Short-range dispersal of recently emerged males and females of Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) monitored by sticky sphere traps baited with protein and Lynfield traps baited with cue-lure

Abstract  Dispersal of immature male and female Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), was assessed over a period of 1 week from a single release point on three separate occasions using an array of Lynfield traps baited with cue-lure and odouriferous yellow or black sticky spheres baited with food lure (protein autolysate). Lynfield traps recaptured males; yellow or black spheres recaptured both sexes in approximately equal proportions, although at a much lower rate. As a percentage of the recapture rate for males by Lynfield traps, the mean recapture rate for yellow spheres ranged from 1.0% to 7.5% for males and 0.7% to 4.0% for females, whereas the recapture rates for black spheres ranged from 0.4% to 3.6% and 0.6% to 1.8%, respectively. The rate of recapture of sterile male flies was greater than that of unsterilised flies; this may have been due to a faster maturation rate in sterile males or because a greater proportion of them remained within the trap array rather than dispersing. There was no significant trend in recapture rate with distance from the release point to the edge of the array (88 m), except in the case of females on sticky traps where no trend was detected between 19 and 88 m. These results lend support to assumptions made about the distribution of males and females with respect to the minimum breeding density of fruit fly propagules invading a fly-free zone, and the method chosen to distribute sterile B. tryoni for the sterile insect technique.     

Understanding Bactrocera dorsalis trapping to calibrate area-wide management

Knowing the dispersal of released insects and estimating the size of field populations are keys to the successful implementation of area-wide management (AWM) programmes based on the sterile insect technique (SIT), as they determine the release strategy of sterile males. Mark–release–recapture (MRR) is a common method used to estimate field populations and spatiotemporal dynamics. However, the extent to which the pest is attracted to lures is often difficult to identify, thereby biasing extrapolation to movement patterns and population size. We performed MRR experiments on the Oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), in a fruit-growing area in Senegal. Methyl eugenol and protein baits were used to trap males and females, respectively. After studying the suitability of marking B. dorsalis with fluorescent pigments at the laboratory, two releases of marked sterile flies were organized in the centre of an organic mango orchard, first in the late mango fruiting stage and second in the fruit setting stage. Traps were placed symmetrically along a 250 and 500 m radius from the release point. A very small fraction of the released individuals was recaptured: 0.45% in the first release and 3.08% in the second. Trapping of both sterile and wild flies was completely anisotropic. Sterile flies were mostly trapped at a relatively short distance (250 m) from the release point, in the first two days. Male trapping using methyl eugenol was highly effective, whereas the response of females to food bait traps was low. The direction of the wind was the main driver of recapture, with flies heading upwind. The results underline the importance of taking the odour plume around the traps into account when estimating populations, and the heterogeneous spread of the wild population in the landscape for the set-up of the release strategy of sterile insects for SIT-based AWM.     

Recapture of sterile Mediterranean fruit flies (Diptera: Tephritidae) in California's Preventative Release Program

In southern California, the sterile insect technique has been used since 1994 to prevent establishment of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann). This method involves the continual mass release of sterile flies, which suppress or eliminate any introduced wild fly populations. In addition, Jackson traps baited with trimedlure are deployed throughout the preventative release region for the dual purpose of detecting wild flies and monitoring released sterile flies. Sterile fly recapture data for a 3-yr period was compared with climate and to host plant (in which traps were placed). Precipitation was negatively correlated; and temperature and relative humidity were positively correlated with fly recapture levels. The highest numbers of flies were recaptured during trapping periods associated with intermediate relative humidity and temperature, and low precipitation. Flies were recaptured throughout the entire year, in traps that had been frequently relocated to host plants with fruit. This finding suggests that these flies were capable of locating acceptable fruit in a variety of abiotic conditions. However, these data do not necessarily suggest that measurements unimportant in explaining sterile fly recapture are not of value in determining other outcomes important to the goals of sterile release programs, such as reducing the likelihood of establishment of an introduced wild Mediterranean fruit fly population. Future research might build on these results in developing more precise models useful in predicting recapture of sterile flies.     

The screw-worm flyChrysomya bezziana villeneuve (Diptera: Calliphoridae) in a sterile insect release trial in Papua New Guinea

The feasibility of the sterile insect release method (SIRM) was tested against natural populations of the Old World screw-worm fly, Chrysomya bezziana in the Musa Valley, Papua New Guinea. Sterile mating frequencies were determined from egg masses laid by native females on wounded, sentinel cattle. The aerial release of sterilised puparia resulted in low frequencies of sterile matings and few trap recaptures of released material. The release of chilled adult flies resulted in higher frequencies of sterile matings and many trap recaptures. The mean density of males released was 230 males per km² per week over a target area of 361 km² (48% of the valley). Sterile masses were first detected 2 weeks after the release of chill flies commenced, reaching a weekly peak of 33% after 5 weeks of releases with 15% of egg masses found to be sterile during the final month. The levels of sterile matings achieved in this trial were similar to comparable SIRM studies made in the USA, Mexico and Guatemala to control the New World screw-worm fly, Cochliomyia hominivorax.     

Persistence of sterile screwworm (Diptera: Calliphoridae) flies at a release site.

Studies to determine the persistence of released, sterile screwworms, Cochliomyia hominivorax (Coquerel), were conducted in Belize, Central America, in 1987-1988. A total of nine releases were made, each consisting of 4,000 females marked with a fluorescent dust. Previous similar studies with baited fly traps indicated that flies died or dispersed from the release site within 3-4 d. For this study, flies were recaptured at sentinel animals. Recapture rates varied greatly between releases, a result that was not correlated with any weather parameter. The pattern of recapture indicated a sharp drop in the released population after 9-10 d, with a few flies persisting in the release area for up to 3 wk. The results suggest that survival of released sterile flies is comparable with estimated survival rate and life span of wild, native flies.     

Empirical evidence of the mediterranean fruit fly movement between orchard types

Understanding species movement in the agroecological system is an important theme in ecology. A mark–release–capture experiment was conducted to study the dispersion behaviour of the Mediterranean fruit fly, Ceratitis capitata (Wied.; Diptera: Tephritidae; Medfly) in northern Israel. Four pairs of pear and citrus orchards were selected for the field experiments. Sterile flies dyed with different colours were released in three seasons during 2015 and 2016, based on the phenological stages of the hosts. The total number of captured marked sterile flies per trap (FT) was approx 300 in both April and August. In November, FT values decreased by about 35% to approximately 200. The wild Medfly that were also captured showed an opposite trend, from an FT of 1.8 and 6.4 in April and August, respectively, to an FT of about 330 in November. Marked sterile flies were captured in both the release and the neighbouring orchard sites. We found that the Medfly migrates from pear to citrus orchards during spring and from citrus to pear during summer, when there are no fruit-bearing trees in the orchards. However, during November, when the wild Medfly population prevails in the area, a clear pattern of migration is hard to identify, perhaps because of a possible interaction with the wild fly's population.     

Capture of Mediterranean fruit flies (Diptera: Tephritidae) in dry traps baited with a food-based attractant and Jackson traps baited with trimedlure during sterile male release in Guatemala

Captures of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), in Jackson traps baited with trimedlure were compared with captures in cylindrical open-bottom dry traps baited with a food-based synthetic attractant (ammonium acetate, putrescine, and trimethylamine). Tests were conducted in Guatemala during a sterile male release program in an area where wild flies were present in low numbers. More wild and sterile females were captured in food-based traps, and more wild and sterile males were captured in trimedlure traps. The food-based traps captured almost twice as many total (male plus female) wild flies as the trimedlure traps, but the difference was not significant. Females made up approximately 60% of the wild flies caught in the food-based attractant traps; the trimedlure traps caught no females. The ratio of capture of males in trimedlure traps to food-based traps was 6.5:1 for sterile and 1.7:1 for wild flies. Because fewer sterile males are captured in the food-based traps, there is a reduction in the labor-intensive process of examining flies for sterility. The results indicate that traps baited with food-based attractants could be used in place of the Jackson/trimedlure traps for C. capitata sterile release programs because they can monitor distributions of sterile releases and detect wild fly populations effectively; both critical components of fruit fly eradication programs by using the sterile insect technique.     

Management and eradication options for Queensland fruit fly

Several tephritid fruit flies have explosive population growth and a wide host range, resulting in some of the largest impacts on horticultural crops, reducing marketable produce, and limiting market access. For these pests, early detection and eradication are routinely implemented in vulnerable areas. However, social and consumer concerns can limit the types of population management tools available for fruit fly incursion responses. Deterministic population models were used to compare eradication tools used at typical densities alone and in combination against the Queensland fruit fly (‘Qfly’), Bactrocera tryoni. The models suggested that tools that prevent egg laying are likely to be most effective at reducing populations. Tools that induced mortality once Qfly was sexually mature only slowed population growth, as successful mating still occurred. Release of sterile Qfly when using the sterile insect technique (SIT) interferes with the successful mating of wild flies, and of the tools investigated here, SIT caused the greatest reduction in the population at the prescribed release rate. Used in tandem with SIT, protein baits slightly improved the rate of population reduction, but the male annihilation technique (MAT) almost nullified control by SIT due to the mortality induced on sterile flies. The model suggested that the most rapid decrease in population size would be achieved by SIT plus protein baits. However, the model predicted both the SIT and protein baits when used alone would result in population reduction. The MAT can be used prior to SIT release to increase overflooding ratios.     

Factors affecting the dispersal of large‐scale releases of the Queensland fruit fly,Bactrocera tryoni

This study investigated two factors potentially affecting the spatial distribution of Queensland fruit fly Bactrocera tryoni (Froggatt) after release from a single point. First, the effect of age at release was investigated using a single cohort of 205 000 males from a mass‐rearing strain used for sterile insect releases. Approximately half were released as immature males and the remainder as sexually mature males (1 week later). Males were collected over 3 weeks from a grid of 135 traps, each containing a pheromone/insecticide bait, positioned between 4 and 500 m from the release point. Variation in the distribution of fly density around the release point was assessed by regressing trapped fly counts against distance. Unexpectedly, no significant differences were found in the spatial distribution of the flies. Second, the effect of inbreeding on spatial distribution was investigated using replicated simultaneous releases of two strains of B. tryoni. One strain was the existing (inbred) mass‐rearing strain that has been selected for high productivity in a mass‐rearing facility. The second strain was deliberately outbred but also selected for high productivity. Almost 100 000 males of each strain were released over the two experiments. Regression of trappings against distance differed significantly between strains in only one of five releases, but in all cases the outbred strain had a greater dispersal distance. As our trapping grid was not regular but contained gaps of up to 100 m, a small preliminary experiment investigated whether flies move faster along tree rows or across open fields. At distances up to 100 m, we found no detectable difference in fly distributions. These results are primarily relevant to the large‐scale point releases carried out as part of an existing B. tryoni sterile insect programme and are discussed in that context.     

Field comparison of chemical attractants and traps for Caribbean fruit fly (Diptera: Tephritidae) in Florida citrus

Field studies in citrus were conducted to compare the following as attractants for the Caribbean fruit fly, Anastrepha suspensa (Loew): torula yeast-borax; propylene glycol (10%); a two-component lure consisting of ammonium acetate and putrescine; a two-component lure consisting of ammonium bicarbonate and putrescine; and a three-component lure consisting of ammonium bicarbonate, methylamine hydrochloride, and putrescine. Various combinations of these attractants in glass McPhail, plastic McPhail-type (Multi-Lure), and sticky panel traps were investigated in two replicated studies. In one study on wild flies, the most effective and least complex trap-lure combination tested was the Multi-Lure with propylene glycol baited with ammonium acetate and putrescine. This trap-lure combination captured significantly more female and male flies than the standard glass McPhail baited with torula yeast-borax in water. All of the trap-lure combinations were female biased, with an overall average of 80.8% (SEM 1.4) flies captured being female. A second study on laboratory-reared, irradiated flies indicated no significant differences among these trap-lure combinations with respect to number of flies recaptured, although rankings based on mean number of flies recovered per trap per day supported results of the first study. The percentage of flies recaptured that were female (83.0%, SEM 0.9) was statistically the same as in the first study. Weekly percentage recovery of flies during the second study was low, possibly due to our fly release strategy. Future release/recovery studies with laboratory-reared flies would benefit from some basic research on release strategies by using different trap densities and on relating recapture rates of laboratory-reared flies (nonsterile and sterile) to capture rates of wild flies.     

Seasonal variation of the capture and field distribution of sterile Anastrepha ludens in Tamaulipas,Mexico

Anastrepha ludens (Loew) (Diptera: Tephritidae) is one of the most important citrus pest in Mexico. The sterile insect technique (SIT) is used against pest populations of fruit flies for suppression, eradication, containment and prevention to reduce damages in fruit‐growing areas. In this study, we analyzed the seasonal variation of captures and field distribution of sterile A. ludens released in different seasons of the year in north‐eastern Mexico. Chilled releases were conducted by air at constant densities per ha on a citrus area for a period of 32 weeks that included the coldest and warmest seasons that is winter, spring and summer. Multilure traps baited with torula yeast pellets were used to capture sterile flies. Fly capture data were compared over the three seasons and correlated with climate. The lowest number of captures of the sterile insect occurred in the summer and the highest in winter and spring. High and low temperatures were negatively correlated with fly captures. Field distribution was also negatively correlated with high temperatures in summer, but no relationships were observed in winter and spring. No relationships were observed between rainfall with capture and field distribution of sterile flies. These results indicate that summer is a season involving agro‐ecological and environmental constraints for the capture and field distribution of sterile flies. This study may be useful for enhancing release strategies and optimizing economic resources in north‐eastern Mexico. Further research on the behaviour of sterile flies under stressful environments is suggested.     

Eradication of the melon fly,Dacus cucurbitae,from Kume is., Okinawa with the sterile insect release method

The sterile insect release method was applied to eradicate the melon fly, Dacus cucurbitae, from the 58.5 km² island of Kume, in the Okinawa Islands group. Weekly releases of 1 to 1.5 million flies irradiated as pupae with 6–7 kR from a cobalt-60 source did not decrease the wild melon fly population. Releases of 1.5–2 million pupae per week made from September, 1975 to January, 1976 decreased the percent egg-hatch of females caught on Kume Is., but did not decrease the percent infestation significantly. The number of pupae released was increased from February, 1976 to accelerate the eradication process. When the number of pupae released exceeded 3.5 million per week, a rapid increase in the ratio of marked (sterile) to unmarked (wild) flies, a remarkable decrease in percent egg-hatch, and a decrease in percent infestation of fruits were observed. There has been no sign of melon fly infestation in wild cucurbit fruits from October, 1976 to the present time (April, 1977), despite the fact that more than 70,000 fruits were carefully examined. The eradication of the melon fly from Kume Is. was thus achieved by April, 1977, after the release of 264 million sterile fly pupae.     

Spatial patterns of sterile Mediterranean fruit fly dispersal

The success of the sterile insect technique (SIT) for the control of the Mediterranean fruit fly or medfly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), depends largely on the ability of sterile flies to spread in the target area and compete with the wild males for wild females. Our objectives in the present study were three‐fold: (1) to evaluate the dispersal ability of sterile male medflies and compare their spatial dispersion patterns with that of wild males, (2) to evaluate how different release methods affect subsequent spatial dispersal, and (3) to determine whether manipulating the pre‐release diet of sterile males affects their dispersal. To achieve these objectives, we conducted three experiments in the field where we quantified and analyzed the spatial and temporal dispersal patterns of sterile medflies and the dispersion of resident wild males. Overall, ca. 5% of the released sterile flies were recaptured 100 m from the release point, and ca. 2% were recaptured 200 m from the release point. The released flies rarely survived longer than 5–7 days. We repeatedly found that the spatial dispersion patterns of sterile males significantly correlated with those of wild males. Release methods strongly affected subsequent fly dispersal in the field as significantly more flies were recaptured following a scattered release vs. a central one. Finally, we show that enriching sterile fly pre‐release diet with protein did not affect subsequent dispersal in the field. We conclude that sterile males are able to match the dispersion patterns of wild males, an outcome that is highly important for SIT success. Large releases from central points distant from each other may leave many areas uncovered. Accordingly, scattered releases, repeated twice a week, will provide better coverage of all available aggregations sites. The spatial performance of protein‐fed males suggests that pre‐release diet amendments may be used without detriment as a sexual stimulant in SIT programs.     

Capture of melon flies, Zeugodacus cucurbitae (Diptera: Tephritidae), in a food-baited Multilure trap: Influence of distance,diet, and sex

Many countries operate trapping programs to detect invasions of pestiferous fruit fly species (Diptera: Tephritidae). Surveillance relies heavily on traps baited with male lures, which, while highly attractive, have limited effectiveness, because (i) they are sex-specific and (ii) males of some species do not respond to the lures currently in use. For these reasons, detection programs also include food-baited traps that are neither sex- nor species-specific. Compared to male lure-baited traps, however, few studies have measured the attractiveness of food-based traps. The present study describes a mark-release-recapture study conducted in a fruit orchard in Hawaii that measured the attractiveness of a liquid protein hydrolysate-based (torula yeast/borax slurry) trap to adults of the melon fly Zeugodacus cucurbitae (Coquillett). Multiple release points were used at varying distances from a single, central trap to generate estimates of distance-dependent capture probabilities. The potential influences of sex and pre-release diet on capture probability were also examined. Flies were released at 14 d of age and were maintained on one of four dietary regimes that offered a protein hydrolysate-rich diet for varying intervals (i.e., 0, 3, 7, or 14?d, respectively). Recapture rates were similar between the sexes and over both sexes and all diets averaged 3.6%, 3.2%, and 0.6% for release distances of 10, 25, and 50?m, respectively. Pre-release diet had a significant effect on recapture probability for releases at 10 and 25?m: flies fed sugar only or protein hydrolysate-rich diet for only 3?d were captured more frequently than flies that had longer access to yeast extract prior to release.     

Release of Sterile Mediterranean Fruit Flies, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), Using an Automated Ground Release Vehicle

A trial was conducted in Tampa, Florida to test an automated ground release machine as an alternative to aerial methods for release of sterile Mediterranean fruit flies, Ceratitis capitata (Wiedemann). Twenty-four Jackson traps baited with trimedlure at three release sites yielded lower than expected numbers of ground released Medflies. Recaptures per trap ranged from 2.8 (±0.7 S.E.) to 6.8 (±1.7 S.E.). Average recovery of sterile flies at each site for all releases combined (144 observations) was similar, 3.4 (±0.5 S.E.), 4.4 (±0.5 S.E.), 4.5 (±0.5 S.E.) for sites 1, 2 and 3 respectively. There was a significant reduction in flight ability from 67.5 (±2.1 S.E.) to 53.6 (±2.9 S.E.)%, from the time of pre-chilling to when immobilized flies were released after 2.5 h in the release container. Further tests are needed to determine what mortality factors may influence recovery and how the automated ground release machine compares to the aerial release method.     

Sterile males of Ceratitis capitata (Diptera: Tephritidae) as disseminators of Beauveria bassiana conidia for IPM strategies

Sterile Mediterranean fruit fly, Ceratitis capitata (Wied.), males were evaluated as vectors to spread Beauveria bassiana (Bals) conidia to wild C. capitata populations under field conditions. The inoculated sterile males were released by air, using the chilled adult technique over 7000 ha of coffee growing in Chimaltenango, Guatemala, Central America. The impact of releases was determined using dry traps baited with a food attractant. The effects of these releases on Apis mellifera, Linnaeus (honey bee), Hypothenemus hampei, Ferrari (coffee berry borer) and the parasitic mite Varroa destructor (Oudeman) were also evaluated. Inoculated sterile males were able to transmit fungal spores to 44% of the wild C. capitata flies captured in traps, which likely were infected through intra- and intersexual interactions during leks, mating or mating attempts. There was no transmission of the fungal spores to non-target insect species such as coffee berry borer, honey bees or varroa. We conclude that sterile males of Mediterranean fruit fly inoculated with B. bassiana can act as effective vectors of conidia to wild populations, constituting a safe, environmentally friendly and selective alternative for suppressing the medfly under a Sterile Insect Technique-based IPM approach.     

Comparative efficacy of three suction traps for collecting phlebotomine sand flies (Diptera: Psychodidae) in open habitats

The efficacy of three suction traps for trapping phlebotomine sand flies (Diptera: Psychodidae) was compared. Traps were baited with Co₂ and used without any light source. CO₂‐baited CDC traps were evaluated either in their standard downdraft orientation or inverted (iCDC traps). Mosquito Magnet‐X (MMX) counterflow geometry traps were tested in the updraft orientation only. Both updraft traps (iCDC and MMX) were deployed with their opening ～10 cm from the ground while the opening of the downdraft (CDC) trap was ～40 cm above ground. Comparisons were conducted in two arid locations where different sand fly species prevail. In the Jordan Valley, 3,367 sand flies were caught, 2,370 of which were females. The predominant species was Phlebotomus (Phlebotomus) papatasi, Scopoli 1786 (>99%). The updraft‐type traps iCDC and MMX caught an average of 118 and 67.1 sand flies per trap night, respectively. The CDC trap caught 32.9 sand flies on average per night, significantly less than the iCDC traps. In the Judean desert, traps were arranged in a 3×3 Latin square design. A total of 565 sand flies were caught, 345 of which were females. The predominant species was P. (Paraphlebotomus) sergenti Parrot 1917 (87%). The updraft traps iCDC and MMX caught an average of 25.6 and 17.9 sand flies per trap per night, respectively. The CDC trap caught 7.8 sand flies on average per night, significantly less than the iCDC traps. The female to male ratio was 1.7 on average for all trap types. In conclusion, updraft traps deployed with their opening close to the ground are clearly more effective for trapping sand flies than downdraft CDC traps in open habitats.     

Movement of sterile male Bactrocera cucurbitae (Diptera: Tephritidae) in a Hawaiian agroecosystem

The melon fly, Bactrocera cucurbitae Coquillett, invaded the Hawaiian Island chain in 1895. In 1999, a program sponsored by the USDA-ARS to control melon fly and other tephritid pests in Hawaii over a wide area was initiated on the islands of Hawaii, Maui, and Oahu. To control these flies in an areawide setting, understanding how flies move within the landscape is important. To explore the movement of this fly, we examined the movement of marked, male, sterile, laboratory-reared B. cucurbitae on the island of Hawaii in an agricultural setting. Two releases of dyed, sterile flies consisting of approximately 15,000 flies, were released 6 wk apart. Released flies were trapped back by using Moroccan traps baited with a male attractant. These two releases suggest that in the Hawaiian agricultural areas where the areawide control is being sought, melon flies do not move extensively when there are abundant larval host and adult roosting sites. Over the course of this study, only one fly made it the maximum distance that we could detect fly movement (approximately 2,000 m in 2 wk). From these data, it seems that the flies dispersed throughout the study area but then moved very little thereafter. This is very apparent in the second release where the recovery rate after the second week was still fairly high, suggesting that if there are plenty of host fields and roosting sites the flies are unlikely to move.     

Yeast hydrolysate supplement increases starvation vulnerability of Queensland fruit fly

Post‐teneral diets containing yeast hydrolysate are reported to increase longevity, reproductive development and sexual performance of Queensland fruit fly (‘Q‐fly’) Bactrocera tryoni Froggatt (Diptera: Tephritidae). Consequently, diets including yeast hydrolysate are recommended for sterile Q‐flies before release in sterile insect technique (SIT) programmes. However, in some tephritids, diets including yeast hydrolysate are associated with an increased vulnerability to starvation. In the present study, the effects of yeast hydrolysate supplementation before release are considered with respect to the longevity of released Q‐fly when food becomes scarce. Experiments are carried out in three settings of varying resemblance to field conditions: 5‐L laboratory cages, 107‐L outdoor cages and 14 140‐L field cages containing potted citrus trees. In all experimental settings, compared with flies that received only sucrose, male and female Q‐flies that are provided with yeast hydrolysate during the first 2 days of adult life have a significantly shorter survival when subsequently deprived of food. Yeast supplementation appears to commit Q‐flies to a developmental trajectory that renders them more vulnerable to starvation. The practical significance of these findings for SIT depends on how often the releases are carried out under conditions in which Q‐flies experience extreme food shortages in the field.     

Attraction of Bactrocera dorsalis (Diptera: Tephritidae) and nontarget insects to methyl eugenol bucket traps with different preservative fluids on Oahu Island, Hawaiian Islands

Attraction of oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), and nontarget insects to preservative fluids ethylene glycol antifreeze, propylene glycol antifreeze, or mineral oil in bucket traps that contained captured decaying male oriental fruit flies, a male lure (methyl eugenol), and a toxicant (DDVP vapor insecticidal strip) were compared with dry control traps. Significantly (P < 0.05) greater numbers of B. dorsalis were captured in propylene glycol antifreeze traps than in other attractant trap types. Among attractant trap types with lowest negative impacts on nontarget insects, control traps captured significantly lower numbers of three species and one morphospecies of scavenger flies, one species of plant-feeding fly, and one species each of sweet-and lipid-feeding ants. Mineral oil traps captured significantly lower numbers of two species of scavengers flies and one morphospecies of plant-feeding fly, and one species of sweet-feeding ant. Because of the fragile nature of endemic Hawaiian insect fauna, the propylene glycol antifreeze bucket trap is best suited for use in environments (e.g., non-native habitats) where endemic species are known to be absent and mineral oil traps are more suited for minimizing insect captures in environmentally sensitive habitats.