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Eusociality has been commonly observed in distinct animal lineages. The reproductive division of labor is a particular feature, achieved by the coordination between fertile and sterile castes within the same nest. The sociogenomic approach in social hymenopteran insects indicates that vitellogenin (Vg) has undergone neo‐functionalization in sterile castes. Here, to know whether Vgs have distinct roles in nonreproductive castes in termites, we investigated the unique characteristics of Vgs in the rhinotermitid termite Reticulitermes speratus. The four Vgs were identified from R. speratus (RsVg1−4), and RsVg3 sequences were newly identified using the RACE method. Molecular phylogenetic analysis supported the monophyly of the four termite Vgs. Moreover, the termites Vg1−3 and Vg4 were positioned in two different clades. The dN/dS ratios indicated that the branch leading to the common ancestor of termite Vg4 was under weak purifying selection. Expression analyses among castes (reproductives, workers, and soldiers) and females (nymphs, winged alates, and queens) showed that RsVg1−3 was highly expressed in fertile queens. In contrast, RsVg4 was highly expressed in workers and female nonreproductives (nymphs and winged adults). Localization of RsVg4 messenger RNA was confirmed in the fat body of worker heads and abdomens. These results suggest that Vg genes are functionalized after gene duplication during termite eusocial transition and that Vg4 is involved in nonreproductive roles in termites. Research highlights: Four vitellogenin (Vg) genes were identified in the termite genome. Vg1−3 and Vg4 genes might have a different evolutionary origin. Vg4 gene was expressed in the fat body of nonreproductive castes, and is likely to be involved in nonvitellogenic roles. [ABSTRACT FROM AUTHOR]

Termite caste differentiation requires hormonal regulation, but understanding of the role of ecdysone is limited. Here, we investigated the expression and function of ecdysone-related genes during soldier differentiation in the damp-wood termite Zootermopsis nevadensis. Ecdysone receptor gene ( EcR) was highly expressed in the head just after the presoldier molt. Knockdown of EcR expression in the early presoldier period inhibited the molts into soldiers. However, knockdown in the middle period affected tyrosine metabolic gene expression and inhibited soldier-specific cuticular tanning. These results suggest that ecdysone activation is involved in soldier-specific cuticle formation. [ABSTRACT FROM AUTHOR]