HATCHLING SIZE IN THE TURTLE CHRYSEMYS-PICTA BELLII FROM WESTERN NEBRASKA - RELATIONSHIPS TO EGG AND MATERNAL BODY-SIZE

Eggs of the turtle Chrysemys picta bellii from four western Nebraska p opulations were incubated under laboratory conditions to compare egg s ize and hatchling size as measures of offspring size among populations and in the context of maternal body size. Generally, hatchling size ( mass and carapace length) was linearly related to egg size (mass, widt h, and length) and did not vary between the two years of the study or among populations after adjusting for egg size. However, hatchling car apace length adjusted for egg width was greatest in a population with the most elongate eggs indicating that linear egg measurements may not be useful for interpopulation comparisons. The smaller range of varia tion, but greater variability in hatchling size relative to egg size a nd a narrow range of maternal body sizes (carapace length and mass), s eemed to preclude a correlation between maternal body size and hatchli ng size within two populations. In two other populations, hatchling ca rapace length, egg width, and egg length increased with maternal carap ace length by a common slope, although egg wet mass had a steeper slop e than did hatchling wet mass. It is probable that under natural incub ation conditions (e.g., warmer, drier, and more variable), hatchling m ass may increase only slightly or not at all with maternal body size. My results suggest that both hatchling and egg size should be consider ed in turtle life history studies, particularly for models that predic t delayed sexual maturation when offspring size and survival increase with maternal body size and age.