Effect on predatory performance of the presence of prey after moulting in the water stick insect, Ranatra linearis

ABSTRACT. During the first 4h following moulting, Ranatra linearis L. (Heteroptera, Nepidae) perform numerous claw and femur foreleg movements, but do not then catch any prey (e.g. Daphnia ). The frequency of these movements depends on the presence of potential prey, and is significantly higher in the presence of potential prey items than in their absence. The presence or absence of prey during these four post-moult hours influenced subsequent performance. Ranatra moulting in the absence of prey showed later a lower catching success and a smaller proportion of complex predatory movements at all stages of development than did Ranatra moulting in the presence of prey, all other factors being similar. The importance of this deficit resulting from depriving Ranatra of the presence of prey during the post-moult period is discussed.     

Ribosomal DNA Sequence of Nucleospora salmonis Hedrick, Groff and Baxa, 1991 (Microsporea: Enterocytozoonidae): Implications for Phylogeny and Nomenclature

ABSTRACT. Rules of zoological nomenclature, morphological data, and robosomal DNA sequence data support the validity of the genus Nucleospora , and its placement in the family Enterocytozoonidae. Although Nucleospora exhibits most of the distinguishing morophological characteristics of the family Enterocytozoonidae Cali and Owne, 1990, the distinctively different hosts (fish and humans, respectively) and sites of development (the nuclei of immature blood cells and the cytoplasm of enterocutes) supprot the placement Nucleospora and Enterocytozoon into separate genera. Ribosomal DNA sequence comparisons between Nucleospora salmonis and Enterocytozoon bieneusi showed 19.8% genetic divergece in the large and small subunit regions. Although more inter- and intrageneric divergence between the two species is sufficiently larg to deter suppression of the genus Nucleospora as a junior synonym of Enterocytozoon. A polymerase chain reaction test for the detection of N. salmonis in chinook salmon ( Oncorhynchus tshawytscha ), based on N. salmonis -specific ribosomal DNA sequence, is described.     

The role of interannual,seasonal, and synoptic climate on the carbon isotope ratio of ecosystem respiration at a semiarid woodland

The terrestrial carbon cycle is influenced by environmental variability at scales ranging from diurnal to interannual. Here, we present 5‐years of growing season (day 131–275) observations of the carbon isotope ratio of ecosystem respiration (δ¹³C_R) from a semiarid woodland. This ecosystem has a large necromass component resulting from 97%Pinus edulis mortality in 2002, is dominated by drought‐tolerant Juniperus monosperma trees, and experiences large variability in the timing and intensity of seasonal and synoptic water availability. Mean growing season δ¹³C_R was remarkably invariant (?23.57±0.4‰), with the exception of particularly enriched δ¹³C_R in 2006 following a winter with anomalously low snowfall. δ¹³C_R was strongly coupled to climate during premonsoon periods (～May to June), including fast (≤2 days) responses to changes in crown‐level stomatal conductance (G_c) and vapor pressure deficit (vpd) following rain pulses. In contrast, δ¹³C_R was relatively decoupled from G_c and environmental drivers during monsoon and postmonsoon periods (July–August and September, respectively), exhibiting only infrequent couplings of δ¹³C_R to vpd and soil water content (SWC) with longer lags (～8 days) and variable response slopes (both positive and negative). Notably, δ¹³C_R exhibited consistent dynamics after rainfall events, with depleted δ¹³C_R occurring within 1 h, progressive hourly δ¹³C_R enrichment over the remainder of the night, and net δ¹³C_R depletions over the multiple nights postevent in monsoon and postmonsoon periods. Overall this ecosystem demonstrated strong dependence of δ¹³C_R on precipitation, with an apparent dominance by the autotrophic δ¹³C signal in premonsoon periods when deep soil moisture is abundant and surface soil moisture is low, and weaker coupling during monsoonal periods consistent with increasing heterotrophic dominance when deep soil moisture has declined and surface moisture is variable.     

Simultaneous Transmission of Three Stable Genotypes in <Emphasis Type="Italic">Drosophila melanogaster</Emphasis>

REPLICATION of the double stranded DNA genomes of bacteria takes place by a semi-conservative mechanism¹, but although autoradiographic studies have confirmed that eukaryotic DNA is replicated semi-conservatively^2,3, our lack of knowledge about the structure of the eukaryotic chromosome means that this finding does not prove that the conserved unit is a single polynucleotide strand of DNA. Indirect information supporting the hypothesis that the conserved unit consisted of a single polydeoxyribonucleotide strand has accumulated from transmission studies in chemical mutation experiments. Two phenotypic classes of mutants are readily distinguishable as a result of chemical mutagenesis; mosaic (fractional) mutants and complete (whole body) mutants. Mutation studies assume that the treated gametes contain one DNA polymer per chromosome and that the polymer is made up of two complementary nucleotide strands. With chemical mutagens (excluding acridine dyes) it is probable that only one of the two complementary strands would be chemically altered⁴. Following fertilization, DNA replication occurs, fixing both the mutational event and its complementary wild type site. The zygote will possess a mutation which will be phenotypically expressed in the adult fly depending on the early morphogenic movements in the fly's development. Assuming that only one strand is altered, the two cell lines would contain a mutant genotype and a wild type genotype. Two genotypically mutant cell lines would arise if two mutational events occur in the opposing polydeoxyribonucleotide strands within the same genie region. In this case, there would be no genotypically wild type cells in the embryo.     

Activity of the diastereoisomers of 13,23-dimethylpenta-triacontane, the sex pheromone of Glossina pallidipes, and comparison with the natural pheromone

ABSTRACT. All three synthetic diastereoisomers of 13,23-dimethyl-pentatriacontane, the pheromone of Glossina pallidipes (Austen), have been tested in the G. pallidipes sex pheromone bioassay, together with one of the four diastereoisomers of 13,17-dimethylpentatriacontane, originally proposed as a candidate pheromone of G. pallidipes. Of the three isomers of 13,23-dimethylpentatriacontane only the (13R,23S) isomer was active with an ED-50 of 4.47±1.09/μg (mean±SD). The (13R,17R)-13,17-dimethylpentatriacontane was inactive. The diastereo-isomeric mixtures of 13,17- and 13,23-dimethylpentatriacontane were active with ED-50 values of 17.88±1.25/μg and 8.88±1.15μg respectively. The natural pheromone was active with an ED-50 of 8.07±1.17 μg indicating it to be a diastereoisomeric mixture.     

Final Days: Japanese Culture and Choice at the End of Life

Final Days: Japanese Culture and Choice at the End of Life . Susan Orpett Long. Honolulu: University of Hawai'i Press, 2005. 287 pp.