| Summary: | 碩士 === 國立臺東大學 === 生命科學系碩士班 === 97 === To investigate the performances of coexistence and competition on the same foodplant resource by three butterflies, this study compared their oviposition positions and microhabitats on two cultivated pipevine foodplants of Aristolochia spp. in Bei-nan and Lu-ye, Taitung, Eastern Taiwan.
On the cultivated foodplants of Aristolochia zolligeriana Miq. in Bei-nan and Lu-ye, Pachliopta aristolochiae interposita Fruhstorfer oviposited all year round, but Troides aeacus formosanus Rothschild and Byasa polyeuctes termessus Fruhstorfer only oviposited in winter, spring and early summer. Nevertheless, P. aristolochiae interposita oviposited distinctly from July to September on A. heterophylla Hemsl in Lu-ye. The oviposition period of T. aeacus formosanus was similar to that on A. zolligeriana. On A. heterophylla, the oviposition period of B. polyeuctes termessus began from autumn, and the females prefered to oviposite on it.
P. aristolochiae interposita and B. polyeuctes termessus laid most
of their eggs specifically on the leave parts, but T. aeacus formosanus laid their eggs widely on various plant parts, especially a quite high proportion of eggs on non-host plant. The three papilionidae butterflies laid the highest proportions of eggs on the leaves of Aristolochia spp.. P. aristolochiae interposita and B. polyeuctes termessus laid up to 90 % of their eggs on the tender leaves. In contrast, T. aeacus formosanus laid more eggs on mature and old leaves, approximately to 21-57 %.
There were certain variations of leaf frequencies distributions in the various leaf stages among micro-sites of the foodplants. On the two pipevine foodplants, the three butterflies selected the sites with higher tender and mature leaves for oviposition. P. aristolochiae interposita even also needed a site with less old leaves than that within the random sampling sites.
Although the three Papilionidae butterflies utilized same food resource, their oviposition niches on the two cultivated food plant have similarity and dis-similarity at time and space scales. The oviposition positions and leaf stages of T. aeacus formosanus were different from that of the other two butterflies. This oviposition segregation will reduce their larval competition, and enhances their coexistence. In contrast, P. aristolochiae interposita and B. polyeuctes termessus have similar ecological niche for oviposition, this will increases the inter-specific competition between the two butterflies. Because the cultivation limited the foodplant height in a smaller range than that in forests, the three papilionidae butterflies had high feeding competition in their larval community on the artificially cultivated foodplants.
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