Temporal and spatial variation in caste proportions in a northern Reticulitermes flavipes colony (Isoptera: Rhinotermitidae)

Reticulitermes flavipes (Kollar) foragers were collected at 2-4 week intervals during spring and fall 1988 from traps placed upon a tree stump and below the soil surface throughout a field site in the City of Scarborough, Ontario. Caste proportions were determined from all collections. Nymphs represented approximately 2% of foragers collected from the tree stump in May and early June, but 31-47% of the foragers collected in this trap from late June through early August. During this same period of June and August, nymphs represented 2-8% of the foragers within the traps placed in the surrounding soil. In late August, nymph proportions in the stump trap declined to the level of those in the soil. No alates were collected from any traps. These results indicate a preferential aggregation of nymphs in the vicinity of a large perennial resource, and support previous suggestions that neotenic reproductives arising from the numerous nymphs that develop in the spring are the major reproductive forms in R. flavipes colonies in the northern portion of the geographic distribution of this species.