Diel rhythm of volatile emissions of males and females of the peach fruit fly Bactrocera zonata

Fruit flies in the genus Bactrocera are among the most destructive insect pests of fruits and vegetables throughout the world. A number of studies have identified volatiles from fruit flies, but few reports have demonstrated behavioral effects or sensitivities of fly antennae to these compounds. We applied a recently developed method of automated headspace analysis using SPME (Solid Phase Microextraction) fibers and GC-MS (gas chromatography mass spectrometry), termed SSGA, to reveal volatiles specific to each sex of B. zonata that are emitted in a diel periodicity. The volatiles released primarily at dusk were identified by GC-MS and chemical syntheses as several spiroacetals, pyrazines, and ethyl esters. Solvent extraction of male rectal glands or airborne collections from each sex, followed by GC-MS, showed that certain of the volatiles increase or decrease in quantity sex-specifically with age of the flies. Electroantennographic (EAG) analysis of dose-response indicates differences in sensitivities of male and female antenna to the various volatiles. Our study provides a comprehensive analysis of the volatile chemicals produced and released by B. zonata and their antennal responses. The possible pheromone and semiochemical roles of the various volatiles released by each sex and the difficulties of establishing behavioral functions are discussed.

Monitoring and mass-trapping methodologies using pheromones: the lesser date moth Batrachedra amydraula

The lesser date moth (LDM) Batrachedra amydraula is a significant pest of date palm fruits. Previously, detection and monitoring of the pest was inaccurate due to high costs of sampling with lifting machines. We report a practical system for detection and monitoring of LDM based on pheromone traps and relevant models. Dose-response experiments with LDM pheromone traps indicated a 1 mg lure is optimal for monitoring. Delta traps with adhesive covering their entire inner surface gave the highest captures while trap colour was unimportant. Sampling pheromone traps throughout the night indicated male flight began at 1:00-2:00 and reached a peak 2 h before sunrise. Monitoring traps exposed all year long in Israel revealed three generations with different abundance. Trapping transects in a date plantation indicated interference from a monitoring trap became minimal at distances >27 m away. Inter-trap distances closer than this may lower efficiency of monitoring and mass trapping in control programs. Our estimate of the circular effective attraction radius (EARc) of a 1 mg delta trap for LDM (3.43 m) shows this bait is among the most attractive compared with baits for other insects. We developed encounter-rate equations with the pheromone trap EARc to model the interplay between population levels, trap density and captures that are useful for detection of invasive LDM and its control by mass trapping. The integrated methodologies are applicable to many pest species.

Inhibition of LTB4 binding to human neutrophils by nordihydroguaiaretic acid

Nordihydroguaiaretic acid (NDGA) was investigated for its ability to interact with leukotriene B4 receptors on human polymorphonuclear leukocytes (hPMNs). 3H-LTB4 binding to specific receptors was reduced in a dose-dependent manner with maximal reduction at 100 microM NDGA and an IC50 of about 50 microM. Binding of another inflammatory stimulus. N-formyl-norleucyl-leucyl-phenylalanine (FNLP) was not affected by similar treatment. Chemotaxis and enzyme release stimulated by LTB4 and oligopeptide were inhibited by NDGA. In addition, LTB4-triggered inflammation in vivo in mice was inhibited by systemic administration of NDGA. These data suggest that LTB4 receptor antagonism may contribute to inhibition of inflammation by NDGA.