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Genetic elimination of field-cage populations of Mediterranean fruit flies.

Leftwich PT, Koukidou M, Rempoulakis P, Gong HF, Zacharopoulou A, Fu G, Chapman T, Economopoulos A, Vontas J, Alphey L - Proc. Biol. Sci. (2014)

Bottom Line: Our results show (i) full functionality of RIDL, (ii) equivalency of RIDL and wild-type strains for life-history characteristics, and (iii) a high level of sexual competitiveness against both wild-type and wild-derived males.Weekly releases of OX3864A males into stable populations of wild-type medfly caused a successive decline in numbers, leading to eradication.The results show that genetic control can provide an effective alternative to SIT for the control of pest insects.

View Article: PubMed Central - PubMed

Affiliation: Oxitec Limited, 71 Innovation Drive, Milton Park, Oxford OX14 4RQ, UK School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK.

ABSTRACT
The Mediterranean fruit fly (medfly, Ceratitis capitata Wiedemann) is a pest of over 300 fruits, vegetables and nuts. The sterile insect technique (SIT) is a control measure used to reduce the reproductive potential of populations through the mass release of sterilized male insects that mate with wild females. However, SIT flies can display poor field performance, due to the effects of mass-rearing and of the irradiation process used for sterilization. The development of female-lethal RIDL (release of insects carrying a dominant lethal) strains for medfly can overcome many of the problems of SIT associated with irradiation. Here, we present life-history characterizations for two medfly RIDL strains, OX3864A and OX3647Q. Our results show (i) full functionality of RIDL, (ii) equivalency of RIDL and wild-type strains for life-history characteristics, and (iii) a high level of sexual competitiveness against both wild-type and wild-derived males. We also present the first proof-of-principle experiment on the use of RIDL to eliminate medfly populations. Weekly releases of OX3864A males into stable populations of wild-type medfly caused a successive decline in numbers, leading to eradication. The results show that genetic control can provide an effective alternative to SIT for the control of pest insects.

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Changing medfly population dynamics through introduction of OX3864A males into large cages of stable wild-type medfly populations. (a) Average daily egg production for each week in treatment and control cages. Weeks 0–8 constituted the population stabilization period (230 pupae added each week). Introductions of 1700 OX3864A pupae into each treatment cage commenced from week 8 onwards, in addition pupal return to each treatment cage was made proportional to the control cages. Six weeks after OX3864A male introductions, there was a clear reduction in egg production in the treatment cages compared with the control cages, continuing until eventual extinction of the wild-type population in both treatment cages (as assessed by two weeks of no egg production) by week 22 (14 weeks post initial RIDL release). The dotted line denotes the average weekly daytime temperature (Celsius) taken from daily midday temperature readings. (b) Numbers of females in treatment and control cages. (c) Proportion of progeny returned to each of the treatment cages from the oviposition traps displaying the DsRed2 fluorescent phenotype. Percentage of returning pupae carrying a copy of the OX3864A transgene reached 100% in both treatment cages by week 17 (11 weeks post-RIDL release).
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RSPB20141372F2: Changing medfly population dynamics through introduction of OX3864A males into large cages of stable wild-type medfly populations. (a) Average daily egg production for each week in treatment and control cages. Weeks 0–8 constituted the population stabilization period (230 pupae added each week). Introductions of 1700 OX3864A pupae into each treatment cage commenced from week 8 onwards, in addition pupal return to each treatment cage was made proportional to the control cages. Six weeks after OX3864A male introductions, there was a clear reduction in egg production in the treatment cages compared with the control cages, continuing until eventual extinction of the wild-type population in both treatment cages (as assessed by two weeks of no egg production) by week 22 (14 weeks post initial RIDL release). The dotted line denotes the average weekly daytime temperature (Celsius) taken from daily midday temperature readings. (b) Numbers of females in treatment and control cages. (c) Proportion of progeny returned to each of the treatment cages from the oviposition traps displaying the DsRed2 fluorescent phenotype. Percentage of returning pupae carrying a copy of the OX3864A transgene reached 100% in both treatment cages by week 17 (11 weeks post-RIDL release).

Mentions: Dramatic decreases in weekly egg production were observed seven weeks post-RIDL release (PR) in treatment cages, compared with a continued stable rate of egg production in control cages (figure 2a). This was due to the proportion of returned progeny carrying the OX3864A transgene increasing in treatment cages, resulting in a rapid decline in the female population (figure 2b). Transgene frequency in the treatment cage populations was monitored by screening the returning pupae (chosen from all the pupae produced at random) for the presence of the DsRed2 fluorescent marker. The frequency of the transgene in the returning progeny of the treatment cages was at 100% by week 8 PR (figure 2c), with both cages considered extinct by week 14 PR (extinction defined as zero egg production for two consecutive weeks).Figure 2.


Genetic elimination of field-cage populations of Mediterranean fruit flies.

Leftwich PT, Koukidou M, Rempoulakis P, Gong HF, Zacharopoulou A, Fu G, Chapman T, Economopoulos A, Vontas J, Alphey L - Proc. Biol. Sci. (2014)

Changing medfly population dynamics through introduction of OX3864A males into large cages of stable wild-type medfly populations. (a) Average daily egg production for each week in treatment and control cages. Weeks 0–8 constituted the population stabilization period (230 pupae added each week). Introductions of 1700 OX3864A pupae into each treatment cage commenced from week 8 onwards, in addition pupal return to each treatment cage was made proportional to the control cages. Six weeks after OX3864A male introductions, there was a clear reduction in egg production in the treatment cages compared with the control cages, continuing until eventual extinction of the wild-type population in both treatment cages (as assessed by two weeks of no egg production) by week 22 (14 weeks post initial RIDL release). The dotted line denotes the average weekly daytime temperature (Celsius) taken from daily midday temperature readings. (b) Numbers of females in treatment and control cages. (c) Proportion of progeny returned to each of the treatment cages from the oviposition traps displaying the DsRed2 fluorescent phenotype. Percentage of returning pupae carrying a copy of the OX3864A transgene reached 100% in both treatment cages by week 17 (11 weeks post-RIDL release).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150327&req=5

RSPB20141372F2: Changing medfly population dynamics through introduction of OX3864A males into large cages of stable wild-type medfly populations. (a) Average daily egg production for each week in treatment and control cages. Weeks 0–8 constituted the population stabilization period (230 pupae added each week). Introductions of 1700 OX3864A pupae into each treatment cage commenced from week 8 onwards, in addition pupal return to each treatment cage was made proportional to the control cages. Six weeks after OX3864A male introductions, there was a clear reduction in egg production in the treatment cages compared with the control cages, continuing until eventual extinction of the wild-type population in both treatment cages (as assessed by two weeks of no egg production) by week 22 (14 weeks post initial RIDL release). The dotted line denotes the average weekly daytime temperature (Celsius) taken from daily midday temperature readings. (b) Numbers of females in treatment and control cages. (c) Proportion of progeny returned to each of the treatment cages from the oviposition traps displaying the DsRed2 fluorescent phenotype. Percentage of returning pupae carrying a copy of the OX3864A transgene reached 100% in both treatment cages by week 17 (11 weeks post-RIDL release).
Mentions: Dramatic decreases in weekly egg production were observed seven weeks post-RIDL release (PR) in treatment cages, compared with a continued stable rate of egg production in control cages (figure 2a). This was due to the proportion of returned progeny carrying the OX3864A transgene increasing in treatment cages, resulting in a rapid decline in the female population (figure 2b). Transgene frequency in the treatment cage populations was monitored by screening the returning pupae (chosen from all the pupae produced at random) for the presence of the DsRed2 fluorescent marker. The frequency of the transgene in the returning progeny of the treatment cages was at 100% by week 8 PR (figure 2c), with both cages considered extinct by week 14 PR (extinction defined as zero egg production for two consecutive weeks).Figure 2.

Bottom Line: Our results show (i) full functionality of RIDL, (ii) equivalency of RIDL and wild-type strains for life-history characteristics, and (iii) a high level of sexual competitiveness against both wild-type and wild-derived males.Weekly releases of OX3864A males into stable populations of wild-type medfly caused a successive decline in numbers, leading to eradication.The results show that genetic control can provide an effective alternative to SIT for the control of pest insects.

View Article: PubMed Central - PubMed

Affiliation: Oxitec Limited, 71 Innovation Drive, Milton Park, Oxford OX14 4RQ, UK School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk NR4 7TJ, UK.

ABSTRACT
The Mediterranean fruit fly (medfly, Ceratitis capitata Wiedemann) is a pest of over 300 fruits, vegetables and nuts. The sterile insect technique (SIT) is a control measure used to reduce the reproductive potential of populations through the mass release of sterilized male insects that mate with wild females. However, SIT flies can display poor field performance, due to the effects of mass-rearing and of the irradiation process used for sterilization. The development of female-lethal RIDL (release of insects carrying a dominant lethal) strains for medfly can overcome many of the problems of SIT associated with irradiation. Here, we present life-history characterizations for two medfly RIDL strains, OX3864A and OX3647Q. Our results show (i) full functionality of RIDL, (ii) equivalency of RIDL and wild-type strains for life-history characteristics, and (iii) a high level of sexual competitiveness against both wild-type and wild-derived males. We also present the first proof-of-principle experiment on the use of RIDL to eliminate medfly populations. Weekly releases of OX3864A males into stable populations of wild-type medfly caused a successive decline in numbers, leading to eradication. The results show that genetic control can provide an effective alternative to SIT for the control of pest insects.

Show MeSH
Related in: MedlinePlus