scholarly journals Medfly Gut Microbiota and Enhancement of the Sterile Insect Technique: Similarities and Differences of Klebsiella oxytoca and Enterobacter sp. AA26 Probiotics during the Larval and Adult Stages of the VIENNA 8D53+ Genetic Sexing Strain

2017 ◽  
Vol 8 ◽  
Author(s):  
Georgios A. Kyritsis ◽  
Antonios A. Augustinos ◽  
Carlos Cáceres ◽  
Kostas Bourtzis
2020 ◽  
Vol 113 (5) ◽  
pp. 2163-2170
Author(s):  
Yair Contreras-Navarro ◽  
Diana Pérez-Staples ◽  
Dina Orozco-Dávila ◽  
Francisco Díaz-Fleischer

Abstract Anastrepha ludens (Loew) (Diptera: Tephritidae) is an endemic pest of Mexico, attacking several fruits of economic importance. The Sterile Insect Technique (SIT), consisting of mass-rearing, irradiation and release of adults, is used to control this pest in affected areas. Currently, a genetic sexing strain (Tapachula 7, Tap-7) consisting only of A. ludens males is being released, yet we lack information on its sexual performance at the early ages when they are released and on its post copulatory behavior in terms of sperm transfer and mating inhibition. Here, sexual competitiveness at young ages and ability to inhibit female re-mating was compared between sterile Tap-7, Standard Bisexual (SB), or wild males both in laboratory and field cage conditions. Sperm stored by females mating with wild, Tap-7, or SB strain males was also compared. Six-day-old sterile Tap-7 males had low mating rates, however, by 7 d of age 80% of males had mated. Tap-7 males were just as likely as wild males to inhibit wild female re-mating. In field cages, sterile Tap-7 males mated faster than wild and sterile males from the SB strain and had comparable mating success to wild males. Females mated to sterile Tap-7 males stored more sperm than those mated to sterile SB males. Females mated to wild males stored more sperm than females mated to any other type of male. Mass-rearing had a greater effect on decreasing sperm stored by females than irradiation. We recommend continuing the release of the GSS strain of A. ludens.


Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 499
Author(s):  
Edwin Ramírez-Santos ◽  
Pedro Rendon ◽  
Georgia Gouvi ◽  
Antigone Zacharopoulou ◽  
Kostas Bourtzis ◽  
...  

Anastrepha ludens (Loew) is one of the most destructive insect pests damaging several fruits of economic importance. The sterile insect technique (SIT) is used under an area-wide integrated pest management approach, to suppress these pest populations. Mass rearing facilities were initially established to produce sterile males of bi-sexual strains in support of SIT. The first genetic sexing strain (GSS) for A. ludens, Tapachula-7, based on pupal color dimorphism, was a key development since the release of males-only significantly increases the SIT efficiency. In this study, we document the development of a novel pupal color-based GSS. Twelve radiation-induced translocation lines were assessed as potential GSS in terms of recombination rates and rearing efficiency at a small scale. The best one, GUA10, was cytogenetically characterized: it was shown to carry a single translocation between the Y chromosome and chromosome 2, which is known to carry the black pupae marker. This GSS was further evaluated at medium and large scales regarding its genetic stability, productivity and quality versus Tapachula-7. GUA10 presented better genetic stability, fecundity, fertility, production efficiency, flying ability, and male mating, clear indicators that GUA10 GSS can significantly improve the efficacy and cost-effectiveness of SIT applications against this pest species.


2020 ◽  
Vol 113 (6) ◽  
pp. 2688-2694
Author(s):  
Mitzy F Porras ◽  
Jose S Meza ◽  
Edwin G Rajotte ◽  
Kostas Bourtzis ◽  
Carlos Cáceres

Abstract The genetic sexing strain (GSS) of the Mediterranean fruit fly (Ceratitis capitata (Wiedemann)) Vienna 8D53− is based on a male-linked translocation system and uses two selectable markers for male-only production, the white pupae (wp) and the temperature sensitivity lethal (tsl) genes. In this GSS, males emerge from brown pupae and are resistant to high temperatures while females emerge from white pupae, are sensitive to high temperatures. However, double homozygous females (wp tsl/wp tsl) exhibit a slower development rate compared to heterozygous males (wp+tsl+/wp tsl) during the larval stage, which was attributed to the pleiotropic effects of the tsl gene. We present the first evidence that this slower development is due to a different gene, here namely slow development (sd), which is closely linked to the tsl gene. Taking advantage of recombination phenomena between the two loci, we report the isolation of a novel temperature sensitivity lethal strain using the wp mutation as a morphological marker, which showed faster development (wp tsl FD) during the larval stage and increased in its temperature sensitivity compared with the normal tsl strain. Moreover, the introgression of this novel wp tsl FD combined trait into the Vienna 8D53− GSS, resulted in a novel Vienna 8D53− FD GSS, where females showed differences in the thermal sensibility, larval development speed, and productivity profiles. The modification of these traits and their impact on the mass rearing of the GSS for sterile insect technique applications are discussed.


Author(s):  
Rubén Sancho ◽  
Ana Guillem-Amat ◽  
Elena López-Errasquín ◽  
Lucas Sánchez ◽  
Félix Ortego ◽  
...  

AbstractThe sterile insect technique (SIT) is widely used in integrated pest management programs for the control of the Mediterranean fruit fly (medfly), Ceratitis capitata. The genetic interactions between the released individuals from the genetic sexing strains (GSS), used for SIT applications worldwide, and wild individuals have not been studied. Under the hypothesis that a number of Vienna GSS individuals released to the field might not be completely sterile and may produce viable offspring, we have analyzed medfly Spanish field populations to evaluate the presence of Vienna strain genetic markers. To this goal, we have used contrasted nuclear and mitochondrial genetic markers, and two novel sets of nuclear polymorphisms with the potential to be markers to discriminate between Vienna and wild individuals. Nuclear Vienna markers located on the 5th chromosome of Vienna males have been found in 2.2% (19 from 875) of the Spanish wild medfly females captured at the area where SIT is applied. In addition, a female-inherited mitochondrial Vienna marker has been found in two from the 19 females showing nuclear Vienna markers. The detection of several of these markers in single individuals represents evidence of the introgression of Vienna strain into natural populations. However, alternative explanations as their presence at low frequency in wild populations in the studied areas cannot be fully discarded. The undesired release of non-fully sterile irradiated GSS individuals into the field and their interactions with wild flies, and the potential environmental implications should be taken into account in the application of the SIT.


Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 308
Author(s):  
Paloma Della Giustina ◽  
Thiago Mastrangelo ◽  
Sohel Ahmad ◽  
Gabriel Mascarin ◽  
Carlos Caceres

A common strategy used to maintain sterile fly quality without sacrificing sterility is to irradiate the insects under an oxygen-reduced atmosphere. So far, sterilizing doses for the South American fruit fly Anastrepha fraterculus have only been determined under normoxia. Our study reports for the first time the dose-sterility response under hypoxia for two different A. fraterculus strains. The pupae were derived from a bisexual strain (a Brazilian-1 population) and a recently developed genetic sexing strain (GSS-89). Two hours prior to irradiation, pupae were transferred to sealed glass bottles and irradiated when oxygen concentration was below 3%. Four types of crosses with nonirradiated flies of the bisexual strain were set to assess sterility for each radiation dose. For males from both strains, Weibull dose–response curves between radiation doses and the proportion of egg hatch, egg-to-pupa recovery, and recovery of adults were determined. The GSS males revealed high sterility/mortality levels compared to males from the bisexual strain at doses < 40 Gy, but a dose of 74 Gy reduced egg hatch by 99% regardless of the male strain and was considered the sterilizing dose. The fertility of irradiated females was severely affected even at low doses under hypoxia.


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