Inferences on the population structure and colonization process of the invasive oriental fruit fly, Bactrocera dorsalis (Hendel).

The phytophagous insects of the Tephritidae family offer different case histories of successful invasions. An example is Bactrocera dorsalis sensu stricto, the oriental fruit fly which has been recognized as a key pest of Asia and the Pacific. It is known to have the potential to establish adventive populations in various tropical and subtropical areas. Despite the economic risk associated with a putative stable presence of this fly, the genetic aspects of its invasion process have remained relatively unexplored. Using microsatellite markers we have investigated the population structure and genetic variability in 14 geographical populations across the four areas of the actual species range: Far East Asia, South Asia, Southeast Asia and the Pacific Area. Results of clustering and admixture, associated with phylogenetic and migration analyses, were used to evaluate the changes in population genetic structure that this species underwent during its invasion process and establishment in the different areas. The colonization process of this fly is associated with a relatively stable population demographic structure, especially in an unfragmented habitat, rich in intensive cultivation such as in Southeast Asia. In this area, the results suggest a lively demographic history, characterized by evolutionary recent demographic expansions and no recent bottlenecks. Cases of genetic isolation attributable to geographical factors, fragmented habitats and/or fruit trade restrictions were observed in Bangladesh, Myanmar and Hawaii. Regarding the pattern of invasion, the overall genetic profile of the considered populations suggests a western orientated migration route from China to the West.

A member of the hsp70 gene family from the Mediterranean fruit fly, Ceratitis capitata.

A gene from the Mediterranean fruit fly (Medfly) Ceratitis capitata, belonging to the hsp70 family of genes, has been cloned and characterized. This gene appears to be an example of a heat shock cognate (hsc) gene based on a variety of structural and functional criteria. The heat shock cognate genes serve critical roles in chaperoning of cellular proteins, and they are expressed in a more constitutive manner compared to the inducible heat shock genes. We determined the sequence of the entire coding region of this gene (designated Cerhsc1) together with 5' and 3' flanking regions. The coding region exhibits specific structural features that are characteristic of the subclass of heat shock genes producing proteins localized to the cytosol. The 5' regulatory region of Cerhsc1 contains onlythe minimal array of canonical heatshock element sequences, a phenomenon commonly seen in heat shock cognates. Abundant transcripts are detected from this gene in adult tissue compared to the larval stage. In larval tissue, heat shock appears to produce only a slight increase in the level of transcripts detected. Based on overall structure and function, this Medfly gene appears to be an ortholog of heat shock cognate gene 4 (Drohsc4) of Drosophila melanogaster.

Actin genes in the Mediterranean fruit fly, Ceratitis capitata.

We have undertaken the study of actin gene organization and expression in the genome of the Mediterranean fruit fly (medfly), Ceratitis capitata. Actin genes have been extensively characterized previously in a wide range of eukaryotic organisms, and they have valuable properties for comparative studies. These genes are typically highly conserved in coding regions, represented in multiple copies per genome and regulated in expression during development. We have isolated a gene in the medfly using the cloned Drosophila melanogaster 5C actin gene as a probe. This medfly gene detects abundant messages present during late larval and late pupal development as well as in thoracic and leg tissue preparations from newly emerged adults. This pattern of expression is consistent with what has been seen for actin genes in other organisms. Using either the D. melanogaster 5C actin gene or the medfly gene as a probe identifies five common cross reacting EcoRI fragments in genomic DNA, but only under less than fully stringent hybridization conditions.

Genetic linkage relationships of eight enzyme/electromorph loci in Anopheles minimus.

Two laboratory stocks of Anopheles minimus, each fixed for variant electromorphs of esterases, aspartate aminotransferase, hydroxyacid dehydrogenase, phosphogluconate dehydrogenase, mannose phosphate isomerase and glycerol dehydrogenase were used to assess linkage relationships between presumed gene loci controlling this variation. The two F1, which had been obtained from crossing the stocks, were backcrossed to a parental stock. Three loci controlled the esterases and one locus each of the other enzymes. Mpi is sex-linked. The rest are autosomal and suggested relationships are: Pgd 2.3% recombination from Aat and unlinked to any other loci; Est-1-33.8%-Est-3-31.5%-Est-2-21.0%-Had. Gcd is unlinked to any other locus. There was evidence of strong interaction between the X chromosome of one stock and autosomes of the other in which individuals bearing the X chromosome of the one suffered relatively greater mortality and had delayed development with respect to other genotypic classes.

Social sychiatric implications of population control in Thailand.

PIP: Several knowledge, attitude, and practice surveys in Thailand have shown that a majority of married women do not want more children because of the economic and physical difficulty of raising the children already born; the ideal number of children was about 3.8. However, population growth in Thailand is about 3.4% annually, one of the highest rates in Asia. The findings that women, particularly younger women, are in favor of family planning is offset by lack of knowledge and fears of side effects. The psychological approach to the prediction of contraceptive behavior, as studied at the Carolina Population Center, shows that, regardless of the method of measurement, intention always emerged with the highest coefficient in discriminating contraceptive users from nonusers. Emotional barriers have been considered 1 of the significant factors in contraceptive use, especially excessive dependency needs and passive-aggressive character. Unwanted pregnancy can also contribute to poor mental health. Since unregulated fertility, poverty, overpopulation, premarital pregnancy, and illegitimacy seriously impair mental health, contraceptive services should be considered a legitimate part of psychiatry and mental health personnel should consider referrals for patients in need.^ieng