| Summary: | 碩士 === 國立屏東科技大學 === 野生動物保育研究所 === 92 === The aim of this study is to examine the reproductive ecology of Microhyla ornata in tropical Southern Taiwan. The field and laboratory investigations on the population and the egg masses of M. ornata were carried out at least once each month from May 2002 to June 2003 in a sampling site including a small pond and a nearby grassland at In-da Farm (22°38’ N, 120°37’ E) in Pingtung county, Southern Taiwan.
Microhyla ornata at In-da Farm was capable of reproducing throughout the year. The major breeding season was from April to September. The number of the egg masses was positively correlated with accumulative rainfall and mean relative humidity over 7 days prior to investigation. The numbers of mature ova in adult females were significantly different among seasons, and the change was consistent with the rainfall fluctuation seasonally. Rainfall is an important factor determining the oviposition activity of M. ornata in Southern Taiwan.
The snout-vent lengths (SVLs) of mature females and males were 19.5 mm and 18.33 mm, respectively. The operational sex ratio was skewed toward males. The numbers of adult males entering the breeding site during 9:00~10:00 pm were less than those during 7:00~8:00 pm.
The various development stages of ova in adult female ovaries suggested that M. ornata probably oviposited several times in a year. The number and mean diameter of mature ova were 630.5 ± 328.1 and 0.95 ± 0.11 mm, respectively. Adult Female SVL was positively correlated with ovarian mass, the number of mature ova, and mean diameter of mature ova. The number of mature ova was positively correlated with mean diameter of mature ova.
The water depth of the egg mass locations was 12.4 ± 9.2 cm. The depth from egg masses to water surface was 0.9 ± 1.6 cm. The distance between egg masses and water edge was 88.8 ± 79.6 cm. Most egg masses attached with plants (40.9%) and litters (39.4%). The distributions of egg masses were different between high- and low-water-level periods. The water depth of the breeding pond may influence M. ornata selecting their oviposition site.
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