| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
Females of the subsocial shield bug, Parastrachia japonensis Scott (Hemiptera : Cydnidae), transport food from the foraging to their young in the nest, a rare behavior among solitary reproducers and phytophagous hemipterans. Thus, the findings of this behavioral ecological study are expected to contribute significantly to the field of social bihavior. The field studics described herein took plate in 1996 and 1997 at Hinokuma Mountain Prefectural Park, in Kanzaki Town, Saga Prefecture, , Japan. We observed female provisioning behavior in manipulated studies using specially constructed cages that were set in the field. In addition, because this insect has been found in Katsudake, Okihawa, we attempted to compara the behavior seen in Saga with that in Okinawa, which has very defferent environmental conditions.
The findings were as follows : 1) Females began provisioning after hatching and adjusted the frequency of provisioning to the developmental stage of the nymphs ; 2) The duration between hatch and nymphal independance from the nest was prsitively correlated with the total number of drupes provided ; 3) Nymphs assessed female provisioning effert to decide the time of independence ; 4) Female longevity was positively correlated to body size, and heavier females established their nests further from the foraging ; 5) Female longevity and the total number of drupes provided decreased with increased distance of the nest from the foraging area.
Although we did locate several host trees, 3 exhaustive searches in 1996 and 1997 in Okinawa failed to locate any subpopulations of P.japonensis. Thus we unable to compare the behavior at the two regions.
The findings of the 1996 study were reported in a paper that is currently in press at the Journal of Insect Behavior ; the results of the 1997 study were presented at the 1997 International Conference of Ethology in Wien, and have been submitted to an international journal.
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