Soc. Am. 76: 51–55.
Mating preference of laboratory-reared and wild Mediterranean fruit flies, Ceratitis capitata (Wiedemann) (medfly), was studied in field cages. When laboratory-reared flies unirradiated and irradiated with 7, 10, 13, and 16 krad in N2 and dyed were compared with wild flies, mating speed of unirradiated, laboratory-reared flies was faster than that of wild flies. The unirradiated, laboratory-reared males preferred mating with unirradiated, laboratory-reared females, and wild males preferred mating with wild females. When laboratory-reared flies irradiated at 7, 10, 13, and 16 krad in N2 were paired with wild flies, however, mating speed was similar for both strains and mating became random apparently because the mating speed of the irradiated, laboratory-reared flies was reduced. In the tests combining flies exposed to all six treatments (laboratory-reared flies irradiated at 7, 10, 13, and 16 krad in N2, unirradiated flies, and wild flies) in one cage, those wild females which mated, mated equally well with wild males, and laboratory-reared males showing no preference and those laboratory males which mated, mated equally well with wild or laboratory females, again showing no preference.
Wong, T.T.Y., J. I. Nishimoto, andH.M. Couey
Diptera; Tephritidae, competition, medfly; irradiation
Journal of Economic Entomology [DOI: http://dx.doi.org/10.1093/jee/tov246 First published online: 28 August 2015]
The effect of cold immobilization and long-distance transport of irradiated Thaumatotibia leucotreta (Meyrick) on the flight ability of male (♂) and female (♀) moths, the longevity of male and female moths, and the realized fecundity of mating pairs CIM (chilled irradiated moths) ♀ × CIM♂, CIM♀ × NIP (nonirradiated pupae) ♂, NIP♀ × CIM♂, and NIP♀ × NIP♂ was examined to improve application of the sterile insect technique (SIT). Adult moths treated with 150 Gy of gamma radiation were immobilized with cold temperature between 4 and 6°C inside a polyurethane cooler box and transported for 12 h by road from Citrusdal, Western Cape Province, to Addo, Eastern Cape Province. Nonirradiated moths were transported as pupae inside a cardboard tray and removed by hand after which male and female pupae were separated and placed inside containers for eclosion. Male and female moths were individually placed inside petri dishes to determine longevity or paired with irradiated and nonirradiated counterparts to evaluate realized fecundity before incubation in 100% darkness at 25°C and 75% relative humidity. Flight tests were conducted indoors at 25°C by release of individual moths per hand. A significant decrease in flight ability and longevity of irradiated false codling moth was found after handling, cold immobilization, and transport, although critically, realized fecundity was not affected. Because of the impact of long-distance transport on quality of the released insects as well as the efficacy of SIT, comprehensive protocols for this critical step in the process need to be developed for a pestiferous insect with phytosanitary status such as false codling moth.
Nepgen ES, Hill MP, Moore SD
South Africa; application technology; citrus; insect shipment, sterile insecte technique
In: Vreysen MJB, Robinson AS, Hendrichs J. (ed) Area-Wide Control of Insect Pests from research to field implementation. Springer, Netherlands, pp 497‒504
fields, and ditches of an herbicide that selectively kills key spring broad leaf hosts of the tarnished plant bug
Lygus lineolaris (Palisot de Beauvois) was developed and implemented in four 23 square kilometre areas. Overall mean numbers of tarnished plant bug adults and nymphs were significantly lower in treated-area cotton. The average reductions in overall mean numbers of plant bugs in the treated areas were 45.5 and 47% for adults and nymphs, respectively, from 1999-2001. Economists at
Mississippi State University conducted an analysis of the programme used on over 8400 hectares of cotton in 1999-2001, and demonstrated that the technology produced savings of USD 14.59/ha in insecticide costs (herbicide application included). An environmental impact study conducted by Louisiana State University, detected no to extremely low levels of herbicide residue in run-off water from conducting the programme. Research is currently being conducted to investigate the use of a fungal entomopathogen, sterile males, and parasitoids to augment or replace the use of herbicides.
ABEL C.A, SNODGRASS G.L. and GORE J.
Tarnished plant bug, Lygus lineolaris, cotton, marginal areas, early season wild host plant, area-wide suppression, herbicides
In: Vreysen MJB, Robinson AS, Hendrichs J. (ed) Area-Wide Control of Insect Pests from research to field implementation. Springer, Netherlands, pp 475‒485
oconut palms in India, Sri Lanka, Indonesia and the Philippines. Recently, this pest has
spread to countries in the Persian Gulf and some areas of the Mediterranean basin where it is aserious menace to date palms. Management of this pest using conventional methods is not effective due to the difficulty of detecting early infestations. Trials were therefore conducted to assess the possibility of eventually
including the sterile insect technique (SIT) to target populations at low densities as part of future integrated management of this pest.The steps taken included the adoption of a new mass-rearing method for weevils using coconut petioles, determination of the sterilization dose at 15Gy, a new relative method for estimating population levels of red palm weevils, and finally field release and recapture studies using pheromone traps. This paper deals with the results of these attempts to develop the SIT for use against the red palm weevil on Poothuruth Island near Dalavapuram Island in Kerala.
Krishnakumar R, Maheshwari P
Red Palmweevil, date palm, release-recapture studies, Kerala, sterile insect technique, IPM
Journal title : Journal of Applied Biological Chemistry Volume 57, Issue ,2, pp.141-144. Publisher : The Korean Society for Applied Biological Chemisty. DOI : 10.3839/jabc.2014.021
The effects of electron beam irradiation on control of Myzus persicae and Planocococcus citri (Risso) were evaluated with the changes of mortality, emergence rate, fecundity, and egg hatchability. As a result of this study, M. persicae and P. citri (Risso) was not directly affected by electron beam irradiation with low doses (30, 60, 90, and 120 Gy) but the irradiation had effects on inhibition of development and reproduction of the pests.
Lee, Gyeong-Ae ; Park, Min-Goo ; Cho, Jae-Young ;
electron beam . insect/pest control . irradiation . Myzus persicae . Planococcus citri (Risso)
Korean journal of applied entomology Volume 53, Issue ,4, pp.391-398. Publisher : Korean Society of Applied Entomology
DOI : 10.5656/KSAE.2014.10.0.054
This study investigated inhibitory doses of electron beam and X-ray irradiation by comparing their effects on the development and reproduction of four insect pests (Myzus persicae, Tetranychus urticae, Liriomyza trifolii, and Frankliniella intonsa). When M. persicae nymphs were irradiated with 100 Gy of electron beam and 30 Gy of X-ray beam, offspring production by adults that developed from the treated nymphs was completely inhibited. When M. persicae adults were irradiated with 200 Gy of electron beam and 50 Gy of X-ray beam, emergence of the generation was inhibited. However, these two ionizing radiations did not affect adult longevity. When T. urticae eggs were irradiated with 150 Gy of electron beam and 50 Gy of X-ray beam, egg hatching was completely inhibited. When L. trifolii pupae were irradiated, the emergence rate decreased with increasing doses of X-ray irradiation. After F. intonsa adults were irradiated with 250 Gy of electron beam and 200 Gy of X-ray beam, egg hatching of the generation was completely suppressed.
Yun, Seung-Hwan ; Kim, Minjun ; Kim, Hyunah ; Lee, Seon-Woo ; Yoo, Dae Hyun ; Kim, Hyun Kyung ; Koo, Hyun-Na ; Kim, Gil-Hah ;
Insect pests . Electron beam . X-ray . Inhibition dose
J. Econ. Entomol. 108(3): 868–872; DOI: 10.1093/jee/tov068
Small hive beetle, Aethina tumida Murray (Coleoptera: Nitidulidae), is considered a serious threat to beekeeping in the Western Hemisphere, Australia, and Europe mainly due to larval feeding on honey, pollen, and brood of the European honeybee, Apis mellifera L. Control methods are limited for this pest. Studies were conducted to provide information on the radiobiology of small hive beetle and determine the potential for sterile insect releases as a control strategy. Adult males and females were equally sensitive to a radiation dose of 80 Gy and died within 5–7 d after treatment. In reciprocal crossing studies, irradiation of females only lowered reproduction to a greater extent than irradiation of males only. For matings between unirradiated males and irradiated females, mean reproduction was reduced by >99% at 45 and 60 Gy compared with controls, and no larvae were produced at 75 Gy. Irradiation of prereproductive adults of both sexes at 45 Gy under low oxygen (1–4%) caused a high level of sterility (>99%) while maintaining moderate survivorship for several weeks, and should suffice for sterile insect releases. Sterile insect technique holds potential for suppressing small hive beetle populations in newly invaded areas and limiting its spread.
DOWNEY DANIELLE, CHUN STACEY, AND FOLLETT PETER
Aethina tumida, honey bee, Apis mellifera, x-ray radiation, sterile insect technique
Tissue and Cell; 46(4):274-285. DOI:10.1016/j.tice.2014.06.003 ·
In the present study we describe the morphology of the male reproductive apparatus and sperm ultrastructure of the red palm weevil - an invasive pest of several palm tree species - as well as the most important steps of spermatogenesis. The reproductive apparatus consists of a pair of testes (each formed by two lobes) a long tube-like accessory gland, a prostate gland and a small accessory gland. Characteristic features of the sperm are: 90 to 100 μm total length, 10 μm nucleus, two mitochondrial derivatives, two accessory bodies, one well-developed puff-like structure and a typical insect 9 + 9 + 2 ﬂagellar axoneme. One of the methods used for the biological control of pests is the Sterile Insect Technique (SIT), for the evaluation of which we make a preliminary comparison of the sperm ultrastructure of non-irradiated and irradiated weevils (at a dose of 80 Gray).
Feasibility of SIT to control red palm weevil (Rhynchophorus ferrugineus Olivier): An integrated physiological, ecological and genetic approach. Available from: http://www.researchgate.net/publication/267526500_Feasibility_of_SIT_to_control_red_palm_weevil_(Rhynchophorus_ferrugineus_Olivier)_An_integrated_physiological_ecological_and_genetic_approach
[accessed Jul 8, 2015].
Paoli Francesco,Dallai Romano, Cristofaro Massimo, Arnone Silvia, Francardi Valeria, Roversi Pio Federico
Genital apparatus; Genital system; Insect spermatogenesis; Sterile insect technique (SIT); TEM
The red palm weevil (RPW), Rhynchophorus ferrugineus (Oliver) (Coleoptera: Dryophthoridae), a weevil native to South- eastern Asia and Melanesia where it is a serious pest of coconuts, is considered the most dangerous pest of Canarian palm trees and date palm trees in Southern Europe, Northern Africa and Middle Asia. Aim of this work was to evaluate the feasibility to control the weevil pest by implementation of sterile insect technique (SIT) , particularly useful in area-wide IPM programs. Bioassays carried out at the ENEA C. R. Casaccia facilities were addressed to test the effects of different doses of γ rays on the weevil reproductive physiology and mating behavior. In spite of the apparent drawbacks in reproductive behavior of females observed in field (polyandry and high levels of fertility), laboratory experiment s satisfy some important requisites for the application of this technique (last male sperm precedence, high vitality and ability of mating of irradiated males) and suggest the possibility to use SIT in particular geographical contexts. Results and perspectiv es are discussed
Musmeci S, Cristofaro M, Arnone S, Sasso R, Baccaro S, Pasquali A, Catarci S
Rhynchophorus ferrugineus, Sterile Insect Technique, red palm weevil, integrated pest management
ESA 60TH Annual Meeting, Knoxville, Tennessee (USA)
Cristofaro M, Arnone S, Musmeci S, Sasso R, Lai A, De Biase A, La Marca A, Belvedere S, Marcari V, Senia G, Catarci S
Bull. Entomol. Res. 103:241–250
Rhynchophorus ferrugineus (Coleoptera, Curculionidae) is the most threatening pest of palms worldwide. The potential of gamma-irradiated males to spread a pathogenic strain of the entomopathogenic fungus Beauveria bassiana (Ascomycota: Clavicipitaceae) to control this pest was studied. First, the effects of gamma irradiation (15 and 25 Gy) on the mating success and performance of adult males irradiated at age one day were studied in the laboratory. Although male longevity decreased after irradiation (118.6 vs. 244.7 days for irradiated and control males, respectively) and their testes suffered from the treatment, fecundity of mated females did not depend on the irradiation status of the male (86.8±5.5 eggs in 15 days). However, egg hatching was significantly lower in couples with irradiated males (31.4% vs. 86.5% for irradiated and control couples, respectively), and this value decreased after a second mating (6.1% vs. 85.9%). Therefore, irradiation did not affect male sexual competiveness but sperm quality. Second, a semi-field assay was carried out to evaluate infestation in young Phoenix canariensis caused by different combinations of couples with irradiated and/or B. bassiana -challenged males. The number of immature stages found in infested palms was significantly higher when females mated with untreated males and lower when mated with irradiated males (either B. bassiana -infected or not). Some females from the fungus-challenged treatments showed post-mortem hyphal growth, and this horizontal transmission proves that irradiated males could act as a vector for B. bassiana and should be considered as a new method to improve the biological control of R. ferrugineus.
Llácer E, Santiago-Álvarez C, Jacas JA
gamma irradiation, horizontal transmission, entomopathogenic fungus,
, autodissemination, sterile males
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.