What characteristic do flies and mosquitoes share in terms of feeding?

Flies and mosquitoes share the characteristic of taking a blood meal, particularly females of certain species. Female mosquitoes require proteins found in blood for their egg development, which is why they seek out hosts to feed on. While not all flies are blood-feeders, there are specific types of flies, such as tsetse flies and some species of horse flies, that also feed on blood. This feeding behavior is crucial for their reproductive processes.

The other choices do not accurately describe the feeding behavior of these insects. For instance, while some insects may feed on plant juices, not all flies or mosquitoes do; instead, many feed on liquids, including nectar. Feeding on fabric is not a behavior associated with these groups. Additionally, both flies and mosquitoes can and do bite; thus, the statement asserting they do not bite is not representative of their feeding habits.