Sterile Insect Technique (SIT) is considered to be suitable for dipterans rather than lepidopterans . Why SIT not much successful against lepidopterans ?
I recommended to study the attach file. I hope it be helpful for you.
I don't think there is a 100 percentage of control effect in any technique!
even none of the technique gives 100 per cent control and there is no need for this
I agree with Jianing Wei there is no a 100 percentage of control effect in any technique.
Do you have any document that Sterile Insect Technique (SIT) is suitable for dipterans rather than lepidopterans ? Is there any experiment for this? Please clarify.
SIT presently is required for pink boll worm of cotton as its problem increases day by day in bt cotton
I apologize that i wrongly framed the question instead of 100 per cent control it should have been 100 per cent sterility. SIT has been an important component of Area Wide Pest management, having said that SIT has been used for eradication of an insect from a particular area (Knipling has been conferred world food prize for this feat) Is eradication a 100 per cent control? This database www. nucleus.iaea.org/ididas suggest that SIT has been partially successful in sterlizing lepidopterous insect but rather fully helpful against dipterans. So Why does SIT has not been successful in 100 per cent sterilization of lepidopterous insects?
Every SIT population has to be generated through sterilization process itself,there could be some error or some level of poor response etc. Thus some individuals would remain fertile.
Well now I found the answer to this question. Hope you all will be satisfied.
Every insect requires a specific safe limit of radiation (in terms of Gy) for sterilization. For Dipterans , A specific safe value is required for male sterilization so that two conditions are met first male become sterilize and secondly it has a good competitive mating ability with respect to wild males but when it comes to lepidopterans no such radiation limit has been prescribed which could meet both the above mentioned condition.
Dear Pradeep Kumar Dalal,
Still this concept required to be documented.Do you have any references?
yes i am totally agree with this that this process to be documented properly and we have to accept the facts
Hope I have reached to the answer:
most lepidopterans are more resistant to radiation than dipterans (Bakri et al., 2005b) and as a consequence, the higher dose of radiation required to completely sterilize lepidopterans reduces their performance in the field.Let me explain:
1- Diptera can be classed as radiation-sensitive, while Lepidoptera is radiation-resistant (Bakri et al., 2005a). This is because they differ in their type of centromere (localized centromere (monokinetic) in Diptera while Lepidoptera has a diffuse centromere (holokinetic). the centromere difference is believed to play a major, although not exclusive, role in radiation sensitivity (Carpenter et al., 2005)
2- Lepidoptera do not show the classical breakage-fusion-bridge cycle that is a characteristic of dominant lethals induced in Diptera. Let me explain:
Breakage-fusion-bridge (BFB) cycle is a mechanism of chromosomal instability.
The BFB cycle begins when the end region of a chromosome, called its telomere, breaks off. When that chromosome subsequently replicates it forms two sister chromatids which both lack a telomere. Since telomeres appear at the end of chromatids, and function to prevent their ends from fusing with other chromatids, the lack of a telomere on these two sister chromatids causes them to fuse with one another. During anaphase the sister chromatids will form a bridge where the centromere in one of the sister chromatids will be pulled in one direction of the dividing cell, while the centromere of the other will be pulled in the opposite direction. Being pulled in opposite directions will cause the two sister chromatids to break apart from each other, but not necessarily at the site that they fused.This results in the two daughter cells receiving an uneven chromatid. Since the two resulting chromatids lack telomeres, when they replicate the BFB cycle will repeat, and will continue every subsequent cell division until those chromatids receive a telomere, usually from a different chromatid through the process of translocation.
So, lepidopteran chromosomes can tolerate telomere loss without the drastic effects that this has on chromosomes in other orders (Tothová and Marec, 2001).
References:
- Bakri, A., K. Mehta, and D. R. Lance. 2005a. Sterilizing insects with ionizing radiation. pp. 233-268 In V. A. Dyck, J. Hendrichs, and A. S. Robinson (eds.), Sterile Insect Technique: Principles and Practice in Area-wide Integrated Pest Management. Springer, Dordrecht, The Netherland. 787 pp.
- Bakri, A., N. Heather, J. Hendrichs, and I. Ferris. 2005b. Fifty years of radiation biology in entomology: lessons learned from IDIDAS. Annals of the Entomological Society of America 98: 1-12.
- Carpenter, J. E., S. Bloem, and F. Marec. 2005. Inherited sterility in insects. pp. 115-146 In V. A. Dyck, J. Hendrichs, and A. S. Robinson (eds.), Principles and Practice in Area-wide Integrated Pest Management. Springer, Dordrecht, The Netherlands. 787 pp.
- Tothová A. and F. Marec 2001. Chromosomal principle of radiation-induced F1 sterility in Ephestia kuehniella (Lepidoptera: Pyralidae). Genome 44: 172–184
Regards,
Wafaa
Seem like I was very close to the answer. I am grateful to have your clarification thanks Wafaa
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