Variation in colony structure in the subterranean termite Reticulitermes flavipes

The genetic organization of colonies of the subterranean termite Reticulite rmes flavipes in two subpopulations in Massachusetts was explored using fiv e polymorphic allozymes and double-strand conformation polymorphism (DSCP) analysis of the mitochondrial control region. Empirically obtained estimate s of worker relatedness and F-statistics were compared with values generate d by computer simulations of breeding schemes to make inferences about colo ny organization. In one study site (G), worker genotypes indicated the pres ence of a mixture of colonies headed by monogamous outbred primary reproduc tives and colonies headed by inbreeding neotenic reproductives, both colony types having limited spatial ranges. A second site (S) was dominated by se veral large colonies with low relatedness among nestmates. Mixed DSCP haplo types in three colonies indicated that nestmates had descended from two or three unrelated female reproductives. Computer simulations of breeding sche mes suggested that positive colony inbreeding coefficients at site S result ed from either commingling of workers from different nests or different col onies. Such an exchange of workers between nests corresponds to the multipl e-site nesting lifetype of many subterranean termites and resembles colony structure in polycalic Formica ants. Our study demonstrates considerable:va riation in R. flavipes colony structure over a small spatial scale, includi ng colonies headed by monogamous:outbred primary reproductives, colonies co ntaining multiple inbred neotenic reproductives and large polydomous coloni es containing the progeny of two or more unrelated queens, and suggests tha t the number of reproductives and nestmate relatedness change with colony a ge and size.