Insulin-like signaling within and beyond metazoans
we can see that there is a recognisable insulin like receptor stemming from the common ancestor leading to both ourselves and sponges. That's pretty far back, marked by the blue lineage arrows in Figure 1 from the review:
"The convergent evolution of ligand-receptor pairs alone cannot explain however the biochemical similarities in the intracellular response to insulin observed outside metazoans, as illustrated above. One way to overcome this seeming inconsistency is by considering that independently evolved upstream components of pathways devoted to processing environmental information may have been tied to evolutionary conserved core metabolic and cellular growth signaling networks".