Analysis of temporal fluctuations in numbers of sexually mature Anastrepha ludens females over an extensive citrus area in northeastern Mexico

The Mexican fruit fly, Anastrepha ludens Loew (Diptera: Tephritidae), is one of the most important pests in citrus‐growing areas in Mexico. In this study, we analyzed the temporal fluctuation of sexually mature females of A. ludens populations with respect to the availability of commercial hosts and climatic factors, as well as population data of females over an extensive citrus area in northeastern Mexico. The numbers of mature females were treated as proportions and analyzed with generalized linear mixed models with a binomial error distribution. Results revealed positive effects on proportions of mature females when commercial hosts (Valencia orange and grapefruit) were available at both medium and high levels, whereas negative effects on proportions were observed when commercial hosts were scarcely available. Monthly analyses indicated positive trends on proportion in March, April, October, and November, whereas negative trends were seen in January and June. A low capture of mature females during the late summer and the onset of winter suggests transitional phenological processes across the year. Overall, no relationships were observed between proportions with temperature and the total number of females; however, a positive relationship was observed between proportion and rainfall. These findings provide insight into the reproductive phenology of A. ludens with practical implications for fruit sampling, as well as for the autocidal or chemical control in an areawide integrated pest management (AW‐IPM) approach in citrus‐growing areas of northeastern Mexico.     

Mapping the spatial variability of the field distribution of sterile Anastrepha ludens over a release area

The sterile insect technique (SIT) is an environmental-friendly method used against Anastrepha ludens Loew (Diptera: Tephritidae) populations. This study aimed to perform an analysis of the spatial variability of the field distribution of sterile A. ludens using a geostatistical approach along with Geographic Information Systems (GIS). Field data on captures of sterile A. ludens during a Valencia orange season over a release area were analysed using spherical, exponential and Gaussian variograms. Such variograms were evaluated by criteria such as the mean absolute error, average standard error, root mean square error and the coefficient of determination. Results revealed a spatially structured distribution of sterile A. ludens across the release area. Interpolated models by Ordinary Kriging technique exhibited continuous surfaces evidencing spatial heterogeneity of the distribution of flies. Such a result evidenced that the spatial dynamics of flies significantly varied despite the planned uniform coverage of the release. The GIS led to integrating spatial information of the spatial dynamics through one single model. The release activity should be improved westward of the studied area, as the final model suggested that the ratio sterile: wild is lower than that in the east. This study provides insights into the spatial analysis of the distribution of sterile flies further than one single geographical point. Moreover, it highlights geostatistical techniques and GIS as useful tools for the assessment of the impact and quality of the release activity over fruit-growing areas subjected to an area-wide integrated pest management approach.     

Simultaneous use of SIT plus disseminator devices of Beauveria bassiana enhances horizontal transmission in Anastrepha ludens

Beauveria bassiana is an entomopathogenic fungus widely used to control different insect pests including Anastrepha ludens (Diptera: Tephritidae), a key pest of citrus and mangoes. Currently, to control this pest, sterile A. ludens males of the Tap-7 genetic sexing strain are released weekly by aircraft at a density of 1,000 males/ha as part of an integrated pest management programme (IPM) in Southern Mexico. Our objective here was to determine whether the sterile insect technique (SIT) could be enhanced by augmenting it with horizontal transmission of fungus conidia by using Beauveria bassiana disseminator devices (DBb) designed to distribute it with minimal impact on non-target species. Four treatments were established: DBb only, DBb + SIT, SIT only and untreated control, and fruit fly populations were monitored using two Multilure traps baited with 250 ml of CeraTrap per plot. We found that the presence of B. bassiana disseminator devices in areas where A. ludens sterile males were released resulted in higher proportions of infected wild fruit flies in the field, and that high relative humidity (rainy season) played an important role in the efficiency of horizontal conidia transmission to the wild populations. We conclude that the simultaneous use of both strategies (SIT + DBb) increases the conidia transmission to wild populations, and that this approach could be incorporated to an integrated pest management for the better suppression of fruit fly populations.     

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.     

Integrating chemical control with sterile insect releases in an integrated pest management programme for Thaumatotibia leucotreta

False codling moth Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is an important indigenous pest of citrus in southern Africa. Successful control is dependent upon integration of area‐wide sterile insect releases and other suppression methods. The aim of this work was to test pyrethroid and organophosphate‐based insecticides (tau‐fluvalinate and chlorpyrifos) for their residual effect on mortality of released irradiated T. leucotreta male moths. Both of these insecticides were effective in killing irradiated T. leucotreta for 7 days after application on leaves, after which degradation of the active ingredient resulted in a marked reduction in efficacy after 14 days and rendering them harmless. Mortality was found to be similar for irradiated and non‐irradiated male T. leucotreta after treatment. Consequently, even though these insecticides might have an effect on moths in the field, ratios of sterile:wild moths should not be altered. Supporting field data from six sites in the Sundays River Valley over a season of sterile insect releases showed the conventional chemical crop protection programme to be as effective as an integrated pest management programme in facilitating effective control of T. leucotreta through sterile insect releases. The study also confirmed that the ratios of sterile:wild male moths in the commercial citrus orchards were not affected by the application of insecticides. These findings confirm the high potential of sterile insect releases for control of T. leucotreta in citrus.     

Factors controlling the distribution of a subtropical corn borer,Diatraea grandiosella (Lepidoptera: Pyralidae)

During this century the southwestern corn borer, Diatraea grandiosella (Lepidoptera: Pyralidae), has extended its range from subtropical Mexico into the United States, below 38° N latitude. This maize‐feeding insect is now found from Arizona east to Alabama and north to Kansas, Missouri, and Tennessee. The species has adapted to the shorter growing seasons, longer summer daylengths, and lower winter temperatures present in the southern US than are present in Mexico. Life history, morphological, and behavioral traits were compared for populations of D. grandiosella from southeastern Missouri and southcentral Mexico and revealed differentiation in a suite of characters, some of which show clear adaptation to a northern climate while others are obviously less adaptive. An electrophoretic comparison of enzymes from D. grandiosella from the central portion of its range in the US and from a population from southcentral Mexico indicated that considerable genetic differentiation has occurred. Quantitative genetic studies should be undertaken on the original and dispersed populations to differentiate between those characters that have been directly responsible for the adaptation of this insect to northern maize‐growing regions and those that have changed merely due to genetic correlations with characters undergoing selection. Data from such studies, together with available information about the dispersal of this insect, should provide insight into factors regulating the movement of tropical insects into temperate regions.     

Outdoor flight activity and immigration of Rhyzopertha dominica into seed wheat warehouses

The flight activity of lesser grain borer, Rhyzopertha dominica F. (Coleoptera: Bostrichidae), was monitored at two Foundation seed wheat warehouses during the 2003 and 2004 field seasons, using pheromone‐baited Lindgren funnel traps positioned indoors and outdoors. General stored‐product insect activity was also monitored using unbaited sticky traps positioned inside the warehouses around overhead doors. Pheromone‐baited traps were useful for monitoring R. dominica activity, however insect captures decreased when lures were not changed weekly. Flight peaks were documented in early May and again from September through October, and insect captures inside warehouses correlated with timing of outdoor captures. Multiple regression analyses showed that slightly more than half of the variability in R. dominica captures could be explained by mean ambient air temperature and wind speed during the 2 h preceding sunset. Stored‐product Coleoptera captured on unbaited glue boards around overhead doors included Ahasverus advena, Cryptolestes ferrugineus, R. dominica, Sitophilus oryzae, Tribolium castaneum, Trogoderma variabile, and Typhaea stercorea. Door gaskets significantly reduced the number of insect captures on glue boards placed around the overhead doors, and generally restricted their entry to ground level. These studies demonstrated that outdoor pheromone‐baited traps are effective monitoring tools for determining when grain‐handling facilities are most susceptible to infestation and that exclusion may be an effective component of a pest management program.     

Seasonality of trichomycetes in larval black flies from South Carolina, USA

Trichomycete fungi are common endobionts of aquatic insect larvae, but little is known of their ecology. In this study, the seasonality of trichomycete colonization of larval black flies (Diptera: Simuliidae) was investigated in three streams in northwestern South Carolina. At least eight species of trichomycetes were found in two species of black flies, and 93.8% of 1819 larval black flies examined contained trichomycetes. Significant differences were found in the seasonal prevalence of Harpella melusinae, Simuliomyces microsporus, and Paramoebidium spp. at one of three sites. At this site, the lowest mean prevalence for H. melusinae occurred in winter (67%) versus the other seasons (96-100%), whereas mean prevalence was lowest in summer for Simuliomyces microsporus (1%) versus the other seasons (2-21%) and lowest in summer for P. spp. (9%) versus the other seasons (45-67%). Significant differences in levels of colonization among seasons were not detected. Conjugations of H. melusinae (representing early stages of sexual reproduction) occurred most frequently in the spring and winter (up to 14% of larvae). Sexual reproduction (represented by zygospores) of Legeriomycetaceae occurred most frequently in the spring and fall (up to 17% of larvae).     

Precocious Mexican fruit fly methoprene‐fed males inhibit female receptivity and perform sexually as mature males

The sterile insect technique (SIT) has been used successfully for the control of fruit flies. The efficiency of this technique can be significantly reduced when sterile released insects are exposed to adverse conditions and predators, as a great number of sterile insects die before reaching sexual maturity and thus fail to mate with wild females. Treatments with juvenile hormone (JH) analogues such as methoprene (M) significantly reduce the time to reach sexual maturity by sterile Anastrepha ludens (Loew) (Diptera: Tephritidae) males. In this study, we compared the sexual performance of non‐treated sexually mature males with young males that had been sexually accelerated with M. Furthermore, we compared the ability of M‐fed males in inhibiting female remating compared with sexually mature males. Results showed that at 5 days M‐fed males had lower mating success than mature males; however, 6‐day‐old (0.1%) M‐fed males had the same amount of matings as mature 13‐day‐old males. Young 5‐ to 10‐day‐old M‐fed males also had similar number of matings as mature non‐treated 12‐ to 17‐day‐old males. There were no differences in copula duration between treatments. Moreover, there were no differences between the fertility, fecundity or refractory period of females mated with either young male fed M or normal sexually mature males. These results indicated that young males that were sexually accelerated with M have the same sexual performance as non‐treated sexually mature males. Implications of using M as a pre‐release treatment for A. ludens controlled through SIT are discussed.     

Control of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in greenhouse tomato crops using the mating disruption technique

The effectiveness of mating disruption to control the tomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), in greenhouse tomato crops was evaluated in four trials carried out in winter–spring and summer–winter growing seasons in Southwestern Sardinia (Italy). Pheromone dispensers loaded with 60 mg of the natural blend of the major and minor sex pheromone component (rate 90 : 10) were applied in disrupted greenhouses at a rate of 1000/ha (60 g of active ingredient/ha). Male captures in monitoring pheromone traps, percentage of tomato plants infested by T. absoluta and damage on leaves and fruits were monitored weekly and compared in disrupted and untreated (control) greenhouses. In greenhouses disrupted with 1000 dispensers/ha, a reduction of 93–97% in male trap captures was observed, compared with control. Leaf damage was significantly lower in greenhouses disrupted with 1000 dispensers/ha than in control ones, with a reduction of infestation throughout the growing season ranging from 57% to 85%. Pheromone dispensers applied at the density of 1000/ha significantly reduced the percentage of damaged fruits by 62–89%. In control greenhouses, the highest damage on leaves and fruits was generally observed in edge plants, while leaf and fruit infestation was uniformly distributed in pheromone‐treated greenhouses, indicating an even distribution of the pheromone cloud inside the greenhouse. Mating disruption showed to be an efficient strategy to control in greenhouse the tomato leafminer and can be included in the overall tomato integrated pest management programs.     

Reasons for success: Rapid evolution for desiccation resistance and life‐history changes in the polyphagous fly Anastrepha ludens

Species that exhibit broad ranges of distribution may successfully navigate environmental changes by modifying some of their life‐history traits. Environmental humidity imposes a critical stress that organisms may overcome by increasing their resistance to desiccation. We used experimental evolution to investigate adaptation to desiccation in the tephritid Anastrepha ludens, a species with high fecundity, late maturation, and long lifespan. We measured morphological, physiological, developmental as well as demographic changes involved in the adaptation to desiccation. Notwithstanding a low heritability (h² = 0.237), desiccation resistance evolved extremely rapidly and few negative trade‐offs were detected. Selected flies exhibited correlated increases in longevity, body size, the amount of body lipids, and bulk water content, and in the duration of the pupal stage. Females further delayed sexual maturation, decreased daily fecundity but retained high lifetime reproductive potential. No differences in male mating competitiveness were found. Selected and control lines differed in longevity but not in total female fecundity, demonstrating that A. ludens flies have the capability for fast adaptation to desiccation without loosing their reproductive capability. Thus, it seems that a rapid evolutionary response to desiccation in this polyphagous insect works as a buffer for environmental variation and reduces the strength of selection on reproductive traits.     

Mating senescence and male reproductive organ size in the Mexican fruit fly

Ageing can reduce the probability that individuals reproduce. The present study investigates whether ageing influences the mating frequency of mass‐reared fertile and sterile Mexican fruit flies Anastrepha ludens (Loew). The ability of males of different ages to inhibit female remating is also determined, and the growth of male reproductive organs is measured as they age. Young males (6 days old) have a lower mating frequency than older males, and also have a lower capacity to inhibit female remating than older males. However, 7‐day‐old males are as likely to inhibit female remating as older males. Young males also have smaller reproductive organs than middle‐aged (21‐day‐old) or senescent males (57‐day‐old). These results have implications for the sterile insect technique because sterilized males of A. ludens are released in the field 6 days after emergence. The highest mating frequency, the lowest mating latency and the largest size of testes are observed at 21 days of age. Older males (57 days old) have more sperm in their seminal vesicles than young males (6 and 9 days old). Accessory glands take longer to grow to their complete size compared with testes, and mating frequency is more closely associated with accessory gland size than testes size. Furthermore, there are more sperm in the seminal vesicles during the afternoon period of peak sexual activity than during the morning when sexual activity is absent. These results indicate that, even at the onset of reproductive senescence, mass‐reared males of A. ludens are still capable of mating, as well as inhibiting remating in females.     

Botanicals,selective insecticides,and predators to control Diaphorina citri （Hemiptera： Liviidae） in citrus orchards

The Asian citrus psyllid （ACP） Diaphorina citri Kuwayama vectors pathogens that cause huanglongbing （HLB） or citrus greening devastating and economically im- portant disease present in most citrus growing regions. Young citrus shoots are required for psyllid reproduction and development. During winter citrus trees produce little or no new growth. Overwintering adults reproduce in spring on newly emerging shoots also attractive to other pests and beneficial insects. Botanicals and relatively selective insecti- cides could help to conserve beneficial insects and reduce pest resistance to insecticides. Sprays of Azadirachtin （Neem）, Tropane （Datura）, Spirotetramat, Spinetoram, and broad- spectrum Imidacloprid were evaluated to control ACP in spring and summer on 10-year-old ＂Kinow＂ Citrus reticulata Blanco trees producing new growth. Psyllid populations were high averaging 5-9 nymphs or adults per sample before treatment application. Nymphs or adults were significantly reduced to 0.5-1.5 per sample in all treatments for 3 weeks, aver- age 61%-83% reduction. No significant reduction in ladybeetles Adalia bipunctata, Ane- glei scardoni, Cheilomenes sexmaculata, and Coccinella septempunctata was observed. Syrphids, spiders and green lacewings were reduced in treated trees except with Tropane. Studies are warranted to assess impact of these predators on ACP and interaction with insecticides. Observed reduction in ACP populations may not be enough considering its reproductive potential and role in the spread of HLB. Follow-up sprays may be required to achieve additional suppression using rotations of different insecticides.     

Nontarget impact of spinosad GF-120 bait sprays for control of the Mexican fruit fly (Diptera: Tephritidae) in Texas citrus

Bait sprays containing the toxicant spinosad (GF-120) were applied to citrus groves in the Rio Grande Valley of Texas where Mexican fruit flies were detected in surveillance traps. The sprays were applied as a supplement to a continuous sterile insect release program. Sterile fly captures were 47-63% lower in the treated groves compared with control groves. Eight of 10 secondary pest populations declined in the test groves subsequent to spray applications, but they also declined in the control groves, suggesting that the decline was a seasonal phenomenon rather than a result of the bait sprays. Citrus whitefly, Dialeurodes citri (Ashmead), populations increased modestly and citrus blackfly, Aleurocanthus woglumi (Ashby), populations remained unchanged compared with pretreatment levels. Thus, no outbreaks of secondary pests occurred as a result of the spinosad bait sprays in this instance, as has been reported for malathion bait sprays in citrus. The bait sprays had no detectable effect on populations of specific indicator species of parasitoids (including Aphytis spp. and Comperiella bifasciata Howard), or on numbers of beneficial insects in general, in the treated groves.     

Sexual development of wild and mass‐reared male Queensland fruit flies in response to natural food sources

Diet has a profound influence on the fitness of adult tephritid flies. Mass‐reared flies are provided yeast hydrolysate as a rich source of nutrition that supports rapid sexual development and mating success. In contrast, wild tephritid flies often live in environments where food may be hard to find, and these are the conditions that sexually immature mass‐reared sterile males encounter when released into the field during sterile insect technique campaigns. The effect of natural food sources (bat guano, bird droppings, citrus pollen, and wheat pollen) on the sexual development of adult mass‐reared fertile, mass‐reared sterile, and wild male Queensland fruit flies, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), was determined by measuring ejaculatory apodeme size. Inclusion of yeast hydrolysate in the adult diet was associated with faster growth of the ejaculatory apodeme in comparison with all other diets. Effects of diet were far less pronounced in mass‐reared males, which may indicate reduced nutritional requirements, whereas the ejaculatory apodeme of wild males fed on natural sources of food or sucrose alone did not increase in size over the first 20 days of adult life.     

The seasonal distribution and characteristics of bush fly Musca vetustissima Walker populations in south-western Australia

In the agricultural region of south-western Australia the bush fly Musca ventustissima Walker was found to occur permanently in the north-eastern half but it died out during winter in the south-west. The abundance of bush flies increased rapidly throughout the overwintering zone in early spring as a result of local breeding. Flies then dispersed south-westwards, completely repopulating the region during October. Immigrant flies were large and therefore highly fecund, and of advanced reproductive maturity. Local breeding then rapidly increased the population. Maximum abundance occurred in mid-spring in the north and east and in early summer in the south and west. Abundance was greatest in the north where large overwintering populations occurred, and in the far south where repopulation occurred early in the seasonal cycle of pasture growth so that the more favourable cattle dung produced flies that were more fecund than their immigrant parents. The abundance of bush flies declined throughout the region in summer, to negligible levels near the south-west coast but, paradoxically, higher levels occurred inland where there were fewer cattle. On average, flies were smaller and reproductively younger in summer. In areas where irrigated pastures produced more favourable dung in summer, the patterns of abundance and other characteristics of flies did not differ substantially from those in comparable non-irrigated areas. The abundance and other characteristics of a bush fly population 10 km from a cattle-grazing breeding site were similar to those at the site, indicating that constant dispersal is the basis of the bush fly's ubiquity.     

Thermal biology,population fluctuations and implications of temperature extremes for the management of two globally significant insect pests

The link between environmental temperature, physiological processes and population fluctuations is a significant aspect of insect pest management. Here, we explore how thermal biology affects the population abundance of two globally significant pest fruit fly species, Ceratitis capitata (medfly) and C. rosa (Natal fruit fly), including irradiated individuals and those expressing a temperature sensitive lethal (tsl) mutation that are used in the sterile insect technique. Results show that upper and lower lethal temperatures are seldom encountered at the field sites, while critical minimum temperatures for activity and lower developmental thresholds are crossed more frequently. Estimates of abundance revealed that C. capitata are active year-round, but abundance declines markedly during winter. Temporal autocorrelation of average fortnightly trap captures and of development time, estimated from an integrated model to calculate available degree days, show similar seasonal lags suggesting that population increases in early spring occur after sufficient degree-days have accumulated. By contrast, population collapses coincide tightly with increasing frequency of low temperature events that fall below critical minimum temperatures for activity. Individuals of C. capitata expressing the tsl mutation show greater critical thermal maxima and greater longevity under field conditions than reference individuals. Taken together, this evidence suggests that low temperatures limit populations in the Western Cape, South Africa and likely do so elsewhere. Increasing temperature extremes and warming climates generally may extend the season over which these species are active, and could increase abundance. The sterile insect technique may prove profitable as climates change given that laboratory-reared tsl flies have an advantage under warmer conditions.     

Induction of dominant lethal mutations for control of the facefly, Musca autumnalis DeGeer

1. Application of the sterile insect technique (SIT) to the facefly, Musca autumnalis DeGeer, is considered. 2. Six-day-old pupae were exposed to ionizing irradiation at doses in the range 100-1600 rads, each treatment being replicated six times. 3. Eclosion was unaffected but fecundity and fertility was inversely proportional to the radiation dose. 4. 1600 rads gave 97% dominant lethality of sperm in treated males and suppressed ovarian development in females. Irradiated flies did not recover fertility. 5. Irradiation of males and females did not affect insemination rates. 6. Sterile males showed a decline in longevity and reduced mating competitiveness. 7. Local eradication of M. autumnalis is considered to be feasible if sufficient diapausing sterile flies are stockpiled and released in early spring, followed by additional releases of non-diapausing flies in late spring and early summer, with further releases of diapausing sterile flies in late summer and autumn.     

Seasonal energy utilization in bamboo by the red panda (Ailurus fulgens)

Seasonal energy intake and digestion of bamboo by red pandas were measured in energy balance trials at the field station at an altitude of 3,100 m in Yele Natural Reserve, Mianning County of Sichuan Province, Peoples Republic of China. Two‐week trials were conducted at monthly intervals by feeding animals with only natural bamboo browse, Bashania spanostachya, from May to November 1995. Results demonstrated that energy intake, digestible energy, and digestibility differed significantly among seasons and diets. Energy digestibilities were high in summer‐autumn, intermediate in spring, and low in winter. These variations correlated positively with the nutrient contents of bamboo. The daily metabolic energy requirement measured varied from 2,603.3 kJ in the spring to 3,139.8 kJ in the summer‐autumn to 2,740.8 kJ in the winter. The results also showed that shoots were more easily digested than leaves and exhibited the highest digestibility. Restricted by the capacity of digestive tracts, red pandas poorly utilized the energy provided by bamboo as indicated by the lower energy digestibility (averaging 26.47% for leaves and 44.08% for shoots among the seasons). To fulfill their daily energy requirements, red pandas ingested a large amount of energy from bamboo leaves, which varied from 10,145.8 kJ in the spring, 12,045.1 kJ in the summer‐autumn, and 12,276.9 kJ in the winter to maximize the rate of energy intake. Zoo Biol 19:27–33, 2000. © 2000 Wiley‐Liss, Inc.     

Capture of mass‐reared vs. wild‐like males of Ceratitis capitata (Dipt., Tephritidae) in trimedlure‐baited traps

The sterile insect technique (SIT) is widely used to suppress or eradicate infestations of the Mediterranean fruit fly, Ceratitis capitata (Wied.), an insect whose broad polyphagy poses a serious threat to fruit and vegetable crops. The SIT involves the production, sterilization and release of sterile insects to obtain sterile male by wild female matings, thus yielding infertile eggs. Mass‐rearing over many generations is known to produce dramatic changes in the behaviour and life history of C. capitata. This study investigated the possibility that mass‐rearing also alters male response to trimedlure, a sex‐specific attractant widely used in detection and monitoring programmes. We compared captures of released males from a mass‐reared strain and a recently established colony of wild flies in trimedlure‐baited Jackson traps at three spatial scales – open field, large field enclosures (75 m²) and small field cages (7 m²) – in two separate years. In the first year, males were used independently of flight ability, while in the second year only males with demonstrated flight capability were used. Trap capture was scored 2 days after release for the open field and the large field enclosures but either 1 h or 1 day after release in the small field cages. The findings were consistent across these different experiments: wild‐like males were captured in significantly greater numbers than mass‐reared males in both years of study, except in the trials lasting 1 day in the small field cages where significantly more wild than mass‐reared males were captured in 1 year but not the other. These results are compared with other studies, and their implications for SIT are discussed.