College of Arts and Sciences
Master of Science in Biology (MS)
Dr. John Hatle
Dr. Matt Gilg
Dr. Jeff Shapiro
Isolated populations that inhabit various geographic and climatic ranges tend to diverge in their life history tactics. When development time is constrained by unfavorable seasons, often an organism must trade-off the investment of resource allocation between somatic and reproductive growth. The variation in reproductive tactics and juvenile hormone titers were studied among three populations of Romalea microptera from Athens, GA, Jacksonville, FL, and Miami, FL, all of which exist on a latitudinal cline. The Athens population was significantly younger at oviposition and gained significantly less body mass than both the Jacksonville and Miami populations, which did not differ from each other. Clutch mass did not differ across populations. With respect to both body size and oviposition age, Athens invested significantly more (measured by clutch size) to their first clutch than either Jacksonville or Miami, which did not differ from each other. Juvenile hormone and lipid profiles did not differ among populations. In response to the markedly reduced season length, results suggest that Athens grasshoppers respond with reproductive tactics that support terminal investment by investing more energy in less time to reproduction, at the expense of future reproduction.
Fronstin, Raime Blair, "Juvenile Hormone and Reproductive Tactics in Romalea Microptera, the Eastern Lubber Grasshopper" (2007). UNF Graduate Theses and Dissertations. 214.