Eusocial insects, such as ants, bees, wasps, and termites, are characterized by a system of caste division (reproductive vs. non-reproductive individuals), where selection favors long lifespan of reproductives, i.e., queens (and kings in termites). Especially in some termite species, AQS (asexual queen succession) acts as a very strong selective pressure on the kings’ longevity. Our order estimation of the average lifespan of primary kings of the AQS termite Reticulitermes speratus based on the data of royal composition of field colonies suggested that it can be longer than 76 years and even 100-year-old king is in the range of possible variations. Because of their caste-specific life histories and extreme lifespan differences derived from epigenetic changes, social insects provide ideal opportunity to identify molecular mechanisms involved in the extended lifespan of reproductive individuals.