Spatial analyses of a neotropical beetle: Cephaloleia fenestrata
Date of Award
Doctor of Philosophy (Ph.D.)
First Committee Member
Carol C. Horvitz - Committee Chair
The Neotropical beetle Cephaloleia fenestrata is a specialist herbivore on Pleiostachya pruinosa in the lowland tropical wet forest of Costa Rica. C. fenestrata spends its entire life cycle on P. pruinosa, feeding primarily in rolled leaves as adults, feeding in the concavity of leaf petioles as larvae, and laying eggs and pupating on the leaf petioles. I investigated an expanding and contracting population of C. fenestrata, testing the population for source-sink (Chapter 2) and metapopulation dynamics (Chapter 4), and modeling the recolonization of the flood zone after a flood event. In chapter 2, I present a temporally-variable source-sink dynamic of C. fenestrata, driven by flooding disturbance. I demonstrate that a stochastic flood event caused the flood zone to be a sink during flood events, but not during periods without floods. Given the observed flood frequency of approximately once per year, the population growth rate in the flood zone was determined to be <1. In chapter 3, I used a population projection matrix model to infer the stage-specific habitat recolonization rate by C. fenestrata into the flood zone. I focused on two aspects of the beetle's movement: (1) patch size-dependent migration, and (2) natal versus breeding dispersal. The probability of patch size-dependent emigration was found to be a negative function of patch size, while the probability of immigration was a positive function of patch size. The model suggests that the natal dispersal rate is 81%. Lastly, in chapter 4, I used and modified a patch occupancy model to evaluate regional dynamics of C. fenestrata. Data suggest that flood events and patch size-dependent migration have significant effects on regional dynamics, while patch quality was apparently unimportant. Spatial autocorrelation is also demonstrated in this study.
Johnson, Derek Marley, "Spatial analyses of a neotropical beetle: Cephaloleia fenestrata" (2003). Dissertations from ProQuest. 1949.