Sterile Insect Release Research Articles

Translocation-Based Genetic Sexing System To Enhance the Sterile Insect Technique Against the Melon Fly (Diptera: Tephritidae)

The autosomal recessive bubble wing (bw) mutant was used to construct a translocation-based genetic sex sorting system in the melon fly, Bactrocera cucurbitae (Coquillett). The translocation stock has females with the bubble wing phenotype that are unable to fly, but the males are wild-type and fly normally. The bubble wing translocation strain has lower egg hatch, larval viability, and eclosion rates than the wild-type strain. Expression of the bubble wing trait is temperature-dependent, with high expression of the trait in 92% of adults at 23°C but in only 15% of adults at 28°C. This translocation-based sex sorting system is the only method available for automatic separation of male and female melon flies in sterile insect release programs.

Increased Remating Frequency in Sex Ratio Distorted Lines of the Mediterranean Fruit Fly (Diptera: Tephritidae)

Remating frequency in a standard laboratory line of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), was 8.4%, which is within the range of values observed in field studies by other workers. In male-skewed and female-skewed lines it had increased to 42 and 37%, respectively. Female genotype was the significant factor in determining remating frequency. A possible role for high remating lines in sterile insect release programs against the Mediterranean fruit fly is discussed.

Waves of extinction from sterile insect release

Employing theoretical models, we show that the sterile insect release method (SIRM) can give rise to travelling waves of fertile insects. The velocity of these waves depends critically upon the density of sterile insects (and thus upon the rate at which sterile individuals are being released into the environment). When the sterile density is sufficiently low, the travelling wave advances, giving rise to an invasion. However, when the sterile density exceeds a critical threshold, the wave reverses direction, thereby retreating and giving rise to local extinction. Both analytical (regular perturbation) methods and numerical methods are used to determine wave velocities and wave profiles. This is the first time traveling wave solutions have been shown for the SIRM.

Light Eye Color Mutants as Genetic Markers for Released Populations of Hawaiian Fruit Flies (Diptera: Tephritidae)

Success in a sterile insect release program is partially dependent on positive classification of population samples to determine the ratio of released insects to the target population. Fluorescent powder applied to tephritid fruit fly pupae and current methods to trap and handle field samples produce uncertain results. We describe mutant phenotypes in three species of Hawaiian fruit flies; the Mediterranean fruit fly, Ceratitis capitata (Wiedemann); the oriental fruit fly, Bactrocera dorsalis (Hendel); and melon fly, Bactrocera cucurbitae (Coquillett), that allow rapid field identification of flies even after they have been dead and dried for several weeks.

Some aspects of mating behavior of Glossina morsitans morsitans males infected with a DNA virus

Abstract Mating behavior of Glossina morsitans morsitans Westwood males, inoculated with the DNA virus during the third-instar larval stage, and sexual receptivity of females premated with such males were studied in the laboratory. Like normal males, the virus-infected males readily located females and mounted them instantaneously. The mean duration of copulation was similar in both normal and infected groups, and all males in both groups experienced the final jerking phase before separating. The value for the degree of insemination (mean spermathecal value) for the females mated with normal males was significantly greater than that for the flies mated with the virus-infected males. Although spermathecae of the latter group were devoid of spermatozoa, attempts to remate them with virile, 7-day-old, normal G.m. morsitans males were mostly unsuccessful. By 72 h after mating, over 80% of the females previously mated with the infected, sterile males showed consistent refractoriness. These observations indicate that the virus-infected tsetse males, despite sterility, retain their normal mating efficiency and would be suitable for use in the sterile-insect release program for control of Glossina species.

Flightless Mutants in the Melon Fly and Oriental Fruit Fly (Diptera: Tephritidae) and Their Possible Role in the Sterile Insect Release Method

Two new mutants that affect adult wing morphology and render the flies incapable of flight-bubble wing( bw ) in the melon fly, Bactrocera cucurbitae (Coquillett), and small wing ( sw ) in the oriental fruit fly, Bactrocera dorsalis (Hendel)-are described. Both mutants have variable expression and are caused by autosomal, recessive genes. We discuss the possible role of these alleles in constructing genetic sex sorting systems to improve the effectiveness and efficiency of the sterile insect release method.

Interaction of Wild Males and Laboratory-Adapted Females of the Mexican Fruit Fly (Diptera: Tephritidae) in Natural Habitats

Despite >40 yr of ecological and behavioral research on reproductive interactions involved in sterile insect release programs, experimental measurement of the intensity of intermale competition for mates and the role of sterile females in these programs has rarely been addressed. Experiments described in this study were designed to evaluate these factors. Virgin females from a mass-rearing strain (mass reared for 36 yr) of the Mexican fruit fly, Anastrepha ludens (Loew), were released and subsequently recaptured along with native Mexican fruit flies in natural habitats in Nuevo Leon, Mexico. Tests were carried out at six locations and replicated four times. Recaptured females were dissected to determine mating status. Data were analysed to determine whether the released females mated with native males, and to evaluate the influence of test site, test date, and wild male and female density on rates of recapture of the released females and their mating status. Results showed that 5–50% of the recaptured females mated with native males. This indicates that released females (even from a strain adapted to mass rearing) may occupy a significant amount of native male reproductive effort and that males in native populations have excess reproductive capacity. Number of native males captured per test was significantly correlated with the percentage of mated females. Plots of percent mating versus number of native males captured showed that when number of captured males was high, percent females mated was always high, but when numbers of males captured was low, percent mating could still be high. A severe freeze during the fourth test greatly reduced the native population. Released females were recaptured up to 7 wk after release and 4 wk after the freeze, indicating that the mass-reared strain had sufficient physiological-behavioral tolerance to survive extreme environmental stress.

Genetic variation in the Old World screw-worm fly,Chrysomya bezziana(Diptera: Calliphoridae)

AbstractThe Old World screw-worm fly,Chrysomya bezzianaVilleneuve, occurs in Africa, the Middle East, Malaysia, Indonesia and Papua New Guinea, but it is not found in Australia. Introduction into Australia from any of these source areas would threaten the viability of much of the grazing industry in the northern part of the continent. Proposed control by the sterile insect release method (SIRM) would be compromised by the existence of sibling species withinC. bezziana.This study examines the degree of genetic differentiation throughout the extensive range of the fly to assess if the degree of geographic differentiation indicates the existence of sibling species and, allows identification of the source of any introduced flies. Electrophoretic analysis of 23 loci from samples collected in southern Africa, the Middle East, Malaysia, Indonesia, and Papua New Guinea revealed 11 polymorphic loci. Overall, populations show remarkably little divergence given the geographic distribution of sample sites. None of the populations sampled were fixed for alternative electromorphs. There is no evidence from this study for the presence of sibling species withinC. bezziana.

Report on a sterile insect release trial for the control of the Old World screw-worm fly Chrysomya bezziana in Papua New Guinea

Australian Veterinary JournalVolume 68, Issue 8 p. 277-279 Report on a sterile insect release trial for the control of the Old World screw-worm fly Chrysomya bezziana in Papua New Guinea GM CLARKE, GM CLARKE DPIE/CSIRO Screw-Worm Fly Unit, PO Box 6712, Boroko, Papua New Guinea *CSIRO Division of Entomology, PO Box 1700, Canberra City, Australian Capital Territory 2601Search for more papers by this author GM CLARKE, GM CLARKE DPIE/CSIRO Screw-Worm Fly Unit, PO Box 6712, Boroko, Papua New Guinea *CSIRO Division of Entomology, PO Box 1700, Canberra City, Australian Capital Territory 2601Search for more papers by this author First published: August 1991 https://doi.org/10.1111/j.1751-0813.1991.tb03243.xCitations: 3 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume68, Issue8August 1991Pages 277-279 RelatedInformation

Prospects for genetic control of the gypsy moth

Male gypsy moths, Lymantria dispar L., that have been irradiated as pupae with a substerilizing dose of gamma radiation (10 krads) and mated with normal females, yield sterile F 1 progeny. This inherited sterility enhances classical sterile-insect release methods, since control is exerted on the target population for two generations with a release in the first generation. However, difficulties associated with large-scale deployment of partially sterile males renders genetic control impractical on a large scale. Diapausing F 1 eggs (progeny of 10-krad male x normal female) can be stockpiled in the laboratory and released into target populations, greatly simplifying deployment of sterile insects. With the release of F 1 eggs, the overflooding of fertile males by F 1 sterile males will reduce reproduction in the year of release, provided that F 1 egg and larval hatch, establishment, development and survival are comparable to that in wild populations. Releasing F 1 egg-masses is a significant step forward in making sterile-insect technology operational for the gypsy moth. Field trials in isolated infestations have been conducted, and the technique has been successfully used in eradicating an isolated population in Bellingham, Washington, U.S.A. Prospects for its continued use in gypsy-moth management programs are discussed.

A Genetic Sexing System to Improve the Sterile Insect Technique against the Mediterranean Fruit Fly

The autosomal recessive allele v wing (v) in the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), produces flies that when reared at 30 degrees C have stubby wings. The mutant was used to construct a translocation-based genetic sexing system in an attempt to improve the efficiency and effectiveness of the sterile insect release method for field control.

The screw‐worm fly Chrysomya bezziana villeneuve (Diptera: Calliphoridae) in a sterile insect release trial in Papua New Guinea

SummaryThe feasibility of the sterile insect release method (SIRM) was tested against natural populations of the Old World screw‐worm fly, Chrysomya bezziana in the Musa Valley, Papua New Guinea. Sterile mating frequencies were determined from egg masses laid by native females on wounded, sentinel cattle. The aerial release of sterilised puparia resulted in low frequencies of sterile matings and few trap recaptures of released material. The release of chilled adult flies resulted in higher frequencies of sterile matings and many trap recaptures. The mean density of males released was 230 males per km2 per week over a target area of 361 km2 (48% of the valley). Sterile masses were first detected 2 weeks after the release of chill flies commenced, reaching a weekly peak of 33% after 5 weeks of releases with 15% of egg masses found to be sterile during the final month. The levels of sterile matings achieved in this trial were similar to comparable SIRM studies made in the USA, Mexico and Guatemala to control the New World screw‐worm fly, Cochliomyia hominivorax.

Radiosensitivity of different larval stage duration pupae of the Mediterranean fruit-fly, Ceratitis capitata Wied

The sensitivity of different larval stage duration pupae of Mediterranean fruit-fly, Ceratitis capitata to gamma irradiation, was tested by exposing pupae, 1 day before adult eclosion, to various gamma ray doses (60, 80 and 100 Gy). The treated pupae were biologically different in their larval span (5, 7 and 9 days). The pupae of med-fly having shorter larval period (5 days) were more resistant to sterilizing effects of gamma irradiation than those having longer larval period (9 days). The longevity of sterilized females developing from irradiated pupae, which had 5-and 7-day larval span, was increased considerably. Treatment of pupae which had 5-day larval span with a dose of 80 Gy, resulted in females which lived 84.3 days, but laid only 2.33 eggs as compared with their control females which lived 51.4 days and laid 976.71 eggs. In general, irradiation of pupae of different larval stage duration with a dose of 60 Gy or greater did not adversely affect the longevity of emerging adults. It is concluded that 60 Gy-irradiation of pupae having long larval span (9 days) should be used in the sterile insect release method for population suppression of Ceratitis capitata .

Relationship between Sperm Competition and Copulation Duration in the Mediterranean Fruit Fly (Diptera: Tephritidae)

Newly identified genetic markers in the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), have been employed to analyze sperm use in multiple-mated females. The sperm of second mating males predominates over that of the initial male in offspring from multiple-mated females. These results are significant for the basic study of the evolution of mating behavior, and for such applied research as the sterile insect release method for field control.

Identification of Sterile Backcross Heliothis Males in Field Collections

Hybridization of Heliothis virescens (F.) males with Heliothis subflexa (Cuennée) females followed by back crossing of the female progeny to H. virescens males produces a backcross (BC) line consisting of fertile females and sterile males each generation. A rapid cytological method for distinguishing between sterile BC Heliothis males and fertile native males is presented. The method requires no fixing or staining of tissues. Application of this technique in future Heliothis suppression programs involving release of sterile BC insects is discussed.

Two Artificial Larval Diets for Rearing Dacus latifrons (Diptera: Tephritidae)

Malaysian fruit fly, Dacus latifrons (Hendel), has been reared on artificial diet for the first time. A carrot and a wheat larval diet were used. Larval recovery for both diets was >50%. Fastest development, highest fecundity, and highest fertility were obtained with the wheat diet. Although reproductive parameters for the wheat diet were less than those for a preferred natural larval host, pepper, Capsicum annuum L. variety jalapeño, scarcity of quality peppers in markets favors use of a wheat artificial diet for mass production of D. latifrons. Results are discussed in relation to mass production of insects for attractants/screening and sterile insect release method (SIRM) programs.

Instructional Simulation: Sterile Insect Release Method with Spatial and Random Effects

A simulation model of the sterile insect release (SIR) method of population suppression was developed as a modeling exercise by advanced students of integrated pest management (IPM). Objectives were to create an instructional model that would demonstrate the principles and operation of the SIR technique to undergraduate IPM students, and allow users to see the effects of relaxing or violating various assumptions of the basic model. In particular, the influence of dispersal, spatial distribution of wild and sterile insects, uncertainty about the initial population density, and stochastic processes can be examined by simulation. Ease of changing the qualitative structure of the model and quantitative values of parameters, along with rapid execution and graphic display on a microcomputer, enhance the instructional value of the model. Simulations show that adjustment of the number of sterile males released can generally compensate for variations in competitiveness of sterile males and uncertainty about the survival rate, fecundity and sex ratio of wild insects. However, dispersal and spatial heterogeneity of the target population place more severe demands on the technique. Release of sterile males in a buffer zone surrounding an isolated population is necessary whenever dispersal is likely, but high mobility of the target species and economic and practical considerations may limit the feasibility and success of this approach. Release ratios that greatly exceed expected necessary levels may fail to ensure eradication due to variations in local pest density and sampling errors. Inadequate detection methods may add to the difficulty of eradicating mobile pests. Knowledge of emigration probabilities and dispersal distances, carefully designed sampling and release programs that take spatial heterogeneity of density into account, and efficient detection methods are all essential to success of the SIR technique.

Mortality, Stadial Duration, and Weight Loss in Three Species of Mass-reared Fruit Fly Pupae (Diptera: Tephritidae) Held with and without Vermiculite at Selected Relative Humidities

Mediterranean fruit fly, Ceratitis capitata (Wiedemann); melon fly, Dacus cucurbitae Coquillett; and oriental fruit fly, Dacus dorsalis Hendel, pupae were held with and without a pupation medium (vermiculite) at 20°C and 90, 60, and 40% RH. For all three species of fruit flies, pupae held with vermiculite were significantly heavier than those held without vermiculite. Storage of pupae in boxes of vermiculite significantly reduced mortality at both 60 and 40% RH. For pupae held without vermiculite, lowest mortality, shortest stadial duration, and highest weight occurred at 90% RH for all three species. At 90% RH, mortality of pupae held without vermiculite did not differ significantly from mortality of those held with vermiculite. Results are discussed with respect to selection of holding procedures for mass-produced fruit fly pupae for programs involving the sterile insect release method.

Suppressive action of Samorin on the cyclical development of pathogenic trypanosomes in Glossina morsitans centralis.

Male Glossina sexually sterilized by gamma-irradiation are as efficient vectors of trypanosomiasis as fertile males. An attempt was made, using isometamidium chloride (Samorin), to interfere with the cyclical development of trypanosomes in sterile males, destined for use in the sterile insect release (SIR) method of tsetse eradication. The infection rate with mature Trypanosoma congolense Broden was effectively reduced in sterile male Glossina morsitans centralis Machado, when the flies were fed on an infected goat 2 days after they were fed as tenerals on an in vitro bloodmeal containing 8 micrograms Samorin/ml blood. The infection rates with mature T.vivax Ziemann and T.brucei brucei Plimmer & Bradford were completely suppressed at this drug dose. Whensterile teneral males were fed on a bloodmeal containing 12 micrograms/ml Samorin and given the infected bloodmeal 10 days later, infections by mature T.vivax, T.congolense and T.b.brucei were completely suppressed. Hence in the management of a tsetse eradication programme utilizing the SIR method, it is recommended that the sterile teneral male tsetse should, prior to release, be given a bloodmeal containing Samorin at 12-15 micrograms/ml blood. This will effectively suppress future disease transmission.

Models of sterile insect releases for populations under attack by parasitoids

Five host-parasitoid models are presented to determine the effects of: (a) host stage parasitized, and (b) position of density-dependent population regulation on the efficiency and dynamics of the sterile insect release method for pest control. Previous models indicate a catastrophic decline of the pest population when sterile releases are above a certain threshold. The five models incorporating parasitoids presented here indicate that this catastrophic decline will usually not occur, but rather the parasitoids will be driven extinct whereupon the system reverts to the one-species dynamics. In this situation, either a population explosion or extinction of the pest species will generally follow, depending on the level of sterile releases and on chance events. The models predict that the behavior of the system is similar regardless of whether the parasitoids parasitize host larvae or host adults. The system dynamics do depend, however, on whether density-dependent population regulation is effective in the hosts or the parasitoids. If population regulation is in the hosts, then the parasitoids may or may not reduce the sterile release rate required for eradication; usually the existence of the parasitoids will substantially reduce this sterile release rate. If population regulation is via the parasitoids, then the sterile release rate required for eradication is greatly reduced over that with no parasitoids; however, the possibility of a major population explosion during the release program is more likely than if population regulation is in the hosts. Model stability was much greater with population regulation in the parasitoids than in the hosts.