Webworms employ their silk to tie together their host's reproductive parts.
The larva at left has used its silk to bring together all of the umbellets in an umbel. Umbels at the bud stage can be securely bound into a dense mass of plant tissue, completely hiding the larva or larvae within. The larvae typically remain inside their webs, feeding on the plant tissues. As they grow, the caterpillars must move and begin construction of new, larger webs to accomodate their increased size. Late instar larvae are rather proprietary when it comes to their webs.