Notes on cicada-killer. Marlatt, C.L. 1907. The larger digger wasp. Packard, A.S. Description of Sphecius speciosus . Pfennig, D.W. and H.K. Reeve.
Larger females tend to win burrow disputes, but there is a resident advantage as well.
Females are less tolerant of intrusion when there is an exposed cicada in the burrow and when the intruder is smaller. Females are more tolerant of their near neighbors than they are of females from more distant burrows. Pfennig, D.W. and H.K. Reeve. Nepotism in a solitary wasp as revealed by DNA fingerprinting. Neighboring females are related, thus providing a kin selection argument for the greater tolerance to burrow intrusion.