The major advantage of sexual reproduction (over asexual
reproduction) is that it promotes genetic variability, despite the
obvious disadvantages of reduced genetic contribution to
offspring and the cost of finding mates. The benefits of sexual
reproduction can be reduced by inbreeding because inbreeding
lowers genetic diversity at both the individual and population
levels. Many termite species undergo royal succession, in which
the primary reproductives who found colonies (king and queen)
are replaced by secondary reproductives from within the nest.
Under normal sexual reproduction, such a breeding system is
expected to result in inbred colonies with limited genetic
We found that the termite Reticulitermes speratusavoids
inbreeding by the conditional use of sexual reproduction and
parthenogenesis. We sampled mature field colonies and found
that in nearly all cases, primary kings were present but primary
queens had been replaced by an average of 55.4 secondary
queens. Genetic analysis showed that secondary queens were
almost exclusively produced parthenogenetically by the original
primary queen, whereas workers and alates (new primary
reproductives) were produced by sexual reproduction and
therefore retained levels of heterozygosity expected under
outbreeding. Moreover, by producing her replacements
parthenogenetically, the queen maintains her full genetic
contribution to the next generation of primary reproductives.
These findings reveal a novel breeding system in which asexually
produced replacement reproductives in colonies of a social
insect are used to boost sexual reproductive output of the
queen to the benefit of both the queen and the colony.
Matsuura, K., Vargo, E.L., Kawatsu, K., Labadie, P.E., Nakano, H.,
Yashiro, T.and Tsuji, K.: Queen succession through asexual
reproduction in termites.Science, 323: 1687 (2009).