Females of the shield bug Parastrachia japonensis Scott (Hemiptera: Parastrachiidae) provision their nymph-containing nests with drupes of the single host tree, Schoepfia jasminodora Sieb. et Zucc (Olacaceae: Rosidae: Santales). We carried out several field experiments to examine the variation in the start of nest abandonment by using field cages set in a copse in Japan. First, in individual cages where female parents could freely provision their nests with drupes provided in abundance in a distant foraging cage, we observed when nymphs began abandoning the nests. Considerable variation was found in the beginning of nest abandonment among nests, with a tendency for it to be delayed in nests where the average number of drupes provided per nymph (average provisioning rate) was high. Second, we excluded females from nests when nymphs were in the second stadium. We then artificially supplied drupes at two levels of abundance to verify whether the delay in the start of nest abandonment was caused by an increase in the nymphal daily food availability. Nymphal nest abandonment started in direct response to the amount of artificially provided food. Finally, a field experiment to determine the ability of nymphs at various developmental stages to reach the foraging site from the nest site revealed that younger independent nymphs were rarely able to succeed. We discuss nymphal nest abandonment with regard to assessing the risk of starvation, attributable to a shortage of food provided by the female parent, and postindependence risk.
Annals of the Entomological Society of America
Vol. 98 • No. 1
Vol. 98 • No. 1