Dear RG friends,
I am providing a complete H. armigera diet for larvae and maintaining the eggs in the growth chamber as well as in-room conditions. But since three months, eggs laid from the moths are not at all hatching. Could anyone tell the reason?
Thanking you.
Dear Kariyanna B. you're welcome. Please also see this potentially useful article entitled
Rearing the Cotton Bollworm, Helicoverpa armigera, on a Tapioca-Based Artificial Diet
Article Rearing the Cotton Bollworm, Helicoverpa armigera, on a Tapi...
This article is freely available as public full text on RG.
Likely that eggs were not fertilized: Several species of moths lay unfertilized eggs. Some deficiency in the diet (which used, synthetic/semisynthetic?) may also be responsible. References may be many more I have but only two for a good semi-synthetic diet:
Ahmed, K., Khalique, F. and Malik, B. A.1998. Modified artificial diet for mass rearing of chickpea pod borer, Helicoverpa (Heliothis) Armigera (Hubn.). Pakistan Journal of Biological Sciences, 1: 183-187.
Krishnareddy, B. and Vageeshbabu, S. H.anur 2015. Enhanced synthetic diet for rearing H. armigera under laboratory conditions. Journal of Entomology and Zoology Studies 3(1): 165-167
If the artificial food meets all the needs of the mating and laying stage, then somehow make sure that the eggs are fertilized
Dear Moslem Aletby thanks for your suggestions.
Now I am working on the male and female ratio in the mating box and will cross check it for fertilisation.
Normally unmated females lay unfertilized eggs take care to get them mated.
First, the eggs should be placed in moist support (moist soil, wet filter paper ...), then in the growth chamber it seems that you have used an aerator that dries the eggs and solidifies them (keep a temperature between 20 and 25 ° C without the eggs being attacked by drafts (lime or cold). The third when you transport the eggs from one medium to another may be the eggs were shocked by the outside climate. Besides, the room temperature was low (you need a heating source that does not emit air). So try to put eggs in moist support in room condition away from air and in temperature that oscillates between 20 and 25 °C.
Regards
Dear Amandeep Kaur and J. Ashoka
Thank you so much for the answer and I will definitely focus on it.
Dear Ramzi Amari
Really worth information to adopt and disseminate.
Thanks for your valuable time, in sharing useful information.
From the information you have provided, I guess the environmental conditions are too cold for the eggs and adults. Adult insects and their other stages of development tend to detect cold conditions and then resort to diapause. I suggest you provide an automatic heater in your experimental room set a temperature ranging 23-25 ° C to help you break the diapause.
Henlay Magara, I kept in growth chamber containing 27 +/-1 degree temperature with 60-70 per cent humidity. So I am trying in all the way. Will come back after trying your suggestion.
Thank you.
I suggest to put sterilized sand about 5cm at the bottom of your chamber as a oviposition media for mated female to lay her eggs.
Incubate the eggs using foan rubber pad and wax coated paper. Wax paper should be used as floor and cover for the eggs. Foam rubber pap dipped in water, sequized and kept around the eggs. Set the temperature at 25 to 26 o C till the completion of incubation period. Namaste This we practice for mulberry silkworm eggs for uniform hatching
Dear J. Ashoka sir
Thank you, I will try the same for my pest of interest
Susrama i Gede Ketut, how best it will increase the egg hatching ? Because, sand media can’t hold moisture.
Dear Юлия Ляска , I cross checked the ingredients and recipe we are using to prepare a diet for H. armigera with others insect. I feel we are preparing accurately.
Using moist sand as oviposition media rather old way. The way Mr. Ashoka explained better.
Dear Susrama i Gede Ketut
Maintaining sand in moist condition is an another challenge. I am undertaking the suggestions of Dr J. Ashoka .
One of the probable reason for unhatching of eggs is male:female ratio. If possible keep more male adults or keep one male and female in small vial for mating for two to three days with sugar solution and white cloth for egg laying.
Dear Shivam Padaliya
We are maintaining good ratio of male and female. Now we are providing good condition to observe their hatchability.
Thanks
Dear Susrama i Gede Ketut
Nothing like that, I am just searching other reason behind it.
Okay, hopefully the finding will be an interesting reason . . .
Yes,
After following all the suggestions given by RG members, I found hatching egg of the H. armigera.
Thanka to all
Hello colleagues,
I think first we must make sure that the eggs are fertilized. If that is ok., I think it's both about the relative humidity and the speed of the fan in the growth chamber.
Dear Kariyanna B. just in case that this is still of interest to you: There is an older, closely related RG thread on the same topic which is entitled
Why did the eggs of Helicoverpa armigera not hatched?
https://www.researchgate.net/post/Why_did_the_eggs_of_Helicoverpa_armigera_not_hatched
Perhaps you'l find some of the answers useful.
Dear Frank T. Edelmann thanks for the useful thread. I will go through it
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