The insect growth regulator insecticide cyromazine causes earlier emergence in Drosophila melanogaster

Abstract

The insecticide cyromazine, classified as an insect growth regulator, inhibits the growth and development of Diptera. The precise mode of cyromazine action remains unknown. We investigated mortality and developmental time effects after exposing first instar Drosophila melanogaster larvae to cyromazine for 8-h intervals. Significant increases in mortality were only observed for cyromazine exposure within the first 16 h of the first instar stage, suggesting that cyromazine accumulates in the larvae over time and that there is a delay between cyromazine exposure and effect. We observed that exposure to cyromazine during the early first instar stage resulted in earlier eclosion of adults when compared to cyromazine exposure at later first instar stages. The presence of 20-hydroxyecdysone during cyromazine exposure significantly reduced the lethal effect of cyromazine. We raise the possibility that the mode of cyromazine action is related to the development hormone, 20-hydroxyecdysone.

Sterilization Effects of Adult-targeted Baits Containing Insect Growth Regulators on Delia antiqua

“…Third, eggs formed normally in female ovaries, but they were resorbed before being laid. Cyromazine is of ecdysone activity, and it has been hypothesized to be related to the development of hormone 20-hydroxyecdysone 40 41 . Low concentrations of ecdysteroid are essential for normal oogenesis, while there is a threshold concentration in egg chambers and that apoptosis at mid-oogenesis is induced when the ecdysteroid levels exceed that threshold 53 .…”

“…Pyriproxyfen is a juvenile hormone mimic which prevents maturation of larvae to adults 39 . Cyromazine is a chitin-synthesis inhibitor with supposed ecdysone activity 40 41 .…”

Laboratory tests of insect growth regulators as bait sprays for the control of the olive fruit fly, Bactrocera oleae (Diptera: Tephritidae)

“…Its precise mode of action remains unknown, although it has been hypothesised to be related to the development hormone 20-hydroxyecdysone. 23 Finally, azadirachtin is a botanical pesticide obtained from the seed kernels of the neem tree Azadirachta indica A. Juss. It has a variety of different effects.…”

A screening of medicinal compounds for their effect on egg strings and nauplii of the salmon louse Lepeophtheirus salmonis (Krøyer)

“…Cyromazine is a moulting disruptor utilized against several pest species. The mode of action is at present not fully discovered (Van de Wouw, Batterham & Daborn ), but the mortal effect on target organisms seems to be delayed after exposure. This compound was a possible candidate to affect the moulting process of sea lice, but this did not seem to be the case in our study.…”