Skewed sex ratio of the Chinese green tree viper, Trimeresurus stejnegeri stejnegeri, at Tsaochiao, Taiwan

Shiuang Wang, Hua Ching Lin, Ming-Chung Tu

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Preliminary collecting of adult Chinese green tree vipers, Trimeresurus stejnegeri stejnegeri, in Tsaochiao, northwestern Taiwan, yielded a male-biased sample. According to the sex ratio theory, a skewed sex ratio is unlikely at birth, and the above results may thus reflect sampling bias or differential mortality after birth. We collected litters of neonates of this viviparous snake from a broader area over a longer period to examine causes of such numerical dominance of males in the adult sample. We collected 23 gravid females from the Tsaochiao area in 3 consecutive reproductive seasons and obtained 50 male and 40 female neonates. The sex ratio at birth was not significantly biased. We marked and released a total of 169 male and 79 female T. s. stejnegeri. Marked snakes were recaptured 940 times. Regardless of season, time of day, transect, or sample area, we always encountered more males than females. Thus, sampling bias did not likely account for this skewed sex ratio. In the adult sample, the ratio of males was greatest in the largest size class, and this suggests that females are subjected to higher mortality. We thus hypothesize that the skewed sex ratio observed in overall adult samples of T. s. stejnegeri reflects such differential mortalities between sexes that are probably derived from a higher cost of reproduction in females.

Original languageEnglish
Pages (from-to)379-385
Number of pages7
JournalZoological Studies
Volume42
Issue number2
Publication statusPublished - 2003 Apr 1

Fingerprint

Trimeresurus
Viperidae
Taiwan
sex ratio
sampling
snakes
neonates
gravid females
litters (young animals)
dominance (genetics)
breeding season
gender

Keywords

  • Activity
  • Habitat
  • Mortality
  • Sex ratio
  • Snake

ASJC Scopus subject areas

  • Animal Science and Zoology

Cite this

Skewed sex ratio of the Chinese green tree viper, Trimeresurus stejnegeri stejnegeri, at Tsaochiao, Taiwan. / Wang, Shiuang; Lin, Hua Ching; Tu, Ming-Chung.

In: Zoological Studies, Vol. 42, No. 2, 01.04.2003, p. 379-385.

Research output: Contribution to journalArticle

@article{1c8d3c23a8784748a5541b856cb5325b,
title = "Skewed sex ratio of the Chinese green tree viper, Trimeresurus stejnegeri stejnegeri, at Tsaochiao, Taiwan",
abstract = "Preliminary collecting of adult Chinese green tree vipers, Trimeresurus stejnegeri stejnegeri, in Tsaochiao, northwestern Taiwan, yielded a male-biased sample. According to the sex ratio theory, a skewed sex ratio is unlikely at birth, and the above results may thus reflect sampling bias or differential mortality after birth. We collected litters of neonates of this viviparous snake from a broader area over a longer period to examine causes of such numerical dominance of males in the adult sample. We collected 23 gravid females from the Tsaochiao area in 3 consecutive reproductive seasons and obtained 50 male and 40 female neonates. The sex ratio at birth was not significantly biased. We marked and released a total of 169 male and 79 female T. s. stejnegeri. Marked snakes were recaptured 940 times. Regardless of season, time of day, transect, or sample area, we always encountered more males than females. Thus, sampling bias did not likely account for this skewed sex ratio. In the adult sample, the ratio of males was greatest in the largest size class, and this suggests that females are subjected to higher mortality. We thus hypothesize that the skewed sex ratio observed in overall adult samples of T. s. stejnegeri reflects such differential mortalities between sexes that are probably derived from a higher cost of reproduction in females.",
keywords = "Activity, Habitat, Mortality, Sex ratio, Snake",
author = "Shiuang Wang and Lin, {Hua Ching} and Ming-Chung Tu",
year = "2003",
month = "4",
day = "1",
language = "English",
volume = "42",
pages = "379--385",
journal = "Zoological Studies",
issn = "1021-5506",
publisher = "Biodiversity Research Center, Academia Sinica",
number = "2",

}

TY - JOUR

T1 - Skewed sex ratio of the Chinese green tree viper, Trimeresurus stejnegeri stejnegeri, at Tsaochiao, Taiwan

AU - Wang, Shiuang

AU - Lin, Hua Ching

AU - Tu, Ming-Chung

PY - 2003/4/1

Y1 - 2003/4/1

N2 - Preliminary collecting of adult Chinese green tree vipers, Trimeresurus stejnegeri stejnegeri, in Tsaochiao, northwestern Taiwan, yielded a male-biased sample. According to the sex ratio theory, a skewed sex ratio is unlikely at birth, and the above results may thus reflect sampling bias or differential mortality after birth. We collected litters of neonates of this viviparous snake from a broader area over a longer period to examine causes of such numerical dominance of males in the adult sample. We collected 23 gravid females from the Tsaochiao area in 3 consecutive reproductive seasons and obtained 50 male and 40 female neonates. The sex ratio at birth was not significantly biased. We marked and released a total of 169 male and 79 female T. s. stejnegeri. Marked snakes were recaptured 940 times. Regardless of season, time of day, transect, or sample area, we always encountered more males than females. Thus, sampling bias did not likely account for this skewed sex ratio. In the adult sample, the ratio of males was greatest in the largest size class, and this suggests that females are subjected to higher mortality. We thus hypothesize that the skewed sex ratio observed in overall adult samples of T. s. stejnegeri reflects such differential mortalities between sexes that are probably derived from a higher cost of reproduction in females.

AB - Preliminary collecting of adult Chinese green tree vipers, Trimeresurus stejnegeri stejnegeri, in Tsaochiao, northwestern Taiwan, yielded a male-biased sample. According to the sex ratio theory, a skewed sex ratio is unlikely at birth, and the above results may thus reflect sampling bias or differential mortality after birth. We collected litters of neonates of this viviparous snake from a broader area over a longer period to examine causes of such numerical dominance of males in the adult sample. We collected 23 gravid females from the Tsaochiao area in 3 consecutive reproductive seasons and obtained 50 male and 40 female neonates. The sex ratio at birth was not significantly biased. We marked and released a total of 169 male and 79 female T. s. stejnegeri. Marked snakes were recaptured 940 times. Regardless of season, time of day, transect, or sample area, we always encountered more males than females. Thus, sampling bias did not likely account for this skewed sex ratio. In the adult sample, the ratio of males was greatest in the largest size class, and this suggests that females are subjected to higher mortality. We thus hypothesize that the skewed sex ratio observed in overall adult samples of T. s. stejnegeri reflects such differential mortalities between sexes that are probably derived from a higher cost of reproduction in females.

KW - Activity

KW - Habitat

KW - Mortality

KW - Sex ratio

KW - Snake

UR - http://www.scopus.com/inward/record.url?scp=0042706374&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0042706374&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0042706374

VL - 42

SP - 379

EP - 385

JO - Zoological Studies

JF - Zoological Studies

SN - 1021-5506

IS - 2

ER -