The distribution of insect galls and its relationship with host plants, microhabitat in Taiwan, with special emphasis on Daphnephila (Cecidomyiidae) galls in host plant Machilus
Date Issued
2006
Date
2006
Author(s)
Tung, Gene-Sheng
DOI
zh-TW
Abstract
Since galling insects are host-specific, they diverse with the host speciation. Regression analysis was used to test of the plant family size hypothesis for 331 galling hosts in Taiwan. The result showed no significant relationship between gall species richness and host plant family’s size. It was probably because small plant families, such as Lauraceae and Fagaceae, are more diverse than big families, such as Orchidaceae and Poaceae, in galling host plants. To test plant family geological age hypothesis, examing galling plants in native, endemic, and exotic host species. The result shows highest gall diversity in the endemic hosts, and exotic hosts are the least. During the investigation in Taiwan, most host-plants are found having only one gall species on it, except dominant galling hosts, such as Lauraecae and Fagaceae. Among those families, the highest GSR is the genus Machilus (37.3%). Fifty-seven gall morphospecies were collected in 8 spp. of the genus Machilus. Most gallers are gall midges (Diptera: Cecidomyiid) (50 spp.), the others are Hemiptera. The gall morphospecies represent species specific. Among 8 Machilus species in Taiwan, there are 9 mophospecies galls being found on M. thunbergii; 2 mophospecies galls on M. konishii; and 6 morphospecies galls on the rest of hosts respectively. In 126 sampling sites of Machilus host in Taiwan, environmental variables were analysized to find correlations to gall species richness and abundance. The result shows only significant correlation in sum of the precipitation from September to November. The result probably because high production of Daphnephila galls are in autumn. Canonical correspondence analysis indicates climate variables are more influencial on hosts than gall communities. For the analysis of microhabitat variables on 10 sampling host Machilus trees at Fushan. The result shows that gall amount is higher at upper canopy stratum. The emergence of univoltine bell-liked Daphnephila galls on M. zuihoenensis was affected by two phenology stages: budburst of host plants in spring and gall development during autumn. Bell-like galls are positively correlated to illumination and spring mean temperature, but negatively correlated to humidity. The larger fluctuation of humidity and higher radiation of upper canopy benefits the development of bell-like galls.
Subjects
蟲癭
楨楠屬
癭蚋科
分布
Gall
Daphnephila
Machilus
Cecidomyiidae
distribution
SDGs
Type
thesis
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