Having studied the brief lives of more than 1 million Mediterranean fruit flies during the past two years, a UC Davis researcher has constructed what he believes is the largest life table ever made for any species. Data from that table suggest that the outer limit of the life span -- at least for the medfly -- is not biologically predetermined. Scientists have long debated whether there are built-in limits to the life spans of humans and other organisms or whether those life spans can be stretched to indeterminate lengths by optimizing environmental conditions "The preliminary analysis of the medfly data suggests that among the oldest individuals of this population, the probability of dying does not increase as they grow older," says James R. Carey, associate professor of entomology. "If the life span were genetically predetermined, we would expect to see the mortality rates accelerate among the very aged. This causes us to completely reconsider the concept of senescence." Carey's work is one component of the $2 million "Oldest-Old Mortality Study," coordinated by the University of Minnesota's Center for Population Analysis and Policy. Carey recently reported his findings at the annual meeting of the Entomological Society of America.