Cockroache; Ecology, behavior & history - W.J. Bell

Fig. 9.8 Trophic shift model for transition from subsociality to
initial stages of eusociality in a termite ancestor. (A) Baseline
conditions. A series of egg cases are laid over a short period of
time, resulting in age differentials within the brood. Adults feed
all offspring; cost of parental care results in reproductive arrest.
Juveniles develop slowly but progressively toward adulthood.
(B) Transition to eusociality. Fourth instars begin feeding
younger siblings; cost of alloparental care results in developmental
arrest of juvenile caregivers. Female resumes oviposition.
After Nalepa (1988b, 1994).
are allowed to take care of neonates for 3 mon prior to
brood removal, however, only 12% oviposit the following
summer. This suggests that parental care may deplete reserves
that were accumulated over the course of their extended
developmental period and are not easily replaced.
Under the constraint of a wood diet, their apparent
semelparity in the field can be attributed to the need for,
and cost of, long-term parental care of the young (Nalepa,
1988b). The life history of a subsocial termite ancestor
similar to that of Cryptocercus is depicted in Fig. 9.8A.
EVOLUTION OF EUSOCIALITY 2:
TRANSITION
It is reasonable to assume that a termite ancestor packaged
its eggs in oothecae, since the basal termite Mastotermes
does so (Nalepa and Lenz, 2000). If the timing of
oviposition in this ancestor was similar to that of Cryptocercus—a
reproductive burst, with several oothecae laid
within a relatively short time frame—nymphs in the family
also exhibited age differentials. It is likely that repro-
162 COCKROACHES