Fig. 1

Queen development and the fat body structure in termites. A Photographs of Reticulitermes speratus colonies. Monogamous pairs of adults found new colonies. Mature field colonies contain a number of queens, which continuously produce eggs over several years. AQ, adult queen; K, king; NQ, neotenic queen; S, soldier; W, worker. B The abdomen of a fully matured termite queen is almost filled with ovaries and fat body. In R. speratus, the fat body appears as whitish loose tissue located around the digestive tube and reproductive organs. The fat body tissue is comprised of two types of cells, that is, adipocytes, which are metabolically active and contain lipid droplets, and urocytes, which are not active but contain urate spherules. The illustration of the histology of the termite fat body was drawn with reference to [14]. C Developmental patterns of queens in R. speratus. Queens are categorized into adult queens (primary queens), nymphoids (nymph-derived neotenics), and ergatoids (worker-derived neotenics). All queens undergo reproductive maturation after adult or neotenic molts. In R. speratus, almost all queens collected in field colonies are nymphoid queens. Ergatoid queens are rarely observed in field colonies [27], yet they can easily be induced under laboratory conditions [28]