Assessment of species specificity of moulting accelerating compounds in Lepidoptera: comparison of activity between Bombyx mori and Spodoptera littoralis by in vitro reporter and in vivo toxicity assays.
BACKGROUND
Dibenzoylhydrazine analogues have been developed successfully as a new group of insect growth regulators, called ecdysone agonists or moulting accelerating compounds. A notable feature is their high activity against lepidopteran insects, raising the question as to whether species-specific analogues can be isolated. In this study, the specificity of ecdysone agonists was addressed through a comparative analysis in two important lepidopterans, the silkworm Bombyx mori L. and the cotton leafworm Spodoptera littoralis (Boisd.).


RESULTS
When collections of non-steroidal ecdysone agonists containing different mother structures (dibenzoylhydrazine, acylaminoketone, tetrahydroquinoline) were tested, in vitro reporter assays showed minor differences using cell lines derived from both species. However, when compounds with high ecdysone agonist activity were examined in toxicity assays, larvicidal activity differed considerably. Of note was the identification of three dibenzoylhydrazine analogues with > 100-fold higher activity against Bombyx than against Spodoptera larvae.


CONCLUSIONS
The present study demonstrated that species-specific ecdysone-agonist-based insecticides can be developed, but their species specificity is not based on differences in the activation of the ecdysone receptor but rather on unidentified in vivo parameters such as permeability of the cuticle, uptake/excretion by the gut or metabolic detoxification.
Soin
Thomas
T
Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
De Geyter
Ellen
E
Mosallanejad
Hadi
H
Iga
Masatoshi
M
Martín
David
D
Ozaki
Shunsuke
S
Kitsuda
Shigeki
S
Harada
Toshiyuki
T
Miyagawa
Hisashi
H
Stefanou
Dimitra
D
Kotzia
Georgia
G
Efrose
Rodica
R
Labropoulou
Vassiliki
V
Geelen
Danny
D
Iatrou
Kostas
K
Nakagawa
Yoshiaki
Y
Janssen
Colin R
CR
Smagghe
Guy
G
Swevers
Luc
L
D000818:Animals; D012831:Bombyx / Q000187:drug effects* / Q000378:metabolism; D002460:Cell Line; D004440:Ecdysone / Q000819:agonists / Q000037:antagonists & inhibitors; D017930:Genes, Reporter / Q000235:genetics*; D006834:Hydrazines / Q000633:toxicity; D007605:Juvenile Hormones / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D018978:Molting / Q000187:drug effects*; D011987:Receptors, Steroid / Q000378:metabolism; D013045:Species Specificity; D018411:Spodoptera / Q000187:drug effects* / Q000378:metabolism; D018675:Toxicity Tests / Q000379:methods*
D006834:Hydrazines; D007605:Juvenile Hormones; D011987:Receptors, Steroid; C055469:ecdysone receptor; D004440:Ecdysone; C082026:tebufenozide