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Eric B. Jang - One of the best experts on this subject based on the ideXlab platform.
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response of Melon Fly diptera tephritidae to weathered splat spinosad cue lure
Journal of Economic Entomology, 2010Co-Authors: Roger I Vargas, Eric B. Jang, Jaime C Pinero, Ronald F L Mau, John D Stark, Luis E Gomez, Lyndsie Stoltman, Agenor MafranetoAbstract:Studies were conducted in Hawaii to measure attraction of male Melon Fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), to SPLAT-Cue-Lure (C-L) and SPLAT-Melo-Lure (M-L) (raspberry ketone formate). Direct field comparisons of SPLAT-C-L and SPLAT-M-L at low (5%) and high (20%) concentrations indicated few differences in attraction over a 15-wk period. Subsequently, only SPLAT-Spinosad-C-L (5%) was compared with Min-U-Gel C-L with naled (standard used in California) in weathering studies. Treatments were weathered for 1, 2, 4, and 8 wk in Riverside, CA, and shipped to Hawaii for attraction/toxicity tests under field and semifield conditions by using released males of controlled ages, and for feeding tests in the laboratory. In terms of attraction, SPLAT-Spinosad-C-L compared favorably to, or outperformed the current standard of Min-U-Gel-C-L with naled. In terms of toxicity, the cumulative 24-h mortality did not differ between the two insecticide-containing C-L treatments in field cage studies after 8 wk. However, in feeding studies in which individual males were exposed for 5 min to the different C-L treatments after 4 wk of weathering, SPLAT-Spinosad-C-L demonstrated reduced mortality compared with the Min-U-Gel-C-L with naled, suggesting reduced persistence of the spinosad material. Spinosad has low contact toxicity and when mixed with SPLAT and C-L offers a reduced risk alternative for control of B. cucurbitae and related C-L-responding species, without many of the negative effects to humans and nontargets of broad-spectrum contact poisons such as naled.
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Suppression of Melon Fly (Diptera: Tephritidae) populations with releases of Fopius arisanus and Psyttalia fletcheri (Hymenoptera: Braconidae) in North Shore Oahu, HI, USA
BioControl, 2010Co-Authors: Ernest J Harris, Eric B. Jang, Roger I Vargas, Renato C Bautista, Avraham Eitam, Luc LeblancAbstract:Field experiments and surveys were conducted to evaluate the efficacy of releasing Fopius arisanus (Sonan) and Psyttalia fletcheri (Silvestri) parasitoids for suppression of Bactrocera cucurbitae (Coquillett) infesting wild Coccinia grandis L. In 2003 and 2004, P. fletcheri releases combined with natural emergence from wild Fly populations resulted in better Fly suppression, compared to the control site. While P. fletcheri developed freely on Melon Fly, F. arisanus was less successful at producing its own progeny, yet causing mortality and a twofold decrease in pupae recovered from ivy gourds. Concurrent releases of both parasitoids exerted a compounded suppressive effect on the Melon Fly population 2–3 times higher than during the pre-release phase. A similar, less obvious, pattern occurred in 2004, due to reduction of the ivy gourd fruit canopy. In 2005, only P. fletcheri was released, with greatly reduced impact, due to ivy gourd destruction and by growers leaving crop culls in fields, producing large numbers of Melon flies unaffected by parasitoid releases.
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cucumber volatile blend attractive to female Melon Fly bactrocera cucurbitae coquillett
Journal of Chemical Ecology, 2010Co-Authors: Matthew S. Siderhurst, Eric B. JangAbstract:The Melon Fly, Bactrocera cucurbitae (Coquillett), is a serious crop pest throughout the Asia Pacific sub-continent and Southeast Asia, causing damage to tree fruits, cucurbits, and related crops. Attractants for female Melon flies are of particular interest as they could be used in control tactics to reduce pest levels. Previous work has shown that freshly sliced cucumbers are attractive to female Melon flies, but the compounds responsible for this attraction were not identified. The objective of the present study was to create a synthetic lure for female B. cucurbitae based on its close association with Cucurbitaceae. Coupled gas chromatography-electroantennogram detection (GC-EAD) analysis of fresh and aged pureed cucumbers identified 31 compounds that were detected by females. Compounds that elicited EAD responses initially were screened as single components in glass McPhail traps in outdoor rotating olfactometer experiments. Four criteria were used to select compounds for testing in blends: a) strength of EAD response elicited; b) amount of compound present; c) relative attractiveness of a single compound; and d) compound novelty to Cucurbitaceae. Several synthetic blends attracted significant numbers of females in outdoor rotating olfactometer experiments; a nine-component blend (lure #7) was the most attractive. Field captures of female B. cucurbitae in traps baited with lure #7 were twice those in traps baited with Solulys protein bait. Besides having a female-biased attraction, this lure may have several advantages over protein baits: it can be used with a dry trap, is long lasting, and it captured low numbers of non-target species. Possible applications of this lure include trapping (for detection and/or monitoring/delimitation) and control/eradication (e.g., mass trapping, attract-and-kill, or as an attractant for existing protein insecticide bait sprays such as GF-120).
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targeted trapping bait spray sanitation sterile male and parasitoid releases in an areawide integrated Melon Fly diptera tephritidae control program in hawaii
American Entomologist, 2008Co-Authors: Eric B. Jang, Grant T. Mcquate, Roger I Vargas, Ernest J Harris, D O Mcinnis, Renato C Bautista, Ronald F L MauAbstract:An areawide integrated pest management approach to Melon Fly Bactrocera cucurbitae (Diptera: Tephritidae) suppression in Kamuela, Hawaii, was undertaken as part of a larger statewide program by the U.S. Department of Agriculture–Agricultural Research Service (USDA–ARS), Areawide Initiative. After a survey on five islands, a grid of 1 trap/km2 over 40 km2 was established in Kamuela to locate areas of infestation. Then a targeted male trapping array was applied based on the distribution of host plants, and these were mapped using geographic information systems. Trap density was determined by monitoring existing traps and by increasing density where catch was high. Sanitation of crops, application of GF120 Naturalyte NF bait spray, Sterile Insect Technique (SIT), and augmentation of Psyttalia fletcheri parasitoids were also used. Pretreatment trapping in the farming area indicated a Melon Fly population peak of 11.94 ± 9.90 flies/trap/day (f/t/d) on 30 Oct. 2000. By 2003, the average catch of the grid traps over 16 wk was 0.016 ± 0.005 f/t/d per km2, a 99.87% reduction. Some resurgence of Melon Fly population to a 12-wk average of 0.191 ± 0.79 f/t/d per km2 occurred when USDA discontinued SIT and parasitoid release and bait spray applications. Resurgence occurred primarily in the off-farm areas where growers had not adopted the three suppression techniques (sanitation, bait spraying, and male annihilation). Restoring USDA bait sprays application and brieFly reapplying SIT returned the population to a mean of 0.033 ± 0.004 f/t/d per km2 between 20 Jan. and 5 April 2004. Between August 2002 and August 2003, infestation in all fruits observed over 40 km2 averaged 14.3 ± 2.9%. In 2002, with all suppression activities implemented, the infestation rate averaged 8.5 ± 4.8% in sampled fruit. That is an 83.2% reduction compared with the 2000–2001 mean infestation of 50.6 ± 4.9%.
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Field Captures of Wild Melon Fly (Diptera: Tephritidae) with an Improved Male Attractant, Raspberry Ketone Formate
Journal of Economic Entomology, 2007Co-Authors: Eric B. Jang, Víctor Casaña-giner, James E. OliverAbstract:Field-trapping evaluations of the new male attractant, formic acid 4-(3-oxobutyl) phenyl ester (raspberry ketone formate [RKF]) were conducted in Hawaii with wild populations of Melon flies, Bactrocera cucurbitae Coquillett (Diptera: Tephritidae), to determine its activity in the field and to evaluate new plastic matrix formulations. All tests were compared with the standard Melon Fly attractant 4-(4-acetoxyphenyl)-2-butanone (cuelure [CL]), which is the attractant of choice for detection programs aimed at Melon Fly and other cuelure-responding Bactrocera fruit flies. Results of these tests over a range of doses on cotton wicks showed that at a 1-g dose raspberry ketone formate was 1.5–2 times more attractive compared with cuelure for up to 11 wk in the field. Lower doses applied on cotton wicks were less active, presumably due to hydrolysis of RKF to raspberry ketone. Raspberry ketone formate embedded in a plastic plug formulation also was field tested, and it was shown to be more attractive to male Melon Fly compared with cuelure. The use of this new attractant in control and detection programs is discussed.
Roger I Vargas - One of the best experts on this subject based on the ideXlab platform.
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age dependent response of female Melon Fly zeugodacus cucurbitae diptera tephritidae to volatiles emitted from damaged host fruits
Journal of Asia-pacific Entomology, 2021Co-Authors: Jaime C Pinero, Steven K Souder, Dong H Cha, Max R Collignon, Roger I VargasAbstract:Abstract In many insect species including fruit flies (Diptera: Tephritidae), the behavioral responses to volatiles emitted by their host plants can be modulated by environmental conditions and by the physiological state of the insect. Here, we quantified (1) the effects of female age on the attraction of female Melon Fly, Zeugodacus cucurbitae (Diptera: Tephritidae) to volatiles emitted by intact and mechanically damaged tomato (Solanum lycopersicum), eggplant (S. Melongena), zucchini (Cucurbita pepo), bitter Melon (Momordica charantia), and cucumber (Cucumis sativus) fruit, and (2) the influence of time elapsed since fruit damage on the outcome. The investigations were conducted under semi-natural conditions in Hawai’i. Results from the first experiment revealed that, for freshly damaged tomato, eggplant, and zucchini, the level of female response was comparatively low and was not affected by female age. For bitter Melon and cucumber, higher levels of response to freshly damaged fruit were documented, and the response levels gradually increased as female age increased from 1 to 4 weeks, reaching 70% for 4-week-old females exposed to cucumber odor. Results from our second experiment indicated that, on average, 56% of the females released responded in 20 min when cucumbers were freshly sliced, and the level of response was reduced 6-fold within a couple of hours. Females did not respond to tomato and cucumber odor when fruits were damaged >8 h before testing. Fruit volatiles involved in female Z. cucurbitae attraction seem to be released shortly upon mechanical damage and they are short-lived. The plasticity of the olfaction-driven behavior observed in Z. cucurbitae depending on female age and on the strength of the olfactory cues associated with preferred and less preferred hosts, adds another dimension to our understanding of the host-seeking behavior of this invasive species.
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effect of physiological state on female Melon Fly diptera tephritidae attraction to host and food odor in the field
Journal of Economic Entomology, 2018Co-Authors: Roger I Vargas, Jaime C Pinero, Neil W MillerAbstract:Foraging behavior of wild female Melon Fly, Bactrocera (Zeugodacus) cucurbitae Coquillett, a worldwide pest of economically important cucurbit crops, was examined through mark and recapture studies in both wild (Kona: dominated by the invasive weed ivy gourd, Coccinea grandis [L.] Voigt [Cucurbitaceae]), and cultivated (Kapoho: dominated by papaya, Carica papaya L. [Caricaceae] orchards) habitats on Hawaii Island. In particular, the extent to which wild Melon flies and color-marked F2 females responded to cucumber odor and Solulys yeast hydrolysate laced with ammonium acetate (1%, wt/vol) according to sexual maturity stage and degree of protein hunger was documented. Kona results indicated that more wild and color-marked F2 females responded to cucumber (Cucumis sativus L. [Cucurbitaceae]) odor than to protein odor with the exception of captured wild flies without eggs, which responded similarly to protein bait and cucumber odor. Results with captured wild females and color-marked F2 females in Kapoho suggested a significant preference for cucumber odor over protein odor regardless of whether or not they had eggs in their ovaries with the exception of protein-deprived color-marked F2 females, which responded to both odors in equal numbers. Implications of these new findings based on wild Melon flies in natural habitats are discussed with respect to integrated pest management control strategies with protein bait sprays used in Hawaii. The possibility of adding cucurbit volatiles to protein-based baits is discussed.
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suppression of female Melon Fly zeugodacus cucurbitae with cue lure and fipronil bait stations through horizontal insecticide transfer
Entomologia Experimentalis Et Applicata, 2018Co-Authors: Helen Spafford, Ronald F L Mau, Ming Y Chou, Roger I VargasAbstract:Melon Fly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), is an important quarantine tephritid fruit Fly with resident populations established in Hawai'i, USA. In the male‐annihilation approach, male flies are targeted using dispensers with cue‐lure (C‐L) and insecticides, typically organophosphates. The efficacy of the male annihilation approach is thought to be limited to individual male flies, contacting the lure and the pesticide, after which they die. Alternative classes of insecticides, such as fipronil, have been investigated for use in male‐annihilation. We hypothesized that ingestion of fipronil by male flies could lead to horizontal transfer and mortality in female flies. Horizontal insecticide transfer extends pesticide control beyond the individual contacting the toxicant through indirect contact via food sharing or other mechanisms. We tested the possibility for horizontal transfer of fipronil from male to female Z. cucurbitae through field and laboratory studies. Two repeated field trials were conducted to compare the numbers of female flies collected in fields treated with Amulet C‐L (0.34% fipronil active ingredient) bait stations, sanitation, and spot treatments of GF‐120 Fruit Fly Bait to numbers collected in fields where sanitation and spot‐treatments were used without Amulet C‐L. In fields with Amulet C‐L bait stations in conjunction with sanitation and weekly protein bait spot treatments of GF‐120 Fruit Fly Bait, female captures were significantly lower than those in field plots treated with weekly protein bait spot treatments and sanitation. In subsequent laboratory studies, all females died within 6 h after direct exposure to male flies that had access to Amulet C‐L for 1–4 min. The possibility that male regurgitant could be a mechanism for horizontal transfer and subsequent female mortality was determined by collecting regurgitated droplets from fipronil‐fed male flies and feeding them to males and females. Both male and female flies exposed to regurgitant from fipronil‐fed male flies or droplets containing fipronil had higher mortality than the male and female flies that were exposed to regurgitant or droplets with only the C‐L compound or sugar solution. Thus, female flies do experience mortality from exposure to regurgitant from males that have fed on fipronil laced solutions. This provides evidence of at least one mechanism of horizontal transfer of insecticide in tephritid fruit flies. These findings are discussed in the context of Z. cucurbitae integrated pest management programs in Hawai'i.
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response of Melon Fly diptera tephritidae to weathered splat spinosad cue lure
Journal of Economic Entomology, 2010Co-Authors: Roger I Vargas, Eric B. Jang, Jaime C Pinero, Ronald F L Mau, John D Stark, Luis E Gomez, Lyndsie Stoltman, Agenor MafranetoAbstract:Studies were conducted in Hawaii to measure attraction of male Melon Fly, Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae), to SPLAT-Cue-Lure (C-L) and SPLAT-Melo-Lure (M-L) (raspberry ketone formate). Direct field comparisons of SPLAT-C-L and SPLAT-M-L at low (5%) and high (20%) concentrations indicated few differences in attraction over a 15-wk period. Subsequently, only SPLAT-Spinosad-C-L (5%) was compared with Min-U-Gel C-L with naled (standard used in California) in weathering studies. Treatments were weathered for 1, 2, 4, and 8 wk in Riverside, CA, and shipped to Hawaii for attraction/toxicity tests under field and semifield conditions by using released males of controlled ages, and for feeding tests in the laboratory. In terms of attraction, SPLAT-Spinosad-C-L compared favorably to, or outperformed the current standard of Min-U-Gel-C-L with naled. In terms of toxicity, the cumulative 24-h mortality did not differ between the two insecticide-containing C-L treatments in field cage studies after 8 wk. However, in feeding studies in which individual males were exposed for 5 min to the different C-L treatments after 4 wk of weathering, SPLAT-Spinosad-C-L demonstrated reduced mortality compared with the Min-U-Gel-C-L with naled, suggesting reduced persistence of the spinosad material. Spinosad has low contact toxicity and when mixed with SPLAT and C-L offers a reduced risk alternative for control of B. cucurbitae and related C-L-responding species, without many of the negative effects to humans and nontargets of broad-spectrum contact poisons such as naled.
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Suppression of Melon Fly (Diptera: Tephritidae) populations with releases of Fopius arisanus and Psyttalia fletcheri (Hymenoptera: Braconidae) in North Shore Oahu, HI, USA
BioControl, 2010Co-Authors: Ernest J Harris, Eric B. Jang, Roger I Vargas, Renato C Bautista, Avraham Eitam, Luc LeblancAbstract:Field experiments and surveys were conducted to evaluate the efficacy of releasing Fopius arisanus (Sonan) and Psyttalia fletcheri (Silvestri) parasitoids for suppression of Bactrocera cucurbitae (Coquillett) infesting wild Coccinia grandis L. In 2003 and 2004, P. fletcheri releases combined with natural emergence from wild Fly populations resulted in better Fly suppression, compared to the control site. While P. fletcheri developed freely on Melon Fly, F. arisanus was less successful at producing its own progeny, yet causing mortality and a twofold decrease in pupae recovered from ivy gourds. Concurrent releases of both parasitoids exerted a compounded suppressive effect on the Melon Fly population 2–3 times higher than during the pre-release phase. A similar, less obvious, pattern occurred in 2004, due to reduction of the ivy gourd fruit canopy. In 2005, only P. fletcheri was released, with greatly reduced impact, due to ivy gourd destruction and by growers leaving crop culls in fields, producing large numbers of Melon flies unaffected by parasitoid releases.
Keng-hong Tan - One of the best experts on this subject based on the ideXlab platform.
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Sex Pheromone Components in Defense of Melon Fly, Bactrocera cucurbitae Against Asian House Gecko, Hemidactylus frenatus
Journal of Chemical Ecology, 2000Co-Authors: Keng-hong TanAbstract:The Asian house gecko, Hemidactylus frenatus , after being acclimatized to feeding on the Melon Fly, Bactrocera cucurbitae , consumed fewer numbers of 15-day-old (DO) and older male Melon flies compared to sexually immature flies 10 DO and younger. The first male Melon Fly that performed mating did so on the 10th day after eclosion (DAE), but >80% of the males performed their first mating between 10 and 15 DAE. This confirmed that between 10 and 15 DAE most male Melon flies are already sexually mature and producing sex pheromone. Synthetic 1,3-nonanediol, a component of male Melon Fly sex pheromone produced endogenously, when topically applied onto the thorax of houseFly Musca domestica at ca. 80 or 320 ng/Fly, reduced consumption by geckos compared with untreated flies in subsequent days after the first day in a four-day feeding test. Raspberry ketone (RK) is consumed and sequestered into the pheromonal gland and later released as a pheromonal component of male Melon Fly. Houseflies topically treated with 2.6 μg RK/Fly did not deter predation by geckos. However, houseflies treated with 5.1 μg RK/Fly caused geckos to consume fewer flies, especially on the third and fourth days during a four-day feeding test, compared with the period when they were offered untreated flies.
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Accumulation ofDendrobium superbum (orchidaceae) fragrance in the rectal glands by males of the Melon Fly,Dacus cucurbitae
Journal of Chemical Ecology, 1993Co-Authors: Ritsuo Nishida, Osamu Iwahashi, Keng-hong TanAbstract:4-(4-Hydroxyphenyl)-2-butanone was characterized from flowers of the orchid Dendrobium superbum as a specific attractant factor for the male Melon Fly, Dacus cucurbitae . The male flies compulsively licked the flower surface and sequestered the compound in significant quantities in their rectal glands. The compound was detected within 6 hr after ingestion and was retained for more than six days in the rectal gland sacs.
Jinjun Wang - One of the best experts on this subject based on the ideXlab platform.
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genome wide analysis of long non coding rnas in adult tissues of the Melon Fly zeugodacus cucurbitae coquillett
BMC Genomics, 2020Co-Authors: Yujia Song, Hongliang Han, Dong Wei, Guy Smagghe, Jinjun WangAbstract:Long non-coding RNAs (lncRNAs) are involved in many fundamental biological processes, such as transcription regulation, protein degradation, and cell differentiation. Information on lncRNA in the Melon Fly, Zeugodacus cucurbitae (Coquillett) is currently limited. We constructed 24 RNA-seq libraries from eight tissues (midgut, Malpighian tubules, fat body, ovary, and testis) of Z. cucurbitae adults. A total of 3124 lncRNA transcripts were identified. Among those, 1464 were lincRNAs, 1037 were intronic lncRNAs, 301 were anti-sense lncRNAs, and 322 were sense lncRNAs. The majority of lncRNAs contained two exons and one isoform. Differentially expressed lncRNAs were analyzed between tissues, and Malpighian tubules versus testis had the largest number. Some lncRNAs exhibited strong tissue specificity. Specifically expressed lncRNAs were identified and filtered in tissues of female and male Z. cucurbitae based on their expression levels. Four midgut-specific lncRNAs were validated by quantitative real-time polymerase chain reaction (RT-qPCR), and the data were consistent with RNA-seq data. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of targets of midgut-specific lncRNAs indicated an enrichment of the metabolic process. This was the first systematic identification of lncRNA in the Melon Fly. Expressions of lncRNAs in multiple adult tissues were evaluated by quantitative transcriptomic analysis. These qualitative and quantitative analyses of lncRNAs, especially the tissue-specific lncRNAs in Z. cucurbitae, provide useful data for further functional studies.
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genome wide gene expression profiling of the Melon Fly zeugodacus cucurbitae during thirteen life stages
Scientific Data, 2020Co-Authors: Dong Wei, Guy Smagghe, Dong Chen, Suyun Zhang, Jinjun WangAbstract:The Melon Fly, Zeugodacus cucurbitae (Coquillett), is an important destructive pest worldwide. Functional studies of the genes associated with development and reproduction during different life stages are limited in Z. cucurbitae. There have yet to be comprehensive transcriptomic resources for genetic and functional genomic studies to identify the molecular mechanisms related to its development and reproduction. In this study, we comprehensively sequenced the transcriptomes of four different developmental stages: egg, larva, pupa, and adults. Using the Illumina RNA-Seq technology, we constructed 52 libraries from 13 stages with four biological replicates in each and generated 435.61 Gb clean reads. We comprehensively characterized the transcriptomes with high-coverage mapping to the reference genome. A total of 13,760 genes were mapped to the reference genome, and another 4481 genes were characterized as new genes. Finally, 14,931 genes (81.85%) were functionally annotated against six annotation databases. This study provides the first comprehensive transcriptome data of all developmental stages of Z. cucurbitae, and will serve as a valuable resource for future genetic and functional studies.
Takahisa Miyatake - One of the best experts on this subject based on the ideXlab platform.
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selection for age at reproduction changes pre mating period and mating frequency in zeugodacus cucurbitae impacts on insect quality control
Entomologia Experimentalis Et Applicata, 2021Co-Authors: Takahisa MiyatakeAbstract:In the mass-rearing of insects for sterile insect technique (SIT), it is important to maintain the quality of mass-reared males so that they can compete with wild males in mating with wild females. Mass-reared insects sometimes have shorter pre-mating periods and higher mating frequencies than their wild conspecifics. Indeed, this was the case for mass-reared individuals of the Melon Fly, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae), used in the SIT program to eradicate the Melon Fly on the Southwest Islands of Japan. Therefore, I hypothesized that divergent artificial selection for age at reproduction altered these traits in the Melon Fly as well. To examine the effects of eggs produced by younger parents on each generation, six artificially selected lines were established, for which eggs were collected from young (Y lines) and old (O lines) females. Then, the pre-mating periods and mating frequencies in males and females of the selected lines were compared. The results show a decreased pre-mating period and an increased mating frequency in younger lines compared to older lines, which was driven by males rather than females. These traits ensure efficient offspring production in mass-rearing, and are likely advantageous to the success of SIT programs. The impact of artificially selecting for these traits, especially in males, on insect quality and the efficiency of SIT is discussed.
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eradication of the Melon Fly bactrocera cucurbitae in japan importance of behavior ecology genetics and evolution
Annual Review of Entomology, 2004Co-Authors: Juro Koyama, Hiroyuki Kakinohana, Takahisa MiyatakeAbstract:The Melon Fly, Bactrocera cucurbitae, is a destructive insect of cucurbit and other fruits. It invaded the Southwestern Islands of Japan from 1919 to 1974. The sterile insect technique (SIT) was successfully applied from 1972 to 1993 to eradicate the Melon Fly. Technical research into SIT functions, such as suppression of density, mass-rearing, sterilization, shipment, release, evaluation of efficacy, and quality control of mass-reared insects, was conducted for this eradication project. Fundamental research into the dispersion, mating and oviposition behavior, population dynamics and estimation of density, eradication models, spatial distribution, genetics, and evolution of the Melon Fly was also undertaken and supported the success of the eradication project.
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The period gene and allochronic reproductive isolation in Bactrocera cucurbitae.
Proceedings. Biological sciences, 2002Co-Authors: Takahisa Miyatake, Akira Matsumoto, Takashi Matsuyama, Hiroki R. Ueda, Tetsuya Toyosato, Teiichi TanimuraAbstract:Clock genes that pleiotropically control circadian rhythm and the time of mating may cause allochronic reproductive isolation in the Melon Fly Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae). Flies with a shorter circadian period (ca. 22 h of locomotor activity rhythm) mated 5 h earlier in the day than those with a longer circadian period (ca. 30 h). Mate-choice tests demonstrated significant pre-mating isolation between populations with short and long circadian periods. Pre-mating isolation did not occur when the mating time was synchronized between the two populations by photoperiodic controls, indicating that reproductive isolation is due to variations in the time of mating and not any unidentified ethological difference between the two populations. We cloned the period (per) gene of B. cucurbitae that is homologous to the per gene in Drosophila. The relative level of per mRNA in the Melon Fly exhibited a robust daily fluctuation under light : dark conditions. The fluctuation of per expression under dark : dark conditions is closely correlated to the locomotor rhythm in B. cucurbitae. These results suggest that clock genes can cause reproductive isolation via the pleiotropic effect as a change of mating time.
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Rapid evolution of larval development time during mass-rearing in the Melon Fly, Bactrocera cucurbitae
Population Ecology, 1999Co-Authors: Takahisa Miyatake, Masaaki YamagishiAbstract:A quantitative genetic analysis of rapid evolution of a life history trait has been conducted on the first 24 generations of mass-rearing in the Melon Fly Bactrocera cucurbitae (Coquillett) (Diptera: Tephritidae). The phenotypic variance of larval development time in each generation was divided into genetic and residual components. Mean and phenotypic coefficients of variation of larval development time decreased gradually as generations proceeded as a result of artificial selection for shorter larval period in the mass-rearing procedure. There was a trend that additive genetic coefficients of variation in larval development time decreased with generations. These changes are entirely attributed to genetic responses to laboratory selection under the mass-rearing environment because the population was maintained at a very large size so as to exclude random genetic drift and inbreeding depression, which would be other factors responsible for the observed genetic changes. The residual coefficients of variation in larval development time did not change with generations. Realized heritability of larval development time was low. The heritabilities for larval development time estimated from parent–offspring regression at generations 60 and 70, when the evolutionary plateau was asymptotically reached, were not significantly larger than 0.
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Genetic Changes of Life History and Behavioral Traits during Mass-Rearing in the Melon Fly, Bactrocera cucurbitae (Diptera: Tephritidae)
Researches on Population Ecology, 1998Co-Authors: Takahisa MiyatakeAbstract:Quantitative genetic studies for life history and behavioral traits are important in quality control for insect mass-rearing programs. Firstly, a brief history of quality control in mass-reared insects is described. Next, the differentiation of many traits of wild and mass-reared Melon flies,Bactrocera cucurbitae, in Okinawa is reviewed, and the factors which have caused variation in these traits are considered. As artificial selection pressures are thought to be more important than inbreeding depression and genetic drift in the mass-reared strain of the Okinawan Melon Fly, two artificial selection experiments were conducted to evaluate genetic variations and genetic correlations among life history and behavioral traits. These are divergent selections for age at reproduction and for developmental period. The genetic relationship among 5 traits, i.e. longevity, age at reproduction, developmental period, circadian period, and time of mating was clarified and discussed in relation to genetic changes of traits during the mass-rearing. The results suggest that the genetic trade-off relationships between traits should be taken into account in mass-rearing programs.
