Answer: Hemolymph

Not only do insects not have blood like we (and other vertebrates) have, but their circulatory system looks quite a bit different from our own. In the human body, blood is circulated through an elaborate and branching system driven by our heart and kept separate from other internal systems.

In insects, however, the lines between “blood” and everything else is a bit more blurred. They have a fluid called “hemolymph” that fills their entire body cavity. Further, instead of a single heart that drives this material through an elaborate network of veins and arteries, they have coordinated body muscle movements and multiple simplistic hearts that serve almost like sump pumps. The fluid is pushed around their bodies where it makes full contact with both their organs and their waste exchange systems.

If the human body functioned in such a fashion, it would be like having a viscous fluid that was squeezed between our major muscles and moved about carrying energy and waste directly between our organs. Thankfully, we have the system in place that we do because the simplistic hemolymph-based system found in insects could never support the kind of oxygen, nutrient, and hormone exchanges required to keep a human body running.