conditions, Drosophila larvae and pupae face heterogeneous environmental conditions (HEC). Analysing the morphology of wild-living adults is a means of evaluating the effects of HEC.
2. Two drosophilid species of the Zaprionus genus that recently invaded the Nile delta were investigated, and three metric, size-related traits, and one meristic trait, the sternopleural bristle number, were measured. Data were compared with those of F₁ generation reared under favourable laboratory conditions.
3. Body size was smaller in nature, but also extremely variable among individuals, with an average coefficient of variation (CV) of 9.1 ± 0.3, against a much lesser value of 2.4 ± 0.1 in laboratory flies. Correlations among size traits were also greater in nature (0.96 ± 0.01) than in the laboratory (0.75 ± 0.04).
4. By contrast, sternopleural bristles produced similar results in wild-living and laboratory flies. In nature, mean numbers were only slightly less than in the laboratory and the CVs were almost identical (10.87 ± 0.70 vs 10.80 ± 0.76).
5. Fluctuating asymmetry of sternopleural bristles was also identical in the two kinds of flies, and was not influenced by HEC, indicating a high level of developmental canalisation with respect to HEC.
6. The implications of the results for the problems of field heritability and developmental stability are discussed.     

Purification and Partial Carbohydrate Analysis of Phytochrome from Avena sativa

Highly purified samples of phytochrome from etiolated oat (Arena satira L.) seedlings were analyzed for sugar content. Phytochrome was found to be a glycoprotein, with about 4% of its weight as carbohydrate. In addition, modifications in the procedure for purifying phytochrome are proposed here and certain details about the protocol are discussed that improve the yield and reproducibility of previously published methods.