L. Filippitsukamoto et al., ADAPTIVENESS OF PARENTAL CARE IN PARCTSTRACHIA-JAPONENSIS (HEMIPTERA,CYDNIDAE), Annals of the Entomological Society of America, 88(3), 1995, pp. 374-383
To understand the adaptiveness of the advanced parental care seen in P
arastrachia japonensis Scott, some characters of egg guarding and prog
ressive provisioning were examined through field experiments and obser
vations of natural nests. A carabid beetle is the first known predator
of this species. Females of P. japonensis could not distinguish their
own eggs from those of other females and guarding of eggs against the
predator was strictly defensive; they primarily used their bodies as
shields or escaped with the egg mass. The sole food resource, drupes o
f the deciduous tree Schoepfia jasminodora (Sieb. et Zucc.), is scarce
and ephemeral, and, because conditions around the host tree are gener
ally unsuitable for nesting, most nests are located well out of range
of the fallen drupes. Females repeatedly left the nests on foraging tr
ips and provisioned nests with drupes. Survival rate of nymphs with a
female and drupes paralleled that of nymphs with only drupes when the
danger from predation was eliminated. The number of drupes provisioned
was positively correlated with the duration of the nymphal nesting pe
riod. Further, nymphs in nests with drupes remained aggregated longer
than those in nests without drupes. Because aggregations are apparentl
y essential for successful feeding in the early stages and a prolonged
nesting period probably affords protection against predation and desi
ccation, progressive provisioning may have evolved in response to thes
e environmental pressures as well as in response to the resource const
raints.