Meffert 9726667 The research will use a model experimental system to simulate the captive management of an endangered species and its subsequent reintroduction into the wild. Standard captive breeding programs for endangered species focus on maximizing genetic diversity with the intention to safeguard the ability to adapt to the unpredictable conditions of the wild. However, some studies suggest that alternative schemes to select against deleterious genes might be more prudent. Anecdotal evidence from actual captive breeding projects supports both sides of this debate, but a comprehensive evaluation is not feasible on a true endangered species. Specifically, controlled comparisons of the contrasting breeding schemes cannot be performed on remnant populations, and long generation lengths obviate long-term studies. Consequently, irreversible decisions are being made in efforts to restore endangered species even though critical examinations of how populations recover from near-extinctions are lacking. This research will take advantage of the amenability of the housefly experimental system for large-scale tests of the long-term effects of reduced population size. Through a collaboration with the conservation biology program at the Houston Zoological Gardens, the experiment will incorporate fertility constraints and captive breeding designs that are realistic for real-life efforts to save endangered species. The experiment has three phases: (1) over the course of ten generations, replicate housefly populations will undergo continual reductions in population size to the point of imminent extinction, (2) each resultant population will then be subjected to eight generations of one of the two contrasting captive breeding designs (maximizing genetic diversity versus selecting against deleterious genes), and (3) over the course of the next eight generations, the populations will be exposed to the environmental stress of unpredictable temperature. Reproductive health and genetic diversity will be asses sed throughout the experiment. This three-year project, spanning 26 generations, will thus obtain data that would take decades or even centuries to glean from actual captive breeding projects. Research in conservation biology applies broadly to understanding the consequences of reduced population size. Many natural populations often undergo cycles of population-crash and rebound, independent of human influences. Rampant invasions by agricultural pests also attest to the ability to spontaneously recover from low population size. Experiments on model systems have proven to be a fertile methodology for detailing the genetic complexities of near-extinctions. However, these same studies have implied that the conventional restoration strategies for present-day endangered species are too simplistic and possibly even counter-productive. This research has unique potential to explain how populations in captivity, agriculture, and nature escape near-extinctions.
