A fundamental decision for parents is how much to invest in offspring. Potentially this involves a tradeoff where more investment in each one reduces the total number of young.. The current dogma for parental care assumes this tradeoff is always present because food is always limiting. If true, parents should strive for a single "optimal" size young and should invest the same amount into every offspring. Further, if food availability changes, parents should change numbers of offspring rather than their size. If parents are not always food limited, however, then parents can match investment to the immediate environment (resulting in offspring of varying size and quality). Although these are very different ways of rearing young, they are not easy to differentiate. Tests require species where: (1) Consequences of offspring size are measurable; and (2) Many young are produced at one time so that offspring size distributions can be quantified and compared. Ants are ideal for testing parental investment strategies. Offspring size strongly affects founding success of new colonies, and mature colonies produce hundreds of young at a time. The goals of our research are to: (1) Quantify the costs and benefits of offspring size in harvester ants, and (2) Experimentally manipulate food for their colonies in the field. Together, the experiments test how ecology affects parental behavior. If parental strategies do track the environment, a major paradigm shift in understanding parent-offspring conflict, offspring sex ratios, and reproduction in social groups will follow. This project will train one graduate student and several undergraduates in field biology, data collection and experimental design. Students from historically underrepresented groups will be recruited through programs (CARE and MARC) supported by UCLA, NSF and NIH. One high school teacher, Ms. Rosa Chan, will be included in all aspects of the project through the Research Experience for Teachers (RET) program. She will be trained to develop inquiry-based lessons for classroom use (which will also be made available online through UCLA's GK-12 program).
