Susceptibility of Queensland fruit fly,Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), to entomopathogenic nematodes

Queensland fruit fly, Bactrocera tryoni (Froggatt), is the economically most significant Australian tephritid pest species with a large invasion potential, yet relatively little work on its biological control has been undertaken. Entomopathogenic nematodes (EPNs) are of potential interest for control of this fruit fly species as it pupates in the soil. Specifically, the pre-pupal stage of B. tryoni may present a unique window for EPN application, as fully developed larvae drop from infested fruit to the soil for pupation. For the first time, we tested the capacity of three EPN species with different foraging strategies, Steinernema feltiae, Steinernema carpocapsae and Heterorhabditis bacteriophora, to cause larval and pupal mortality in B. tryoni across a range of EPN concentrations (50, 100, 200, 500 and 1000 infective juveniles IJs cm^-2), substrate moisture (10, 15, 20 and 25% w/v) and temperatures (15, 20, 25 and 30 °C). We found that all EPN species tested caused environment and density dependent mortality in the third larval instar while pupae were not affected. Steinernema feltiae caused high mortality across different IJ concentrations and over a wider moisture and temperature range than the other two EPN species. High mortality caused by S. carpocapsae and H. bacteriophora was more limited to high IJ concentrations and a narrower moisture and temperature range. Our findings highlight the potential of EPNs for the control of B. tryoni and warrant further laboratory and field experiments to evaluate their efficacy under the wide environmental conditions that B. tryoni can occur in.     

Pheromone deposition on leaf territories by male Caribbean fruit flies,Anastrepha suspensa (loew) (Diptera: Tephritidae)

Male Caribbean fruit flies apply everted anal membranes associated with pheromone glands to the substrate while on leaf territories. There is a peak in abdominal dipping at the onset of the photoperiod, followed by a decline and then a more extensive period of activity in the second half of the photoperiod. During peak signaling periods, most males had a distinct set of lateral abdominal phermone glands protruded for most of the time. However, the frequency of anal pheromone gland dipping varied considerably over time. Episodes of wing fanning (which may disperse pheromones) and abdomen dipping coincide during a male's tenure on a host leaf. Host-plant leaves were contained for 48 h with signaling males or immature females or kept without insects. Several, though not all, of the constituents of the pheromone were found on leaves within 1 h of removing signaling males. None of these compounds occurred on either type of control leaf. Mature virgin female flies were more likely to be found in contact with host leaves that had been previously exposed for 48 h to the activities of sexually mature males than with unexposed control leaves. There was no difference in the reaction of mature virgin female flies to unexposed control leaves or leaves previously exposed to the activities of other sexually immature female or male flies for 48 h. Presumably, the deposition of pheromones by mature males accounts for the difference in reactions.     

Electronic traps for detection and population monitoring of adult fruit flies (Diptera: Tephritidae)

During the last decades, the economic importance of tephritid fruit flies (FF) has increased worldwide because of recurrent invasions and expansions into new areas, and reduced control capabilities of current control systems. Efficient monitoring systems, thus, are required to provide fast information to act promptly. With this aim in mind, we developed two electronic trap (e‐trap) versions for adult FF: one with specific volatiles for male and female adult Ceratitis capitata, and the second, based on the attraction of adult FF to yellow colour, targeting Dacus ciliatus, Rhagoletis cerasi and Bactrocera oleae. In the case of B. oleae, the female pheromone and ammonium bicarbonate were added as synergists. In the two versions, attracted FF were retained in the trap on glued surfaces. Real‐time images of the surfaces were automatically taken and transmitted to a server. We tested the two e‐trap versions in insect‐proof cages, where flies were released and recaptured, and in commercial orchards throughout the Mediterranean: C. capitata in peach orchards in Italy; R. cerasi in cherry orchards in Greece; B. oleae in olive orchards in Spain and in Greece; and D. ciliatus in melons in plastic tunnels in Israel. The e‐trap showed excellent abilities to transmit real‐time images of trapped FF and a high specificity for trapping different FF species. The ability of the entomologist to correctly classify FF from images in the office was >88%. In addition, average number of flies/trap in e‐trap grids did not differ from numbers reported on grids of conventional traps that were operating simultaneously. The e‐traps developed and tested in this study provide the basis for the real‐time monitoring of FF were no olfactory attractants are available, and for the surveillance of alien FF incursions where generic, but not specific, olfactory attractants exists.     

Function of multiple sperm storage organs in female Mediterranean fruit flies (Ceratitis capitata, Diptera: Tephritidae)

Sperm storage organs allow females to temporally separate insemination from fertilization, manipulate ejaculates and control fertilization. In the reproductive tract of female fruit flies (Diptera: Tephritidae), sperm are found in two different organs--a pair or triplet of spermathecae, and a "fertilization chamber". In order to understand the specific function of each of these organs, we tested the following hypotheses: (1) Sperm are distributed equally amongst the various sperm storage organs; (2) Both organ types maintain sperm viability; and (3) Sperm used in fertilization come from the fertilization chamber. We counted sperm in spermathecae and fertilization chamber of Mediterranean fruit flies (Ceratitis capitata) every 3 days for 18 days following insemination, and used a live/dead staining technique to determine the viability of sperm in these organs. Finally, by extirpating spermathecae from inseminated females and allowing them to oviposit, we were able to identify the fertilization chamber as the source of fertilizing sperm. Numbers of sperm in the spermathecae declined from an average of 3575 on the day of copulation to 649, 18 days later. Conversely, the fertilization chamber maintained a fairly constant level of sperms, ranging between an average of 207 cells on day 3 to 115 sperms on day 18. Throughout the period we monitored, we found high levels of sperm viability in both organs (> 80%). Sperm viability was similarly high in the fertilization chambers of females without spermathecae. However, fertility of eggs laid by these females declined rapidly, as did the number of sperm in the fertilization chamber. We conclude that both the spermathecae and the fertilization chamber are active sperm storage organs, with separate functions: the spermathecae for long-term storage and the fertilization chamber, periodically filled by the spermathecae, a staging point for fertilizing sperm. We suggest that the use of both organs by females results in sperm economy, which adaptively prolongs the intervals between copulations.     

基于mtDNA COI基因序列的中国柑橘果实蝇的分子鉴定及柑橘大实蝇种群的遗传多样性分析

【目的】探明危害我国柑橘的实蝇种类以及柑橘大实蝇Bactrocera minax不同地理种群和不同寄主种群的遗传多样性。【方法】利用mtDNA COI基因对危害柑橘的果实蝇进行种类鉴定,采用MEGA软件对其中28个地理种群的535头果实蝇COI基因片段(约505 bp)序列进行比对,分析种间及种内遗传距离,构建系统发育树。使用DnaSP软件分析柑橘大实蝇不同地理种群和不同寄主种群的遗传多样性。【结果】从柑橘虫果内共鉴定出4种实蝇,分别为柑橘大实蝇B.minax、桔小实蝇B.dorsalis、蜜柑大实蝇B.tsuneonis和瑞丽果实蝇B.ruiliensis。这4种实蝇的种间遗传距离为0.0264～0.2410,种内遗传距离为0.0000～0.0140,种间与种内遗传距离没有重叠区域。单个柑橘虫果内一般仅有1种实蝇,极个别柑橘果实可同时被两种实蝇危害(4/43);在这些为害柑橘的实蝇种类中,以柑橘大实蝇的个体数量比例最大,占90.70%。柑橘大实蝇地理种群遗传多样性高,28个种群共有17个单倍型。【结论】柑橘大实蝇是所调查地区柑橘实蝇的绝对优势种,其种群遗传分化程度较高,扩散危害风险大。本研究结果对柑橘果实蝇类的监测和防控具有重要意义。     

Ant cues affect the oviposition behaviour of fruit flies (Diptera: Tephritidae) in Africa

Abstract. Although most studies on fruit fly oviposition behaviour focus on horizontal interactions with competitors and cues from host plants, vertical interactions with predators are poorly documented. The present study provides direct evidence indicating that the oviposition behaviour of the two main mango fruit fly species, Ceratitis cosyra (Walker) and Bactrocera invadens Drew‐Tsurata & White, is affected by secretions of the dominant arboreal ant Oecophylla longinoda (Latreille). When offered ant‐exposed and unexposed mangoes in the absence of the ants, both fly species are reluctant to land on ant‐exposed fruits and, when having landed, often take off quickly and fail to oviposit. The number of puparia collected from unexposed mangoes is approximately eight‐fold higher than from ant‐exposed ones. The results obtained from laboratory experiments and field observations confirm that adult fruit flies are more affected through repellence by ant cues than by direct predation. The use of cues by fruit flies in predator avoidance has implications for evolutionary ecology, behavioural ecology and chemical ecology.     

Amino acid increases in fruit infested by fruit flies of the family Tephritidae

Solanum mauritianum Scop, (wild tobacco) fruit is the major host of the fruit fly Dacus cacuminatus (Hering), and is a major source of food for the brown pigeon Macropygia phasianella (Temminck) in eastern Queensland. Amino acid analyses were undertaken on fruit fly infested and uninfested S. mauritianum fruits. Infested fruits contained approximately twice the level of protein and essential amino acids compared to uninfested fruit. This increase is probably due to the plant adding additional amino acids to infested tissue and the accompanying growth of bacteria established in the fruit during oviposition. The infested fruit would provide a valuable source of protein during the pigeon breeding season.     

实蝇共生菌研究进展

实蝇类昆虫(双翅目Diptera:实蝇科Tephritidae)是重要的农业害虫,为害农作物茎秆和水果,严重影响农业生产和果蔬贸易,被许多国家列为重要的检疫性有害生物。实蝇共生菌对宿主实蝇的取食、生殖、发育及环境适应能力具有重要作用。目前,已有21个属的共生细菌(Enterobacter、Klebsiella、Citrobacter、Pseudomonas、Providencia、Erwinia、Acetobacter、Serratia、Proteus、Hafnia、Cedecea、Arthrobacter、Lactobacillus、Micrococcus、Streptococcus、Staphylococcus、Vibrio、Hafnia、Deinococcacea、Bacillus、Wolba-chia)以及1个属的共生真菌(Candida)被鉴定。其中,肺炎杆菌Klebsiella pneumoniae、产酸克雷伯氏菌Klebsiella oxytoca、成团泛菌Pantoea agglomerans、费氏柠檬酸杆菌Citrobter freundii、阴沟肠杆菌Enterobacter cloaca...     

Generic phytosanitary radiation treatment for tephritid fruit flies provides quarantine security for Bactrocera latifrons (Diptera: Tephritidae)

Bactrocera latifrons (Hendel) (Diptera: Tephritidae) is a quarantine pest of several solanaceous crops and tropical fruits that are treated using irradiation before export from Hawaii to the U.S. mainland. A dose of 150 Gy is approved as a generic irradiation treatment for tephritid fruit flies, but no confirmation of efficacy has been reported for B. latifrons. Dose response of B. latifrons was used to determine the most tolerant life stage and identify a dose that prevents adult emergence. Data indicated doses (plus 95% confidence limits) required to prevent adult emergence of 13.4 (10.0-29.6), 17.5 (14.4-24.8), and 88.1 (68.0-133.8) Gy for eggs, first instars and third instars, respectively. In large-scale confirmatory tests of the most radiotolerant life stage, a radiation dose of 150 Gy applied to B. latifrons late third instars in bell peppers (Capsicum annuum L.) resulted in no survival to the adult stage of 157,112 individuals, a treatment efficacy consistent with Probit 9-level mortality. The relative radiotolerance of melon fly Bactrocera cucurbitae Coquillet, and B. latifrons also was tested using a diagnostic radiation dose of 30 Gy. In diet, a mean of 6.9% of irradiated B. cucurbitae third instars developed to the adult stage, whereas no B. latifrons third instars developed to adults. In papaya, Carica papaya L., fruit, a mean of 3.3% of irradiated B. cucurbitae third instars developed to the adult stage, whereas 0.5% B. latifrons third instars developed to adults. This report supports the use of a generic radiation dose of 150 Gy in quarantine scenarios to control tephritid fruit flies on fresh commodities.     

Attraction of female Chiracanthium mildei(Araneae: Clubionidae) to olfactory cues from maleMediterranean fruit flies Ceratitis capitata(Diptera: Tephritidae)

Chiracanthium mildei, a common sac spider (Clubionidae) in Israel, is an important predator of pest insects in citrus and apple orchards. Field observations indicate that the females of this hunting spider are attracted to traps containing the parapheromone trimedlure and males of the Mediterranean fruit fly (Ceratitis capitata),which were caught in these traps. Laboratory testsshow that C. mildei females are attractedto olfactory cues from male C. capitata, but notto trimedlure. This suggests that C. mildeimay be an important nocturnal predator of C.capitata.     

Marking of host fruit by maleRhagoletis boycei Cresson flies (Diptera: Tephritidae) and its effect on egg-laying

MaleRhagoletis boycei flies (Cresson) have been shown previously to guard egg-laying punctures on host walnut (Juglans major) fruit. During their tenure,R. boycei males were observed to dip the posterior portion of their abdomen repeatedly toward the fruit surface. Closeup video analysis revealed that, during this dipping behavior, a clear viscous substance emanating from the cercus was deposited directly on the fruit. Laboratory assays indicated that the rate of abdomen-dipping was significantly higher on fruit bearing simulated egg-laying punctures than on control fruit and significantly higher in the area of the puncture than elsewhere on the fruit. In a final experiment, the occurrence of abdomen-dipping in the vicinity of a puncture was manipulated independently on separate punctures on the same fruit. On such fruit and in the absence of males, previously mated, reproductively mature females attempted oviposition significantly more often in or near a puncture exposed to males than in or near an unexposed control puncture. Possible functions of the putative male-marking behavior from the perspectives of both male and female are discussed.     

Sex-specific glands in tephritid fruit flies of the genera Anastrepha,Ceratitis, Dacus and Rhagoletis (Diptera : Tephritidae)

The objectives of this work were to systematically examine males and females of tephritid fruit flies from the genera Anastrepha, Ceratitis, Dacus and Rhagoletis for the presence of possible sex pheromone glands, and to determine whether particular glands may be characteristic of certain genera. Flies from the 4 genera were examined from paraffin embedded histological sections. Pleural epidermal glands and sexually dimorphic, enlarged salivary glands were found in males, but not in females, of 7 species of Anastrepha and in 2 species of Ceratitis. Females of these species do not develop the pleural epidermal glands at all, and although they have salivary glands, the glands do not have the large glandular mass of tissue that is found in males. The pleural glands were similar in all the males, and consisted of a single layer of enlarged, columnar epidermal cells in the pleural region of abdominal segments 3, 4 and 5. The salivary glands of males were divided into 4 types based upon structure.Pleural glands and enlarged salivary glands were searched for, but were not found, in 2 species of Rhagoletis and in 3 species of Dacus. Anal glands, opening externally on the last segment, were confirmed in C. capitata, and were found in C. rosa. Anal glands were not found in any of the other species. A diverticulum from the rectum, the rectal pouch or gland, was confirmed in D. dorsalis, D. cucurbitae and D. tryoni as already published, but this gland was not found in species of other genera. Growth of the pleural glands and salivary glands in males of A. ludens, A. fraterculus and C. capitata was described as a function of age of flies.     

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.     

Reproductive behaviour of the South American fruit fly Anastrepha fraterculus (Diptera: Tephritidae): laboratory and field studies

Abstract. The mate choice, courtship and oviposition behaviour of laboratory-reared and field-collected Anastrepha fraterculus (Wied.) were compared. In laboratory cultures in Southampton the duration of male calling activity in small leks increased gradually from 1-2h at 5 days old to up to 7 h at 10 days. This finding correlates with previous reports on the time at which male salivary glands, which are believed to produce sex pheromone, are fully developed. Wild flies which emerged from infested fruits in Brazil began to oviposit on the day they mated, whereas in laboratory flies oviposition began 1 day following the first mating. Both types of fly usually defended their position on a particular fruit throughout the day, and re-mated with either virgin or mated males. There was no significant difference in mating duration. Females did not copulate before the mean age (±SE) of 16.8±0.9 days. For both types of flies mating initiation occurred in the first 2h of photophase, with virgin females choosing mainly mated males. The average number of matings in the laboratory was three for females and four for males, and the interval between matings in females was significantly increased after the second mating. It is suggested that the tendency of virgin females to mate with mated males will lead to increased fitness, as males are on average 48 days old at their second mating. The potential life span of around 200 days for both sexes would allow adults to bridge the gap between seasonally available fruits in warm-temperate and sub-tropical South America.     

基于CLIMEX的桔小实蝇在中国适生区的预测

桔小实蝇Bactroceradorsalis(Hendel),属双翅目Diptera,果实蝇科Tetriphitidae,主要分布在热带和亚热带地区。温度和湿度是影响桔小实蝇分布的重要气候因子。根据桔小实蝇对温湿度等气候因子的反应,采用CLIMEX软件对桔小实蝇在中国大陆的适生区进行了预测。设置了CLIMEX中的相应参数17个:发育起点温度DV0、生长最适宜温度范围DV1～DV2、致死高温DV3、有效发育积温PDD。生长发育所需最低土壤湿度临界SM0、最适宜湿度范围SM1～SM2、最高土壤湿度临界SM3。冷胁迫日度临界DTCS及其积累速率DHCS,热胁迫临界温度TTHS及其积累速率THHS,干旱胁迫临界SMDS及其积累速率HDS,湿胁迫SMWS及其积累速率HWS。以印度和夏威夷为已知适生分布区,反复调试修正上述这些参数值,使之与已知广泛分布的地区达到最大程度的吻合。然后用优化后的参数和中国大陆85个气象站点的气象资料模拟桔小实蝇在中国大陆的适生分布,结果显示:广东、海南、香港、广西、四川、云南、湖南、湖北、福建、江西、浙江等11个省(区)是桔小实蝇的适生分布区。主要分布在我国的华南和西南大部分地区,以及华中和华东的部分地区。根据CLIMEX模拟结果的EI值大小,将桔小实蝇在我国大陆的适生分布情况进一步划分为最适宜、次适宜、适宜和非适宜4个气候区,即华南地区全部以及广西省全境是桔小实蝇的最适宜分布区,除桂林(EI=17)外,其余气象点的EI值均大于40;西南地区的四川、云南两省及福建沿海地区是桔小实蝇的次适宜分布区,平均EI值为29.7;适宜分布区包括湖南、湖北、江西、浙江的少数地区,除赣州(EI=17)外,其余点的EI值均小于10;长江以北的广大地区是桔小实蝇的非适宜区,这些地区不适合桔小实蝇生存。     

Parasitism of fruit fliesCeratitis capitata andAnastrepha SPP. [Diptera: Tephritidae] in Guatemala

In a 4-year surveyDoryctobracon crawfordi Viereck andBiosteres longicaudatus Ashmead were the most common parasitoids recovered from bothCeratitis capitata (Wiedemann) andAnastrepha spp. Other braconids recovered from both genera wereD. areolatus Szepligeti,Bracanastrepha anastrephae (Viereck), and a Cynipid. Combined parasitization in both generally by ranged from 0.04 to 7.95% (Av. 1.5%). The numbers were particularly low in economically important fruit crops such as coffee, orange, and peach. Combined parasitoid population was correlated with the combined fruit fly infestation at 5 elevation strata.