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Vol. 49 No. 6, 2010
Ecology and Reproductive Characteristics of the Skink Sphenomorphus incognitus on an East
Asian Island, with Comments on Variations in Clutch Size with
Reproductive Modes in Sphenomorphus
Wen-San
Huang*
Department
of Zoology, National Museum of Natural Science, 1 Kuan-Chien Rd.,
Taichung 404, Taiwan
Wen-San
Huang (2010) I describe the diet, and male and female
reproductive cycles of Sphenomorphus
incognitus, an oviparous skink in Taiwan. Most individuals
of S. incognitus were first
observed in a leaf litter microhabitat or at the edge of a
forest. The diet of S.
incognitus consists mostly of orthopteran insects. Two
prey categories, crickets and ants, numerically dominated the
diet. The stomachs of 2 lizards contained spiders, 2 lizards had
eaten insect larvae, and 2 had eaten the blind snake, Ramphotyphlops braminus. The
mean snout-vent length (SVL) of adult males was 87.6 mm (n = 45), and that of females was
79.8 mm (n = 43). Males had a significantly larger SVL than
females. Females exhibited spring and summer vitellogenesis, with
parturition occurring from Mar. to July. The onset of
vitellogenesis was not correlated with the female liver mass.
Females produced 3-6 eggs per clutch, and clutch size was not
correlated with the SVL. Male testis mass showed significant
monthly variations, with an increase commencing in Dec. and a peak
maintained from Jan. to Apr. Female and male liver masses did not
coincide with the period of reproductive activity. Clutch size
variations in other Sphenomorphus
groups were compared to those in S. incognitus. Clutch sizes of
oviparous skinks were not larger than those of viviparous ones, and
clutch size relative to female SVL showed a positive correlation in
oviparous skinks but not in viviparous ones. Similarities of the
reproductive cycle found in this study and other congeneric
Sphenomorphus inhabiting temperate and subtropical areas of Taiwan
might be explained by phylogenetic constraints.
Key words: Reproductive
cycle, Clutch size, Lizard, Food habits.
*Correspondence: Tel: 886-4-23226940 ext. 510. Fax:
886-4-23232146. E-mail:wshuang@mail.nmns.edu.tw
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