Prerelease exposure to methyl eugenol increases the mating competitiveness of sterile males of the oriental fruit fly (Diptera: Tephritidae) in a Hawaiian orchard.

Males of the oriental fruit fly, Bactrocera dorsalis (Hendel), are strongly attracted to methyl eugenol (ME), and recent work demonstrated that ingestion of this chemical enhances male mating success, apparently owing its role as a precursor in the synthesis of the male sex pheromone. The current study expanded upon earlier laboratory and field-cage experiments by assessing whether prerelease exposure to ME increased the mating competitiveness of mass-reared, sterile males in Hawaiian orchards. Releases of sterile males from a pupal color-based sexing strain were made weekly in two fruit orchards over 8 mo, with the sterile males at one site given ME for 24 h before release (treated) and the sterile males at the other site given no ME before release (control). Fruits were collected periodically during the study period, and eggs were dissected and incubated to score hatch rate. At both sites, releases of sterile males increased the proportion of unhatched eggs well above prerelease levels, but the incidence of egg sterility was consistently, and statistically, greater in the orchard receiving ME-exposed males. Computed over the entire release period, the average value of Fried's competitive index (that characterizes the mating success of sterile males relative to their wild counterparts) for ME-treated males was 3.5 times greater than that for control males, although this difference was not statistically significant. However, when computed over the period during which egg sterility values were elevated and stable, presumably when females inseminated before the releases were rare or absent, the competitive indices were significantly higher for ME-treated sterile males. The implications of these results for implementing the Sterile Insect Technique against this species are discussed.

Chemical and microbiological parameters in New Orleans floodwater following Hurricane Katrina.

Hurricane Katrina, rated as a Category 4 hurricane on the Saffir-Simpson scale, made landfall on the U.S. Gulf Coast near New Orleans, Louisiana on Monday, August 29, 2005. The storm brought heavy winds and rain to the city, and several levees intended to protect New Orleans from the water of Lake Pontchartrain were breached. Consequently, up to 80% of the city was flooded with water reaching depths in excess of three meters in some locations. Research described in this paper was conducted to provide an initial assessment of contaminants present in floodwaters shortly after the storm and to characterize water pumped out of the city into Lake Pontchartrain once dewatering operations began several days after the storm. Data are presented which demonstrate that during the weeks following the storm, floodwater was brackish and well-buffered with very low concentrations of volatile and semivolatile organic pollutants. Dissolved oxygen was depleted in surface floodwater, averaging 1.6 mg/L in the Lakeview district and 4.8 mg/L in the Mid-City district. Dissolved oxygen was absent (< 0.02 mg/L) at the bottom of the floodwater column in the Mid-City district 9 days afterthe storm. Chemical oxygen demand (Mid-City average = 79.9 mg/L) and fecal coliform bacteria (Mid-City average = 1.4 x 10(5) MPN/100 mL) were elevated in surface floodwater but typical of stormwater runoff in the region. Lead, arsenic, and in some cases, chromium, exceeded drinking water standards but with the exception of some elevated Pb concentrations generally were typical of stormwater. Data suggest that what distinguishes Hurricane Katrina floodwater is the large volume and the human exposure to these pollutants that accompanied the flood, rather than very elevated concentrations of toxic pollutants.

Medfly (Diptera: Tephritidae) genetic sexing: large-scale field comparison of males-only and bisexual sterile fly releases in Guatemala.

The effect of releases of bisexual (males and female) and unisexual (male only) sterilized medflies was compared in three large field evaluations over a 3-yr period (1995-1997) in southwestern Guatemala. The two strains tested were a genetic sexing strain, Vienna-4/Tol-94, carrying the temperature sensitive tsl gene to eliminate females in the egg stage, and the standard bisexual Petapa strain. Flies were mass-reared, sterilized by irradiation as pupae, shipped to a field center, and released by air as young adults over 2 km by 2 km core areas in the centers of separate 6 km by 6 km test plots. Strain performance was monitored weekly by trapping sterile and wild male adults in core and buffer areas and by collecting eggs from coffee berries to determine induced sterility. Results indicated a several-fold advantage for the males-only strain as measured by the level of induced sterility, especially at the very high release ratios of 100:1 recorded in 1997. During that final test year, sterile-fly release rates were increased to provide high sterile:wild (S:W) fly ratios in the field, and egg sterility reached levels in excess of 70% in plots were the male-only strain was used. However, in the plots where the bisexual strain was released, induced sterility only reached 12% despite S:W ratios above 1,000:1.

Improving male mating competitiveness and survival in the field for medfly, Ceratitis capitata (Diptera: Tephritidae) SIT programs.

The success of the sterile insect technique (SIT) depends critically upon mating between released sterilized males and wild females. In Hawaii, improvements in the efficiency of sterile males were attempted on two separate fronts--mating enhancement and survival improvement. In the former, two methods have been investigated--selective breeding and aromatherapy. In the latter, flies which survived in field cages for several days were selected and bred to produce progeny with enhanced survival ability compared to control flies. Regarding mating selection, standard laboratory-reared males that successfully mated with wild females in field cages were allowed to breed. F1 offspring were inbred, then the selection procedure was repeated for four additional cycles. In the aromatherapy procedure, laboratory-reared males were exposed to ginger root oil for several hours 1 day prior to testing in field cages. Compared to controls, the selected flies improved the mating competitiveness of male flies ca. 3-fold, irradiation reduced this increase to ca. 2.5-fold. Exposing the selected, hybrid strain raised the fitness of the lab males to ca. 9-fold that of wild males. In the ongoing survival selection study, we have obtained lines in which the selected males survived ca. 2-fold better than laboratory control males over several days in an outdoor field cage, with food and water provided. The goal is to combine the traits of higher survival and mating ability into a single strain for SIT release.

Exposure to ginger root oil enhances mating success of irradiated, mass-reared males of Mediterranean fruit fly (Diptera: Tephritidae).

Previous research revealed that exposure to ginger root oil, Zingiber officinale Roscoe, containing the known male attractant (a-copaene) increased the mating success of male Mediterranean fruit flies, Ceratitis capitata (Wiedemann), from a newly established laboratory colony. The goal of the current study was to determine whether exposure to ginger root oil likewise enhanced the mating competitiveness of irradiated C. capitata males from a 5-yr-old mass-reared strain. Mating tests were conducted in field cages containing guava trees (Psidium guajava L.) to monitor the mating frequency of irradiated, mass-reared and wild males competing for wild females. In the absence of chemical exposure, wild males outcompeted the mass-reared males and obtained 74% of all matings. However, following exposure to ginger root oil (20 microl for 6 h), the mating frequencies were reversed. Whether exposed as mature (3-d-old) or immature (1-d-old) adults, mass-reared males achieved approximately 75% of all matings in tests conducted 2 or 4 d following exposure, respectively. Irradiated, mass-reared males prevented from contacting the oil directly (i.e., exposed to the odor only for 6 h) still exhibited a mating advantage over wild males. In an additional study, signaling levels and female arrivals were compared between males exposed to ginger root oil and nonexposed males, but no significant differences were detected. The implications of these findings for the sterile insect technique are discussed.

The effects of lip bumper therapy in the mixed dentition.

A prospective clinical trial was undertaken to study the effects of 6 months of continuous lip bumper therapy on patients in the mixed dentition with mild-to-moderate mandibular arch perimeter deficiency. Thirty-four patients, ages 7.9 to 13.1 years (mean = 10.2), seeking treatment in the postgraduate orthodontic clinic of the Medical College of Virginia, presented possessing 3 to 8 mm of mandibular crowding, with both mandibular primary second molars, were randomly placed in either the treatment or nontreatment group. Treated subjects underwent continuous lip bumper therapy, whereas the control subjects were monitored without undergoing any active treatment, each for 6 months. Arch dimension changes were assessed with study models. Alterations of mandibular incisor position were measured from lateral cephalometric radiographs. Mandibular left permanent first molar position changes were determined from both lateral cephalometric and tomographic radiographs, with the resolution of each imaging technique in measuring molar tooth movement also compared. It was found that significant differences in mandibular incisor inclination, molar position, arch length, and arch perimeter existed between treated and untreated subjects. In addition, multiple observer analysis showed that cephalometric examination lacks sensitivity when used to measure molar movement.

Resolution of populations of the Mediterranean fruit fly at the DNA level using random primers for the polymerase chain reaction.

We have used the polymerase chain reaction (PCR) and the random amplified polymorphic DNA (RAPD) method to identify DNA polymorphisms that can be used as genetic markers to characterize populations of the Mediterranean fruit fly, Ceratitis capitata. In this study, RAPD markers have been used to resolve genetic variability between populations of this major agricultural pest species. The populations analyzed represent either laboratory stocks or wild collections originating from different geographic localities. Using the same set of individual flies from each of several populations, we show that the use of different primers in the RAPD method permits detection of different levels of population differentiation. We show results from RAPD primers (e.g., primer 14) that identify regions of the genome (through PCR amplification) that are essentially monomorphic in all flies originating from a particular geographic locality. We also show RAPD primers (e.g., primer 67) that identify what appear to be highly variable regions of the genome. We have used primers of this type to produce genetic markers that can distinguish even between laboratory versus wild populations as well as subpopulations of flies from more broadly defined geographic localities, such as within the Hawaiian islands. These results show that the RAPD method is a broadly applicable, high resolution method for documenting genetic variability within and between populations of insect pest species.

Genetic variation between strains of the Mediterranean fruit fly, Ceratitis capitata, detected by DNA fingerprinting.

DNA fingerprinting has been used to detect genetic variation in the Mediterranean fruit fly, Ceratitis capitata. Three different probes have been identified that can be used to detect DNA restriction fragment length polymorphisms between strains of this species. The strains used in this study differ only in terms of their geographic origin or genetic background. One of the probes used is the bacteriophage vector M13, and the other two are repetitive sequences derived from the medfly genome based on a weak homology to M13. Within a strain, each probe produces a consistent restriction fragment profile that is not affected by the method or timing of DNA extraction. Between strains, when M13 is used as a probe, an average of 10% of the observable bands are polymorphic. Use of the medfly genomic sequences as a probe increases the proportion of polymorphic bands between strains up to 30%. The fact that genetic differences between even such closely related strains can be reliably detected by this method holds great promise for studies of insect pests including the ability to monitor the movements of pest species, determining the extent of genetic variation in pest populations, and in making identifications from otherwise unidentifiable material.

Age-related response of male melon fliesDacus cucurbitae (Diptera: Tephritidae) to cue-lure.

Laboratory-reared and wild adults of the melon fly,Dacus cucurbitae Coquillett, were tested for response to cue-lure at various ages. Virgin laboratory (4, 6, 8, 10, 12, and 14 days old) and wild (10, 12, 14, 16, 18, 20, and 22 days old) flies were released into outdoor field cages and trapped from 0800 until 1600 hr. Response of males to cue-lure increased with age and corresponded with sexual maturity for each strain. Females of both strains were relatively nonresponsive to cue-lure. Failure to eradicate in past male annihilation programs againstD. cucurbitae may be explained in part by the fact that only older males, which may have already mated with gravid females, respond to cue-lure.

Relationship of sexual maturation rate to response of oriental fruit fly strains (Diptera: Tephritidae) to methyl eugenol.

Laboratory-reared and wild, fruit-reared adults of the Oriental fruit fly,Dacus dorsalis Hendel, were tested for response to methyl eugenol at various ages. Virgin laboratory (2, 4, 6, 8, and 10 days old) and wild (7, 11, 15, 19, and 23 days old) flies were released into an outdoor field cage and trapped over a two-day period. Response of males increased with age as ca. 32% and 22% of laboratory and wild males responded at 2 and 7 days of age, respectively, while ca. 93% of both strains responded at 10 and 23 days of age, respectively. These correspond approximately to the ages at which they reach sexual maturity. Female response did not increase with age and fluctuated between 15% and 29% for the laboratory strain and 10% and 45% for the wild strain. The age-related response profiles, when integrated with sexual maturation curves, indicate that one of the major reasons the male-annihilation technique is effective is because methyl eugenol is able to attract 40-50% of male flies prior to the onset of sexual maturation.

Isolation and identification of male medfly attractive components inLitchi chinensis stems andFicus spp. stem exudates.

Short-range attraction/feeding stimulation of male Mediterranean fruit flies [Ceratitis capitata (Wiedemann), (Diptera: Tephritidae)] to a stem extract of a host plant,Litchi chinensis Sonn. (Sapindaceae), and to milky exudates from stems of nonhost plants,Ficus retusa L. andF. benjamina L. (Moraceae), were attributed to the presence of the sesquiterpene α-copaene. The presence of α-copaene in the milky exudate from stems ofF. benghalensis L. is also suggested as eliciting similar behavioral responses in male medflies. The presence of minor quantities of α-ylangene in the plants and its contributory effects to the behavioral response of male medflies is discussed. Short-range attraction/feeding stimulation of male medflies to equal amounts of α-ylangene-free α-copaene samples (94.5%+), prepared from α-copaene-enriched angelica seed oil and copaiba oil, respectively, showed no difference in intensity of response. α-Ylangene elicited a slightly less intense response for male medflies than α-copaene.

Comparative study of responses to neomycins B and C by microbiological and gas-liquid chromatographic assay methods.

The relative responses of neomycins B and C have been determined by a microbiological agar-diffusion method, a turbidimetric method, and by a recently developed gas-liquid-chromatographic (GLC) method capable of separating the neomycin isomers. The ratios of response of neomycin C to neomycin B by the individual methods were as follows: agar-diffusion method, 1:3; turbidimetric method, 1:2.5; and GLC method, 1:1. When neomycin C is assumed to have 35% biological activity of neomycin B, the calculated drug contents of neomycin sulfate powders obtained by the GLC method correlated well with values obtained by the microbiological agar-diffusion assay method.