Click on the picture in this post to see a slideshow of more pictures from the field.
So as you know we had 3 different hypothesis that we were testing during our time in the field down in Florida. I want to review each of those hypothesis and let you know what we did to collect data to test each one.
#1) The Brown Anole population faces different relative selection pressures in different parts of the environment.
To test this one we put out 50 clay models in 5 locations that were carefully chosen (forest, park, residential area, beach and island) and recorded all bites in the models from predators and lizards. We only got one lizard bite but we got many predator bites. We tried putting out models with and without paper dewlaps. After the first week we moved the models to new but similar locations. We also took careful photos of the shade cover where each model was placed. A computer will analyze these photos and we will check to see if the amount of cover above a model affected how often it was attacked by predators.
#2) Morphological (physical) differences exist in the lizards in different parts of the habitat.
To test this one we planned to measure hundreds of lizards (we measured more than 800) and record careful data about the locations they were spotted in. Unfortunately this part of the project suffered a bit from our high work load. We did not have time to measure carefully the locations of each captured lizard. However, we do have careful measurements for each lizard in our island experiment so when we go back to collect lizards again we will be able to see if physical differences begin to exist on the different experimental islands.
•#3 Biased Operational sex ratios will affect population growth and natural selection (evolution).
To test this hypothesis we released 835 lizards on 9 different islands. The islands were not all the same size so we released them in numbers that kept population densities (lizards per square meter) the same. On 4 of the islands we released 66.6% males and 33.3% females. On 5 other islands we did the opposite. We will be going back at the end of the summer to catch babies and record population sizes. We will take DNA samples of all the new hatchlings and compare them to the DNA of the founding populations to see which males and females are having the most reproductive success.
