Statistical Analysis
All statistical analyses were conducted in R programming language (R
Core Development Team) and RStudio v.2022.02.1 (RStudio Team). In the
first analysis, we fit a logistic regression with the presence/absence
of gnathiids as a function of fish functional group to determine if any
groups consumed gnathiids as often as dedicated cleaners. In the second
analysis, a zero-inflated negative binomial (ZINB) regression was used
to fit gnathiid count (per individual gut) against fish functional group
to determine if any functional groups ate as many gnathiids as dedicated
cleaners. We used ZINB due to overdispersion of other model fits as well
as excess “0” counts which could not be predicted by model fits
besides ZINB or Zero-Inflated Poisson (ZIP). This analysis utilized the
pscl package (Zeileis et al. 2008)