I want to rear Sitobion avenae, its predators (ladybird beetle and green lacewing) and parasitoid (Aphidius gifuensis) in the rearing room. But I am confused about the requirements of temperature and relative humidity in room. Kindly tell me at which temperature and RH, I reared these insects?
Hi Bilal,
maybe you can get something from the ff references:
best of luck!
http://etd.fcla.edu/UF/UFE0002842/hallborg_k.pdf
http://www.zin.ru/animalia/coleoptera/addpages/Andrey_Ukrainsky_Library/References_files/Khan02a.pdf
http://www.hindawi.com/journals/psyche/2011/868546/
http://search.proquest.com/openview/50afaddbbc7782209d3b946e894f329c/1?pq-origsite=gscholar&cbl=1596357
http://14.139.155.167/test5/index.php/kjas/article/viewFile/945/938
There is no single optimal answer. However, there is a range of values that work and the idea is somewhat host dependent. So rearing aphids on wheat may have an optimal range slightly different than rearing on rye. The difference may be small.
Temperature in Aphis gossypii does a number of things that might be important to predators and parasites. A. gossypii reared under cooler temperatures and uncrowded conditions becomes larger and dark green. A. gossypii reared under warm/hot temperatures and crowded conditions becomes small and yellow. I am not sure about S. avenae. There is a large body of literature on life history traits of the aphid. Here is one example:
Daily temperature extremes play an important role in predicting thermal effects
By: Ma, Gang; Hoffmann, Ary A.; Ma, Chun-Sen
JOURNAL OF EXPERIMENTAL BIOLOGY Volume: 218 Issue: 14 Pages: 2289-2296 Published: JUL 2015
High relative humidity may encourage fungal entomopathogens or plant pathogens. It also will encourage sooty mold growing on leaves covered in honeydew.
Generally speaking, aphids are not difficult to rear. They do well under the temperature range from 20-28oC, and RH 50-80% depending on the aphid species and the host plant you use to feed them. I have reared Green Peach Aphid (GPA) Myzus persicae and Cotton Aphid (CA) Aphis gossypi before. GPA did well in a little cooler condition at 22-25oC on capsicum plant, while CA was reared well in relatively higher temp at 25-28oC with cotton or capsicum plants ( cotton was better than capsicum in higher temp and the plant can last longer). For a different species you rear, I suggest you to try a combination of the these main factors- host plant, Temp and RH (in the above mentioned range). Also pay attention to air circulation and light/dark setting.
I reared S. avenae at 23ºC. It worked well. Some colleagues use wheat plants in vegetative stage. I used wheat plants in reproductive stage (wheat ear developed), and the results were very good.
I reared Lysiphlebus testaceipes on Aphis gossypii. There was also another student that was rearing coccinellids on A. gossypii. We reared the aphid on cottom and watermelon. I have forgotten the specific cultivar. Leaf hairiness is important which more glabrous hosts being favored. The temperature and humidity were in the range described by Marcus, Liang, Mark, and Justine. One of the biggest problems was keeping the plants free of pests, and keeping the aphid colonies free of parasitoids/predators. Mostly this was managed by going from greenhouse to aphid colony and then to the parasitoid/predator colony and never ever going back. The parasitoids were easy. The coccinellids ate too much.
I am rather dismayed that the writer of the question has not reacted to any of the several answers that were provided by various learned readers to his confusion regarding temperature and RH in rearing S. avenae and its parasitoid in the room! The session of Q & A becomes one-sided when the originator of the question remain silent or does not contribute. In fact, the list of answers seem to be getting longer which possibly might have confused the author of the question more than before until he prefers to break his silence and speak his mind.
I am very thankful to you all for participating in my question and giving me nice suggestions.
Thank you very much for your contribution in my question. Actually I was busy in previous days, so I didn't reply to anyone. So I am feeling very sorry to all the contributors including Mr. Basant K. Agarwala.
We have resolved problems of "rearing temperature and humidity choices" for any of the studied insects we wanted to rear just by measuring the conditions in the fields where they occur naturally. The so called squirrels help to measure several data and register them on the spot. These are the conditions you start with. Then you know that an increase in temperature accelerates the development and reducing temperature makes it slower (between thresholds). Trying them out in the lab you get optimum, minimum and maximum temperatures. With this principle in mind (read nature and you get the answers) you can "serve your local insects" better then copying other conditions from literature.
The problem with Carola's answer is that using temperatures recorded from a nearby weather station is not a great way to determine those thresholds because most insects live in a narrow boundary layer that will have very different temperature/humidity conditions than ambient. The other issue is that nature is dynamic while laboratory conditions are relatively static. 102F may be lethal with 24H exposure but have little effect if it lasts for 10 minutes.
There is also the problem that some organisms make major transitions at sublethal temperatures. An example is the winter versus summer morph of the melon/cotton aphid. At least for a parasitoid, there will be a significant effect on parasitoid size depending on whether you use a summer (small) or winter (large) adapted melon aphid colony. Wasps get bigger if more food is available, and larger wasps are able to produce more offspring.
While in principle "read nature and you get the answers" is a great idea, you need to be very careful about the application. The world is a very different place when you are the size of an ant. Using the literature is great because it provides an answer based on what other people have done within the limitations of the laboratory setting.
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