12.4. Evolution and maintenance of eusociality
At first impression the complex social systems of hymenopterans and termites bear a close resemblance and it is tempting to suggest a common origin. However, examination of the phylogeny presented in Chapter 7 (Fig. 7.2) shows that these two orders, and the social aphids and thrips, are distantly related and a single evolutionary origin is inconceivable. Thus, the possible routes for the origin of eusociality in Hymenoptera and Isoptera are examined separately, followed by a discussion on the maintenance of social colonies.
Broken lines indicate uncertain relationships. Thysanura sensu lato refers to Thysanura in the broad sense. (Data from several sources)