Capture of Mediterranean Fruit Flies and Melon Flies (Diptera: Tephritidae) in Food-Baited Traps in Hawaii

Food-based attractants are an important component of tephritid fruit fly detection programs, because they are general baits that are neither sex- nor species-specific. Two widely used food baits are enzymatic hydrolyzed torula yeast, which is presented as an aqueous solution that also serves to catch insects (wet trap), and a synthetic lure that combines ammomonium acetate, putrescine, and trimethylamine and may be presented with or without a water-based catch system. Recently, the liquid attractant CeraTrap, which is an enzymatic hydrolyzed animal protein, has been shown to be equally or more effective than traditional protein baits in capturing species of Anastrepha. The present study compares capture of wild Mediterranean fruit flies, Ceratitis capitata (Wiedemann), and melon flies, Zeugodacus cucurbitae (Coquillett) in traps baited with torula yeast or CeraTrap. In addition, one sampling interval compared the catch of C. capitata in wet traps baited with torula yeast, a synthetic food lure, or CeraTrap. CeraTrap was generally more effective in capturing both sexes of C. capitata than the other food baits, while torula yeast resulted in higher captures of Z. cucurbitae than CeraTrap. Results are compared with other trapping studies of tephritids involving food-based attractants

Capturing Males of Pestiferous Fruit Flies (Diptera: Tephritidae): Is the Combination of Triple-Lure Wafers and Insecticidal Strips as Effective as Standard Treatments?

The detection of invasive tephritid fruit fly pests relies primarily on traps baited with male-specific lures. Three different male lures are typically used, and accordingly three sets of traps are deployed: those baited with liquid methyl eugenol (ME) or liquid cue lure (CL) for different Bactrocera species and those baited with plug-bearing trimedlure (TML) for Ceratitis species. The liquid lures contain the insecticide naled, whereas the trimedlure plugs contain no toxicant. Preparing the liquid solutions and servicing three types of traps requires consid- erable labor, and handling naled (and possibly ME) introduces potential health risks. The purpose of this study was to compare the effectiveness of Jackson traps baited with a solid dispenser (wafer) containing all three male lures plus a separate insecticidal (DDVP; 2, 2-dichlorovinyl dimethyl phosphate) strip with Jackson traps baited with the standard male lure/toxicant combinations. Trapping was conducted during two 12-week periods in a coffee field on Oahu, Hawaii. The effectiveness of the wafer-baited traps varied among different species. Catch of Bactrocera dorsalis (Hendel) males was similar between wafer-baited and liquid ME-baited traps for both sampling periods. Conversely, traps baited with the standard TML plug captured significantly more Ceratitis capitata (Wiedemann) males than the wafer-baited traps in both sampling periods. The relative effectiveness of the two trap treatments varied between sampling periods for Bactrocera cucurbitae (Coquillett) males. Based on these results, the triple-lure wafer plus separate kill strip does not, at present, appear to be a viable substitute for the male lure/toxicant combinations currently in use

Testing the Temporal Limits of Lures and Toxicants for Trapping Fruit Flies (Diptera: Tephritidae): Additional Weathering Studies of Solid Bactrocera and Zeugodacus Male Lures and Associated Insecticidal Strips

Detection of pestiferous fruit flies (Diptera: Tephritidae) relies largely on traps baited with male-specific attractants. Surveillance programs in Florida and California use liquid methyl eugenol (ME, attractive to males of Bactrocera dorsalis (Hendel)) and liquid cue-lure (CL, attractive to males of Zeugodacus cucurbitae (Coquillett)) mixed with the toxicant naled to bait detection traps. However, this practice requires considerable time and may subject personnel to health risks. Recent work indicates that solid male lures deployed with a separate insecticidal (DDVP) strip are as effective as the standard liquid formulations. Specifically, solid ME and CL dispensers and DDVP strips were weathered for 6 or 12 weeks under summer conditions in AZ and FL and subsequently field tested in Hawaii. Results showed that (i) solid ME dispensers weathered for 6 weeks, but not 12 weeks, were as attractive as fresh liquid ME, and (ii) solid CL dispensers and the insecticidal strips were as effective as fresh liquid formulation for at least 12 weeks. The present study expands upon these earlier findings and addresses two specific questions: Could solid ME dispensers be deployed for 8 or 10 weeks without loss of effectiveness? Could solid CL dispensers and insecticidal strips be deployed for intervals even longer than 12 weeks? Adopting the same protocol noted above, the present study indicates that effective field longevities are 10 weeks for solid ME dispensers, at least 20 weeks for solid CL dispensers, and 12 weeks for the DDVP strips. Comparisons are drawn with related studies, and implications for tephritid surveillance programs are discussed

Trapping Pestiferous Fruit Flies (Diptera: Tephritidae): Additional Studies on the Performance of Solid Bactrocera Male Lures and Separate Insecticidal Strips Relative to Standard Liquid Lures

Detection of pestiferous Bactrocera fruit flies relies largely on traps baited with male-specific attractants. Surveillance programs in Florida and Cali- fornia use liquid methyl eugenol (ME, attractive to males of B. dorsalis (Hendel)) and liquid cue-lure (CL, attractive to males of B. cucurbitae (Coquillett)) mixed with the toxicant naled to bait traps. However, the application of the liquids requires considerable time and may subject personnel to health risks from inadvertent exposure to the lure and the insecticide. Recent studies have shown that solid dispensers containing a toxicant perform as well or better than liquid lures, but the combination of lure and toxicant in the same solid dispenser faces registration problems. Fewer studies have assessed the efficacy of solid, and separate, lures and toxicants, but existing data are promising. Here, we present the results of two independent studies that further assess the effectiveness of solid ME and CL lures and their associated, but separate, insecticidal strips. The first study, conducted exclusively in Hawaii over a 12 week period, found that captures of B. dorsalis or B. cucurbitae males were similar between traps baited with the standard liquid formulation and traps baited with solid lure dispensers and either 1 or 2 insecti- cidal strips. In the second study, solid lure dispensers and associated insecticide strips were weathered for 6 or 12 weeks under summer conditions in Arizona and Florida, where high temperatures were presumed to result in high volatility and thus provide a rigorous test of field longevity. Aged materials were shipped to Hawaii for testing against fresh (non-weathered) lures and insecticidal strips in wild populations. The results were fairly consistent between Arizona- and Florida- weathered devices and indicated that (i) solid ME dispensers were effective for 6 weeks but lost significant attractancy at 12 weeks and (ii) CL solid lures and the insecticidal strips were effective for at least 12 weeks. Collectively, these findings provide additional evidence that surveillance programs could switch to solid lures and toxicants and maintain a high level of detection sensitivity

Wafers in Saddle Bags: A Novel Dispensing System for Male Lures Used to Detect Invasive Fruit Flies (Diptera: Tephritidae)

Detection of the agricultural pests Bactrocera dorsalis (Hendel) and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) relies heavily on traps baited with male-specific attractants. For B. dorsalis, traps are baited with liquid (6 ml) methyl eugenol (ME), while polymeric plugs containing trimedlure (TML; 2 g) are used in traps targeting C. capitata. In both cases, the attractant volatilizes rapidly, and lures are changed out every 6 weeks to insure high trap attractancy. Lures having greater longevity would be beneficial, because they would lengthen the trap servicing interval and thus reduce both supply and labor costs. Here, we tested the effectiveness of a saddle bag dispenser that (i) held two solid wafers impregnated with male lure, thus eliminating handling of liquid methyl eugenol (a potential carcinogen), (ii) was easy to place in traps, and (iii) allowed a high loading of male lure in trap (total loading of 6 g per trap for each lure). Field experiments, each lasting 12–14 weeks, were conducted on Hawaii island and Oahu, Hawaii, that compared captures of B. dorsalis and C. capitata males in traps baited in the standard manner versus traps baited with saddle bag dispensers. Traps baited with ME saddle bags weathered up to 12 or 14 weeks generally captured similar numbers of B. dorsalis males as traps baited with fresh ME liquid and significantly more males than traps baited with weathered ME liquid. Similar results were obtained for C. capitata: traps baited with TML saddle bags weathered up to 12 or 14 weeks captured similar numbers of C. capitata males as traps baited with fresh TML plugs and significantly more males than traps baited with weathered TML plugs

Weathering of Torula Yeast Borax Food Bait and Capture of Oriental, Mediterranean, and Melon Fruit Flies in Hawaii (Diptera: Tephritidae)

Detection of pestiferous tephritid fruit flies relies largely on traps baited with male-specific attractants, termed male lures. Although male lures are quite powerful, two factors limit their effectiveness: they do not target females, and males of many tephritid species are not attracted to these compounds. Consequently, food-baited traps are an important component of fruit fly monitoring programs, because, despite their relatively low attractancy, food baits are general attractants that are neither sex- nor species-specific. Enzymatic torula yeast in an aqueous solution is a standard food attractant used in tephritid trapping programs worldwide. Torula yeast bait is not particularly long-lasting, and replacement is recommended every 7–14 d. Few data exist regarding the attractiveness of this food bait over time, and the present study was undertaken to compare captures of wild Bactrocera dorsalis (Hendel), Ceratitis capitata (Wiedemann), and Zeugodacus cucurbitae (Coquillett) in Multilure traps baited with torula yeast slurry weathered for 3, 6, 9, or 12 d. No significant variation in trap catch was detected among these weathering intervals for any of the three species. In a second experiment, trap captures were compared between food bait weathered 3 vs. 21 d, and in this case significantly more C. capitata and Z. cucurbitae were captured in the 3-d-old bait, whereas catch of B. dorsalis was similar for traps containing food bait weathered for 3 or 21 d. Results are compared with those of previous studies

Big Genomes Facilitate the Comparative Identification of Regulatory Elements

The identification of regulatory sequences in animal genomes remains a significant challenge. Comparative genomic methods that use patterns of evolutionary conservation to identify non-coding sequences with regulatory function have yielded many new vertebrate enhancers. However, these methods have not contributed significantly to the identification of regulatory sequences in sequenced invertebrate taxa. We demonstrate here that this differential success, which is often attributed to fundamental differences in the nature of vertebrate and invertebrate regulatory sequences, is instead primarily a product of the relatively small size of sequenced invertebrate genomes. We sequenced and compared loci involved in early embryonic patterning from four species of true fruit flies (family Tephritidae) that have genomes four to six times larger than those of Drosophila melanogaster. Unlike in Drosophila, where virtually all non-coding DNA is highly conserved, blocks of conserved non-coding sequence in tephritids are flanked by large stretches of poorly conserved sequence, similar to what is observed in vertebrate genomes. We tested the activities of nine conserved non-coding sequences flanking the even-skipped gene of the teprhitid Ceratis capitata in transgenic D. melanogaster embryos, six of which drove patterns that recapitulate those of known D. melanogaster enhancers. In contrast, none of the three non-conserved tephritid non-coding sequences that we tested drove expression in D. melanogaster embryos. Based on the landscape of non-coding conservation in tephritids, and our initial success in using conservation in tephritids to identify D. melanogaster regulatory sequences, we suggest that comparison of tephritid genomes may provide a systematic means to annotate the non-coding portion of the D. melanogaster genome. We also propose that large genomes be given more consideration in the selection of species for comparative genomics projects, to provide increased power to detect functional non-coding DNAs and to provide a less biased view of the evolution and function of animal genomes

Field Capture of Male Melon Flies, Bactrocera cucurbitae (Coquillett), in Jackson Traps Baited with Cue-Lure Versus Raspberry Ketone Formate in Hawaii

The melon fly, Bactrocera cucurbitae (Coquillett), is an invasive worldwide pest of vegetables, particularly various species of squashes and melons. Because it poses a serious economic threat, many countries operate continuous trapping programs to detect incipient infestations. Detection currently relies on traps baited with a chemical (cue-lure, CL) that is attractive to males of this species. Earlier research suggested that a chemically similar compound (raspberry ketone formate, RKF) is more attractive than CL and thus might improve surveillance efforts. The present study describes the results of field experiments in Hawaii that compare captures of B. cucurbitae males in traps baited with (1) CL liquid versus a solid formulation (so-called plugs) of RKF or (2) CL liquid versus RKF liquid. In the first experiment, the traps with CL liquid captured more males than traps baited with RKF plugs in three of the four study sites, with no difference observed between lures at the remaining area. In the second experiment, the traps baited with CL liquid captured more males than traps baited with RKF liquid at two of the four study areas, with no difference observed between lures at the remaining two sites. The discrepancy between earlier studies and the present one highlights the need for additional field testing of RKF to assess its value as a replacement for CL

Capture of Bactrocera Males (Diptera: Tephritidae) in Parapheromone-Baited Traps: Performance of Solid Dispensers with Different Loadings of Attractants and Toxicant

Bactrocera cucurbitae (Coquillett) and B. dorsalis (Hendel) (Diptera: Tephritidae) are important agricultural pests of the Pacific region. Detection of these species relies on traps baited with male-specific attractants, namely cue lure for B. cucurbitae and methyl eugenol for B. dorsalis. At present, these lures (plus naled, an insecticide) are applied in liquid form, although this procedure is time-consuming, and naled as well as methyl eugenol may pose human health risks. Recent field tests have shown that traps baited with a solid formulation (termed a wafer) that contains both lures (plus DDVP, an insecticide) capture as many or even more Bactrocera males than traps with the standard liquid lures. However, these previous studies used relatively large wafers, which would likely be inadequate for large-scale trapping programs, as fitting them into traps was inconvenient and time-consuming. The purpose of the present study was to compare captures of B. cucurbitae and B. dorsalis males in traps baited with liquids versus traps baited with different-sized wafers, which also contained different loadings of the male lures. Based on a series of field tests, we found that traps with a slightly smaller (medium-sized) wafer, which is more easily inserted and removed from the traps, performed as well or better than traps with the standard liquid lures or the original large-sized wafer. In addition, field tests with medium wafers showed that the DDVP level could be halved without any loss of trap effectiveness