(RUI) From Complex Environments to Underlying Mechanisms: A Network Approach to Multi-trait Tradeoffs

University Of The Pacific, Stockton CA

Investigators

Abstract

To survive and persist, an organism must acquire food, be able to reproduce, avoid being eaten, and prevent infection. However, each of these important traits is costly to maintain, which can lead to tradeoffs among the traits. That is, investment into one trait comes at a cost to another. The researchers propose an experimental approach examining simultaneous tradeoffs among three important biological traits (e.g., immunity, reproduction, and body movement) that will provide insight into the role of multi-trait tradeoffs in shaping how animals survive. Given that trait tradeoffs are influenced by the environment, these studies will occur in a range of manipulated environments that simulate the dynamics of environmental change in North America. Under stressful conditions, investment into one trait can take precedence over investment into another trait. However, if individuals encounter favorable environments (e.g., unlimited access to food), two traits, such as reproduction and immunity, may be maintained, suggesting that tradeoffs may be dependent upon food availability. The effects of food availability are often influenced by other environmental factors that may accompany reduced food availability (e.g., heat waves), and interactions between food availability and temperature may profoundly influence tradeoffs. This research will be the first to characterize the interplay between environmental variability and animal life history strategies using a network analysis approach. This approach has proven to be a powerful tool for studying diverse phenomena, such as social interactions, the structure of the Internet, and for optimizing solutions to engineering problems. Much of this research will be performed by students from under-represented minority groups, and it will be complemented by a science outreach program designed to educate community members (particularly K-8 students) on the importance of insect biology. The proposed research will use a manipulative approach in a wing-dimorphic field cricket to examine tradeoffs among investment into three life history traits of widespread importance: reproduction, immune function, and locomotion. Resultant empirical data will be used for a network analysis approach to characterize dynamic relationships among these traits through the determination of several network metrics (e.g., connectivity, betweenness, and modularity). They will also examine linkages between the life history networks and a network of underlying physiological traits (e.g., antioxidant defense and metabolic rate). Further, they will use a network approach to determine the independent and interactive role of two universal environmental constraints (food availability and temperature) in multi-trait tradeoffs and trait-trait interactions. Thus, the proposed study will use an integrative approach to better understand how complex trait systems develop and are maintained. It will have impact on multiple biological disciplines, including ecological immunology, ecological physiology, network analyses, and life history evolution. The researchers will provide extensive research training to students, many of whom come from under-served minority groups representative of both the region and the student body at Georgia Southern University (GSU). To complement their research goals, they will develop an outreach program designed to educate young people about insects, an important taxonomic group. They will create a website and an accompanying outreach exhibition at the GSU Museum that provides information about local insects. They will also construct and disseminate an educational module designed to meet the State of Georgia's Department of Education performance standards; this will contain structured activities, informational handouts, and live crickets that K-8 students can use to develop scientific literacy.