The joint-winged treeworm has replaced the cave palmworm. With barely any competition, some larvae have planted themselves outside the caves. Over many generations, the photosynthetic wings become jointed. The elbow's spike helps the wings stick to the ground. Tough rods develop in the wings to keep them supported. Also, the vestigial legs disappear completely. Because the genes required for legs is gone, the larvae will have to squirm to their plantation site. Because there are no predators, there was no need for legs. Another change is their tail has thick muscles to support it. Like their ancestral forms, joint-winged treeworms have a root-like tongue. It has about ten protrusions. They depend on the xenobee for pollination. Because this treeworms ancestor, the cave palmworm, was less efficient, it became extinct.