Premium
Demography of the Striped Plateau Lizard, Sceloporus Virgatus
Author(s) -
Vinegar Marian B.
Publication year - 1975
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1935309
Subject(s) - fecundity , survivorship curve , lizard , range (aeronautics) , ecology , biology , avian clutch size , hatching , habitat , wet season , dry season , geography , zoology , reproduction , demography , population , materials science , cancer , sociology , composite material , genetics
The demography of Sceloporus virgatus was studied in the Chiricahua Mountains, Arizona, from 1970 to 1973 to (1) determine variation in age—specific survivorship and fecundity, and (2) compare life history phenomena in S. virgatus with the closely related lizard S. undulatus. Growth and survivorship were determined by mark—recapture methods; size—specific fecundity was determined by sampling. Sceloporus virgatus lays one clutch per year, averaging 9.5 eggs per clutch, after the start of the rainy season. Females reproduce for the first time 10 or 22 mo after hatching, depending on the size attained before their 10th mo. No difference in survivorship was found between females that matured in their first year and females that did not. Survivorship was higher between 1971 and 1972 than between 1970 and 1971. Size—specific fecundity, mean size of yearlings, and proportion of mature yearlings were greater in 1972 than in 1971. Rainfall was greater from July 1971 to April 1972 than from July 1970 to April 1971. These differences suggest that food supply was greater between 1971 and 1972 than between 1970 and 1971, and that the lizards can perhaps adjust the energy expended on reproduction to the food supply. The restricted range of S. virgatus may be related to its having only one clutch per year during a restricted rainy season, whereas the ability of S. undulatus to live in a wide variety of habitats may be related to having multiple clutches per year. Sceloporus virgatus probably moved between mountain ranges to achieve its present range during the last glacio—pluvial.