Interesting article about juvenile hormone and dsx

[Oak]

http://column.odokon.org/2015/0410_142600.php

I wonder if world records can be broken with the use of JH? 

[JKim]

This must be a part of Be-Kuwa article... Before I even read this article in Be-Kuwa, I actually constructed a hypothetical study in enlarging insects by either transplanting corpora allata or somehow injecting juvenile hormone to extent larval stage, and asked comments from my insect physiology professor, and he said: that's not gonna work. 😅😅

He commented me that properly transplanting such organ is nearly impossible, and even with success to have it produce additional juvenile hormone, larvae may not successfully molt (pupate) to pupal stage properly.

Have you ever experienced a particular larva (among group of same generation) not pupate forever, and eventually die off?? That's the abnormal case where JH is continually produced, and never letting larvae pupate. Of course that doesn't mean they feed more and more to gain weight. I experienced couple times in the past. I think this is what has happened. There might be some more Japanese blog articles regarding to this. I remember reading some articles saying their Japanese rhinoceros beetle (Trypoxylus sp.) larvae just stayed as larval stage over an year, and eventually died.

HOWEVER, a reverse actually worked... By removing corpora allata, insect could skip couple molting, and pupate right away. I read a research article long time ago (10+ years ago) that is done in Lepidoptera. Leps usually take about 5-6 caterpillar stages. They removed corpora allata to completely stop juvenile hormone production, and the result was as expected. Caterpillars only went through 3 stages (upto L3), and pupated. All other lab conditioned normal specimens went through 5-6 stages. Try search Juvenile hormone lepidoptera, or in similar combination, you may be able to freely access the research article.