Apoptosis : an International Journal on Programmed Cell Death 20(1):1-9 (DOI: 10.1007/s10495-014-1055-3).
Transcriptional activation of pro-apoptotic genes in response to cytotoxic stimuli is a conserved feature of the cell death pathway in metazoans. However, understanding the extent of this conservation in insects has been limited by the lack of known pro-apoptotic genes in non-drosophilids. Recently, we described the pro-apoptotic genes, Asrpr and Ashid, from the tephritid, Anastrepha suspensa, that now allow us to explore the conservation of pro-apoptotic gene regulation between a tephritid and drosophilids. In this study, we determined the developmental profiles of Asrpr and Ashid transcripts during embryogenesis and in embryos exposed to γ-irradiation. Transcript levels of both genes determined by qRT-PCR were low throughout embryogenesis, with strong Ashid expression occurring during early to mid-embryogenesis and Asrpr expression peaking in late embryogenesis. This correlated to acridine orange stained apoptotic cells first appearing at 17 h and increasing over time. However, when irradiated at 16 h post-oviposition embryos exhibited significant levels of apoptosis consistent with strong induction of Asrpr and Ashid transcript levels by γ-irradiation in young embryos <24 h post-oviposition. Furthermore, embryos irradiated <24 h post-oviposition failed to hatch, those irradiated between 24 and 32 h had increased hatching rates, but between 48 and 72 h irradiation had no effect on egg hatching. This indicates a transition of embryos from an irradiation-sensitive to irradiation-resistance stage between 24 and 48 h. Throughout post-embryonic development, the two pro-apoptotic genes share similar patterns of up-regulated gene expression, which correlate to ecdysone-induced developmental events, especially during metamorphosis. Together these results provide the first direct evidence for a conserved molecular mechanism of the programmed cell death pathway in insects.
Nirmala X, Schetelig MF, Zimowska GJ, Zhou L, Handler AM
Ashid, Asrpr, Irradiation, Ecdysteroids, Cell death, Tephritids
MAGNT Research Report (ISSN. 1444-8939) Vol.3 ( 2). PP: 319-326
(Full text pdf attached)
Irradiation as a commercial insect control technique was applied for the first time in 1929 to cigars to control lasioderma serricorne although the X-ray machine used turned out to be unsuitable for continuous processing. Sterile insect technique (SIT) is a promising environment-friendly method for control or eradication of a number of insect pests. It is rapidly becoming a major component of integrated pest management for fruit fly control. Gamma irradiation is currently the most common method used to sterilize mass reared males for SIT and effectiveness of SIT depends greatly on the production of good quality sterile males that are released into target wild populations. To ensure that released males are effective at inducing reproductive failure in their mates, it is important that irradiation procedures achieve an adequate level of sterility. The Ultraviolet (UV) portion of the spectrum has been widely used as a germicide and as an attractant for insects in embryological physiological studies for the surface disinfection of insect eggs from pathogens and for the suppression of insects and different stages of the life cycle.
Espo E, Eyidozehi K, Ravan S
insect, history, Sterile insect technique
Journal of Economic Entomology 107: 154-160. DOI: 10.1603/EC13226
Phlyctinus callosus (Boheman) (Coleoptera: Curculionidae) is a pest of major phytosanitary concern for some of South Africa's biggest export markets such as the United States and Europe because this pest does not occur there. At present, fumigation with methyl bromide is the only postharvest disinfestation treatment against this pest; therefore, sustainable alternatives are needed. One such alternative is irradiation treatment of whole pallets of packed fruit to sterilize insects that may be present within the cartons. Wild adult P. callosus weevils were treated with 5, 10, 20, 40, and 80 Gy of gamma-irradiation and then cross mated to breed with either treated or nontreated adults of the opposite sex. Fecundity and fertility were monitored and recorded. Trials were conducted during the 2009-2010 and 2010-2011 fruit harvesting seasons. The results from both seasons indicated that irradiation did not affect fecundity but fertility was significantly affected, decreasing as irradiation doses increased. Egg hatch was zero for mating crosses that involved females weevils treated with a dose of 80 Gy gamma-irradiation. Probit analysis indicated that in the first season, the estimated LD95 for crosses involving treated males and treated females was 30 Gy, while in the second season it was 49.5 Gy. Respective estimated LD99S were 47.9 and 169.4 Gy. Ultimately, a dose lower than the current generic dose of 400 Gy, approved for irradiation disinfestation treatments, would control P. callosus should they occur in packed export fruit.
Duvenhage AJ, Johnson SA.
Journal of Stored Products Research 59:108-112
The biological activity of basil (Ocimum basilicum L.) oil vapor was tested against the stored product pest rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Adult weevils were exposed to seven different concentrations of basil oil ranging from 0.12 ml/mle0.60 ml/ml in Petri dishes and mortality was assessed at 3, 4 and 5 d post treatment. Mortality increased with increasing exposure time and basil oïl concentration. At 3, 4 and 5 d post treatment, the LC50 values were 8.14, 6.50 and 4.91 ml/ml of basil oil, respectively. S. oryzae was also exposed to 0.12 or 0.24 ml/ml basil oil and irradiated at 20, 40, 60, 80, 100 or 120 Gy in Petri dishes before mortality assessment at 5 d post treatment. The effectiveness of irradiation treatment against S. oryzae was enhanced by exposure to basil oil. S. oryzae exposed to 0.12 and 0.24 ml/ml of basil oil were 4.1 and 5.3 times more sensitive to irradiation, respectively, compared to control weevils treated only with irradiation. The effect of basil oil and irradiation on mortality was synergistic when used in combination against S. oryzae in packaged rice. The type of rice package affected treatment efficacy. In paper rice packages, 78% mortality was observed with 2.5 ml/ml basil oil and a radiation dose of 200 Gy at 5 d post treatment. In plastic packages, 100% mortality was achieved with 0.83 ml/ml basil oil and a radiation dose of 200 Gy at 5 d post treatment. Basil oil has potential as a synergist to lower the radiation dose required to control phytosanitary pests.
Hossain Farah, Lacroix Monique, Salmieri Stephane, Vu Khanh, Follett Peter A.
The mango pulp weevil, Sternochetus frigidus (F.), is an important quarantine pest preventing the export of mangoes from the Philippines to the United States and other countries. Previously, a radiation dose of 100 Gy was proposed for phytosanitary treatment of S. frigidus based on dose-response studies with larvae, pupae, and adult weevils. To validate an irradiation treatment, large-scale confirmatory tests were conducted with adults (the most radiation-tolerant stage) in mangoes at 100 and 150 Gy. After treatment, adults were removed from fruit, sexed, and mated in pairs to observe any reproduction. At 100 Gy, adults laid a small number of eggs but none of the eggs hatched. At 150 Gy (measured doses 96.7-164.1 Gy),4,559 treated weevils laid no eggs, indicating that this dose caused complete sterility. Irradiation treatment with a minimum absorbed dose of 165 Gy will therefore provide quarantine security for S. frigidus in exported Philippine mangoes.
Obra GB, Resilva SS, Follett PA, Lorenzana LRJ.
Sternochetus frigidus, mango pulp weevil, postharvest phytosanitary treatment, quarantine pest, disinfestation
Malaria Journal 13:484 doi:10.1186/1475-2875-13-484
full pdf (www.malariajournal.com/content/pdf/1475-2875-13-484.pdf
The success of the sterile insect technique (SIT) depends the release of large numbers of sterile males, which are able to compete for mates with the wild male population within the target area. Unfortunately, the processes of colonisation, mass production and irradiation may reduce the competitiveness of sterile males through genetic selection, loss of natural traits and somatic damage. In this context, the capacity of released sterile Anopheles arabiensis males to survive, disperse and participate in swarms at occurring at varying distances from the release site was studied using mark-release-recapture (MRR) techniques.
In order to assess their participation in swarms, irradiated and marked laboratory-reared male mosquitoes were released 50, 100 or 200 m from the known site of a large swarm on three consecutive nights. Males were collected from this large swarm on subsequent nights. Over the three days a total of 8,100 males were released. Mean distance travelled (MDT), daily probability of survival and estimated population size were calculated from the recapture data. An effect of male age at the time of release on these parameters was observed.
Five per cent of the males released over three days were recaptured. In two-, three- and four-day-old males, MDT was 118, 178 and 170 m, and the daily survival probability 0.95, 0.90 and 0.75, respectively. From the recapture data on the first day following each release, the Lincoln index gives an estimation of 32,546 males in the natural population.
Sterile An. arabiensis males released into the field were able to find and participate in existing swarms, and possibly even initiate swarms. The survival probability decreased with the age of male on release but the swarm participation and the distance travelled by older males seemed higher than for younger males. The inclusion of a pre-release period may thus be beneficial to male competitiveness and increase the attractiveness of adult sexing techniques, such as blood spiking.
Ageep Tellal B, Damiens David, Alsharif Bashir, Ahmed Ayman, Salih Elwaleed HO, Ahmed Fayez TA, Diabaté Abdoulaye, Lees Rosemary S, Gilles Jeremie RL and El Sayed Badria B
Malaria, Sterile insect technique, SIT, Mark release recapture, Dispersion, Survival,
Malaria Journal 2014, 13:460 doi:10.1186/1475-2875-13-460
Free full text
Abstract Background Understanding the factors that account for male mating competitiveness is critical to the development of the sterile insect technique (SIT). Here, the effects of partial sterilization with 90 Gy of radiation on sexual competitiveness of Anopheles coluzzii allowed to mate in different ratios of sterile to untreated males have been assessed. Moreover, competitiveness was compared between males allowed one versus two days of contact with females. Methods Sterile and untreated males four to six days of age were released in large cages (~1.75 sq m) with females of similar age at the following ratios of sterile males: untreated males: untreated virgin females: 100:100:100, 300:100:100, 500:100:100 (three replicates of each) and left for two days. Competitiveness was determined by assessing the egg hatch rate and the insemination rate, determined by dissecting recaptured females. An additional experiment was conducted with a ratio of 500:100:100 and a mating period of either one or two days. Two controls of 0:100:100 (untreated control) and 100:0:100 (sterile control) were used in each experiment. Results When males and females consort for two days with different ratios, a significant difference in insemination rate was observed between ratio treatments. The competitiveness index (C) of sterile males compared to controls was 0.53. The number of days of exposure to mates significantly increased the insemination rate, as did the increased number of males present in the untreated: sterile male ratio treatments, but the number of days of exposure did not have any effect on the hatch rate. Discussion The comparability of the hatch rates between experiments suggest that An. coluzzii mating competitiveness experiments in large cages could be run for one instead of two days, shortening the required length of the experiment. Sterilized males were half as competitive as untreated males, but an effective release ratio of at least five sterile for one untreated male has the potential to impact the fertility of a wild female population. However, further trials in field conditions with wild males and females should be undertaken to estimate the ratio of sterile males to wild males required to produce an effect on wild populations.
Maïga H, Damiens D, Niang A, Sawadogo SP, Fatherhaman O, Lees RS, Roux O, Dabiré RK, Ouédraogo GA, Tripet F, Diabaté A, Gilles JR.
Male mating biology, Anopheles coluzzii, Sterile insect technique, Competitiveness
Journal of Applied Entomology, 138: 708–714. doi: 10.1111/jen.12112
The New World screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), has been eradicated from North and Central America using the sterile insect technique. This success has been based on mass production of high-quality screwworms using artificial diets since 1958. Many diet formulations for both larvae and adults have been developed, mainly driven by cost efficiency and material supply. However, only four larval and two adult diet formulations have been applied in the six sterile fly mass production plants in the USA, Mexico and Panama. Herein, we briefly review the history of screwworm diet research and development, introduce the diet formulations used in mass rearing and discuss their advantages and disadvantages in terms of plant application. Finally, we propose future research on screwworm nutrition, potential protein sources, feeding stimulants, further optimization of screwworm formulations and possible methods to reduce the negative qualities of waste generated during the mass production.
Chen, H., Chaudhury, M. F., Sagel, A., Phillips, P. L. and Skoda, S. R.
sterile insect technique;
waste diet management
Entomological Science. doi: 10.1111/ens.12120
Two- to three-day-old male Drosophila melanogaster flies were irradiated with 1, 2, 4, 6, 8, 10, 20, 25, 30, 40 and 50 Gy doses of gamma radiation. The longevity and rate of development were observed for three successive generations to assess the impact of irradiation. The mean lifespan of irradiated flies was significantly increased at 1, 2 and 8 Gy, while it was vice versa for high doses at 30, 40 and 50 Gy. Paternal irradiation had an impact on F1 generation, with significantly increased mean longevity at 2 (female), 4, 6, 8 and 10 and decreased mean longevity at 40 and 50 Gy (male and female). Significant increase in the longevity was observed in the F2 generation of the 8 (male and female) and 10 Gy (male) irradiated groups, while decreased longevity was observed in F2 female progeny at 40 Gy. In the case of F3 progeny of irradiated flies, longevity did not show significant difference with the control. Paternal exposure to radiation had a significant impact on the mean egg to adult developmental time of the F1 generation; it was shortened at 2 Gy and extended at 25, 30, 40 and 50 Gy compared to the control. Mean development time at 30, 40 and 50 Gy was significantly increased in the F2 generation, while there were no significant changes in the F3 generation. The present study concludes that the effect of acute gamma irradiation on longevity and “egg to adult” development time of D. melanogaster may persist to following generations
Shameer, P. M., Sowmithra, K., Harini, B. P., Chaubey, R. C., Jha, S. K. and Shetty, N. J.
Entomologia Experimentalis et Applicata, 153: 55–63. doi: 10.1111/eea.12228
Mating ability, survival, and fitness of mass-produced sterile insects when released into the wild, are critical to the success of the sterile insect technique (SIT) as a pest management strategy, but their field performance remains one of the greatest challenges. Thermal stress tolerance by irradiated insects is a determinant of sterile insect quality, hence knowledge of their physiological competitiveness is essential for developing the SIT. Here, we report the results of experiments investigating effects of laboratory rearing and increasing radiation dosage on thermal limits to activity of the adult stage of Eldana saccharina Walker (Lepidoptera: Pyralidae). The critical thermal maximum (CTmax) and critical thermal minimum (CTmin) were assayed using a dynamic method on both sexes of E. saccharina moths in laboratory vs. wild populations (to determine effect of rearing history). Furthermore, the laboratory population was exposed to 150, 200, and 250 Gy, to determine the effect of radiation dose. Laboratory-reared E. saccharina were more heat tolerant compared to wild moths for both sexes (CTmax = 44.5 vs. 44.3 °C), whereas in the case of CTmin (3.7 vs. 4.4 °C), wild moths were more cold tolerant than their laboratory-reared counterparts. Irradiation had a negative effect on both CTmax and CTmin. Moths treated at the lowest radiation dose were more cold and heat tolerant than those treated at the highest dosages (CTmin = 4.5 vs. 6.2 °C; CTmax = 43.9 vs. 43.5 °C), thereby reinforcing the importance of lower dosages rather than those that induce full sterility against E. saccharina. In general, sex had no influence on critical thermal limits in all moth treatments except for those irradiated at 150 Gy. The data presented in this article provide evidence that increasing radiation dose impacts on fitness of laboratory-produced moths relative to their wild counterparts, which in turn could affect the effectiveness of the SIT programme.
Mudavanhu, P., Addison, P. and Conlong, D. E.
critical thermal limits;
sterile insect technique;
Radiation Measurements 67: 48-54
h i g h l i g h t s
Behaviour of Gafchromic HD-810 film is investigated for low energy X radiation. Its response significantly depends on the surrounding material during irradiation. Response is found to be proportional to kerma for the surrounding material. Response of Gafchromic MD-V2-55 is independent of surrounding material.
Recent developments have produced low energy X ray systems capable of providing a radiation dose to adequate volumes suitable for sterile inset programmes. To support the adoption of these new systems, the performance of the Gafchromic® HD-810 dosimetry system previously used for gamma irradiation needed to be better understood at the lower photon energies. For low energy photons, the optical density of the irradiated Gafchromic HD-810 film dosimeters significantly depends on the material surrounding them. For example, if paper, Mylar® or PVC is used to house the dosimeter during irradiation, the optical density can vary by as much as a factor of three or more for the same dose. This paper is an attempt to elucidate the performance of the Gafchromic HD-810 film dosimeters for such low energy X radiation (~150 keV). Our data show that this behaviour can be explained by the fact that these materials have significantly different photon mass attenuation coefficient. This conclusion was reinforced with mathematical simulation using Monte Carlo modelling. We also show that with the different structure of another Gafchromic film dosimeter (MD-V2-55) this effect is virtually non-existent. An understanding of the behaviour of thin film dosimeters like Gafchromic HD-810 under radiation is crucial for reliable dosimetry.
Mehta Kishor, Parker Andrew, Tessier Frederic
Journal of Economic Entomology 107(3):1172-1178
The sterile insect technique has been routinely used to eradicate fruit fly Bactrocera tryoni (Froggatt) incursions. This study considers whether fly quality in a mass-rearing facility can be improved by reducing irradiation doses, without sacrificing reproductive sterility. Pupae were exposed to one of five target irradiation dose ranges: 0, 40-45, 50-55, 60-65, and 70-75 Gy. Pupae were then assessed using routine quality control measures: flight ability, sex ratio, longevity under nutritional stress, emergence, and reproductive sterility. Irradiation did not have a significant effect on flight ability or sex ratio tests. Longevity under nutritional stress was significantly increased at 70-75 Gy, but no other doses differed from 0 Gy. Emergence was slightly reduced in the 50-55, 60-65, and 70-75 Gy treatments, but 40-45 Gy treatments did not differ from 0 Gy, though confounding temporal factors complicate interpretation. Reproductive sterility remained acceptable (> 99.5%) for all doses--40-45 Gy (99.78%), 50-55 Gy (100%), 60-65 Gy (100%), and 70-75 Gy (99.99%). We recommend that B. tryoni used in sterile insect technique releases be irradiated at a target dose of 50-55 Gy, providing improved quality and undiminished sterility in comparison with the current 70-75 Gy standard while also providing a substantial buffer against risk of under dosing.
Dominiak BC, Sundaralingam S, Jiang L, Fanson BG, Collins SR, Banos C, Davies JB, Taylor PW
Bactrocera,, insect quality parameter, mass production, sterile insect technique, Tephritidae
Journal of Applied Entomology, 138: 355–360. doi: 10.1111/jen.12076
Irradiation is a post-harvest quarantine treatment option to control ants and other hitchhiker pests on fresh horticultural products traded between countries. As little is known about irradiation effects on ants, radiotolerance of the Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae: Dolichoderinae), was studied to determine a dose sufficient for its control. Queens collected from Buenos Aires, Argentina, were irradiated with 30, 60, 90 Gy or left untreated as controls, and then followed for 8 weeks to evaluate their survival and fecundity. Overall queen survival and brood viability decreased with increasing irradiation dose. The number of eggs was reduced by 50%, 69% and 56% in the 30, 60 and 90 Gy doses, respectively, compared with untreated control queens. The percentage of eggs that developed into larvae decreased from 41.1% in the control to 22.5%, 1.4%, and 0% in the 30, 60, and 90 Gy treatments, respectively. Thus, the number of larvae was reduced by 69% in the 30 Gy treatment compared with the control, only one larva was observed in the 60 Gy treatment, and none in the 90 Gy treatment. Only one pupa was observed in the 30 Gy treatment and none in the 60 and 90 Gy treatments during the 8-week experiment. Queens irradiated with 60 and 90 Gy had significantly reduced longevity compared with queens treated with lower doses or untreated queens. Radiation dose ≥90 Gy stopped brood development in Argentine ant queens and should be sufficient as a phytosanitary treatment. The radiotolerance of Argentine ant appears to be similar to that of two other important invasive ants.
Coulin, C., Calcaterra, L. A. and Follett, P. A.
Linepithema humile ;
Irradiation is a postharvest quarantine treatment option for exported commodities such as stone fruits and small fruits to prevent movement of the new invasive pest spotted wing drosophila, Drosophila suzukii (Walker) (Diptera: Drosophilidae). The effects of irradiation on larval and pupal development and adult reproduction in D. suzukii were examined. Larvae (Þrst, second, and third
instars) and pupae (1-2-d-old, 3-5-d-old, and 7-8-d-old) on diet were irradiated at target doses of 20, 30, 40, and 50 Gy in replicated factorial experiments and survival to the adult stage was recorded. Tolerance to radiation increased with increasing age and developmental stage. Males and females were equally susceptible.Aradiation dose of 40 Gy applied to Þrst- and second-instar larvae prevented adult emergence. The late-stage pupa was the most radiation-tolerant stage that occurs in fruit, and individuals irradiated at this stage readily emerged as adults; therefore, prevention of F1 adults was the desired treatment response for large-scale validation tests with naturally infested fruit. In largescale tests, a radiation dose of 80 Gy applied to late-stage pupae in sweet cherries or grapes resulted
in no production of F1 adults in 33,000 treated individuals, which meets the zero tolerance requirement
for market access. A minimum absorbed dose of 80 Gy is recommended for quarantine control of D. suzukii.
FOLLETT PETER A., SWEDMAN ALLISON, AND PRICE DONALD K.
X-ray radiation, radio-tolerance, invasive species, regulatory pest, phytosanitary treatment
• Behaviour of Gafchromic HD-810 film is investigated for low energy X radiation.
• Its response significantly depends on the surrounding material during irradiation.
• Response is found to be proportional to kerma for the surrounding material.
• Response of Gafchromic MD-V2-55 is independent of surrounding material.
Recent developments have produced low energy X ray systems capable of providing a radiation dose to adequate volumes suitable for sterile inset programmes. To support the adoption of these new systems, the performance of the Gafchromic® HD-810 dosimetry system previously used for gamma irradiation needed to be better understood at the lower photon energies. For low energy photons, the optical density of the irradiated Gafchromic HD-810 film dosimeters significantly depends on the material surrounding them. For example, if paper, Mylar® or PVC is used to house the dosimeter during irradiation, the optical density can vary by as much as a factor of three or more for the same dose. This paper is an attempt to elucidate the performance of the Gafchromic HD-810 film dosimeters for such low energy X radiation (∼150 keV). Our data show that this behaviour can be explained by the fact that these materials have significantly different photon mass attenuation coefficient. This conclusion was reinforced with mathematical simulation using Monte Carlo modelling. We also show that with the different structure of another Gafchromic film dosimeter (MD-V2-55) this effect is virtually non-existent. An understanding of the behaviour of thin film dosimeters like Gafchromic HD-810 under radiation is crucial for reliable dosimetry. We hope that this work can also provide guidance in the use of other thin film dosimeters at similar low photon energies.
Mehta Kishor, Parker Andrew, Tessier Frédéric
The mosquito Aedes albopictus (Skuse, 1895) is a potent vector of several arboviral diseases, most notably chikungunya and dengue fever. In the context of the sterile insect technique (SIT), the sterilization of the male mosquitoes before their release can be achieved by gamma-ray irradiation. As gamma-ray irradiators are becoming increasingly problematic to purchase and transport, the suitability of an X-ray irradiator as an alternative for the sterilization of Ae. albopictus males was studied. The sterilization of up to 200,000 pupae at one time can be achieved with relative ease, and the sterility results obtained were comparable with those achieved by gamma irradiation, where 99% sterility is induced with a dose of 40 Gy. A significant reduction of longevity was observed in the latter stages of the males' life after irradiation treatments, especially at doses >40 Gy, which is consistent with the negative effects on longevity induced by similar radiation doses using gamma rays. Females irradiated at 40 Gy were not only 100% sterile, but also failed to oviposit entirely, i.e., all of the females laid 0 eggs. Overall, it was found that the X-ray irradiator is generally suitable for the sterilization process for sterile insect technique programs, as it showed a high processing capacity, practicality, high effectiveness, and reproducibility.
Yamada, H.; Parker, A. G.; Oliva, C. F.; Balestrino, F.; Gilles, J.R.L
Aedes albopictus; induced sterility; longevity; sterile insect technique; x-ray irradiation
Bulletin of Entomological Research 104, 251–261 doi:10.1017/S0007485313000758
The sterile insect technique (SIT) is a non-chemical approach used to control major pests from several insect families, including Tephritidae, and entails the mass-release of sterile insects that reduce fertility of wild populations. For SIT to succeed, released sterile males must mature and compete with wild males to mate with wild females. To reach sexual maturity, the Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), must obtain adequate nutrition after adult emergence; however, in current SIT programs sterile B. tryoni receive a pre-release diet that lacks key nutrients required to sustain sexual development. The chief objective of this study was to determine whether pre-release yeast hydrolysate (YH) supplements affect the persistence and abundance of sexually mature sterile male B. tryoni under field conditions. Experiments were run in outdoor cages under conditions of low and high environmental stress that differed markedly in temperature and humidity, and in the field. Under low environmental stress conditions, survival of sterile B. tryoni was monitored in cages under three diet treatments: (i) sugar only, (ii) sugar plus YH or (iii) sugar plus YH for 48h and sugar only thereafter. Under high environmental stress conditions survival of sterile B. tryoni was monitored in cages under four diet treatments: (i) white sugar only, (ii) brown sugar only, (iii) white sugar plus YH and (iv) brown sugar plus YH. In a replicated field study, we released colour-marked
sterile B. tryoni from two diet regimes, YH-supplemented or YH-deprived, and monitored abundance of sexually mature males. In the low-stress cage study, there
was no effect of diet, although overall females lived longer than males. In the high stress cage study, mortality was lower for YH-fed flies than YH-deprived flies and females lived longer than males. In the field, YH supplementation resulted in higher abundance of sexually mature sterile males, with 1.2 YH-fed flies trapped for every YH-deprived fly trapped. Under field conditions, YH supplementation can increase over-flooding ratios and hence may improve the effectiveness of SIT programmes.
Reynolds O.L., Orchard B.A., Collins S.R.
and Taylor P.W.
Diptera, Tephritidae, protein, diet, nutrition, sterile insect technique
Bulletin of Entomological Research 104, 176–181 doi:10.1017/S0007485313000643
Fruit flies (Diptera: Tephritidae) are major pests worldwide. The sterile insect technique, where millions of flies are reared, sterilized by irradiation and then released, is one of the most successful and ecologically friendly methods of controlling populations of these pests. The mating behaviour of irradiated and nonirradiated flies has been compared in earlier studies, but there has been little attention paid to the anti-predator behaviour of mass-reared flies, especially with respect to wild flies. Tephritid flies perform a supination display to their jumping spider predators in order to deter attacks. In this study,we evaluated the possibility of using this display to determine the anti-predator capabilities of mass-reared irradiated,
non-irradiated flies, and wild flies. We used an arena setup and observed bouts between jumping spiders (Phidippus audax Hentz) and male Mexican fruit flies
(Anastrepha ludens Loew). We show that although all flies performed a supination display to their predator, wild flies were more likely to perform a display and were
significantly more successful in avoiding attack than mass-reared flies. We suggest that this interaction can be used to develop a rapid realistic method of quality control in evaluating anti-predator abilities of mass-reared fruit flies.
Rao D., Aguilar-Argüello S., Montoya P. and Díaz-Fleischer F.
salticidae, supination, predator–prey interaction, sterile insect technique
PLoS ONE 9(1): e88128. doi:10.1371/journal.pone.0088128
Early life events can have dramatic consequences on performance later in life. Exposure to stressors at a young age affects development, the rate of aging, risk of disease, and overall lifespan. In spite of this, mild stress exposure early in life can have beneficial effects on performance later in life. These positive effects of mild stress are referred to as physiological conditioning hormesis. In our current study we used anoxia conditioning hormesis as a pretreatment to reduce oxidative stress and improve organismal performance, lifespan, and healthspan of Caribbean fruit flies. We used gamma irradiation to induce mild oxidative damage in a low-dose experiment, and massive oxidative damage in a separate high-dose experiment, in pharate adult fruit flies just prior to adult emergence. Irradiation-induced oxidative stress leads to reduced adult emergence, flight ability, mating performance, and lifespan. We used a hormetic approach, one hour of exposure to anoxia plus irradiation in anoxia, to lower post-irradiation oxidative damage. We have previously shown that this anoxic-conditioning treatment elevates total antioxidant capacity and lowers post-irradiation oxidative damage to lipids and proteins. In this study, conditioned flies had lower mortality rates and longer lifespan compared to those irradiated without hormetic conditioning. As a metric of healthspan, we tracked mating both at a young age (10 d) and old age (30 d). We found that anoxia-conditioned male flies were more competitive at young ages when compared to unconditioned irradiation stressed male flies, and that the positive effects of anoxic conditioning hormesis on mating success were even more pronounced in older males. Our data shows that physiological conditioning hormesis at a young age, not only improves immediate metrics of organismal performance (emergence, flight, mating), but the beneficial effects also carry into old age by reducing late life oxidative damage and improving lifespan and healthspan.
Full paper: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0088128
López-Martínez G, Hahn DA
As part of sterile insect technique (SIT) programs, irradiation can effectively induce sterility in insects by damaging genomic DNA. However, irradiation also induces other off-target side effects that reduce the quality and performance of sterilized males. Thus, treatments that reduce off-target effects of irradiation on male performance while maintaining sterility can improve the feasibility and economy of SIT programs. Exposure to ionizing radiation induces the formation of damaging free radicals in biological systems that may reduce sterile male performance. Here, we test whether exposure to an anoxic environment for 1 h before and during irradiation improves male performance, while maintaining sterility in males of the cactus moth, Cactoblastis cactorum (Berg). We show that exposure to 1 h of anoxia increases the moths antioxidant capacity and that irradiation in anoxia after1hof anoxic conditioning decreases irradiation-induced oxidative damage to the moths lipids and proteins. Anoxia treatment that reduced oxidative damage after irradiation also produced moths with greater flight performance, mating success, and longevity, while maintaining F1 male sterility at acceptable levels for SIT. We conclude that anoxia pretreatment followed by irradiation in anoxia is an efficient way to improve the quality of irradiated moths and perhaps lower the number of moths needed for release SIT moth operations.
LOPEZ-MARTINEZ GIANCARLO, CARPENTER JAMES E., HIGHT STEPHEN D., AND HAHN DANIEL A.
gamma radiation, oxidative damage, antioxidant, hormesis, anoxia
Journal of Stored Products Research 52: 63-67.
Irradiation is a quarantine treatment option for stored products pests. Dose response tests were conducted to identify a post-harvest radiation treatment that would control rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) in rice. Rice infested with adult or immature weevils was treated at radiation doses of 30, 60, 90, or 120 Gy, or left untreated as a control. Live and dead beetles were counted weekly for 15 24 weeks. Treatment of adult weevils at a radiation dose of 120 Gy resulted in no live adults after two weeks, indicating that this radiation dose caused adult mortality and sterility, whereas a total of 1261 adult beetles emerged during 24 weeks in the untreated controls. Treatment of immature life stages (a mixture of eggs, larvae and pupae) with a radiation dose of 90 or 120 Gy resulted in no adults emerging after five or two weeks, respectively, indicating that these doses prevented reproduction, whereas a total of 4275 adults emerged throughout 15 weeks in the untreated controls. Weight loss of rice infested with immature or adult weevils was significantly reduced by irradiation treatment at 60 Gy and 120 Gy. In a large-scale confirmatory test, a radiation dose of 120 Gy applied to 38,025 adult weevils in rice resulted in no reproduction. Irradiation at 120 Gy will provide quarantine security for rice weevil, and prevent post-irradiation weight loss caused by insect feeding in the commodity. Irradiation may be particularly helpful in controlling phosphine-resistant populations, and could help manage resistance by preventing the spread of resistant weevils in exported grains. Irradiation is a control option for stored product insects. Rice weevil is the most serious pest of stored rice worldwide. Adult and immature weevils were treated at 0, 30, 60, 90 or 120 Gy in rice. Radiation treatment at 120 Gy sterilized rice weevil and prevented further damage. Irradiation can prevent the spread of phosphine-resistant weevils in exported grain.
Follett PA, Snook K, Janson A, Antonio B, Haruki A, Okamura M, Bisel J.
Journal of Entomology and Nematology Vol. 5(4), pp. 45-49
The effect of gamma irradiation on the specific activity of ATP-ase, AChE and amino acid contents in different larval ages of Corcyra cephalonice (Staint) were studied. In general, the effect of irradiation on enzymes activity was highly noticed with AChE enzyme than ATP-ase enzyme. The higher the dose of gamma irradiation, the higher the rate of enzyme inhibition and vice versa. Also, the influence of gamma radiation on free and protein hydrolysate amino acid contents was more pronounced by
increasing the irradiation dose and time after treatment. Increasing the dose was accompanied by reducing the free and protein amino acid contents. The results revealed that reduction in percent pupation, adult emergence, fecundity and fertility of the resulting adults depended upon the dose and larval age at the time of treatment. The severe reduction in fecundity and fertility was observed in 25 days old larvae treated with 80 Gy.
Al khalaf Areej Abdelkareem and Abdel Baki Salwa M.
Gamma irradiation, larvae, Corcyra cephalonice.
Appl Radiat Isot;73:101-8
This study investigated the effects of two substerilizing doses of gamma radiation, 100 and 150 Gray (Gy), and/or the plant extract Conyza dioscorides (Barnoof) in two solvents on certain biological aspects and the energy budget of the Black cutworm, Agrotis ipsilon (Hufnagel). Data revealed that the treatment combination of gamma radiation with the plant extract significantly increased reproduction compared with the control at all treatment levels (doses and concentrations). Most of the treatments increased the values of developmental/day and larval duration in the F(1) progeny compared with the progeny from the control treatment, although the percentage survival was decreased in all treatments. These values were more obvious in the combination treatments compared with either gamma radiation or plant extract treatments alone. The coefficient of metabolizable energy (C.M.E.) was not affected by any treatments. No consistent effect on the efficiency of storage of ingested energy [E.S.I.(E.)] and the efficiency of storage of metabolizable energy [E.S.M.(E.)] when the F(1) progeny were treated with plant extract alone or with the plant extract combined with the 100 Gy dose of radiation was noted, while they were both significantly increased at all treatment levels when the 150 Gy dose of radiation was combined with the plant extract. The results obtained are discussed in terms of their implications for the best substerilizing dose of radiation on parental male pupae of A. ipsilon.
Modified atmosphere packaging (MAP) produces a low-oxygen (O2) environment that can increase produce shelf life by decreasing product respiration and growth of pathogens. However, low O2 is known to increase insect tolerance to irradiation, and the use of MAP with products treated by irradiation before export to control quarantine pests may inadvertently compromise treatment efficacy. Melon fly, Bactrocera cucurbitae Coquillet (Diptera: Tephritidae), is an important economic and quarantine pest of tropical fruits and vegetables, and one of the most radiation-tolerant tephritid fruit flies known. The effect of low O2 generated by MAP on the radiation tolerance of B. cucurbitae was examined. Third-instar larval B. cucurbitae were inoculated into ripe papayas and treated by 1) MAP + irradiation, 2) irradiation alone, 3) MAP alone, or (4) no MAP and no irradiation, and held for adult emergence. Three types of commercially available MAP products were tested that produced O2 concentrations between 1 and 15%, and a sublethal radiation dose (50 Gy) was used to allow comparisons between treatments. Ziploc storage bags (1-4% O2) increased survivorship to adult from 14 to 25%, whereas Xtend PP61 bags (3-8% O2) and Xtend PP53 bags (11-15% O2) did not enhance survivorship to the adult stage in B. cucurbitae irradiated at 50 Gy. Radiation doses approved by the United States Department of Agriculture and the International Plant Protection Commission for B. cucurbitae and Ceratitis capitata (Wiedemann) (Mediterranean fruit fly) are 150 and 100 Gy, respectively. In large-scale tests, 9,000 B. cucurbitae and 3,800 C. capitata larvae infesting papayas in Ziploc bags were irradiated at 150 and 100 Gy, respectively, with no survivors to the adult stage. MAP can increase insect survivorship during irradiation treatment at certain doses and O2 concentrations, but should not compromise the efficacy of the 150-Gy generic radiation treatment for tephritid fruit flies or the 100-Gy radiation treatment for C. capitata.
Follett PA, Wall M, Bailey W
irradiation, Melon fly, Ceratitis capitata, quarantine, generic dose, modified atmosphere
Cold storage is used to preserve fruit quality after harvest during transportation in marketing channels. Low temperature can be a stressor for insects that reduces survivorship, and cold storage may contribute to the efficacy of postharvest quarantine treatments such as irradiation against quarantine insect pests. The combined effect of irradiation and cold storage was examined in a radiation-tolerant fruit fly, Bactrocera cucurbitae Coquillet (melon fly), and a radiation-intolerant fruit fly,Ceratitis capitat (Wiedemann) (Mediterranean fruit fly) (Diptera: Tephritidae). Third instars on diet or in papaya were treated with a sublethal radiation dose of 30 Gy and stored at 4 or 11_C for 3-13 d and held for adult emergence. For both fruit fly species, survival of third instars to the adult stage generally decreased with increasing cold storage duration at 4 or 11_C in diet or papaya. Survivorship differences were highly significant for the effects of substrate (diet > papaya), temperature (11 > 4 degrees C), and irradiation (0>30 Gy). Few Mediterranean fruit flies survived in any cold storage treatment after receiving a radiation dose of 30 Gy no melon fly larvae survived to the adult stage after irradiation and 11 d cold storage at 4 or 11 degree C in papayas. Cold storage enhances the efficacy and widens the margin of security in postharvest irradiation treatments. Potentially irradiation and cold storage can be used in combination to reduce the irradiation exposure requirements of quarantine treatments.
FOLLETT PETER A. and SNOOK KIRSTEN
irradiation, quarantine, postharvest, phytosanitary treatment, systems approach
Pakistan Journal of Biological Sciences, 16: 1730-1736.
The sterile insect technique is one of the most methods of fruit flies control. Flight ability of the Peach Fruit Fly (PFF), Bactrocera zonata was conducted under laboratory conditions to evaluate the effect of gamma radiation on flight ability of PFF, B. zonata. Pupae of PFF, B. zonata, were irradiated in an air atmosphere at 24, 48 and 72 h before adult emergence with three doses of Cobalt60 (10, 30 and 50 Gray) and tested against 6, 12 and 20 cm tube heights. Flight Ability Percentage (FAP) of PFF was carried out for newly emerged flies and six-days-old of adult flies. FAP of newly emerged-and six- days-old of adult flies was inversely proportional to the tube heights, doses of gamma rays and with progress the age of flies. The FAP value was significantly higher at 6 cm tube height, followed by 12 cm then 20 cm tube heights for all tested levels of gamma rays, respectively.
El-Gendy I.R., El-Aw M.A.M., Hashem A.G. and Draz K.A.,
Sterile insect technique
Entomologia Experimentalis et Applicata, 148: 203–212. doi: 10.1111/eea.12096
The sterile insect technique (SIT) potentially provides a socially acceptable approach for insect eradication of new pest incursions. The light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), was discovered in Berkeley (CA, USA) in 2006, leading to an incursion response that included this technology. In this study, we assessed factors affecting mating success from a bisex release of irradiated moths: effects of radiation dose on male multiple mating, male flight competition, female sex pheromone titre and attractiveness of irradiated females to males, and identification of successful mating in vineyards of either irradiated or wild males (identified by isotope analysis of spermatophores from sentinel females). There was a significant negative relationship between male radiation dose and mating frequency. In head-to-head flights of irradiated males against non-irradiated males to a pheromone lure in a wind tunnel, irradiated males reached the lure first only 31% of the time. With increasing radiation dose, the production of the major sex pheromone component in females, (E)-11-tetradecenyl acetate, dropped, from 0.7 ± 0.1 ng per female in non-irradiated females to 0.2 ± 0.07 ng per female when irradiated at 300 Gy. Male catch was reduced to 11% of control females in traps containing females irradiated at 300 Gy. Isotope analysis of spermatophores found in the bursa copulatrix of females indicated that mating success of irradiated males inside the live (entry-only) traps containing virgin females was lower (13.1 ± 3.3%) than suggested by male catch (21.2 ± 3.8%) in pheromone traps, the current standard for assessing field competitiveness. Impacts of irradiation on male and female moth fitness should be taken into account to improve estimates of irradiated to wild male E. postvittana overflooding ratios needed for population suppression.
Stringer, L. D., Sullivan, N. J., Sullivan, T. E.S., Mitchell, V. J., Manning, L.-A. M., Mas, F., Hood-Nowotny, R. C. and Suckling, D. M.
sterile insect technique;
Epiphyas postvittana ;
Mutagenesis 28 (5): 531-541. doi: 10.1093/mutage/get030 First published online: June 22, 2013
The response of eukaryotic cells to ionising radiation (IR)-induced double-strand DNA breaks is highly conserved and involves a DNA repair mechanism characterised by the early phosphorylation of histone protein H2AX (producing the active form γH2AX). Although the expression of an induced γH2AX variant has been detected in Drosophila melanogaster, the expression and radiation response of a γH2AX homologue has not been reported in economically important fruit flies. We use Bactrocera tryoni (Diptera: Tephritidae, Queensland fruit fly or ‘Q-fly’) to investigate this response with a view to developing molecular assays to detect/quantify exposure of fruit flies to IR and consequent DNA damage. Deep sequencing confirmed the presence of a H2AX homologue that we have termed H2AvB (i.e. variant Bactrocera) and has an identical sequence to a histone reported from the human disease vector Glossina morsitans. A linear dose–response of γH2AvB (0–400 Gy IR) was observed in whole Q-fly pupal lysates 24h post-IR and was detected at doses as low as 20 Gy. γH2AvB signal peaked at ~20min after IR exposure and at 24h post-IR the signal remained elevated but declined significantly by 5 days. Persistent and dose-dependent γH2AvB signal could be detected and quantified either by western blot or by laser scanning cytometry up to 17 days post-IR exposure in histone extracts or isolated nuclei from adult Q-flies (irradiated as pupae). We conclude that IR exposure in Q-fly leads to persistent γH2AvB signals (over a period of days) that can easily be detected by western blot or quantitative immunofluorescence techniques. These approaches have potential as the basis for assays for detection and quantification of prior IR exposure in pest fruit flies.
Mohammad S. Siddiqui, Erika Filomeni, Maxime François, Samuel R. Collins, Tamara Cooper, Richard V. Glatz, Phillip W. Taylor, Michael Fenech1 and Wayne R. Leifert
Diptera, Tephritidae, Bactrocera, deep sequencing, dna, gene sequencing, sequencing
Ph.D. thesis, Imperial College London. Centre for Environmental Policy, Department of Life Sciences,
Silwood Park Campus.
Walker Catherine Sophie
BIOCONTROL SCIENCE AND TECHNOLOGY , VOL 22; NUMB 12, pages 1429-1441
We evaluated the effects of X-ray irradiation on larvae of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), with the aim of finding a treatment that prevented adult fly emergence, yet did not adversely affect larval quality as rearing hosts for the parasitoid Diachasmimorpha longicaudata (Ashmead) (Hymenoptera: Ichneumonidae). Two experiments were carried out. In the first experiment, small numbers of larvae were held in Petri dishes with and without small amounts of rearing media and then irradiated with doses of X-rays ranging from 0 to 8333.6 R (equivalent to 80 Gy). In the second experiment, higher numbers of larvae were held in a manner resembling mass-rearing conditions, and were then irradiated with X-rays ranging from 0 to 10,417 R (equivalent to 100 Gy). In both experiments, the only factor that significantly affected fly emergence was irradiation of larvae. Fly emergence decreased markedly as the irradiation dose increased, and complete suppression of fly emergence was achieved at 6250.2 R (equivalent to 60 Gy) when larvae were irradiated in small batches with or without rearing media. Irradiation also affected the fertility of those flies that did emerge following treatment. In the second experiment, we found the parasitoids reared from irradiated larvae produced a higher parasitism rate and a higher number of female offspring than did parasitoids reared from control (non-irradiated) larvae. Mean fecundity of F1 parasitoids reared from irradiated larvae were affected positively by irradiation only at the 8333.6 R (80 Gy) dose. Our results show that X-ray irradiation can be used to inhibit fruit fly adult emergence and that irradiated larvae are at least as good a rearing substrate as non-irradiated larvae. Future studies should focus on the adjustment of our findings to a mass-rearing scale.
Viscarret, M.M. Conte, C.A. Paladino, L.Z.C. Lopez, S.N. Segura, D.F. Muntaabski, I. Lanzavecchia, S.B. Cladera, J.L.
Diachasmimorpha longicaudata ,
Ceratitis capitata ,