Effects of a brassinosteroid analogue to mosquito larvae.
Many plant compounds are able to modulate herbivore growth and reproduction by directly interacting with steroid hormones systems. In insects, several classes of phytochemicals, including brassinosteroids and related substances, interfere with molting and reproduction. The effects of the molting-hormone antagonist pesticide DI-31, a brassinosteroid analogue, on Aedes aegypti mosquito larvae were tested in two different exposure scenarios. After static exposure of first-instar larvae, the calculated NOEC, LOEC, and LC(50) values referenced to 19 d were 0.03, 0.036, and 0.04 mg/mL, respectively. Semistatic exposure of fourth-instar larvae revealed them to be slightly less susceptible than the younger larvae (NOEC 0.03 mg/mL, LOEC 0.036 mg/mL, LC(50) 0.049 mg/mL referenced to 19 days). In both cases mortality was immediate and larval development was retarded. This study suggests that A. aegypti could be a useful model for the detection of hormonally active substances such as DI-31.
Davison
Gema P
GP
Center for Research and Biological Evaluation (CIEB-IFAL), University of Havana, 10400, Havana, Cuba. rrestrep@ecopetrol.com.co
Restrepo
Ricardo
R
Martínez
Gregorio
G
Coll
Francisco
F
León
Olga Sonia
OS
D000330:Aedes; D000818:Animals; D001681:Biological Assay; D004440:Ecdysone / Q000037:antagonists & inhibitors*; D004784:Environmental Monitoring / Q000379:methods; D007814:Larva / Q000254:growth & development; D007928:Lethal Dose 50; D010575:Pesticides / Q000633:toxicity*; D013256:Steroids / Q000633:toxicity*
C483960:DI-31 compound; D010575:Pesticides; D013256:Steroids; D004440:Ecdysone