Meeting Abstract
In experimental studies, researchers are often unable to track individuals through a natural lifetime and must rely on proxies of lifetime reproductive success. The number of offspring produced at first reproduction is readily measured and has been used as a proxy for lifetime reproductive output in studies using copepods, including the species Tigriopus californicus. However, the accuracy of such a proxy has been questioned and to date no validation of this approach to estimating lifetime reproductive success has been undertaken. In this study, we undertook such a validation of using the number of first-clutch offspring as a proxy for lifetime reproduction by observing the reproductive output of female T. californicus for the entirety of their reproductive life spans. We measured several life history traits including egg gestation duration, the number of offspring produced per clutch, the total number of clutches, offspring survival, offspring development, offspring size, and female lifespan. We found that the size of the first clutch was positively correlated with many of these measures of reproductive fitness, even after controlling for difference in female lifespan. Additionally, we analyzed variation in life history traits over the entire life span of T. californicus females and found that reproductive output generally declined, suggesting senescence in these small crustaceans.
