Flanders, S.E. 1965 Competition and cooperation among parasitic Hymenoptera related to biological control.. Canadian Entomologist 97: 409-422.

Notes: Since the earliest days of this century the interactions of parasitic Hymenoptera that attack the same host species have been reported from time to time in connection with studies on the natural enemy fauna of pest insects. These studies indicate that the synchronous attack by two or more parasitic species on an individual of a host population, multiple parasitism, is of little, if any, importance in the economy of that population, whereas the attack by two or more parasitic species on a sequence of a host's developmental stages and instars, sequential parasitism, may be highly important, especially from the standpoint of host regulation. Since the host-regulating capacity of a parasite species may vary both seasonally and geographically, sequential parasitism is highly conducive to continuity in the conservation of the host's food supply, the practical measure of regulative parasitism are discussed. The parasite fauna of the black scale, Saissetia oleae (Bernard), is used to exemplify these aspects of parasitism.