The recent discovery of a sesquiterpene, β-caryophyllene (CP) as a male attractant of the guava fruit fly, Bactrocera correcta (Bezzi) (Diptera: Tephritidae) prompted investigations into the attractancy of CP to the Oriental fruit fly, B. dorsalis (Hendel). This is because males of both species of fruit flies are attracted to, and feed on a phenylpropanoid compound, methyl eugenol (ME). Although CP was a more potent attractant than ME for B. correcta, it is not known if males of B. dorsalis are also attracted to CP. The possible attraction of B. dorsalis to CP as a sesquiterpene may indicate its wide host range through its attraction to different groups of plant volatiles i.e., phenylpropanoids and sesquiterpenes. In this paper, we report that males of B. dorsalis were also attracted to, and feed on CP. Subsequently, we conducted a probit regression analysis to determine the quantal response of sexually mature male flies that were attracted to CP in cage bioassays. Therefore, as a measure of male B. dorsalis' sensitivity of CP, the median dose of CP required to elicit a positive response in 50% of the tested B. dorsalis population (ED50) was calculated as 3.7 mg. This value was over 10,000x higher than known ED50 of B. dorsalis' male attraction ME (between 171 and 268 ng). We propose that the attraction of male B. dorsalis flies to CP was much weaker than to ME. Further, we suggest that in any fruit fly surveillance and monitoring programme, application of lures must consider the specificity and potency of each compound to target fruit fly species. The probit regression analysis of male fly quantal response to lure offers such information.
Two performance (efficacy and attractiveness) comparisons of neonicotinoid baits QuickBayt® (imidacloprid) and Agita® (thiamethoxam) against filth flies were conducted under field conditions to determine suitability for use outdoors. The first experiment compared bait performance and the second compared effects of different applications on QuickBayt® performance. Applications compared were: (i) scattered in petri dish (SPD); (ii) wet-down in petri dish (WPD); (iii) scattered on cardboard (SCB) and (iv) painted on cardboards (PCB). Efficacy and attractiveness were assessed based on knockdown percentage (KD%) and number of flies feeding on baits, respectively. The KD% of QuickBayt® (34% ± 3.0%) was not significantly higher than Agita® (29% ± 1.3%) (t-test, P>0.05). Agita® (101 ± 5.7 flies) was significantly more attractive to flies than QuickBayt® (76 ± 4.8 flies) and the sugar solution (49 ± 7.2) (one-way ANOVA, P<0.05). The PCB and SCB applications were significantly more attractive to filth flies than WPD and SPD (One-way ANOVA, P<0.05), however differences in KD% were not significantly different (One-way ANOVA, P>0.05). The two baits provided the same level of efficacy in a wide-open area against filth flies of various species. QuickBayt® was more versatile; efficacy was not significantly affected by different applications. Surface area and moisture affects attractiveness of the bait.
Pharmacophagy of methyl eugenol (ME)--a highly potent male attractant, by Bactrocera papayae results in the hydroxylation of ME to sex pheromonal components, 2-ally-4,5-dimethoxyphenol (DMP) and (E)-coniferyl alcohol (CF). These compounds, which are also male attractants, are then sequestered and stored in the rectal gland prior to their release during courtship at dusk. Chemical analyses of the digestive tract (excluding the crop and rectal gland) showed the absence of the sex pheromonal components and their precursor, ME. However, B. papayae males were attracted to and fed on the ME-fed male hemolymph extracts but not on hemolymph extracts of ME-deprived males. After thin layer chromatography in a hexane:ethyl acetate solvent system, flies were attracted to and fed on the original point on the TLC plate where the hemolymph extract had been spotted, suggesting that the pheromone components were bound in polar complexes. Chemical analyses of the ME-fed male hemolymph and crop extracts revealed the presence of the sex pheromonal components. The presence of the ME-derived pheromonal components and the absence of ME in the hemolymph suggest that the hemolymph is involved in the transportation of sex pheromonal components from the crop to the rectal gland.
The natural occurrence, distribution (within a plant) and roles of four phenylbutanoid compounds (anisyl acetone, cue-lure, raspberry ketone and zingerone) are elucidated for the Asia-Pacific and Oceania regions. These phenylbutanoids may act individually or in combination to attract true fruit fly males belonging to a tribe Dacini of subfamily Dacinae (Diptera: Tepritidae). Of special interest are the mutualistic interactions between the Dacini fruit fly males and the tropical daciniphilous (attracting exclusively Dacini fruit flies) orchids - leading to cross pollination for the orchids and enchanced mating success for the flies. When offered to male flies, anisyl acetone and cue-lure are generally converted to raspberry ketone. Upon consumption, raspberry ketone and zingerone are individually sequestered in the male rectal (pheromonal) gland unchanged. Attracted male flies readily imbibe the phenylbutanoid(s) in the floral synomone to compliment the endogenously synthesized male sex pheromonal components - to enhance attraction of conspecific females during courtship as well as attract conspecific males to form 'leks'. The phenylbutanoid(s) may also act as an allomone to deter vertebrate predators, especially geckos, besides possessing antimicrobial and antioxidant activities. Cue-lure, raspberry ketone and zingerone are important attractants/lures used in pest surveillance and mass trapping under the integrated pest management (IPM) program against quarantine Dacini fruit fly pest species, particularly Bactrocera tryoni and Zeugodacus cucurbitae.
The occurrence of Cryptococcus neoformans in bird excreta in Klang valley, Malaysia was determined in this study. Of 544 samples of bird excreta collected from a local zoo, pet shops and public areas, 20 strains of C. neoformans were isolated. All C. neoformans strains were serotype A and thus identified as C. neoformans variety grubii. All did not produce color changes on canavanine-glycine-bromothymol blue agar. All were of alpha-mating types, as determined by a pheromone-specific PCR assay. The antifungal susceptibility testing using agar diffusion method Neo-sensitabs showed that all were susceptible to amphotericin B, fluconazole and itraconazole.