Protection mutualists display territorial behaviors that provide protective services for their host species. To investigate how protection mutualists impact the colonization and establishment of host-associated species, we conducted a two-stage experiment using a coral reef cryptofauna community as our study system. Pocillopora meandrina is a fairly common, branching coral species that forms habitat that is utilized by a variety of marine organisms. There is a guild of protection mutualists that associate with P. meandrina including Trapeziidae crabs and Alpheidae shrimp. We manipulated coral colonies to have Trapeziidae crabs, Alpheidae shrimp, both, or neither. For the first part of our experiment, we observed colonization of marine invertebrates to these colonies every other day for two months, while resetting the treatment levels every seven days. For the second part of our experiment, we surveyed the community composition weekly and then monthly for a total of six months without interference. During both experiments, we measured the initial and final size of the host coral colonies as a metric of fitness. Data are provided for observed marine decapods through time on each of forty experimental coral colonies for the colonization and the establishment experiments. Data are also provided for coral colony size at the beginning and end of each experiment.     

The community composition data were collected through visual surveys of the coral colonies conducted on SCUBA using a dive light to observe species in between the coral branches. For the colonization experiment (two month duration), surveys were done every other day and colonizers were removed from the corals every seven days. The colonization data includes community survey data and organism removal data. For the establishment experiment (six month duration), surveys were conducted weekly and then monthly with no interference to the community composition. Coral colony size was measured at the beginning and the end of the colonization experiment by transporting coral colonies into the lab and using buoyant weights. These weights have been processed to dry weights based on the density of the seawater when each colony was weighed. Coral colony size was measured at the beginning and the end of the establishment experiment through planar colony size measurements taken from top-down photographs of each colony. These photographs were scaled and aligned using the cement blocks to which each coral colony was secured.

For more information on how these data were collected and how they have been analyzed, see Counsell and Donahue 2021 in Oikos doi:  10.1111/oik.08282.