Cypermethrin inhibits egg development in the ixodid tick, Amblyomma hebraeum

Author
Friesen, Kevin
Kaufman, Ruben
Faculty Advisor
Date
2003
Keywords
cypermethrin , vitellogenesis , 20-Hydroxyecdysone , amblyomma hebraeum , Ticks , pyrethroid
Abstract (summary)
The pyrethroid insecticide, cypermethrin (CyM), stimulates vitellogenesis in Ornithodoros moubata (an argasid tick) by stimulating the release of the normal vitellogenesis-inducing factor (a neuropeptide) and subsequent release of the vitellogenic hormone [19]. Here we examine the effects of CyM on egg development in the ixodid tick, Amblyomma hebraeum. Ovary weight, oocyte size, and vitellin content of the ovary were measured after CyM treatment; in partially fed ticks, none of these parameters were affected significantly. However, CyM treatment caused an inhibition of ovary development, as well as reduction of both hemolymph 20-hydroxyecdysone (20E; the vitellogenic hormone in this species) and vitellogenin (Vg)-concentrations in engorged ticks. In addition, the degree of salivary gland degeneration (which is triggered by 20E) was slightly reduced in CyM-treated engorged ticks. These results indicate that CyM acts differently in Amblyomma compared to Ornithodoros. Instead of stimulating vitellogenesis, CyM inhibits egg development perhaps in part as a result of inhibiting release of 20E.
Publication Information
Friesen, K. J., & Kaufman, W. R. (2003). Cypermethrin inhibits egg development in the ixodid tick, Amblyomma hebraeum. Pesticide Biochemistry and Physiology, 76(1), 25-35. doi:10.1016/S0048-3575(03)00032-4
DOI
Notes
Item Type
Article
Language
English
Rights
All Rights Reserved