Identification of an oviposition-regulating pheromone in the European grapevine moth,Lobesia botrana (Lepidoptera: Tortricidae)

The oviposition of the European grapevine moth (EGVM)Lobesia botrana can be deterred by an extract of conspecific eggs corresponding to 20 egg equivalents. The reduction of the oviposition behavior is dose-dependent. Nine chemicals have been extracted from the eggs and identified as straight chain fatty acids and esters of fatty acids. A mixture of these rather simple molecules induces the same levels of deterrence as the total extract. It might be possible to use oviposition regulating pheromone in the future for the control of EGVM populations.     

Sequence and analysis of chromosome 3 of the plant Arabidopsis thaliana

Arabidopsis thaliana is an important model system for plant biologists. In 1996 an international collaboration (the Arabidopsis Genome Initiative) was formed to sequence the whole genome of Arabidopsis and in 1999 the sequence of the first two chromosomes was reported. The sequence of the last three chromosomes and an analysis of the whole genome are reported in this issue. Here we present the sequence of chromosome 3, organized into four sequence segments (contigs). The two largest (13.5 and 9.2 Mb) correspond to the top (long) and the bottom (short) arms of chromosome 3, and the two small contigs are located in the genetically defined centromere. This chromosome encodes 5,220 of the roughly 25,500 predicted protein-coding genes in the genome. About 20% of the predicted proteins have significant homology to proteins in eukaryotic genomes for which the complete sequence is available, pointing to important conserved cellular functions among eukaryotes.     

Inter-specific avoidance of egg-associated semiochemicals in four tortricids

Oviposition of four tortricid pests of vineyards (the European grapevine moth and the grape berry moth) and fruit orchards (the codling moth and the oriental fruit moth) is deterred by a blend of straight chain fatty acids and esters of fatty acids that have been identified in the eggs of one of them: the European grapevine moth (EGVM)Lobesia botrana. This is the first evidence of inter-specific recognition of an egg-like signal in moths. We demonstrate that oviposition site selection is influenced by population density, avoidance of deterrent being most important when females are isolated. Inter-specific egg recognition might be an important phenomenon, especially in species competing for a common food resource. We propose the term oviposition regulating synomone for molecules and blends that affect the inter-specific spacing of eggs.     

Diet and habitat of northern flying squirrels ( Glaucomys sabrinus ) in the Black Hills of South Dakota

During the summers of 2005 and 2006, northern flying squirrels ( Glaucomys sabrinus Shaw) were live-captured in the northern Black Hills of South Dakota from mixed deciduous/coniferous and coniferous habitats. Squirrel captures were significantly correlated with volume of downed wood and number of snags. Diets were examined from scat collections ( n = 40, deciduous/coniferous; n = 10, coniferous). Number of fungal spores in the scat was significantly correlated with number of snags. From each scat collection, the frequencies of plant, animal, fungal, and unidentified components were determined. Hypogeous fungi were a frequent component of the diet, being found in 98.3% and 78.8% of the scat observed in 2005 and 2006. In 2006, as the frequency of dietary fungi decreased, the frequency of plant material increased from <1.0% to 8.0% and frequency of unidentified material increased from 2.0% to 74.0%. Animal content in the scat was negligible (<1.0% to 1.0%). Rhizopogon was the most frequently occurring hypogeous fungus observed. Rhizopogon spores made up 97.9% of the spores counted in 2005 and 96.4% in 2006. Elaphomyces, Gautieria, Geopora, Hymenogaster, and Hysterangium were observed at much lower frequencies. Sporocarps were collected throughout the trapping periods. Fourteen were collected in 2005 and 12 in 2006. Of the 26 sporocarps collected, 11 were Rhizopogon, 4 Elaphomyces, 2 Gautieria, 1 Hymenogaster, 7 Hysterangium, and 1 Tuber. This study is the first to examine flying squirrel diets in the Black Hills and the first to report Elaphomyces, Gautieria, Hymenogaster, Hysterangium, Rhizopogon, and Tuber sporocarps from the South Dakota Black Hills.     

Somatic misexpression of germline P granules and enhanced RNA interference in retinoblastoma pathway mutants

Caenorhabditis elegans homologues of the retinoblastoma (Rb) tumour suppressor complex specify cell lineage during development. Here we show that mutations in Rb pathway components enhance RNA interference (RNAi) and cause somatic cells to express genes and elaborate perinuclear structures normally limited to germline-specific P granules. Furthermore, particular gene inactivations that disrupt RNAi reverse the cell lineage transformations of Rb pathway mutants. These findings suggest that mutations in Rb pathway components cause cells to revert to patterns of gene expression normally restricted to germ cells. Rb may act by a similar mechanism to transform mammalian cells.