Some Micro-organisms Associated with the Weevils Sitophilus granarius (L.) and Sitophilus oryza (L.), (Coleoptera): II. Population differences of mycetomal micro-organisms in different strains of S. granarius

Abstract

Certain kinds of micro-organisms occurring in close internal association with insects, and often harboured in apparently specialized organs, are, at least in some species, of benefit to the insects in supplying them with needed dietary constituents, e.g., vitamins of the B complex (3).During the past twenty years conflicting statements have been made about the presence of mycetomal micro-organisms in Sitophilus granarius (6, 11). Recently some general clarification has been achieved (9). It seems that while this species commonly harbours such micro-organisms, there exists an Egyptian strain apparently free of them. Furthermore, a variety africana, distinguishable by its smaller size and lighter colour, has been described from the Nile Valley (1, 5).