Island biogeography and competition drive rapid venom complexity evolution across rattlesnakes

Understanding how human-mediated environmental change affects biodiversity and the timescale of an evolutionary response is key for conserving evolvability. Islands are proxies for fragmented landscapes and allow us to use historical changes in biodiversity under Island Biogeography Theory (IBT) to predict the consequences of immediate anthropogenic impacts on trait evolution. Rattlesnake venoms are molecular phenotypes that mediate interactions with prey, and diet and venom complexity are positively correlated. Consequently, rattlesnake venoms allow us to investigate how functional traits co-vary with changes in biodiversity according to IBT. We collected venom from 83 rattlesnakes across multiple species and 11 islands in the Gulf of California and estimated venom complexity using the Shannon Diversity Index. Using a mixed effects modeling approach, we found that the number of congeneric competitors, island isolation, and island area best predicted variation in venom complexity. All v..., , , **Files and Descriptions**

1. **Spatial_Modeling_SRH_MAB_Unscaled.rmd**
* This script performs mixed-effects modeling using unscaled Shannon_H values to analyze venom complexity. The model incorporates spatial and ecological variables to assess their effects on venom complexity without scaling the Shannon_H metric.
* Note, geographic coordinates (latitude and longitude) of are not included in the dataset used in this analysis; therefore, models using spacial autocorrelation will not function. See note for the dataset for more information. 
2. **Spatial_Modeling_SRH_MAB_Scaled.rmd**
* This script performs the same mixed-effects modeling as the unscaled version but uses scaled Shannon_H values for venom complexity.
* Note, geographic coordinates (latitude and longitude) of are not included in the dataset used in this analysis; therefore, models using spacial autocorrelation will not function. See note for the dataset for more information. 
3. **fig3_script.R**
* This scrip...,