Blow fly responses to semiochemicals produced by decaying carcasses

Volatiles from mouse carcasses in decay stages ranging from fresh to 33 days old were used to investigate oriented flight and landings in male and female blow flies of Calliphora vicina Robineau‐Desvoidy (Diptera: Calliphoridae). Oriented flight increased significantly from 36% towards fresh carcasses to 68%, 61% and 65% towards carcasses aged 3 days, 6 days and 9 days, respectively. Carcasses aged 20 days and 33 days were significantly less attractive, achieving 51% and 41% attraction, respectively. No differences emerged between the sexes in oriented flight, but a significant increase in female landings at the most attractive carcasses was observed. Headspace collections from the different stages of decay showed a succession in the volatile profile emitted from the carcasses and identified nine chemicals which peak in quantity in concurrence with the most attractive stages of decay. Three of these chemicals also showed dose–response effects as indicated by a significant correlation between the amount present and the proportion of flies responding. Blow flies are important pests and efficient traps are needed. The significant interaction between fly sex and carcass age highlights behavioural differences between male and female blow flies which can be exploited in blow fly trapping. Three new volatile chemicals, butylated hydroxyl toluene, 3‐hydroxy‐2‐butanone and nonanal, emitted from dead mice are suggested as potential attractants.     

Trapping oestrid parasites of reindeer: the relative age, fat body content and gonotrophic conditions of Cephenemyia trompeand Hypoderma tarandifemales caught in baited traps

Abstract. Dissection of flies caught in northern Norway revealed that only mated, gravid females of H.tarandi (L.) and larviparous C.trompe (Modeer) were caught in host-mimicking C0₂-baited traps. Trapped females had the same gonotrophic and fat body (FB) conditions as females caught on and around reindeer. Most trapped females of both species were of middle to old age, having only one-half to no FB reserves left and only a few to moderate numbers of eggs or larvae remaining. Most young females trapped also had previously oviposited or larviposited at least once, and some newly eclosed, mated females were present throughout the fly season. Based on the known location of reindeer herds, it was evident that trapped flies that had recently oviposited or larviposited had dispersed into the trapping area from 25–100 km away. Declining FB reserves sustained wild-caught C.trompe females (and in utero larvae) in the laboratory for 14 days and H.tarandi females for 18 days. Reserve FB also was depleted during long flights. Females of both species that flew for the longest times (5.1–11.7 h) on a laboratory flight mill had low FB reserves, but nearly maximum numbers of eggs or larvae. Conversely, most females that flew for less than 5 h on the flight mill had little or no FB remaining, and few eggs or larvae. The large FB reserves accumulated as larvae feed in the vertebrate host enable the non-feeding adults to survive and infect their hosts even after prolonged periods of flight-inhibiting climatic conditions.     

Flower nitrogen status and populations of Frankliniella occidentalis feeding on Lycopersicon esculentum

Alighting and capture of wild olive fruit flies, Bactrocera oleae (Rossi) (Diptera, Tephritidae), on spheres of seven different colours was studied on Chios island, Greece. The 70-mm-diam plastic spheres, coated with adhesive, were suspended on olive trees. Yellow and orange spheres trapped the greatest number of males while red and black spheres trapped the greatest number of females. White and blue spheres were the least effective for both sexes. Peak captures occurred in the late afternoon and especially around sunset. Since mating takes place in the last hours of the photophase, the increased captures during that period may be related to the sexual behaviour of the fly. When red spheres were assessed against glass McPhail traps baited with 2% ammonium sulphate, which consist a standard tool for monitoring the olive fruit fly in Greece, there were no significant differences in male captures. However, spheres trapped almost three times as many females as McPhail traps. The possible mechanisms underlying colour discrimination, the motivation of alighting flies and the possible use of red spheres for monitoring and controlling B. oleae are discussed.     

The ecology of terrestrial invertebrates on Pacific salmon carcasses

In coastal streams throughout the north Pacific region, spawning salmon (Oncorhynchus spp.) subsidize terrestrial communities with their nutrients and carcasses. We document the previously unreported composition and ecology of terrestrial invertebrates using salmon carcasses in forest habitats from two high salmon density watersheds in coastal British Columbia. From experimental placement of 186 carcasses, terrestrial Diptera-dominated salmon carcass decay (85.5% of carcasses). Overall, we recorded over 60 species from salmon carcasses, including saprophagous Diptera and Coleoptera (15 spp.), dipteran predators (eight spp.) and parasitoids (four spp.), and opportunistic predators, scavengers, and detritivores (24 spp.). Using stable isotopes of nitrogen and carbon, we reconstruct the dietary niches of select species relative to salmon muscle tissue and previously sampled non-salmon feeding invertebrate species. From comparisons across seasons, sampling locations and larval and adult life stages, we find evidence for a diet of salmon tissue in flies (Calliphora terraenovae and Dryomyza anilis), and beetles (Nicrophorus investigator and Anthobium fimetarium). The parasitic wasps Alysia alticola and Atractodes sp. had the highest levels of enrichment of all species, representing their larval diet of fly larvae that have fed on salmon carcasses 1 year prior to adult wasp sampling. Temporal and spatial isotopic variation in insect indicator species varies by species mobility and the pathway of salmon nutrient uptake. Cataloguing these associations may be useful for developing indices of intact salmon runs, bear foraging, and subsequent nutrient transfer in coastal watersheds.     

Breeding sites of Phlebotomus sergenti, the sand fly vector of cutaneous leishmaniasis in the Judean Desert

Phlebotomine sand flies transmit Leishmania, phlebo-viruses and Bartonella to humans. A prominent gap in our knowledge of sand fly biology remains the ecology of their immature stages. Sand flies, unlike mosquitoes do not breed in water and only small numbers of larvae have been recovered from diverse habitats that provide stable temperatures, high humidity and decaying organic matter. We describe studies designed to identify and characterize sand fly breeding habitats in a Judean Desert focus of cutaneous leishmaniasis. To detect breeding habitats we constructed emergence traps comprising sand fly-proof netting covering defined areas or cave openings. Large size horizontal sticky traps within the confined spaces were used to trap the sand flies. Newly eclosed male sand flies were identified based on their un-rotated genitalia. Cumulative results show that Phlebotomus sergenti the vector of Leishmania tropica rests and breeds inside caves that are also home to rock hyraxes (the reservoir hosts of L. tropica) and several rodent species. Emerging sand flies were also trapped outside covered caves, probably arriving from other caves or from smaller, concealed cracks in the rocky ledges close by. Man-made support walls constructed with large boulders were also identified as breeding habitats for Ph. sergenti albeit less important than caves. Soil samples obtained from caves and burrows were rich in organic matter and salt content. In this study we developed and put into practice a generalized experimental scheme for identifying sand fly breeding habitats and for assessing the quantities of flies that emerge from them. An improved understanding of sand fly larval ecology should facilitate the implementation of effective control strategies of sand fly vectors of Leishmania.     

Survey of the native insect natural enemies of Hyphantria cunea (Drury) (Lepidoptera: Arctiidae) in China

The fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), is an invasive and important pest in China. Investigations on insect natural enemies have been conducted from 1996 to 1999 in five provinces and one municipality of China in order to select effective species for biological control. Two carabid predators (Coleoptera) and 25 parasitoid species were found, among which 23 were parasitic wasps (Hymenoptera), including five hyperparasitic species and two tachinid flies (Diptera). The two carabids preyed on young larvae inside webs, two braconid wasps parasitized larvae, and 18 parasitoid species attacked the fall webworm during the pupal and/or 'larval-pupal' stages. Among these parasitoids, there were one genus and nine species that are new to science and four species new to China, which were described and published by the senior author Yang. The average parasitism rates of fall webworm pupae were 25.8% and 16.1% in the overwintering generation and the first generation (summer generation), respectively. These findings reveal that these natural enemies play an important role in the natural control of the pest. Chouioia cunea Yang (Hymenoptera: Eulophidae), a gregarious pupal endo-parasitoid, was recommended as a promising biological control agent against the fall webworm in China.     

Interactions between the Social Digger Wasp, <Emphasis Type="Italic">Cerceris rubida</Emphasis>, and Its Brood Parasitic Flies at a Mediterranean Nest Aggregation

The fitness consequence of many behaviours of the small digger wasp, Cerceris rubida (Hymenoptera: Crabronidae), the only European species of its genus in which females share nests, are still unknown. Here, I present novel data on the nesting patterns and nest parasites of an Italian population of this wasp, with emphasis on which behavioural strategies may have evolved to reduce brood parasitism. Nests were established mainly in horizontal surfaces with scarce vegetation and hard soil, resulting in spatially clumped nests; the extent of nest aggregation increased over a 6-year period. Wasp brood cells are attacked by the miltogrammine fly Pterella grisea (Diptera: Sarcophagidae), which waits for nest-returning wasps on perching sites and then follows them in flight (satellite flight), eventually landing on the nest entrance and larvipositing without entering further in the tunnel. This technique seems to be adaptive for the parasitic flies, which would be rejected from nests by the guarding wasps if attempting to enter. The daily activity of the flies closely matched the host wasp’s provisioning activity, but C. rubida females were able to partially confound the tracking flies by performing evasive manoeuvres while returning to the nest. Patches with higher nest density and nests with more resident females did suffer more fly landings on nest entrances (a prerequisite for larviposition). These trends, however, disappeared on a per nest basis and on a per wasp provisioning flight basis, respectively. Across two years, only 6% of brood cells were parasitized, a picture similar to what observed for miltogrammine flies at nest aggregations of other Cerceris spp., and new data are necessary to test if there is a benefit of either nest density or nest sharing against P. grisea parasitism.     

Physiological status of Drosophila suzukii (Diptera: Drosophilidae) affects their response to attractive odours

An improved understanding of the biology of the invasive pest, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is critical for the development of effective management strategies. Trapping is one technique used for both detection and control; however, the efficacy of trapping can vary depending on the target insect's physiological state, its behavioural priorities and the type of attractant used in the trap. We conducted a series of caged trapping experiments and a greenhouse trapping experiment to investigate the effects of D. suzukii feeding status, age, mating status, ovipositional status and seasonal morph type on the capture rate of traps baited with fermentation odours. Starved flies were trapped at greater rates compared to fed flies; more virgin flies were trapped than mated flies; flies deprived of an oviposition substrate were trapped more frequently than flies given an oviposition substrate. It is still unclear whether age or seasonal morphology affect bait response. Lastly, a caged choice experiment investigated the relationship between female reproductive status and attraction to fermentation or fruit odours. Fermentation‐based traps captured female flies regardless of their reproductive status but, ripe fruit‐based traps were more attractive to flies with more than seven eggs. In summary, studies that use fermentation‐based traps should recognize that capture rates of D. suzukii will depend on the feeding, mating and oviposition experiences of the population; also, fruit‐based traps may better target gravid females.     

Laboratory studies on the biology ofSpalangia nigra [Hym.: Pteromalidae]

At 21 °C,Spalangia nigra Latreille (Hymenoptera: Pteromalidae) averaged 29.3 days between exposure and emergence of 1^st progeny from host house flies,Musca domestica L. (Diptera: Muscidae). At 27 °C, the average developmental time to 1^st emergence was reduced to 26.6 days, and a majority of adult wasps emerged from host house fly puparia between 29 and 40 days postoviposition. The sex ratio of progeny ranged from 1.4 to 1.8 female-to-male, but all progeny of virgin females were male. Male wasps lived from 6.8–15 and females 11–17.8 days at 27 °C; honey as a food source increased longevity. No significant differences in parasitism byS. nigra were associated with host house fly pupal densities ranging from 1 to 200 pupae per female-male pair of wasps, but average percent parasitism decreased at host densities greater than 50. House fly pupae exposed to parasitism at ages ranging from 4 to 96 h did not differ in subsequent production of adult flies.S. nigra did not demonstrate preference for house flies or stable flies,Stomoxys calcitrans (L.) (Diptera: Muscidae) as hosts. The results of these studies indicate thatS. nigra may contribute significantly to previously unexplained mortality of house flies and stable flies.      

The Flight Heights of Chalcid Wasps (Hymenoptera,Chalcidoidea) in a Lowland Bornean Rain Forest: Fig Wasps are the High Fliers1

Tropical rain forests are characterized by their rich plant diversity and highly diverse insect faunas containing mainly rare species. Phytophagous and parasitoid insects utilizing such fragmented resources often must travel considerable distances to find suitable hosts. For small, weak‐flying insects, entry into the fast‐flowing air above the canopy can provide one way by which long‐distance dispersal is achieved. Using sticky traps placed at different heights in a lowland rain forest of Borneo, we compared the diurnal and nocturnal flight heights of chalcids, a group of mainly very small parasitoids and phytophages, to determine if the air above the canopy was used for dispersal. Most families were represented throughout the range of trap heights, including those above the general canopy. A higher proportion of individuals were trapped above the canopy at night than during the day. Fig wasps were exceptional in that they were trapped almost entirely above the canopy. They included species associated with host trees that do not fruit in the canopy, suggesting that these short‐lived, slow‐flying insects actively fly up above the canopy and then use the wind to passively carry them the long distances needed to reach their highly localized and ephemeral hosts. Once the fig wasps detect the species‐specific volatiles released by their host figs, they then may fly down into the canopy, where the lower wind speeds would allow them to fly actively upwind to their hosts.     

Traits reveal ecological strategies driving carrion insect community assembly

1. The succession of carrion-associated (necrophilous) insects on decomposing carrion is well documented. To exploit the changing nutritious and dynamic resources available throughout the carrion decomposition process, different species colonise and consume carrion in a predictable temporal sequence. The traits of these necrophilous insects should reflect their ecological strategies. Morphological traits of these insects, such as body size and wing size, however, have not previously been examined during active and advanced decomposition. 2. We used fourth-corner multivariate generalised linear models to identify insect community morphological trait patterns and to quantify their change through time on decomposing rabbit carcasses in grassland and woodland environments. 3. We found that larger-bodied species of flies and carrion-specialist beetles were associated with the early stages of decomposition. The morphological traits of ants, in contrast, showed no changes at carcasses through time and instead showed body size differences between grassland and woodland environments. 4. Our findings indicate that specialist flies and beetles that arrive early in the decomposition process possess traits that enable rapid discovery of carrion at a large scale. Generalist beetles and ants do not share this same trait and are instead adapted to locate and consume a wider variety of resources in their preferred habitat type at their local scale. 5. Our results provide insights into the morphological adaptations linked to the ecological strategies of distinct components of carrion insect communities. Further, our results offer insights into the community assembly dynamics that structure the communities of necrophilous insect species.     

云南西部实蝇的多样性

2005和2006年,在云南西部瑞丽、潞江坝、六库、保山、大理5个地区,采用信息素引诱法及被害瓜果内实蝇收集法对5个地区实蝇多样性进行分析.结果表明,5个地区实蝇丰富度的发生模式明显分为2种类型:瑞丽和潞江坝实蝇全年发生;六库、保山和大理实蝇季节性发生;瑞丽的实蝇种类丰富度最高,有20种,其次是潞江坝,11种,而保山、大理的实蝇种类丰富度低,分别为4种和3种;该区域实蝇优势种为桔小实蝇(Bactrocera dorsalis)和南亚果实蝇(B. tau);2年实蝇多样性指数均以六库最低,以潞江坝最高.各地实蝇种类相似性变化较大, 相似性系数在0.15～1.00 之间.结果为了解云南西部实蝇种类分布以及预防实蝇危害提供了基础数据.     

The diurnal periodicity and cycle of behaviour of the adult cabbage root fly (Erioischia brassicae)

Adult cabbage root fly (Erioischia brassicae (Bouché)) exhibited a diurnal periodicity in behaviour. Trapping tests indicated that the flies fed from hedgerow flowers in the morning, visited the crop in the early afternoon and returned to the hedges in the late afternoon. In the laboratory the flies also showed a cyclical pattern in behaviour. Feeding preceded oviposition by 3 days and this was reflected in the field by a relative increase in the movement of females away from the hedges and to the crop when they became gravid. The diurnal periodicity and the cycle in behaviour of males was similar to that of the females, indicating that some of the flies' movement was non-appetitive. The tendency of flies to stay for most of the day at hedges resulted in progressive declines in the numbers captured with increasing distances from hedges.     

Volatile host fruit odors as attractants for the oriental fruit fly (Diptera: Tephritidae)

We examined the responses of oriental fruit flies, Bactrocera dorsalis Hendel, to the odors of different stages and types of fruit presented on potted trees in a field cage. Females were most attracted to odors of soft, ripe fruit. Odors of common guava were more attractive to females than papaya and starfruit, and equally as attractive as strawberry guava, orange, and mango. In field tests, McPhail traps baited with mango, common guava, and orange captured equal numbers of females. Traps baited with mango were compared with 2 commercially available fruit fly traps. McPhail traps baited with mango captured more females than visual fruit-mimicking sticky traps (Ladd traps) and equal numbers of females as McPhail traps baited with protein odors. Results from this study indicate that host fruit volatiles could be used as lures for capturing oriental fruit flies in orchards.     

Bimodal cue complex signifies suitable oviposition sites to gravid females of the common green bottle fly

Gravid females of the common green bottle fly, Lucilia sericata Meigen (Diptera: Calliphoridae), readily locate recently deceased vertebrates as oviposition sites, particularly when these animals have been injured. We investigated semiochemical and visual cues that mediate attraction of gravid females to fresh rat carrion. Female flies were more strongly attracted to incised rat carrion than to intact carrion. They were also attracted to Porapak Q headspace volatile (HSV) extract of incised rat carrion. Analyzing aliquots of Porapak Q HSV extract by gas chromatographic‐electroantennographic detection revealed nine components [phenol, para‐ and/or meta‐cresol (could not be separated), guaiacol, dimethyl trisulfide (DMTS), phenylacetaldehyde, (E)‐2‐octenal, nonanal, and tetramethyl pyrazine] that consistently elicited responses from blow fly antennae. In laboratory experiments, a synthetic blend of these nine components was as attractive to gravid females as Porapak Q HSV extract, but blend attractiveness was due entirely to DMTS. In both laboratory and field experiments, increasing doses of DMTS attracted increasingly more flies. Coupled with DMTS, carrion‐type color cues (dark red, black) were more effective than bright color cues (white, yellow) in attracting flies. In field experiments, dark traps baited with DMTS captured a total of 214 calliphorid flies (200 L. sericata, 10 Lucilia illustris Meigen, three Calliphora vicina Robineau‐Desvoidy, one Calliphora vomitoria L.), all of which were gravid females. These results support the conclusion that DMTS and dark color represent a bimodal cue complex that signifies suitable oviposition sites to gravid calliphorid females, particularly L. sericata.     

Comparison of two synthetic food-odor lures for captures of feral Mexican fruit flies (Diptera: Tephritidae) in Mexico and implications regarding use of irradiated flies to assess lure efficacy

Feral Mexican fruit flies, Anastrepha ludens (Loew) (Diptera: Tephritidae), were trapped in a citrus orchard in Mexico by using two types of synthetic food-odor lures, the AFF lure (Anastrepha fruit fly lure, APTIV, Inc., Portland, OR) and the BioLure (two-component MFF lure, Suterra LLC, Inc., Bend, OR). In Multilure traps (Better World Manufacturing, Inc., Miami, FL) containing water, BioLures captured about the same numbers of flies as AFF lures. In Multilure traps containing antifreeze solution, BioLures captured 2 and 5 times more flies than AFF lures in two experiments. BioLures, and AFF lures did not differ in attractiveness when used on sticky traps (Intercept trap, APTIV, Inc.; and sticky cylinder trap). Multilure traps captured >4 times as many flies as sticky traps with the exception that captures of females did not differ between Multilure and sticky traps baited with AFF lures. The percentage of females captured in Multilure traps was greater when traps were baited with BioLures compared with AFF lures, but the reverse was true for sticky traps. Sticky cylinder traps captured a higher percentage of females than Multilure traps. The most effective trap/lure combination was the Multilure trap baited with BioLure and antifreeze. In comparison with tests of these two lures in Texas, results were similar for Multilure traps, but they differed for sticky cylinder traps in that AFF lures were consistently more attractive than BioLures in Texas, but not in Mexico.     

The influence of host fruit and temperature on the body size of adult Ceratitis capitata (Diptera: Tephritidae) under laboratory and field conditions

The adult body size of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), varies in natural conditions. Body size is an important fitness indicator in the Mediterranean fruit fly; larger individuals are more competitive at mating and have a greater dispersion capacity and fertility. Both temperature during larval development and host fruit quality have been cited as possible causes for this variation. We studied the influence of host fruit and temperature during larval development on adult body size (wing area) in the laboratory, and determined body size variation in field populations of the Mediterannean fruit fly in eastern Spain. Field flies measured had two origins: 1) flies periodically collected throughout the year in field traps from 32 citrus groves, during the period 2003-2007; and 2) flies evolved from different fruit species collected between June and December in 2003 and 2004. In the lab, wing area of male and female adults varied significantly with temperature during larval development, being larger at the lowest temperature. Adult size also was significantly different depending on the host fruit in which larvae developed. The size of the flies captured at the field, either from traps or from fruits, varied seasonally showing a gradual pattern of change along the year. The largest individuals were obtained during winter and early spring and the smallest during late summer. In field conditions, the size of the adult Mediterannean fruit fly seems apparently more related with air temperature than with host fruit. The implications of this adult size pattern on the biology of C. capitata and on the application of the sterile insect technique are discussed.     

Seasonal abundance of the stable fly Stomoxys calcitrans in southwest England

The stable fly Stomoxys calcitrans (L.) is a cosmopolitan biting fly of both economic and welfare concern, primarily as a result of its painful bite, which can cause blood loss, discomfort and loss of productivity in livestock. Between June and November in 2016 and May and December in 2017, Alsynite sticky‐traps were deployed at four Donkey Sanctuary sites in southwest England, which experience recurrent seasonal biting fly problems. The aim was to evaluate the seasonal dynamics of the stable fly populations and the risk factors associated with abundance. In total, 19 835 S. calcitrans were trapped during the study period. In both years, abundance increased gradually over summer months, peaking in late August/September. There were no relationships between seasonally detrended abundance and any climatic factors. Fly abundance was significantly different between sites and population size was consistent between years at three of the four sites. The median chronological age, as determined by pteridine analysis of flies caught live when blood‐feeding, was 4.67 days (interquartile range 3.8–6.2 days) in males and 6.79 days (interquartile range 4.8–10.4 days) in females; there was no significant, consistent change in age or age structure over time, suggesting that adult flies emerge continuously over the summer, rather than in discrete age‐related cohorts. The data suggest that flies are more abundant in the vicinity of active animal facilities, although the strong behavioural association between flies and their hosts means that they are less likely to be caught on traps where host availability is high. The implications of these results for fly management are discussed.     

Bean seed fly (Delia platura, Delia florilega) and onion fly (Delia antiqua) incidence in England and an evaluation of chemical and biological control options

Bean seed fly and onion fly are significant pests of alliaceous crops in the UK. Their activity was monitored using yellow water traps at three field sites in England in 2002 and 2003. Bean seed fly were not split between Delia platura or Delia florilega because from the growers point of view control measures are independent of species. The traps were effective at catching bean seed fly, which was present from April until September. A total of 1729 bean seed fly were trapped in 2002 and 4501 in 2003, with peak activity in May in both years. In 2003, there appeared to be three to four peaks in abundance of the pest. Only 113 onion flies were trapped in 2002 and 23 in 2003. More male onion fly were trapped than females. Pot experiments were carried out to evaluate efficacy of a range of insecticides, garlic and two parasitic nematode species (Steinernemafeltiae and Steinernema kraussei) against bean seed fly and onion fly. Pots of salad onions were exposed to natural oviposition by bean seed fly, but the onion fly experiment was carried out in a glasshouse with eggs of the pest being inoculated into the pots. Tefluthrin seed treatment appeared to be especially effective at preventing bean seed fly damage and produced the most robust seedlings but did not appear to kill the larvae. A drench of chlorpyrifos at the ‘crook’ stage gave 100% control of bean seed fly larvae. A chlorpyrifos drench was the only treatment to give effective control of onion fly. There was some evidence that the parasitic nematode S. feltiae reduced numbers of bean seed fly larvae by about 50%. Guidelines for control of both bean seed fly and onion fly are discussed.     

Mean life expectancy of Old World screwworm fly,Chrysomya bezziana,inferred from the reproductive age-structure of native females caught on swormlure-baited sticky traps

Abstract. The reproductive status of native (wild) screwworm fly, Chrysomya bezziana, caught on swormlure-baited sticky traps in Papua New Guinea is described. A total of 1122 females and 25 males were trapped. Of these females 595 were scored for insemination status and stage of ovarian development (on a scale of 2–10) of which 20% were in suitable condition for assignment to first, second and third ovarian cycles. Of the nulliparous females, only 17% were inseminated at stage 3 of ovarian development, 70% at stage 4, 93-97% at stages 5 and 6, and all of stages 7–10 (gravids). All parous females were inseminated. More than half of the captured females were parous (58%) and only 7% of the total were gravid. Proportions of females in ovarian cycles 1, 2 and 3 were 41%, 50% and 9% respectively. Survival of female Ch. bezziana in the laboratory was adequately described by lognormal and Gompertz survival functions, for both of which the mortality rate is an increasing function of reproductive age. Analysis of the reproductive age distribution of native females estimated their mean life-expectancy at 9 days under the prevailing mean field temperature of 26.5^oC. This equates to completion of 1.7 ovarian cycles and an estimated mean lifetime fecundity of 146 female progeny. The survival models, which also allowed responsiveness of females to swormlure-baited traps (female trappability) to vary according to their stage of ovarian development, indicated significant age-dependent trapping bias. These findings are compared with similar data for the New World screwworm fly, Cochliomyia hominivorax.