The reproductive strategies in neighbouring populations of the European pond turtle, Emys orbicularis, in central Italy

Two large Emys orbicularis populations of coastal central Italy, from San Rossore and Camp Darby (Tuscany), were studied to test patterns of reproductive biology variability, and life history traits. No significant difference was found between the localities for any of the considered linear measurements (raw data), either of males or females. Despite this, analysis of covariance revealed differences for most of the parameters examined (log-transformed variable). Females from San Rossore were significantly larger, heavier and longer than those from Camp Darby, and produced a significantly larger clutch than those of Camp Darby (six vs five eggs). Combining radiographic, ultrasonic and manual techniques, it was found that more than 77% of all adult-sized females reproduced annually and more than 50% of them laid a second clutch during the same season. While egg size did not vary between localities (raw data), analysis of covariance on egg shape (all variables considered together) revealed a significant difference. The observed differences in reproductive traits of these populations are significant and hypothesised to be related to ecological as well as to demographic constraints.