*2.2. Other Biological Sources of ROS*

A variety of cellular developmental and metabolic activities and other biological events can lead to the generation of ROS (Table 1). Increased malondialdehyde (MDA) concentrations, an indicator of oxidative stress, were also observed during embryonic development as well as larval maturation of the ticks such as *Rhipicephalus microplus* and *Haemaphysalis longicornis* [34,35]. In mosquitoes, an increase in metabolic activities, including oogenesis, also results in the generation of ROS and these ROS accumulate over time and can affect the fecundity of mosquitoes [36]. Since mosquitoes are flying insects, ROS generation is further accelerated by the increased mitochondrial activity of the flight muscles [37]. Although it is not proven in blood-feeding arthropods, studies in insect models such as *Drosophila* indicate that a high production of ROS in the insect nervous system results in the ROS-mediated decline of neuron survival [16].


**Table 1.** Biological sources of ROS aside from blood meals.
