International Journal of Research in Agricultural Sciences (IJRAS) Volume 2, Issue 1, pp. 29-33
The objective of this research was to evaluate the effect of gamma irradiation on fruit fly (Ceratitiscapitata) eggs and larvae (1st, 2nd and 3rd instars) in ‘Valencia’ oranges, and evaluate the effect of the irradiation on the chemical composition of the fruits. The fruits were artificially infested with the immature stages of the fruit fly and treated with 0, 10, 20, 30, 40, 50, 100, 150 and 200 Gy Cobalt-60 doses. The treatment with gamma irradiation can be recommended for quarantine treatment of all immature stages of C. capitata in ‘Valencia’ oranges if applied at the doses of 72.88 Gy. Larvae of 3rd instar are more radio resistent when compared to eggs and larval of 1st and 2nd instar. The doses of gamma radiation used do not affect the chemical proprieties of ‘Valencia’ orange fruits.
IDIDAS COMMENT: infestation was artificial, so results may not reflect the natural situation for which a treatment must be efficacious. Also, no data on effect of the treatment (dose not stated) on fruit were given other than the comment that quality was similar to non-irradiated ‘Valencia’ orange.
Bortoli, Sergio A. De; de Albergaria, Nuno M. M. S.; Dória, Háyda O. S.; Vacari, Alessandra M.; Duarte, Rogério T.; Arthur, Valter
Ionizing Radiation, Quarantine Treatment, Disinfestation, Ceratitis Capitata, Citrus Sinensis
Pest Manag Sci. article published online: 10 September 2014
(wileyonlinelibrary.com) DOI 10.1002/ps.3905
BACKGROUND: The number of insect eradication programmes is rising in response to globalisation. A database of arthropod and plant pathogen eradications covers 1050 incursion responses, with 928 eradication programmes on 299 pest and disease taxa in 104 countries (global eradication database b3.net.nz/gerda). METHODS: A subset of the database was assembled with 211 eradication or response programmes against 17 species of fruit flies (Tephritidae) in 31 countries, in order to investigate factors affecting the outcome. RESULTS: The failure rate for fruit fly eradication programmeswas about 7%, with 0% for Ceratitis capitata (n=85 programmes) and 0% for two Anastrepha species (n = 12 programmes), but 12% for 13 Bactrocera species (n = 108 programmes). A number of intended eradication programmesagainst long-established populationswere not initiated because of cost and other considerations, or evolved during the planning phase into suppression programmes. Cost was dependent on area, ranged from $US 0.1 million to $US 240 million and averaged about $US 12 million (normalised to $US in 2012). In addition to the routine use of surveillance networks, quarantine and fruit destruction, the key tactics used in eradication programmes were male annihilation, protein bait sprays (which can attract both sexes), fruit destruction and the sterile insect technique. CONCLUSIONS: Eradication success generally required the combination of several tactics applied on an area-wide basis. Because the likelihood of eradication declines with an increase in the area infested, it pays to invest in effective surveillance networks that allowearly detection and delimitationwhile invading populations are small, thereby greatly favouring eradication success. © 2014 Society of Chemical Industry
Suckling David Maxwell, Kean John M, Stringer Lloyd D,
Cáceres-Barrios Carlos, Hendrichs Jorge, Reyes-Flores Jesus
and Dominiak Bernard C.
Tephritidae; male annihilation; sterile insect technique; bait; trap; surveillance; incursions; quarantine
Biocontrol Science and
Technology, 25:9, 1092-1103, DOI: 10.1080/09583157.2015.1030723
Diachasmimorpha longicaudata is a koinobiont larval parasitoid that is currently used to control fruit flies of the genera Anastrepha, Ceratitis and Bactrocera. In the rearing process, a fraction of the host larvae that are exposed to parasitoids
escape from parasitism and develop into viable and fertile flies. This creates the need to eliminate emerging flies before the parasitoids are shipped for release,
increasing costs due to additional handling steps. Exposure of fly eggs or larvae to
gamma-irradiation before they are parasitised has been used to reproductively
sterilise hosts, or even inhibit their emergence. Our aim was to determine whether
X-ray radiation applied to Anastrepha fraterculus third instar larvae before they
are exposed to parasitoids, inhibits fly emergence in non-parasitised larvae
without affecting the performance of the parasitoids that emerge from parasitised
larvae. Three X-ray doses: 6250.2 R, 8333.6 R and 10417 R (equivalent to 60, 80
and 100 Gy, respectively) and one γ-ray dose (100 Gy) were tested. Fly emergence
decreased with increasing doses of radiation, showing null values for the higher
X-ray dose and the dose of 100 Gy. Irradiation showed either no impact or a
positive effect on parasitism rate and fecundity. Sex rate was biased towards
females in almost every dose. We conclude that the two types of radiation evaluated here were equally effective in suppressing fly emergence with no
detrimental effects on the biological quality of the produced parasitoids. X-rays
offer an alternative method of irradiation than the conventional radiation source,
i.e. γ-rays. These results represent a significant improvement in the development of
a biological control programme against A. fraterculus.
Bachmann Guillermo E., Paladino Leonela Z. Carabajal, Claudia A. Conte, Francisco Devescovi, Fabián H. Milla, Jorge L. Cladera, Diego F. Segura & Mariana M. Viscarret
biological control; gamma rays; Anastrepha fraterculus; Diachasmimorpha
longicaudata; fruit fly pests; natural enemies
J. Rediat. Res. Appl. Sci.
Three substerilizing doses 50, 100 and 150 Gy of gamma radiation were tested against full grown male and female pupae or against full-grown male or female pupae of
The results showed that fecundity of irradiated females crossed with irradiated males was
decreased by increasing irradiation dose. The decrease in egg hatchability % and increase in sterility % induced by gamma radiation were found to be positively correlated with the dose level. The parentage of larval and pupal mortality increased significantly (p
Salem HM, Fouda MA, Abas A
A, Ali WM, Gabarty A ().
Journal of Entomology and Nematology, Vol.7(3), pp. 26-29.
Fruit flies are regarded as one of the most devastating pest of fruits and vegetables on earth planet. Generally chemical control is implemented for their control but it poses lot of eco-environmental concerns so the emphasis is now turning towards eco-friendly management practices. Bio-control is an efficient and environmentally sound approach and augmentation is primarily focus on classical biological control program. In this study, eight sub-sterilizing doses of 0, 20, 30, 40, 50, 60, 70 and 80 were tested against Bactrocera zonata and Bactrocera cucurbitae pupae. The results showed that radiation prolong the duration of pupal stage and hatching is reduced by applying radiation. This also shows that when the quantity of the radiation increases, the adult emergence decreases. This study could be very useful in exploiting the potential host for longer period of time for culturing their pupal parasitoids.
NAVEED M., ARIF MJ., AHMAD N.
Sub sterilizing doses, radiation, fruit flies and emergence.
International Journal of Applied Radiation and Isotopes 20: 791-795.
The effect of gamma radiation from a cobalt-60 Source on adults of the fruit fly (Dacus ciliatus Loew) following pupal exposure was determined. When 7 days old pupae were irradiated at 5 krad., partial sterility with normal longevity was observed in the adults while irradiation at doses of 8·5 and 10 krad. induced complete sterility with normal longevity and preoviposition period which lasted throughout their adult life. The optimum sterilizing dose for this fly thus lies in the range of 8·5–10 krad. and can be safely utilized for the eradication of this fly from Karachi area by sterile male release method.
Huque H. and Ahmad C.R.
Journal of Northwest A&F University 40: 57-61
The experiment was to study elimination effects of irradiation against different stages citrus red mite (Panonychus citri Mcgregor) and to conform the effective dosage in order to achieve inspection and quarantine. The eggs, larvae, protonymphs of citrus red mite were selected and irradiated by gamma irradiation (0, 100, 200, 300, 400 Gy), while adults were at the dosage of 0, 200, 400, 600 and 800 Gy). The effect of irradiation against hatching rates and mortality of different stages of citrus red mites was studied. It was found that after being irradiated at the dosage of 200 Gy, the 24 h-old eggs of citrus red mites were not hatched, so the gamma irradiation at the dosage of 200 Gy obviously had lethal effect on the eggs. After irradiated at the dosage of 400 Gy, the mortality of the larvae was as high as 96%. Gamma irradiation among the 300-400 Gy made the larvae sterile and the dosage of 400 Gy was sterile dosage to the protonymphs of citrus red mite. The adults laid less eggs which did not hatch at more than dosage of 400 Gy. After 15 days, the mortality of adult mites irradiated at the dosage of 400-600 Gy was 100%; while irradiated at the dosage of 800 Gy, the mortality was 100% after 13 days. So the irradiation among the 400-800 Gy made the adults sterile or lethal. The gamma irradiation at the dosage 400 Gy made citrus red mite at different stages lethal or sterile. So the citrus fruits irradiated at 400 Gy could achieve quarantine treatment requirement.
Zhu FW, Deng YY, Weng QF, Hu M.Y.
mites, Panonychus citri, plant protection, irradiation, Citrus
Radiation Physics and Chemistry 90: 111-119.
Osouli Sh, Ziaie F, Haddad Irani Nejad K, Moghaddam M.
Acta Agriculturae Zhejiangensis 25:533-536.
Wu Q, Lin WC, Wang BK, Qi WY, Xiong LD, Wei JY, Chen JY.
Journal of Huazhong Agricultural University 21: 347-351.
Zhou LJ, Hu MY, Huang JG, Xu WS, Cheng DM, Wang WX.
citrus rust mite, China
Nukleonika 41: 81-88.
Ignatowicz S, Wróblicka-Sysiak M.
Arthur V, Machi AR.
Final Report to International Atomic Energy Agency.
Aculus schlechtendali, Eriophyes pyri
Arthur V, Machi AR.
Acari, oxygen, air, atmospher, mites
Entomological Research, 45: 110–115. doi: 10.1111/1748-5967.12101
Ionizing radiation is increasingly used as an alternative to post-harvest crop fumigation by methyl bromide. We studied the effects of gamma irradiation on Helicoverpa assulta (Lepidoptera: Noctuidae) at different stages of development to determine the minimal dose for the prevention of normal emergence of adults. We selected five doses of gamma rays (100, 200, 300, 400 and 500 Gy) based on preliminary experiments and irradiated eggs, larvae, pupae and adults. A dose of 100 Gy to eggs allowed 21.83% of larvae to pupate, but these all died during the pupal stage. A dose of 100 Gy to last-instar larvae caused larval or pupal death, or the emergence of abnormal adults; no normal adults developed. Irradiation of pupae with doses of 300 Gy and above resulted either in their death or emergence of abnormal adults; however, after 100 or 200 Gy, normal adults emerged and F1 eggs were produced, but no eggs hatched. Following irradiation of adults, eggs were produced at all doses, although the numbers were significantly decreased compared to untreated controls (P < 0.05; 69.45–125.50 vs. 475.05 eggs per female); however, none of the eggs hatched. As prevention of normal emergence is a key outcome for measuring the effectiveness of radiation, then the 100 Gy dose was effective for irradiation of eggs and larvae, and 300 Gy for pupae.
Park, J. S., Lee, J. Y., Jeong, S. Y., Ahn, S.-J. and Kim, I.
Oriental tobacco budworm;
Journal of Insect Physiology Volume 75, Pages 85–90
• Argiope keyserlingi males perform vibratory courtship before mating with females.
• The thread assay is an appropriate proxy representing courtship on a female web.
• We quantify the dosage of gamma ray resulting in complete sterilization.
• The correct dosage of irradiation does not affect male courtship behaviour.
The sterile male technique is a common method to assign paternity, widely adopted due to its relative simplicity and low cost. Male sterility is induced by exposure to sub lethal doses of chemosterilants or irradiation, the dosage of which has to be calibrated for every species to provide successful male sterilisation, without affecting male physiology and behaviour. While the physiological effects of sterilisation are usually assessed for each study, the behavioural ones are rarely analysed in detail. Using the orb web spider Argiope keyserlingi as a model we first tested (1) the validity of the thread assay, which simulates male courtship behaviour in a standardised context, as a proxy representing courtship on a female web. We then investigated (2) the effectiveness of male sterilisation via irradiation and (3) its consequences on male courtship behaviour. Our results validate the thread assay and the sterile male technique as legitimate tools for the study of male courtship behaviour and fertilisation success. We show that these techniques are time and cost effective and reduce undesirable variation, thereby creating opportunities to study and understand the mechanisms underlying sexual selection.
Magris Martina, Wignall Anne E., Herberstein Marie E.
Emomologia Experimentalis et Applicata 155: 117-122
DOl: 10.1 111/eca. l2289
The Ethiopian fruit fly, Dacus ciliatus (Loew) (Diptera: Tephritidae), is a significant pest of cucurbit crops in Asia and Africa and is currently controlled with insecticides. The sterilizing effect of gamma radiation on D. ciliatus adults was investigated to assess the suitability of sterile insect technique (SIT) for use as an alternative, non-chemical strategy for the control of this pest. Late pupae (48 h before emergence) were irradiated with 60, 80, 100, 120, and 140 Gy of gamma rays emitted by a 60Co source. Following emergence, the biological characteristics of the experimental cohorts (including all possible male-female combinations of irradiated and untreated flies) were recorded. No significant negative effects of irradiation on pupal eclosion or the ability of newly emerged flies to fly were observed. Samples of eggs at reproductive fly-ages (12-, 15-, and 17-day-old pairs) were collected and their hatch rates were assessed. At 60 Gy, females were completely sterilized, whereas complete sterilization of the males was observed only at 140 Gy (a small amount of fertility persisted even at 120 Gy). In addition to the above experiments, three fruit infestation trials were conducted with zucchini [Cucurbita pepo L. (Cucurbitaceae)] as the plant host and the pupae produced in those trials were collected and recorded. We observed significant (ca. 10%) infestation following treatment with up to 120 Gy and zero progeny only at 140 Gy, mirroring the egg-hatch results. Our findings support the feasibility of SIT for the control of D. ciliatus.
Rempoulakis, P., Castro, R., Nemny-Lavy, E. and Nestel, D.
sterile insect technique;
J. Econ. Entomol. 108(1): 88–94; DOI: 10.1093/jee/tou013
The fruit fly Bactrocera tau (Walker) is an important quarantine pest that damages fruits and vegetables throughout Asian regions. Host commodities shipped from infested areas should undergo phytosanitary measures to reduce the risk of shipping viable flies. The dose–response tests with 1-d-old eggs and 3-, 5-, 7-, 8-d-old larvae were initiated to determine the most resistant stages in fruits, and the minimum dose for 99.9968% prevention of adult eclosion at 95% confidence level was validated in the confirmatory tests. The results showed that 1) the pupariation rate was not affected by gamma radiation
except for eggs and first instars, while the percent of eclosion was reduced significantly in all instars at all radiation dose; 2) the tolerance to radiation increased with increasing age and developmental stage; 3) the estimated dose to 99.9968% preventing adult eclosion from late third instars was 70.9 Gy (95% CL: 65.6–78.2, probit model) and 71.8 Gy (95% CL: 63.0–87.3, logit model); and iv) in total, 107,135 late
third instars cage infested in pumpkin fruits were irradiated at the target dose of 70 Gy (62.5–85.0, Gy measured), which resulted in no adult emergence in the two confirmatory tests. Therefore, a minimum dose of 85 and 72 Gy, which could prevent adult emergence at the efficacy of 99.9972 and 99.9938% at the 95% confidence level, respectively, can be recommended as a minimum dose for phytosanitary treatment
of B. tau in any host fruits and vegetables under ambient atmospheres.
Zhan Guoping , Ren Lili , Shao Ying , Wang Qiaoling , Yu Daojian , Wang Yuejin , Li Tianxiu
Bactrocera tau, phytosanitary irradiation, gamma radiation, irradiation, pumpkin
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.
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.
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
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
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