Aberrant variations of P. regius that have not been officially described, and rarely encountered color/pattern variations of typical P. regius.
Insects and other spiders, the typical prey of Phidippus.
Once they obtain aberrant coloration at molt, the abnormal behavior comes along with it. They will readily hunt and capture various prey, but almost immediately release their prey the majority of the time, seemingly only holding on to it when close to starvation.
The abnormal behavior is likely the reason these atypical P. regius are so infrequently encountered in the wild, as they probably just starve to death.
To date the only prey I have found that they readily capture and consume are other recently molted, defenseless spiders. Foraging Phidippus often investigate sacs they encounter, and molting or freshly molted spiders are easy prey.
Aberrant P. regius also decimate shed skins they encounter in other sacs. Normal Phidippus that utilize previously inhabited sacs with cast skins simply discard the skin in one or more pieces by biting it and pulling out of the sac, while aberrant P. regius chew the skins up into little pieces, attempting to extract any available nutrients.
The change from 'normal' to 'atypical' can likely occur at any instar, but so far only observed from fourth or fifth to ultimate instar. Early instar atypical P. regius can rarely be reared to maturity in captivity, and generally males more often than females. Most captive specimens eventually exhibit erratic seizure like behavior when disturbed, with random legs curling or fully extending while trying to flee.
The spiders quit eating and eventually die, although not necessarily from starvation, rather an unknown cause.