When studying gene expression in microbe-animals symbioses collected in the field it is essential to quickly and efficiently preserve in situ symbiont and host protein abundance patterns. One of the most commonly used sample preservation methods for samples targeted for proteomic analyses is flash freezing, however, liquid nitrogen or dry ice needed for flash freezing are often not available at remote field sites. We replicated our experiment from PXD014591 to test if RNAlater allows preserving proteins in animal-microbe symbioses as efficiently as flash freezing and without introducing issues with downstream processing. We used the marine gutless oligochaete Olavius algarvensis as a model for testing. Olavius algarvensis lives in shallow water sediments off the coast of Elba, Italy. It has no digestive and excretory system and harbors five bacterial symbionts that fulfill its nutritional and waste recycling needs (Kleiner et al., 2012, PNAS 109(19):1173-82). We compared six RNAlater preserved and eight flash frozen samples in terms of the number of identified proteins, abundances of individual proteins and potential biases against specific protein or taxonomic groups. Six worms were incubated in RNAlater for 24 hours. After incubation, RNAlater was removed and samples were stored at -80°C. Eight worms were directly flash frozen in liquid nitrogen and stored at -80 °C immediately after preservation.