Expression analysis of glutathione S-transferases and ferritins during the embryogenesis of the tick Haemaphysalis longicornis .

In the tick life cycle, embryogenesis is the only stage of development wherein no blood meal is required. Nevertheless, even in the absence of a blood meal, which is the source of nutrients as well as the ferrous iron and heme that could cause oxidative stress in ticks, malondialdehyde (MDA) has been reported to increase during this period. Additionally, the knockdown of some oxidative stress–related molecules such as ferritin has resulted in abnormal eggs and embryonic death.